benefits of nuclear energy essay pdf

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings

Preview improvements coming to the PMC website in October 2024. Learn More or Try it out now .

• Advanced Search
• Journal List
• v.45(Suppl 1); 2016 Jan

Nuclear power in the 21st century: Challenges and possibilities

Akos horvath.

MTA Centre for Energy Research, KFKI Campus, P.O.B. 49, Budapest 114, 1525 Hungary

Elisabeth Rachlew

Department of Physics, Royal Institute of Technology, KTH, 10691 Stockholm, Sweden

The current situation and possible future developments for nuclear power—including fission and fusion processes—is presented. The fission nuclear power continues to be an essential part of the low-carbon electricity generation in the world for decades to come. There are breakthrough possibilities in the development of new generation nuclear reactors where the life-time of the nuclear waste can be reduced to some hundreds of years instead of the present time-scales of hundred thousand of years. Research on the fourth generation reactors is needed for the realisation of this development. For the fast nuclear reactors, a substantial research and development effort is required in many fields—from material sciences to safety demonstration—to attain the envisaged goals. Fusion provides a long-term vision for an efficient energy production. The fusion option for a nuclear reactor for efficient production of electricity has been set out in a focussed European programme including the international project of ITER after which a fusion electricity DEMO reactor is envisaged.

Introduction

All countries have a common interest in securing sustainable, low-cost energy supplies with minimal impact on the environment; therefore, many consider nuclear energy as part of their energy mix in fulfilling policy objectives. The discussion of the role of nuclear energy is especially topical for industrialised countries wishing to reduce carbon emissions below the current levels. The latest report from IPCC WGIII ( 2014 ) (see Box 1 for explanations of all acronyms in the article) says: “Nuclear energy is a mature low-GHG emission source of base load power, but its share of global electricity has been declining since 1993. Nuclear energy could make an increasing contribution to low-carbon energy supply, but a variety of barriers and risks exist ”.

Demand for electricity is likely to increase significantly in the future, as current fossil fuel uses are being substituted by processes using electricity. For example, the transport sector is likely to rely increasingly on electricity, whether in the form of fully electric or hybrid vehicles, either using battery power or synthetic hydrocarbon fuels. Here, nuclear power can also contribute, via generation of either electricity or process heat for the production of hydrogen or other fuels.

In Europe, in particular, the public opinion about safety and regulations with nuclear power has introduced much critical discussions about the continuation of nuclear power, and Germany has introduced the “Energiewende” with the goal to close all their nuclear power by 2022. The contribution of nuclear power to the electricity production in the different countries in Europe differs widely with some countries having zero contribution (e.g. Italy, Lithuania) and some with the major part comprising nuclear power (e.g. France, Hungary, Belgium, Slovakia, Sweden).

Current status

The use of nuclear energy for commercial electricity production began in the mid-1950s. In 2013, the world’s 392 GW of installed nuclear capacity accounted for 11 % of electricity generation produced by around 440 nuclear power plants situated in 30 countries (Fig.  1 ). This share has declined gradually since 1996, when it reached almost 18 %, as the rate of new nuclear additions (and generation) has been outpaced by the expansion of other technologies. After hydropower, nuclear is the world’s second-largest source of low-carbon electricity generation (IEA 2014 1 ).

Total number of operating nuclear reactors worldwide. The total number of reactors also include six in Taiwan (source: IAEA 2015) ( https://www.iaea.org/newscenter/focus/nuclear-power )

The Country Nuclear Power Profiles (CNPP 2 ) compiles background information on the status and development of nuclear power programmes in member states. The CNPP’s main objectives are to consolidate information about the nuclear power infrastructures in participating countries, and to present factors related to the effective planning, decision-making and implementation of nuclear power programmes that together lead to safe and economical operations of nuclear power plants.

Within the European Union, 27 % of electricity production (13 % of primary energy) is obtained from 132 nuclear power plants in January 2015 (Fig.  1 ). Across the world, 65 new reactors are under construction, mainly in Asia (China, South Korea, India), and also in Russia, Slovakia, France and Finland. Many other new reactors are in the planning stage, including for example, 12 in the UK.

Apart from one first Generation “Magnox” reactor still operating in the UK, the remainder of the operating fleet is of the second or third Generation type (Fig.  2 ). The predominant technology is the Light Water Reactor (LWR) developed originally in the United States by Westinghouse and then exploited massively by France and others in the 1970s as a response to the 1973 oil crisis. The UK followed a different path and pursued the Advanced Gas-cooled Reactor (AGR). Some countries (France, UK, Russia, Japan) built demonstration scale fast neutron reactors in the 1960s and 70s, but the only commercial reactor of this type currently operating is in Russia.

Nuclear reactor generations from the pioneering age to the next decade (reproduced with permission from Ricotti 2013 )

Future evolution

The fourth Generation reactors, offering the potential of much higher energy recovery and reduced volumes of radioactive waste, are under study in the framework of the “Generation IV International Forum” (GIF) 3 and the “International Project on Innovative Nuclear Reactors and Fuel Cycles” (INPRO). The European Commission in 2010 launched the European Sustainable Nuclear Industrial Initiative (ESNII), which will support three Generation IV fast reactor projects as part of the EU’s plan to promote low-carbon energy technologies. Other initiatives supporting biomass, wind, solar, electricity grids and carbon sequestration are in parallel. ESNII will take forward: the Astrid sodium-cooled fast reactor (SFR) proposed by France, the Allegro gas-cooled fast reactor (GFR) supported by central and eastern Europe and the MYRRHA lead- cooled fast reactor (LFR) technology pilot proposed by Belgium.

The generation of nuclear energy from uranium produces not only electricity but also spent fuel and high-level radioactive waste (HLW) as a by-product. For this HLW, a technical and socially acceptable solution is necessary. The time scale needed for the radiotoxicity of the spent fuel to drop to the level of natural uranium is very long (i.e. of the order of 200 000–300 000 years). The preferred solution for disposing of spent fuel or the HLW resulting from classical reprocessing is deep geological storage. Whilst there are no such geological repositories operating yet in the world, Sweden, Finland and France are on track to have such facilities ready by 2025 (Kautsky et al. 2013 ). In this context it should also be mentioned that it is only for a minor fraction of the HLW that recycling and transmutation is required since adequate separation techniques of the fuel can be recycled and again fed through the LWR system.

The “Strategic Energy Technology Plan” (SET-Plan) identifies fission energy as one of the contributors to the 2050 objectives of a low-carbon energy mix, relying on the Generation-3 reactors, closed fuel cycle and the start of implementation of Generation IV reactors making nuclear energy more sustainable. The EU Energy Roadmap 2050 provides decarbonisation scenarios with different assumptions from the nuclear perspective: two scenarios contemplate a nuclear phase-out by 2050, whilst three others consider that 15–20 % of electricity will be produced by nuclear energy. If by 2050 a generation capacity of 20 % nuclear electricity (140 GWe) is to be secured, 100–120 nuclear power units will have to be built between now and 2050, the precise number depending on the power rating (Garbil and Goethem 2013 ).

Despite the regional differences in the development plans, the main questions are of common interest to all countries, and require solutions in order to maintain nuclear power in the power mix of contributing to sustainable economic growth. The questions include (i) maintaining safe operation of the nuclear plants, (ii) securing the fuel supplies, (iii) a strategy for the management of radioactive waste and spent nuclear fuel.

Safety and non-proliferation risks are managed in accordance with the international rules issued both by IAEA and EURATOM in the EU. The nuclear countries have signed the corresponding agreements and the majority of them have created the necessary legal and regulatory structure (Nuclear Safety Authority). As regards radioactive wastes, particularly high-level wastes (HLW) and spent fuel (SF) most of the countries have long-term policies. The establishment of new nuclear units and the associated nuclear technology developments offer new perspectives, which may need reconsideration of fuel cycle policies and more active regional and global co-operation.

Open and closed fuel cycle

In the frame of the open fuel cycle, the spent fuel will be taken to final disposal without recycling. Deep geological repositories are the only available option for isolating the highly radioactive materials for a very long time from the biosphere. Long-term (80–100 years) near soil intermediate storages are realised in e.g. France and the Netherlands which will allow for permanent access and inspection. The main advantage of the open fuel cycle is its simplicity. The spent fuel assemblies are first stored in interim storage for several years or decades, then they will be placed in special containers and moved into deep underground storage facilities. The technology for producing such containers and for excavation of the underground system of tunnels exists today (Hózer et al. 2010 ; Kautsky et al. 2013 ).

