The history and the prospects of japanese nuclear power development program

FBRs are regarded as the most probable option among non-fossil energy resources which will underpin the future energy demand in Japan, considering the effective uranium utilization and the need to lower the burden on the natural environment. However, it will take a long time to utilize FBRs due to a number of pending technical issues and improvements of cost efficiency. For the time being, therefore, light water reactors will continue to play a dominant role in power generation: thus, it is urgently necessary to establish the quasi-domestic nuclear fuel cycle for them, especially in the field of enrichment and spent fuel reprocessing — a goal of the Japanese nuclear policy since the dawn. Furthermore, public acceptance is significant factor which must be considered. This can best be achieved by more safety performance of light water reactors and through publication of extensive information, including decisions by the industry and government.     

The encapsulated nuclear heat source reactor for low-waste proliferation-resistant nuclear energy

The encapsulated nuclear heat source (ENHS) is a new Pb-Bi cooled modular reactor concept that features a combination of the following useful features that may make nuclear energy more attractive: (1) 20 years of full power operation without refueling. (2) Nearly constant fissile fuel contents and k_eff. (3) No on-site refueling and fueling hardware. (4) The ENHS modules are factory manufactured and transported already fueled to the site. (5) No access to neutrons. (6) No mechanical connections between the ENHS module and the energy conversion plant (The ENHS module has the function of a nuclear battery — with 20 years of full power operation at 125 MW_th). (7) At end of life, the ENHS module serves as a spent fuel storage cask and, later, as a spent fuel shipping cask. That is, the fuel is locked inside the ENHS from “cradle to grave”. (8) 100% natural circulation resulting in passive load following capability and autonomous control. This combination of features offers a highly safe nuclear energy system that is characterized by low waste, high proliferation resistance and high uranium utilization. The low waste and high uranium ore utilization are achieved by recycling the Pu and MA many times using a proliferation-resistant dry process; only fission products are to be extracted between cycles. Spent LWR fuel can provide for the HM make-up. The high level of proliferation resistance is obtained by restricting access to the fuel and neutrons and by eliminating the economic incentive of the client country to invest in sensitive technologies or infrastructure that can be used for clandestine production of strategic nuclear materials.     

Nuclear energy strategy in the environment of utility business deregulation

Nuclear power has contributed to the reduction and stabilization of electricity rate in Japan. However, its economic competitiveness has been eroding since mid 80's. Deregulation is hitting nuclear power just at the time its competitiveness is declining, and it poses a threat to drive short-sighted market orientation and precludes long term focus on achieving a balance between “environmental agenda” and “competitiveness in market”. Lowering the electricity rate is one of the important agenda to improve the nation's industrial competitiveness in the global market. However, it will be very difficult to win the competition of gas and oil prices with other developed countries in Europe and North America due to a handicap of long transportation distance. Only nuclear power and natural energy have no relation to such a handicap of economic distance from resources. Without securing economic superiority of those energy sources, Japan will not be able to clear the handicap of energy costs. The Japanese utilities are trying hard to regain the competitive edge of nuclear power. We have established short-term strategies for both existing and new LWRs as well as a long-term strategy for technological development. With these strategies we will be able to regain the competitiveness of nuclear power.     

Atomic energy and the environment

Conclusions In periods of scientific and technological revolution, the protection of the environment from pollution ranks as one of the most important problems. The power industry is a major source of environmental pollution and the problem of protecting the environment from its wastes is particularly urgent because of the rapid rise in energy demand.From the point of view of environmental conservation and human health, nuclear power has an important advantage over traditional power sources using solid and liquid organic fuels. The extensive development of nuclear power in the future will require timely scientific solutions to a number of problems. The largest of these is the problem of solid and liquid wastes, solution of which will ensure reliable protection of the environment. Although air-borne APS emissions do not constitute a danger to the environment, the endeavor to reduce them further retains its urgency. This is because in the long term it is necessary not only to ensure negligible radiation of the population living close to the APS but also to prevent a significant rise in the overall dose to the population. A particularly important problem is to find foolproof means of preventing accidental contamination of the environment, which would be a significant step toward siting APS and atomic and thermal power centers close to large cities.The possibility of a rise in the collective-dose level in the early stages of nuclear-power development must be met in a number of ways: by reducing the existing radiation load due to irrational activity (above all, x-ray diagnostics), by investigating the biological effects of small and extremely small doses (including the combined effect of radiation and chemical factors), and by developing work on the theoretical basis for the normalization of radiation effects.Translated from Atomnaya Énergiya, Vol. 43, No. 5, pp. 374–384, November, 1977.     

Clean development mechanism and nuclear energy in China

With economy developing rapidly and energy demand increasing promptly, the environmental pollution was intensified in China. In order to achieve economy sustainable development, the electricity industry must adjust existing energy structure and adopt new efficiency clean generation technology. However, in exiting electricity planning, nuclear energy develops slowly due to lack of funds and technology. The Clean Development Mechanism (CDM) provided an opportunity and challenge for developing country parties in achieving sustainable development.

The “Clean Development Mechanism” (CDM) was proposed by the Kyoto Protocol to the United Nation Framework Convention on Climate Change. It aims at assisting developing country parties to achieve sustainable development, and assisting developed country parties to achieve their obligation of emission reduction promised in the Kyoto Protocol in lower cost. It means it is a mutual beneficial mechanism that could be implemented between developed and developing countries. Therefore there is much interest in CDM by international bodies.     