The European Academies Science Advisory Board recently released the report on “Management of spent nuclear fuel and its waste” (EASAC 2014 ). The report discusses the challenges associated with different strategies to manage spent nuclear fuel, in respect of both open cycles and steps towards closing the nuclear fuel cycle. It integrates the conclusions on the issues raised on sustainability, safety, non-proliferation and security, economics, public involvement and on the decision-making process. Recently Vandenbosch et al. ( 2015 ) critically discussed the issue of confidence in the indefinite storage of nuclear waste. One complication of the nuclear waste storage problem is that the minor actinides represent a high activity (see Fig.  3 ) and pose non-proliferation issues to be handled safely in a civil used plant. This might be a difficult challenge if the storage is to be operated economically together with the fuel fabrication.

Radiotoxicity of radioactive waste

The open (or ‘once through’) cycle only uses part of the energy stored in the fuel, whilst effectively wasting substantial amounts of energy that could be recovered through recycling. The conventional closed fuel cycle strategy uses the reprocessing of the spent fuel following interim storage. The main components which can be further utilised (U and Pu) are recycled to fuel manufacturing (MOX (Mixed Oxide) fuel fabrication), whilst the smaller volume of residual waste in appropriately conditioned form—e.g. vitrified and encapsulated—is disposed of in deep geological repositories.

The advanced closed fuel cycle strategy is similar to the conventional one, but within this strategy the minor actinides are also removed during reprocessing. The separated isotopes are transmuted in combination with power generation and only the net reprocessing wastes and those conditioned wastes generated during transmutation will be, following appropriate encapsulation, disposed of in deep geological repositories. The main factor that determines the overall storage capacity of a long-term repository is the heat content of nuclear waste, not its volume. During the anticipated repository time, the specific heat generated during the decay of the stored HLW must always stay below a dedicated value prescribed by the storage concept and the geological host information. The waste that results from reprocessing spent fuel from thermal reactors has a lower heat content (after a period of cooling) than does the spent fuel itself. Thus, it can be stored more densely.

A modern light water reactor of 1 GWe capacity will typically discharge about 20–25 tonnes of irradiated fuel per year of operation. About 93–94 % of the mass of typical uranium oxide irradiated fuel comprises uranium (mostly 238 U), with about 4–5 % fission products and ~1 % plutonium. About 0.1–0.2 % of the mass comprises minor actinides (neptunium, americium and curium). These latter elements accumulate in nuclear fuel because of neutron capture, and they contribute significantly to decay heat loading and neutron output, as well as to the overall radiotoxic hazard of spent fuel. Although the total minor actinide mass is relatively small—20 to 25 kg per year from a 1 GWe LWR—it has a disproportionate impact on spent fuel disposal because of its long radioactive decay times (OECD Nuclear Energy Agency 2013 ).

Generation IV development

To address the issue of sustainability of nuclear energy, in particular the use of natural resources, fast neutron reactors (FNRs) must be developed, since they can typically multiply by over a factor 50 the energy production from a given amount of uranium fuel compared to current reactors. FNRs, just as today’s fleet, will be primarily dedicated to the generation of fossil-free base-load electricity. In the FNR the fuel conversion ratio (FCR) is optimised. Through hardening the spectrum a fast reactor can be designed to burn minor actinides giving a FCR larger than unity which allows breeding of fissile materials. FNRs have been operated in the past (especially the Sodium-cooled Fast Reactor in Europe), but today’s safety, operational and competitiveness standards require the design of a new generation of fast reactors. Important research and development is currently being coordinated at the international level through initiatives such as GIF.

In 2002, six reactor technologies were selected which GIF believe represent the future of nuclear energy. These were selected from the many various approaches being studied on the basis of being clean, safe and cost-effective means of meeting increased energy demands on a sustainable basis. Furthermore, they are considered being resistant to diversion of materials for weapons proliferation and secure from terrorist attacks. The continued research and development will focus on the chosen six reactor approaches. Most of the six systems employ a closed fuel cycle to maximise the resource base and minimise high-level wastes to be sent to a repository. Three of the six are fast neutron reactors (FNR) and one can be built as a fast reactor, one is described as epithermal, and only two operate with slow neutrons like today’s plants. Only one is cooled by light water, two are helium-cooled and the others have lead–bismuth, sodium or fluoride salt coolant. The latter three operate at low pressure, with significant safety advantage. The last has the uranium fuel dissolved in the circulating coolant. Temperatures range from 510 to 1000 °C, compared with less than 330 °C for today’s light water reactors, and this means that four of them can be used for thermochemical hydrogen production.

The sizes range from 150 to 1500 MWe, with the lead-cooled one optionally available as a 50–150 MWe “battery” with long core life (15–20 years without refuelling) as replaceable cassette or entire reactor module. This is designed for distributed generation or desalination. At least four of the systems have significant operating experience already in most respects of their design, which provides a good basis for further research and development and is likely to mean that they can be in commercial operation well before 2030. However, when addressing non-proliferation concerns it is significant that fast neutron reactors are not conventional fast breeders, i.e. they do not have a blanket assembly where plutonium-239 is produced. Instead, plutonium production happens to take place in the core, where burn-up is high and the proportion of plutonium isotopes other than Pu-239 remains high. In addition, new reprocessing technologies will enable the fuel to be recycled without separating the plutonium.

In January 2014, a new GIF Technology Roadmap Update was published. 4 It confirmed the choice of the six systems and focused on the most relevant developments of them so as to define the research and development goals for the next decade. It suggested that the Generation IV technologies most likely to be deployed first are the SFR, the lead-cooled fast reactor (LFR) and the very high temperature reactor technologies. The molten salt reactor and the GFR were shown as furthest from demonstration phase.

Europe, through sustainable nuclear energy technology platform (SNETP) and ESNII, has defined its own strategy and priorities for FNRs with the goal to demonstrate Generation IV reactor technologies that can close the nuclear fuel cycle, provide long-term waste management solutions and expand the applications of nuclear fission beyond electricity production to hydrogen production, industrial heat and desalination; The SFR as a proven concept, as well as the LFR as a short-medium term alternative and the GFR as a longer-term alternative technology. The French Commissariat à l’Energie Atomique (CEA) has chosen the development of the SFR technology. Astrid (Advanced Sodium Technological Reactor for Industrial Demonstration) is based on about 45 reactor-years of operational experience in France and will be rated 250 to 600 MWe. It is expected to be built at Marcoule from 2017, with the unit being connected to the grid in 2022.

Other countries like Belgium, Italy, Sweden and Romania are focussing their research and development effort on the LFR whereas Hungary, Czech Republic and Slovakia are investing in the research and development on GFR building upon the work initiated in France on GFR as an alternative technology to SFR. Allegro GFR is to be built in eastern Europe, and is more innovative. It is rated at 100 MWt and would lead to a larger industrial demonstration unit called GoFastR. The Czech Republic, Hungary and Slovakia are making a joint proposal to host the project, with French CEA support. Allegro is expected to begin construction in 2018 operate from 2025. The industrial demonstrator would follow it.

In mid-2013, four nuclear research institutes and engineering companies from central Europe’s Visegrád Group of Nations (V4) agreed to establish a centre for joint research, development and innovation in Generation IV nuclear reactors (the Czech Republic, Hungary, Poland and Slovakia) which is focused on gas-cooled fast reactors such as Allegro.

The MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) 5 project proposed in Belgium by SCK•CEN could be an Experimental Technological Pilot Plant (ETPP) for the LFR technology. Later, it could become a European fast neutron technology pilot plant for lead and a multi-purpose research reactor. The unit is rated at 100 thermal MW and has started construction at SCK-CEN’s Mol site in 2014 planned to begin operation in 2023. A reduced-power model of Myrrha called Guinevere started up at Mol in March 2010. ESNII also includes an LFR technology demonstrator known as Alfred, also about 100 MWt, seen as a prelude to an industrial demonstration unit of about 600 MWe. Construction on Alfred could begin in 2017 and the unit could start operating in 2025.

Research and development topics to meet the top-level criteria established within the GIF forum in the context of simultaneously matching economics as well as stricter safety criteria set-up by the WENRA FNR demand substantial improvements with respect to the following issues:

• Primary system design simplification,
• Improved materials,
• Innovative heat exchangers and power conversion systems,
• Advanced instrumentation, in-service inspection systems,
• Enhanced safety,

and those for fuel cycle issues pertain to:

• Partitioning and transmutation,
• Innovative fuels (including minor actinide-bearing) and core performance,
• Advanced separation both via aqueous processes supplementing the PUREX process as well as pyroprocessing, which is mandatory for the reprocessing of the high MA-containing fuels,
• Develop a final depository.

Beyond the research and development, the demonstration projects mentioned above are planned in the frame of the SET-Plan ESNII for sustainable fission. In addition, supporting research infrastructures, irradiation facilities, experimental loops and fuel fabrication facilities, will need to be constructed.

Regarding transmutation, the accelerator-driven transmutation systems (ADS) technology must be compared to FNR technology from the point of view of feasibility, transmutation efficiency and cost efficiency. It is the objective of the MYRRHA project to be an experimental demonstrator of ADS technology. From the economical point of view, the ADS industrial solution should be assessed in terms of its contribution to closing the fuel cycle. One point of utmost importance for the ADS is its ability for burning larger amounts of minor actinides (the typical maximum in a critical FNR is about 2 %).

The concept of partitioning and transmutation (P&T) has three main goals: reduce the radiological hazard associated with spent fuel by reducing the inventory of minor actinides, reduce the time interval required to reach the radiotoxicity of natural uranium and reduce the heat load of the HLW packages to be stored in the geological disposal hence reducing the foot print of the geological disposal.

Advanced management of HLW through P&T consists in advanced separation of the minor actinides (americium, curium and neptunium) and some fission products with a long half-life present in the nuclear waste and their transmutation in dedicated burners to reduce the radiological and heat loads on the geological disposal. The time scale needed for the radiotoxicity of the waste to drop to the level of natural uranium will be reduced from a ‘geological’ value (300 000 years) to a value that is comparable to that of human activities (few hundreds of years) (OECD/NEA 2006 ; OECD 2012 ; PATEROS 2008 6 ). Transmutation of the minor actinides is achieved through fission reactions and therefore fast neutrons are preferred in dedicated burners.

At the European level, four building blocks strategy for Partitioning and Transmutation have been identified. Each block poses a serious challenge in terms of research & development to be done in order to reach industrial scale deployment. These blocks are:

• Demonstration of advanced reprocessing of spent nuclear fuel from LWRs, separating Uranium, Plutonium and Minor Actinides;
• Demonstration of the capability to fabricate at semi-industrial level dedicated transmuter fuel heavily loaded in minor actinides;
• Design and construct one or more dedicated transmuters;
• Fabrication of new transmuter fuel together with demonstration of advanced reprocessing of transmuter fuel.

MYRRHA will support this Roadmap by playing the role of an ADS prototype (at reasonable power level) and as a flexible irradiation facility providing fast neutrons for the qualification of materials and fuel for an industrial transmuter. MYRRHA will be not only capable of irradiating samples of such inert matrix fuels but also of housing fuel pins or even a limited number of fuel assemblies heavily loaded with MAs for irradiation and qualification purposes.

Options for nuclear fusion beyond 2050

Nuclear fusion research, on the basis of magnetic confinement, considered in this report, has been actively pursued in Europe from the mid-60s. Fusion research has the goal to achieve a clean and sustainable energy source for many generations to come. In parallel with basic high-temperature plasma research, the fusion technology programme is pursued as well as the economy of a future fusion reactor (Ward et al. 2005 ; Ward 2009 ; Bradshaw et al. 2011 ). The goal-oriented fusion research should be driven with an increased effort to be able to give the long searched answer to the open question, “will fusion energy be able to cover a major part of mankind’s electricity demand?”. ITER, the first fusion reactor to be built in France by the seven collaborating partners (Europe, USA, Russia, Japan, Korea, China, India) is hoped to answer most of the open physics and many of the remaining technology/material questions. ITER is expected to start operation of the first plasma around 2020 and D-T operation 2027.

The European fusion research has been successful through the organisation of EURATOM to which most countries in Europe belong (the fission programme is also included in EURATOM). EUROfusion, the European Consortium for the Development of Fusion Energy, manages European fusion research activities on behalf of EURATOM. The organisation of the research has resulted in a well-focused common fusion research programme. The members of the EUROfusion 7 consortium are 29 national fusion laboratories. EUROfusion funds all fusion research activities in accordance with the “EFDA Fusion electricity. Roadmap to the realisation of fusion energy” (EFDA 2012 , Fusion electricity). The Roadmap outlines the most efficient way to realise fusion electricity. It is the result of an analysis of the European Fusion Programme undertaken by all Research Units within EUROfusion’s predecessor agreement, the European Fusion Development Agreement, EFDA.

The most successful confinement concepts are toroidal ones like tokamaks and helical systems like stellarators (Wagner 2012 , 2013 ). To avoid drift losses, two magnetic field components are necessary for confinement and stability—the toroidal and the poloidal field component. Due to their superposition, the magnetic field winds helically around a system of nested toroids. In both cases, tokamak and stellarator, the toroidal field is produced by external coils; the poloidal field arises from a strong toroidal plasma current in tokamaks. In case of helical systems all necessary fields are produced externally by coils which have to be superconductive when steady-state operation is intended. Europe is constructing the most ambitious stellarator, Wendelstein 7-X in Germany. It is a fully optimised system with promising features. W7-X goes into operation in 2015. 8

Fusion research has now reached plasma parameters needed for a fusion reactor, even if not all parameters are reached simultaneously in a single plasma discharge (see Fig.  4 ). Plotted is the triple product n•τ E• T i composed of the density n, the confinement time τ E and the ion temperature T i . For ignition of a deuterium–tritium plasma, when the internal α-particle heating from the DT-reaction takes over and allows the external heating to be switched off, the triple product has to be about >6 × 10 21  m −3  s keV). The record parameters given as of today are shown together with the fusion experiment of its achievement in Fig.  4 . The achieved parameters and the missing factors to the ultimate goal of a fusion reactor are summarised below:

• Temperature: 40 keV achieved (JT-60U, Japan); the goal is surpassed by a factor of two
• Density n surpassed by factor 5 (C-mod,USA; LHD,Japan)
• Energy confinement time: a factor of 4 is missing (JET, Europe)
• Fusion triple product (see Fig.  4 : a factor of 6 is missing (JET, Europe)
• The first scientific goal is achieved: Q (fusion power/external heating power) ~1 (0,65) (JET, Europe)
• D-T operation without problems (TFTR (USA), JET, small tritium quantities have been used, however)
• Maximal fusion power for short pulse: 16 MW (JET)
• Divertor development (ASDEX, ASDEX-Upgrade, Germany)
• Design for the first experimental reactor complete (ITER, see below)
• The optimisation of stellarators (W7-AS, W7-X, Germany)

Progress in fusion parameters. Derived in 1955, the Lawson criterion specifies the conditions that must be met for fusion to produce a net energy output (1 keV × 12 million K). From this, a fusion “triple product” can be derived, which is defined as the product of the plasma ion density, ion temperature and energy confinement time. This product must be greater than about 6 × 10 21  keV m −3  s for a deuterium–tritium plasma to ignite. Due to the radioactivity associated with tritium, today’s research tokamaks generally operate with deuterium only ( solid dots ). The large tokamaks JET(EU) and TFTR(US), however, have used a deuterium–tritium mix ( open dots ). The rate of increase in tokamak performance has outstripped that of Moore’s law for the miniaturisation of silicon chips (Pitts et al. 2006 ). Many international projects (their names are given by acronyms in the figure) have contributed to the development of fusion plasma parameters and the progress in fusion research which serves as the basis for the ITER design

After 50 years of fusion research there is no evidence for a fundamental obstacle in the basic physics. But still many problems have to be overcome as detailed below:

Critical issues in fusion plasma physics based on magnetic confinement

• confine a plasma magnetically with 1000 m 3 volume,
• maintain the plasma stable at 2–4 bar pressure,
• achieve 15 MA current running in a fluid (in case of tokamaks, avoid instabilities leading to disruptions),
• find methods to maintain the plasma current in steady-state,
• tame plasma turbulence to get the necessary confinement time,
• develop an exhaust system (divertor) to control power and particle exhaust, specifically to remove the α-particle heat deposited into the plasma and to control He as the fusion ash.

Critical issues in fusion plasma technology

• build a system with 200 MKelvin in the plasma core and 4 Kelvin about 2 m away,
• build magnetic system at 6 Tesla (max field 12 Tesla) with 50 GJ energy,
• develop heating systems to heat the plasma to the fusion temperature and current drive systems to maintain steady-state conditions for the tokamak,
• handle neutron-fluxes of 2 MW/m 2 leading to 100 dpa in the surrounding material,
• develop low activation materials,
• develop tritium breeding technologies,
• provide high availability of a complex system using an appropriate remote handling system,
• develop the complete physics and engineering basis for system licensing.

The goals of ITER

The major goals of ITER (see Fig.  5 ) in physics are to confine a D-T plasma with α-particle self-heating dominating all other forms of plasma heating, to produce about ~500 MW of fusion power at a gain Q  = fusion power/external heating power, of about 10, to explore plasma stability in the presence of energetic α-particles, and to demonstrate ash-exhaust and burn control.

Schematic layout of the ITER reactor experiment (from www.iter.org )

In the field of technology, ITER will demonstrate fundamental aspects of fusion as the self-heating of the plasma by alpha-particles, show the essentials to a fusion reactor in an integrated system, give the first test a breeding blanket and assess the technology and its efficiency, breed tritium from lithium utilising the D-T fusion neutron, develop scenarios and materials with low T-inventories. Thus ITER will provide strong indications for vital research and development efforts necessary in the view of a demonstration reactor (DEMO). ITER will be based on conventional steel as structural material. Its inner wall will be covered with beryllium to surround the plasma with low-Z metal with low inventory properties. The divertor will be mostly from tungsten to sustain the high α-particle heat fluxes directed onto target plates situated inside a divertor chamber. An important step in fusion reactor development is the achievement of licensing of the complete system.

The rewards from fusion research and the realisation of a fusion reactor can be described in the following points:

• fusion has a tremendous potential thanks to the availability of deuterium and lithium as primary fuels. But as a recommendation, the fusion development has to be accelerated,

Fusion time strategy towards the fusion reactor on the net (EFDA 2012 , Fusion electricity. A roadmap to the realisation of fusion energy)

In addition, there is the fusion technology programme and its material branch, which ultimately need a neutron source to study the interaction with 14 MeV neutrons. For this purpose, a spallation source IFMIF is presently under design. As a recommendation, ways have to be found to accelerate the fusion development. In general, with ITER, IFMIF and the DEMO, the programme will move away from plasma science more towards technology orientation. After the ITER physics and technology programme—if successful—fusion can be placed into national energy supply strategies. With fusion, future generations can have access to a clean, safe and (at least expected of today) economic power source.

The fission nuclear power continues to be an essential part of the low-carbon electricity generation in the world for decades to come. There are breakthrough possibilities in the development of new generation nuclear reactors where the life-time of the nuclear waste can be reduced to some hundreds of years instead of the present time-scales of hundred thousand of years. Research on the fourth generation reactors is needed for the realisation of this development. For the fast nuclear reactors a substantial research and development effort is required in many fields—from material sciences to safety demonstration—to attain the envisaged goals. Fusion provides a long-term vision for an efficient energy production. The fusion option for a nuclear reactor for efficient production of electricity should be vigorously pursued on the international arena as well as within the European energy roadmap to reach a decision point which allows to critically assess this energy option.

Box 1 Explanations of abbreviations used in this article

Biographies

is Professor in Energy Research and Director of MTA Center for Energy Research, Budapest, Hungary. His research interests are in the development of new fission reactors, new structural materials, high temperature irradiation resistance, mechanical deformation.

is Professor of Applied Atomic and Molecular Physics at Royal Institute of Technology, (KTH), Stockholm, Sweden. Her research interests are in basic atomic and molecular processes studied with synchrotron radiation, development of diagnostic techniques for analysing the performance of fusion experiments in particular development of photon spectroscopic diagnostics.

1 http://www.iea.org/ .

2 https://cnpp.iaea.org/pages/index.htm .

3 GenIV International forum: ( http://www.gen-4.org/index.html ).

4 https://www.gen-4.org/gif/jcms/c_60729/technology-roadmap-update-2013 .

5 http://myrrha.sckcen.be/ .

6 www.sckcen.be/pateros/ .

7 https://www.euro-fusion.org/ .

8 https://www.ipp.mpg.de/ippcms/de/pr/forschung/w7x/index.html .

Contributor Information

Akos Horvath, Email: [email protected] .

Elisabeth Rachlew, Email: es.htk@kre .

• Bradshaw AM, Hamacher T, Fischer U. Is nuclear fusion a sustainable energy form? Fusion Engineering and Design. 2011; 86 :2770–2773. doi: 10.1016/j.fusengdes.2010.11.040. [ CrossRef ] [ Google Scholar ]
• EASAC. 2014. EASAC Report 23—Management of spent nuclear fuel and its waste. http://www.easac.eu/energy/reports-and-statements/detail-view/article/management-o.html .
• EFDA. 2012. Fusion electricity. A roadmap to the realization of fusion energy. https://www.euro-fusion.org/wpcms/wp-content/uploads/2013/01/JG12.356-web.pdf .
• Garbil, R., and G. Van Goethem. (ed.). 2013. Symposium on the “Benefits and limitations of nuclear fission for a low carbon economy”, European Commission, Brussels, ISBN 978-92.79.29833.2.
• Hózer, Z. S. Borovitskiy, G. Buday, B. Boullis, G. Cognet, S. A. Delichatsios, J. Gadó, A. Grishin, et al. 2010. Regional strategies concerning nuclear fuel cycle and HLRW in Central and Eastern European Countries. International conference on management of spent fuel from Nuclear Power Reactors, Vienna, Conference ID:38089 (CN-178).
• IEA (International Energy Authority). 2014. World Energy Outlook 2014. http://www.iea.org/ .
• IPCC. 2014. Summary for policymakers WGIII AR5, SPM.4.2.2 Energy supply.
• Kautsky, U., T. Lindborg, and J. Valentin (ed.). 2013. Humans and ecosystems over the coming millenia: A biosphere assessment of radioactive waste disposal in Sweden. Ambio 42(4): 381–526. [ PMC free article ] [ PubMed ]
• OECD. 2011–2012. Fact book: Economic, environmental and social statistics. Retrieved from http://www.oecd-ilibrary.org/economics/oecd-factbook-2011-2012_factbook-2011-en .
• OECD/NEA. 2006. Potential benefits and impacts of advanced nuclear fuel cycles with actinide partitioning and transmutation. ISBN: 978-92-64-99165-1, http://www.oecd-nea.org/science/reports/2011/6894-benefits-impacts-advanced-fuel.pdf .
• OECD Nuclear Energy Agency. 2013. Minor actinide burning in thermal reactors. A report by the Working Party on Scientific Issues of Reactor Systems, NEA #6997. http://www.oecd-nea.org/science/pubs/2013/6997-minor-actinide.pdf .
• Pitts R, Buttery R, Pinches S. Fusion: The way ahead. Physics World. 2006; 19 :20–26. doi: 10.1088/2058-7058/19/3/35. [ CrossRef ] [ Google Scholar ]
• Ricotti ME. Nuclear energy: Basics, present, future. EPJ Web of Conferences. 2013; 54 :01005. doi: 10.1051/epjconf/20135401005. [ CrossRef ] [ Google Scholar ]
• Vandenbosch R, Vandenbosch SE. Nuclear waste confidence: Is indefinite storage safe? APS Physics and Society. 2015; 44 :5–7. [ Google Scholar ]
• Wagner, F. 2012. Fusion energy by magnetic confinement. IPP 18/3, http://hdl.handle.net/11858/00-001M-0000-0026-E767-A .
• Wagner F. Physics of magnetic confinement fusion. EPJ Web of Conferences. 2013; 54 :01007. doi: 10.1051/epjconf/20135401007. [ CrossRef ] [ Google Scholar ]
• Ward DJ. The contribution of fusion to sustainable development. Fusion Engineering and Design. 2009; 82 :528–533. doi: 10.1016/j.fusengdes.2007.02.028. [ CrossRef ] [ Google Scholar ]
• Ward DJ, Cook I, Lechon Y, Saez R. The economic viability of fusion power. Engineering and Design. 2005; 75–79 :1221–1227. doi: 10.1016/j.fusengdes.2005.06.160. [ CrossRef ] [ Google Scholar ]

Nuclear Power: Technical and Institutional Options for the Future (1992)

Chapter: 5 conclusions and recommendations, conclusions and recommendations.

The Committee was requested to analyze the technological and institutional alternatives to retain an option for future U.S. nuclear power deployment.

A premise of the Senate report directing this study is “that nuclear fission remains an important option for meeting our electric energy requirements and maintaining a balanced national energy policy.” The Committee was not asked to examine this premise, and it did not do so. The Committee consisted of members with widely ranging views on the desirability of nuclear power. Nevertheless, all members approached the Committee's charge from the perspective of what would be necessary if we are to retain nuclear power as an option for meeting U.S. electric energy requirements, without attempting to achieve consensus on whether or not it should be retained. The Committee's conclusions and recommendations should be read in this context.

The Committee's review and analyses have been presented in previous chapters. Here the Committee consolidates the conclusions and recommendations found in the previous chapters and adds some additional conclusions and recommendations based upon some of the previous statements. The Committee also includes some conclusions and recommendations that are not explicitly based upon the earlier chapters but stem from the considerable experience of the Committee members.

Most of the following discussion contains conclusions. There also are a few recommendations. Where the recommendations appear they are identified as such by bold italicized type.

GENERAL CONCLUSIONS

In 1989, nuclear plants produced about 19 percent of the United States ' electricity, 77 percent of France's electricity, 26 percent of Japan's electricity, and 33 percent of West Germany's electricity. However, expansion of commercial nuclear energy has virtually halted in the United States. In other countries, too, growth of nuclear generation has slowed or stopped. The reasons in the United States include reduced growth in demand for electricity, high costs, regulatory uncertainty, and public opinion. In the United States, concern for safety, the economics of nuclear power, and waste disposal issues adversely affect the general acceptance of nuclear power.

Electricity Demand

Estimated growth in summer peak demand for electricity in the United States has fallen from the 1974 projection of more than 7 percent per year to a relatively steady level of about 2 percent per year. Plant orders based on the projections resulted in cancellations, extended construction schedules, and excess capacity during much of the 1970s and 1980s. The excess capacity has diminished in the past five years, and ten year projections (at approximately 2 percent per year) suggest a need for new capacity in the 1990s and beyond. To meet near-term anticipated demand, bidding by non-utility generators and energy efficiency providers is establishing a trend for utilities acquiring a substantial portion of this new generating capacity from others. Reliance on non-utility generators does not now favor large scale baseload technologies.

Nuclear power plants emit neither precursors to acid rain nor gases that contribute to global warming, like carbon dioxide. Both of these environmental issues are currently of great concern. New regulations to address these issues will lead to increases in the costs of electricity produced by combustion of coal, one of nuclear power's main competitors. Increased costs for coal-generated electricity will also benefit alternate energy sources that do not emit these pollutants.

Major deterrents for new U.S. nuclear plant orders include high capital carrying charges, driven by high construction costs and extended construction times, as well as the risk of not recovering all construction costs.

Construction Costs

Construction costs are hard to establish, with no central source, and inconsistent data from several sources. Available data show a wide range of costs for U.S. nuclear plants, with the most expensive costing three times more (in dollars per kilowatt electric) than the least expensive in the same year of commercial operation. In the post-Three Mile Island era, the cost increases have been much larger. Considerable design modification and retrofitting to meet new regulations contributed to cost increases. From 1971 to 1980, the most expensive nuclear plant (in constant dollars) increased by 30 percent. The highest cost for a nuclear plant beginning commercial operation in the United States was twice as expensive (in constant dollars) from 1981 to 1984 as it was from 1977 to 1980.

Construction Time

Although plant size also increased, the average time to construct a U.S. nuclear plant went from about 5 years prior to 1975 to about 12 years from 1985 to 1989. U.S. construction times are much longer than those in other major nuclear countries, except for the United Kingdom. Over the period 1978 to 1989, the U.S. average construction time was nearly twice that of France and more than twice that of Japan.

Billions of dollars in disallowances of recovery of costs from utility ratepayers have made utilities and the financial community leery of further investments in nuclear power plants. During the 1980s, rate base disallowances by state regulators totaled about $14 billion for nuclear plants, but only about $0.7 billion for non-nuclear plants.

Operation and maintenance (O&M) costs for U.S. nuclear plants have increased faster than for coal plants. Over the decade of the 1980s, U.S. nuclear O&M-plus-fuel costs grew from nearly half to about the same as those for fossil fueled plants, a significant shift in relative advantage.

Performance

On average, U.S. nuclear plants have poorer capacity factors compared to those of plants in other Organization for Economic Cooperation and Development (OECD) countries. On a lifetime basis, the United States is barely above 60 percent capacity factor, while France and Japan are at 68 percent, and West Germany is at 74 percent. Moreover, through 1988 12 U.S. plants were in the bottom 22. However, some U.S. plants do very well: 3 of the top 22 OECD plants through 1988 were U.S. U.S. plants averaged 65 percent in 1988, 63 percent in 1989, and 68 percent in 1990.

Except for capacity factors, the performance indicators of U.S. nuclear plants have improved significantly over the past several years. If the industry is to achieve parity with the operating performance in other countries, it must carefully examine its failure to achieve its own goal in this area and develop improved strategies, including better management practices. Such practices are important if the generators are to develop confidence that the new generation of plants can achieve the higher load factors estimated by the vendors.

Public Attitudes

There has been substantial opposition to new plants. The failure to solve the high-level radioactive waste disposal problem has harmed nuclear power's public image. It is the Committee's opinion, based upon our experience, that, more recently, an inability of states, that are members of regional compact commissions, to site low-level radioactive waste facilities has also harmed nuclear power's public image.

Several factors seem to influence the public to have a less than positive attitude toward new nuclear plants:

no perceived urgency for new capacity;

nuclear power is believed to be more costly than alternatives;

concerns that nuclear power is not safe enough;

little trust in government or industry advocates of nuclear power;

concerns about the health effects of low-level radiation;

concerns that there is no safe way to dispose of high-level waste; and

concerns about proliferation of nuclear weapons.

The Committee concludes that the following would improve public opinion of nuclear power:

a recognized need for a greater electrical supply that can best be met by large plants;

economic sanctions or public policies imposed to reduce fossil fuel burning;

maintaining the safe operation of existing nuclear plants and informing the public;

providing the opportunity for meaningful public participation in nuclear power issues, including generation planning, siting, and oversight;

better communication on the risk of low-level radiation;

resolving the high-level waste disposal issue; and

assurance that a revival of nuclear power would not increase proliferation of nuclear weapons.

As a result of operating experience, improved O&M training programs, safety research, better inspections, and productive use of probabilistic risk analysis, safety is continually improved. The Committee concludes that the risk to the health of the public from the operation of current reactors in the United States is very small. In this fundamental sense, current reactors are safe. However, a significant segment of the public has a different perception and also believes that the level of safety can and should be increased. The

development of advanced reactors is in part an attempt to respond to this public attitude.

Institutional Changes

The Committee believes that large-scale deployment of new nuclear power plants will require significant changes by both industry and government.

One of the most important factors affecting the future of nuclear power in the United States is its cost in relation to alternatives and the recovery of these capital and operating charges through rates that are charged for the electricity produced. Chapter 2 of this report deals with these issues in some detail. As stated there, the industry must develop better methods for managing the design and construction of nuclear plants. Arrangements among the participants that would assure timely, economical, and high-quality construction of new nuclear plants, the Committee believes, will be prerequisites to an adequate degree of assurance of capital cost recovery from state regulatory authorities in advance of construction. The development of state prudency laws also can provide a positive response to this issue.

The Committee and others are well aware of the increases in nuclear plant construction and operating costs over the last 20 years and the extension of plant construction schedules over this same period. 1 The Committee believes there are many reasons for these increases but is unable to disaggregate the cost effect among these reasons with any meaningful precision.

Like others, the Committee believes that the financial community and the generators must both be satisfied that significant improvements can be achieved before new plants can be ordered. In addition, the Committee believes that greater confidence in the control of costs can be realized with plant designs that are more nearly complete before construction begins, plants that are easier to construct, use of better construction and management methods, and business arrangements among the participants that provide stronger incentives for cost-effective, timely completion of projects.

It is the Committee's opinion, based upon our experience, that the principal participants in the nuclear industry--utilities, architect-engineers, and suppliers –should begin now to work out the full range of contractual arrangements for advanced nuclear power plants. Such arrangements would

increase the confidence of state regulatory bodies and others that the principal participants in advanced nuclear power plant projects will be financially accountable for the quality, timeliness, and economy of their products and services.

Inadequate management practices have been identified at some U.S. utilities, large and small public and private. Because of the high visibility of nuclear power and the responsibility for public safety, a consistently higher level of demonstrated utility management practices is essential before the U.S. public's attitude about nuclear power is likely to improve.

Over the past decade, utilities have steadily strengthened their ability to be responsible for the safety of their plants. Their actions include the formation and support of industry institutions, including the Institute of Nuclear Power Operations (INPO). Self-assessment and peer oversight through INPO are acknowledged to be strong and effective means of improving the performance of U.S. nuclear power plants. The Committee believes that such industry self-improvement, accountability, and self-regulation efforts improve the ability to retain nuclear power as an option for meeting U.S. electric energy requirements. The Committee encourages industry efforts to reduce reliance on the adversarial approach to issue resolution.

It is the Committee's opinion, based upon our experience, that the nuclear industry should continue to take the initiative to bring the standards of every American nuclear plant up to those of the best plants in the United States and the world. Chronic poor performers should be identified publicly and should face the threat of insurance cancellations. Every U.S. nuclear utility should continue its full-fledged participation in INPO; any new operators should be required to become members through insurance prerequisites or other institutional mechanisms.

Standardization. The Committee views a high degree of standardization as very important for the retention of nuclear power as an option for meeting U.S. electric energy requirements. There is not a uniformly accepted definition of standardization. The industry, under the auspices of the Nuclear Power Oversight Committee, has developed a position paper on standardization that provides definitions of the various phases of standardization and expresses an industry commitment to standardization. The Committee believes that a strong and sustained commitment by the principal participants will be required to realize the potential benefits of standardization (of families of plants) in the diverse U.S. economy. It is the Committee's opinion, based upon our experience, that the following will be necessary:

Families of standardized plants will be important for ensuring the highest levels of safety and for realizing the potential economic benefits of new nuclear plants. Families of standardized plants will allow standardized approaches to plant modification, maintenance, operation, and training.

Customers, whether utilities or other entities, must insist on standardization before an order is placed, during construction, and throughout the life of the plant.

Suppliers must take standardization into account early in planning and marketing. Any supplier of standardized units will need the experience and resources for a long-term commitment.

Antitrust considerations will have to be properly taken into account to develop standardized plants.

Nuclear Regulatory Commission

An obstacle to continued nuclear power development has been the uncertainties in the Nuclear Regulatory Commission's (NRC) licensing process. Because the current regulatory framework was mainly intended for light water reactors (LWR) with active safety systems and because regulatory standards were developed piecemeal over many years, without review and consolidation, the regulations should be critically reviewed and modified (or replaced with a more coherent body of regulations) for advanced reactors of other types. The Committee recommends that NRC comprehensively review its regulations to prepare for advance reactors, in particular. LWRs with passive safety features. The review should proceed from first principles to develop a coherent, consistent set of regulations.

The Committee concludes that NRC should improve the quality of its regulation of existing and future nuclear power plants, including tighter management controls over all of its interactions with licensees and consistency of regional activities. Industry has proposed such to NRC.

The Committee encourages efforts by NRC to reduce reliance on the adversarial approach to issue resolution. The Committee recommends that NRC encourage industry self-improvement, accountability, and self-regulation initia tives . While federal regulation plays an important safety role, it must not be allowed to detract from or undermine the accountability of utilities and their line management organizations for the safety of their plants.

It is the Committee's expectation that economic incentive programs instituted by state regulatory bodies will continue for nuclear power plant operators. Properly formulated and administered, these programs should improve the economic performance of nuclear plants, and they may also enhance safety. However, they do have the potential to provide incentives counter to safety. The Committee believes that such programs should focus

on economic incentives and avoid incentives that can directly affect plant safety. On July 18, 1991 NRC issued a Nuclear Regulatory Commission Policy Statement which expressed concern that such incentive programs may adversely affect safety and commits NRC to monitoring such programs. A joint industry/state study of economic incentive programs could help assure that such programs do not interfere with the safe operation of nuclear power plants.

It is the Committee's opinion, based upon our experience, that NRC should continue to exercise its federally mandated preemptive authority over the regulation of commercial nuclear power plant safety if the activities of state government agencies (or other public or private agencies) run counter to nuclear safety. Such activities would include those that individually or in the aggregate interfere with the ability of the organization with direct responsibility for nuclear plant safety (the organization licensed by the Commission to operate the plant) to meet this responsibility. The Committee urges close industry-state cooperation in the safety area.

It is also the Committee's opinion, based upon our experience, that the industry must have confidence in the stability of NRC's licensing process. Suppliers and utilities need assurance that licensing has become and will remain a manageable process that appropriately limits the late introduction of new issues.

It is likely that, if the possibility of a second hearing before a nuclear plant can be authorized to operate is to be reduced or eliminated, legislation will be necessary. The nuclear industry is convinced that such legislation will be required to increase utility and investor confidence to retain nuclear power as an option for meeting U.S. electric energy requirements. The Committee concurs.

It is the Committee's opinion, based upon our experience, that potential nuclear power plant sponsors must not face large unanticipated cost increases as a result of mid-course regulatory changes, such as backfits. NRC 's new licensing rule, 10 CFR Part 52, provides needed incentives for standardized designs.

Industry and the Nuclear Regulatory Commission

The U.S. system of nuclear regulation is inherently adversarial, but mitigation of unnecessary tension in the relations between NRC and its nuclear power licensees would, in the Committee's opinion, improve the regulatory environment and enhance public health and safety. Thus, the Committee commends the efforts by both NRC and the industry to work

more cooperatively together and encourages both to continue and strengthen these efforts.

Department of Energy

Lack of resolution of the high-level waste problem jeopardizes future nuclear power development. The Committee believes that the legal status of the Yucca Mountain site for a geologic repository should be resolved soon, and that the Department of Energy's (DOE) program to investigate this site should be continued. In addition, a contingency plan must be developed to store high-level radioactive waste in surface storage facilities pending the availability of the geologic repository.

Environmental Protection Agency

The problems associated with establishing a high-level waste site at Yucca Mountain are exacerbated by the requirement that, before operation of a repository begins, DOE must demonstrate to NRC that the repository will perform to standards established by the Environmental Protection Agency (EPA). NRC's staff has strongly questioned the workability of these quantitative requirements, as have the National Research Council's Radioactive Waste Management Board and others. The Committee concludes that the EPA standard for disposal of high-level waste will have to be reevaluated to ensure that a standard that is both adequate and feasible is applied to the geologic waste repository.

Administration and Congress

The Price-Anderson Act will expire in 2002. The Committee sought to discover whether or not such protection would be required for advanced reactors. The clear impression the Committee received from industry representatives was that some such protection would continue to be needed, although some Committee members believe that this was an expression of desire rather than of need. At the very least, renewal of Price-Anderson in 2002 would be viewed by the industry as a supportive action by Congress and would eliminate the potential disruptive effect of developing alternative liability arrangements with the insurance industry. Failure to renew Price-Anderson in 2002 would raise a new impediment to nuclear power plant orders as well as possibly reduce an assured source of funds to accident victims.

The Committee believes that the National Transportation Safety Board (NTSB) approach to safety investigations, as a substitute for the present NRC approach, has merit. In view of the infrequent nature of the activities of such a committee, it may be feasible for it to be established on an ad hoc basis and report directly to the NRC chairman. Therefore, the Committee recommends that such a small safety review entity be established. Before the establishment of such an activity, its charter should be carefully defined, along with a clear delineation of the classes of accidents it would investigate. Its location in the government and its reporting channels should also be specified. The function of this group would parallel those of NTSB. Specifically, the group would conduct independent public investigations of serious incidents and accidents at nuclear power plants and would publish reports evaluating the causes of these events. This group would have only a small administrative structure and would bring in independent experts, including those from both industry and government, to conduct its investigations.

It is the Committee's opinion, based upon our experience, that responsible arrangements must be negotiated between sponsors and economic regulators to provide reasonable assurances of complete cost recovery for nuclear power plant sponsors. Without such assurances, private investment capital is not likely to flow to this technology.

In Chapter 2 , the Committee addressed the non-recovery of utility costs in rate proceedings and concluded that better methods of dealing with this issue must be established. The Committee was impressed with proposals for periodic reviews of construction progress and costs--“rolling prudency” determinations--as one method for managing the risks of cost recovery. The Committee believes that enactment of such legislation could remove much of the investor risk and uncertainty currently associated with state regulatory treatment of new power plant construction, and could therefore help retain nuclear power as an option for meeting U.S. electric energy requirements.

On balance, however, unless many states adopt this or similar legislation, it is the Committee's view that substantial assurances probably cannot be given, especially in advance of plant construction, that all costs incurred in building nuclear plants will be allowed into rate bases.

The Committee notes the current trend toward economic deregulation of electric power generation. It is presently unclear whether this trend is compatible with substantial additions of large-scale, utility-owned, baseload generating capacity, and with nuclear power plants in particular.

It is the Committee's opinion, based upon our experience, that regional low-level radioactive waste compact commissions must continue to establish disposal sites.

The institutional challenges are clearly substantial. If they are to be met, the Committee believes that the Federal government must decide, as a matter of national policy, whether a strong and growing nuclear power program is vital to the economic, environmental, and strategic interests of the American people. Only with such a clearly stated policy, enunciated by the President and backed by the Congress through appropriate statutory changes and appropriations, will it be possible to effect the institutional changes necessary to return the flow of capital and human resources required to properly employ this technology.

Alternative Reactor Technologies

Advanced reactors are now in design or development. They are being designed to be simpler, and, if design goals are realized, these plants will be safer than existing reactors. The design requirements for the advanced reactors are more stringent than the NRC safety goal policy. If final safety designs of advanced reactors, and especially those with passive safety features, are as indicated to this Committee, an attractive feature of them should be the significant reduction in system complexity and corresponding improvement in operability. While difficult to quantify, the benefit of improvements in the operator 's ability to monitor the plant and respond to system degradations may well equal or exceed that of other proposed safety improvements.

The reactor concepts assessed by the Committee were the large evolutionary LWRs, the mid-sized LWRs with passive safety features, 2 the Canadian deuterium uranium (CANDU) heavy water reactor, the modular high-temperature gas-cooled reactor (MHTGR), the safe integral reactor (SIR), the process inherent ultimate safety (PIUS) reactor, and the liquid metal reactor (LMR). The Committee developed the following criteria for comparing these reactor concepts:

safety in operation;

economy of construction and operation;

suitability for future deployment in the U.S. market;

fuel cycle and environmental considerations;

safeguards for resistance to diversion and sabotage;

technology risk and development schedule; and

amenability to efficient and predictable licensing.

With regard to advanced designs, the Committee reached the following conclusions.

Large Evolutionary Light Water Reactors

The large evolutionary LWRs offer the most mature technology. The first standardized design to be certified in the United States is likely to be an evolutionary LWR. The Committee sees no need for federal research and development (R&D) funding for these concepts, although federal funding could accelerate the certification process.

Mid-sized Light Water Reactors with Passive Safety Features

The mid-sized LWRs with passive safety features are designed to be simpler, with modular construction to reduce construction times and costs, and to improve operations. They are likely the next to be certified.

Because there is no experience in building such plants, cost projections for the first plant are clearly uncertain. To reduce the economic uncertainties it will be necessary to demonstrate the construction technology and improved operating performance. These reactors differ from current reactors in construction approach, plant configuration, and safety features. These differences do not appear so great as to require that a first plant be built for NRC certification. While a prototype in the traditional sense will not be required, the Committee concludes that no first-plant mid-sized LWR with passive safety features is likely to be certified and built without government incentives, in the form of shared funding or financial guarantees.

CANDU Heavy Water Reactor

The Committee judges that the CANDU ranks below the advanced mid-sized LWRs in market potential. The CANDU-3 reactor is farther along in design than the mid-sized LWRs with passive safety features. However, it has not entered NRC's design certification process. Commission requirements are complex and different from those in Canada so that U.S. certification

could be a lengthy process. However, the CANDU reactor can probably be licensed in this century.

The heavy water reactor is a mature design, and Canadian entry into the U.S. marketplace would give added insurance of adequate nuclear capacity if it is needed in the future. But the CANDU does not offer advantages sufficient to justify U.S. government assistance to initiate and conduct its licensing review.

Modular High-Temperature Gas-Cooled Reactor

The MHTGR posed a difficult set of questions for the Committee. U.S. and foreign experience with commercial gas-cooled reactors has not been good. A consortium of industry and utility people continue to promote federal funding and to express interest in the concept, while none has committed to an order.

The reactor, as presently configured, is located below ground level and does not have a conventional containment. The basic rationale of the designers is that a containment is not needed because of the safety features inherent in the properties of the fuel.

However, the Committee was not convinced by the presentations that the core damage frequency for the MHTGR has been demonstrated to be low enough to make a containment structure unnecessary. The Oak Ridge National Laboratory estimates that data to confirm fuel performance will not be available before 1994. The Committee believes that reliance on the defense-in-depth concept must be retained, and accurate evaluation of safety will require evaluation of a detailed design.

A demonstration plant for the MHTGR could be licensed slightly after the turn of the century, with certification following demonstration of successful operation. The MHTGR needs an extensive R&D program to achieve commercial readiness in the early part of the next century. The construction and operation of a first plant would likely be required before design certification. Recognizing the opposite conclusion of the MHTGR proponents, the Committee was not convinced that a foreseeable commercial market exists for MHTGR-produced process heat, which is the unique strategic capability of the MHTGR. Based on the Committee 's view on containment requirements, and the economics and technology issues, the Committee judged the market potential for the MHTGR to be low.

The Committee believes that no funds should be allocated for development of high-temperature gas-cooled reactor technology within the commercial nuclear power development budget of DOE.

Safe Integral Reactor and Process Inherent Ultimate Safety Reactor

The other advanced light water designs the Committee examined were the United Kingdom and U.S. SIR and the Swedish PIUS reactor.

The Committee believes there is no near-term U.S. market for SIR and PIUS. The development risks for SIR and PIUS are greater than for the other LWRs and CANDU-3. The lack of operational and regulatory experience for these two is expected to significantly delay their acceptance by utilities. SIR and PIUS need much R&D, and a first plant will probably be required before design certification is approved.

The Committee concluded that no Federal funds should be allocated for R&D on SIR or PIUS.

Liquid Metal Reactor

LMRs offer advantages because of their potential ability to provide a long-term energy supply through a nearly complete use of uranium resources. Were the nuclear option to be chosen, and large scale deployment follow, at some point uranium supplies at competitive prices might be exhausted. Breeder reactors offer the possibility of extending fissionable fuel supplies well past the next century. In addition, actinides, including those from LWR spent fuel, can undergo fission without significantly affecting performance of an advanced LMR, transmuting the actinides to fission products, most of which, except for technetium, carbon, and some others of little import, have half-lives very much shorter than the actinides. (Actinides are among the materials of greatest concern in nuclear waste disposal beyond about 300 years.) However, substantial further research is required to establish (1) the technical and the economic feasibility of recycling in LMRs actinides recovered from LWR spent fuel, and (2) whether high-recovery recycling of transuranics and their transmutation can, in fact, benefit waste disposal. Assuming success, it would still be necessary to dispose of high-level waste, although the waste would largely consist of significantly shorter-lived fission products. Special attention will be necessary to ensure that the LMR's reprocessing facilities are not vulnerable to sabotage or to theft of plutonium.

The unique property of the LMR, fuel breeding, might lead to a U.S. market, but only in the long term. From the viewpoint of commercial licensing, it is far behind the evolutionary and mid-sized LWRs with passive safety features in having a commercial design available for review. A federally funded program, including one or more first plants, will be required before any LMR concept would be accepted by U.S. utilities.

Net Assessment

The Committee could not make any meaningful quantitative comparison of the relative safety of the various advanced reactor designs. The Committee believes that each of the concepts considered can be designed and operated to meet or closely approach the safety objectives currently proposed for future, advanced LWRs. The different advanced reactor designs employ different mixes of active and passive safety features. The Committee believes that there currently is no single optimal approach to improved safety. Dependence on passive safety features does not, of itself, ensure greater safety. The Committee believes that a prudent design course retains the historical defense-in-depth approach.

The economic projections are highly uncertain, first, because past experience suggests higher costs, longer construction times, and lower availabilities than projected and, second, because of different assumptions and levels of maturity among the designs. The Electric Power Research Institute (EPRI) data, which the Committee believes to be more reliable than that of the vendors, indicate that the large evolutionary LWRs are likely to be the least costly to build and operate on a cost per kilowatt electric or kilowatt hour basis, while the high-temperature gas-cooled reactors and LMRs are likely to be the most expensive. EPRI puts the mid-sized LWRs with passive safety features between the two extremes.

Although there are definite differences in the fuel cycle characteristics of the advanced reactors, fuel cycle considerations did not offer much in the way of discrimination among reactors, nor did safeguards and security considerations, particularly for deployment in the United States. However, the CANDU (with on-line refueling and heavy water) and the LMR (with reprocessing) will require special attention to safeguards.

SIR, MHTGR, PIUS, and LMR are not likely to be deployed for commercial use in the United States, at least within the next 20 years. The development required for commercialization of any of these concepts is substantial.

It is the Committee's overall assessment that the large evolutionary LWRs and the mid-sized LWRs with passive safety features rank highest relative to the Committee 's evaluation criteria. The evolutionary reactors could be ready for deployment by 2000, and the mid-sized could be ready for initial plant construction soon after 2000. The Committee's evaluations and overall assessment are summarized in Figure 5-1 .

FIGURE 5.1 Assessment of advanced reactor technologies.

This table is an attempt to summarize the Committee's qualitative rankings of selected reactor types against each other , without reference either to an absolute standard or to the performance of any other energy resource options, This evaluation was based on the Committee's professional judgment.

The Committee has concluded the following:

Safety and cost are the most important characteristics for future nuclear power plants.

LWRs of the large evolutionary and the mid-sized advanced designs offer the best potential for competitive costs (in that order).

Safety benefits among all reactor types appear to be about equal at this stage in the design process. Safety must be achieved by attention to all failure modes and levels of design by a multiplicity of safety barriers and features. Consequently, in the absence of detailed engineering design and because of the lack of construction and operating experience with the actual concepts, vendor claims of safety superiority among conceptual designs cannot be substantiated.

LWRs can be deployed to meet electricity production needs for the first quarter of the next century:

The evolutionary LWRs are further developed and, because of international projects, are most complete in design. They are likely to be the first plants certified by NRC. They are expected to be the first of the advanced reactors available for commercial use and could operate in the 2000 to 2005 time frame. Compared to current reactors, significant improvements in safety appear likely. Compared to recently completed high-cost reactors, significant improvements also appear possible in cost if institutional barriers are resolved. While little or no federal funding is deemed necessary to complete the process, such funding could accelerate the process.

Because of the large size and capital investment of evolutionary reactors, utilities that might order nuclear plants may be reluctant to do so. If nuclear power plants are to be available to a broader range of potential U.S. generators, the development of the mid-sized plants with passive safety features is important. These reactors are progressing in their designs, through DOE and industry funding, toward certification in the 1995 to 2000 time frame. The Committee believes such funding will be necessary to complete the process. While a prototype in the traditional sense will not be required, federal funding will likely be required for the first mid-sized LWR with passive safety features to be ordered.

Government incentives, in the form of shared funding or financial guarantees, would likely accelerate the next order for a light water plant. The Committee has not addressed what type of government assistance should be provided nor whether the first advanced light water plant should be a large evolutionary LWR or a mid-sized passive LWR.

The CANDU-3 reactor is relatively advanced in design but represents technology that has not been licensed in the United States. The Committee did not find compelling reasons for federal funding to the vendor to support the licensing.

SIR and PIUS, while offering potentially attractive safety features, are unlikely to be ready for commercial use until after 2010. This alone may limit their market potential. Funding priority for research on these reactor systems is considered by the Committee to be low.

MHTGRs also offer potential safety features and possible process heat applications that could be attractive in the market place. However, based on the extensive experience base with light water technology in the United States, the lack of success with commercial use of gas technology, the likely higher costs of this technology compared with the alternatives, and the substantial development costs that are still required before certification, 3 the Committee concluded that the MHTGR had a low market potential. The Committee considered the possibility that the MHTGR might be selected as the new tritium production reactor for defense purposes and noted the vendor association's estimated reduction in development costs for a commercial version of the MHTGR. However, the Committee concluded, for the reasons summarized above, that the commercial MHTGR should be given low priority for federal funding.

LMR technology also provides enhanced safety features, but its uniqueness lies in the potential for extending fuel resources through breeding. While the market potential is low in the near term (before the second quarter of the next century), it could be an important long-term technology, especially if it can be demonstrated to be economic. The Committee believes that the LMR should have the highest priority for long-term nuclear technology development.

The problems of proliferation and physical security posed by the various technologies are different and require continued attention. Special attention will need to be paid to the LMR.

Alternative Research and Development Programs

The Committee developed three alternative R&D programs, each of which contains three common research elements: (1) reactor research using federal facilities. The experimental breeder reactor-II, hot fuel examination facility/south, and fuel manufacturing facility are retained for the LMR; (2) university research programs; and (3) improved performance and life extension programs for existing U.S. nuclear power plants.

The Committee concluded that federal support for development of a commercial version of the MHTGR should be a low priority. However, the fundamental design strategy of the MHTGR is based upon the integrity of the fuel (=1600°C) under operation and accident conditions. There are other potentially significant uses for such fuel, in particular, space propulsion. Consequently, the Committee believes that DOE should consider maintaining a coated fuel particle research program within that part of DOE focused on space reactors.

Alternative 1 adds funding to assist development of the mid-sized LWRs with passive safety features. Alternative 2 adds a LMR development program and associated facilities--the transient reactor test facility, the zero power physics reactor, the Energy Technology Engineering Center, and either the hot fuel examination facility/north in Idaho or the Hanford hot fuel examination facility. This alternative would also include limited research to examine the feasibility of recycling actinides from LWR spent fuel, utilizing the LMR. Finally, Alternative 3 adds the fast flux test facility and increases LMR funding to accelerate reactor and integral fast reactor fuel cycle development and examination of actinide recycle of LWR spent fuel.

None of the three alternatives contain funding for development of the MHTGR, SIR, PIUS, or CANDU-3.

Significant analysis and research is required to assess both the technical and economic feasibility of recycling actinides from LWR spent fuel. The Committee notes that a study of separations technology and transmutation systems was initiated in 1991 by DOE through the National Research Council's Board on Radioactive Waste Management.

It is the Committee's judgment that Alternative 2 should be followed because it:

provides adequate support for the most promising near-term reactor technologies;

provides sufficient support for LMR development to maintain the technical capabilities of the LMR R&D community;

would support deployment of LMRs to breed fuel by the second quarter of the next century should that be needed; and

would maintain a research program in support of both existing and advanced reactors.

The construction of nuclear power plants in the United States is stopping, as regulators, reactor manufacturers, and operators sort out a host of technical and institutional problems.

This volume summarizes the status of nuclear power, analyzes the obstacles to resumption of construction of nuclear plants, and describes and evaluates the technological alternatives for safer, more economical reactors. Topics covered include:

• Institutional issues—including regulatory practices at the federal and state levels, the growing trends toward greater competition in the generation of electricity, and nuclear and nonnuclear generation options.
• Critical evaluation of advanced reactors—covering attributes such as cost, construction time, safety, development status, and fuel cycles.

Finally, three alternative federal research and development programs are presented.

READ FREE ONLINE

Welcome to OpenBook!

You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

Do you want to take a quick tour of the OpenBook's features?

Show this book's table of contents , where you can jump to any chapter by name.

...or use these buttons to go back to the previous chapter or skip to the next one.

Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

Switch between the Original Pages , where you can read the report as it appeared in print, and Text Pages for the web version, where you can highlight and search the text.

To search the entire text of this book, type in your search term here and press Enter .

Share a link to this book page on your preferred social network or via email.

View our suggested citation for this chapter.

Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

Get Email Updates

Do you enjoy reading reports from the Academies online for free ? Sign up for email notifications and we'll let you know about new publications in your areas of interest when they're released.

Information

• Author Services

Initiatives

You are accessing a machine-readable page. In order to be human-readable, please install an RSS reader.

All articles published by MDPI are made immediately available worldwide under an open access license. No special permission is required to reuse all or part of the article published by MDPI, including figures and tables. For articles published under an open access Creative Common CC BY license, any part of the article may be reused without permission provided that the original article is clearly cited. For more information, please refer to https://www.mdpi.com/openaccess .

Feature papers represent the most advanced research with significant potential for high impact in the field. A Feature Paper should be a substantial original Article that involves several techniques or approaches, provides an outlook for future research directions and describes possible research applications.

Feature papers are submitted upon individual invitation or recommendation by the scientific editors and must receive positive feedback from the reviewers.

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

Original Submission Date Received: .

• Active Journals
• Find a Journal
• Proceedings Series
• For Authors
• For Reviewers
• For Editors
• For Librarians
• For Publishers
• For Societies
• For Conference Organizers
• Open Access Policy
• Institutional Open Access Program
• Special Issues Guidelines
• Editorial Process
• Research and Publication Ethics
• Article Processing Charges
• Testimonials
• Preprints.org
• SciProfiles
• Encyclopedia

Article Menu

• Subscribe SciFeed
• Recommended Articles
• Google Scholar
• on Google Scholar
• Table of Contents

Find support for a specific problem in the support section of our website.

Please let us know what you think of our products and services.

Visit our dedicated information section to learn more about MDPI.

JSmol Viewer

Rooftop pv development suitability and carbon benefits: an anhui province case study.

Share and Cite

He, Q.; Luan, X.; Wang, J.; Liu, Y.; Yang, S. Rooftop PV Development Suitability and Carbon Benefits: An Anhui Province Case Study. Sustainability 2024 , 16 , 5604. https://doi.org/10.3390/su16135604

He Q, Luan X, Wang J, Liu Y, Yang S. Rooftop PV Development Suitability and Carbon Benefits: An Anhui Province Case Study. Sustainability . 2024; 16(13):5604. https://doi.org/10.3390/su16135604

He, Qianhao, Xiaoxiao Luan, Jiayi Wang, Yuzhong Liu, and Shuyun Yang. 2024. "Rooftop PV Development Suitability and Carbon Benefits: An Anhui Province Case Study" Sustainability 16, no. 13: 5604. https://doi.org/10.3390/su16135604

Article Metrics

Further information, mdpi initiatives, follow mdpi.

Subscribe to receive issue release notifications and newsletters from MDPI journals

• The exponential growth of solar power will change the world
• China’s giant solar industry is in turmoil
• Private firms are driving a revolution in solar power in Africa

↓ Here comes the sun

The past and a possible future.

Global useful energy consumption*

Traditional

Terawatt hours, ’000

Sources: Rupert Way; Our World in Data

*Primary energy adjusted for waste-heat losses

†From Way et al. (2022)

‡Electricity-conversion technologies (eg green hydrogen)

terawatt hours, ’000

Fast-transition

↓ Sun seekers

Sunlight and solar capacity.

Solar capacity*

Gigawatts, Q1 2024

*Total within 8,500km 2 grid cell

Sources: Global Solar Atlas; TransitionZero

Global horizontal irradiation

2022, KWh/m 2 per day

*Total within 8,500km 2 grid cell Sources: Global Solar Atlas; TransitionZero

*Total within 8,5002km 2 grid cell Sources: Global Solar Atlas; TransitionZero

More from undefined

Already have a subscription? Log in

Try The Economist for free

Unlock your free trial to continue.

Explore all our independent journalism for free for one month. Cancel any time