加速器驱动次临界系统（ADS）与核能可持续发展

描述了ADS系统的主要技术特点和在我国核能可持续发展战略中的作用及地位;介绍了国内外ADS研究的状态和发展趋势;提出了ADS研发必须解决的关键技术问题及解决这些问题的时间表;分析了ADS研发与国内核能相关发展计划的关系;并就我国开展ADS的研发提出了一些建议。     

Molten salts and nuclear energy production

Molten salts (fluorides or chlorides) were considered near the beginning of research into nuclear energy production. This was initially due to their advantageous physical and chemical properties: good heat transfer capacity, radiation insensitivity, high boiling point, wide range solubility for actinides. In addition it was realised that molten salts could be used in numerous situations: high temperature heat transfer, core coolants with solid fuels, liquid fuel in a molten salt reactor, solvents for spent nuclear solid fuel in the case of pyro-reprocessing and coolant and tritium production in the case of fusion. Molten salt reactors, one of the six innovative concepts chosen by the Generation IV international forum, are particularly interesting for use as either waste incinerators or thorium cycle systems. As the neutron balance in the thorium cycle is very tight, the possibility to perform online extraction of some fission product poisons from the salt is very attractive. In this article the most important questions that must be addressed to demonstrate the feasibility of molten salt reactor will be reviewed.     

Hydrogen and its relationship with nuclear energy

In broad terms it is estimated that the world will need 17 TW of additional primary energy to meet its needs by 2050. Much of this growth in energy demand will take place in developing countries. Wind, biomass, solar, nuclear and coal will all compete to fill this gap as oil market share declines. Economics, environmental issues, and public acceptance elements of sustainable development goals will be as important as the engineering issues of efficiency and reliability in this competition.

Nuclear power is increasingly recognized as a principal contender to provide economic, “carbon free” electricity for the grid, but it does not directly provide a transportation fuel as flexible as is gasoline. Nuclear-produced hydrogen might help to fill this transportation fuel gap. This presentation will discuss the processes for manufacture of hydrogen from nuclear heat, and the integration of nuclear-produced hydrogen into the transportation fuel system – in part via synergies with traditional oil, natural gas and coal, and/or synergies with nontraditional shale and tar sands. We will discuss the nuclear hydrogen system as we expect it to appear in 2050 and will discuss some of processes that will provide a pathway to creating that system.     

Defect production mechanisms in metals and covalent semiconductors

We discuss how defect production mechanisms in displacement cascades vary according to the nature of the irradiated material. Our discussion is based on Molecular Dynamics (MD) simulation studies and reveal very different mechanisms for metals and covalent semiconductors. For metals we show how melting of the cascade core, in combination with long replacement collision sequences along low index crystallographic directions leads to the production of large number of defects in clusters and a small (≈ 10%) fraction of isolated interstitials well separated from the cascade region. In silicon, we show how the energy deposition process leads to the production of local amorphous regions and very few isolated Frenkel pairs. Because replacement collision sequences are extremely short in the open diamond lattice, very few or no isolated interstitials result. We argue that these observations provide a basis to understand the very large difference in freely migrating defect production efficiency in metals and silicon. The results provide an underlying cause for the extremely high bulk recombination efficiency observed in ion implanted and annealed silicon and provide a physical basis for the “+1” interstitial model in ion implanted silicon.     

Nuclear-energy complexes and the economic and ecological problems of nuclear power development

Conclusions In the long term, serious economic and ecological problems may arise if the required scale and rate of growth of power production is to be ensured while retaining the principle of dispersed location of ever larger power stations in regions with high population density and a developed infrastructure, since the ecological capacity of these regions is limited. This is particularly true of nuclear power, which in the long term will become the main source of electrical energy.Prospects for a solution to the economic and ecological problems of nuclear power and for an increase in its economic efficiency are offered by the construction of nuclear-energy complexes—large industrial units that contain within a single site a group of atomic power stations of total rated power output of the order of 10–50,000 MW and also the facilities of the external fuel cycle, the complexes being remote from densely populated regions but connected to the centers of energy demand by electrical transmission lines.Translated from Atomnaya Énergiya, Vol. 43, No. 5, pp. 369–373, November, 1977.     

Political aspects of nuclear energy

In Switzerland as in other countries public opinion on nuclear energy has drastically changed with time. Surveys show that a majority at present favours abandoning nuclear energy in Switzerland, but does not consider feasible an immediate switchover to other forms of energy. The behaviour is contradictory because increasingly more electric power is used, even after Chernobyl. The resistance has many facets. The debate is largely focused on the question of future technological and economic development. Nuclear energy also became the scapegoat for a development of the last few decades it has not been responsible for (destruction of the environment, waste of natural resources). For the sake of the environment and future economic development, the continued use of nuclear energy has to be ensured. This calls for great efforts in order to convince the people that nuclear power is an essential and logical part of our energy supply. In this process, the fear of a nuclear energy and the unease about industrial society must not be dismissed as irrelevant.     

High power accelerators in fundamental physics and nuclear technology

The trends of the high power accelerators development are outlined. The natural examples of their applications in nuclear physics and technology are discussed: muon physics, physics of rare decays, intense 14 MeV — neutron source based on muon catalyzed fusion (INS — MCF) and accelerator driven system (ADS) for nuclear waste incineration. The accelerator with power ˜ 10 MW and particle energy ˜ 1 GeV/nucl is considered as the best candidate for these purposes.     

AMBIDEXTER nuclear energy complex: a practicable approach for rekindling nuclear energy application

Aiming at one of the decisive alternatives for long-term perspectives of the nuclear power, an integral and closed nuclear energy system concept is proposed; namely, the Advanced Molten-salt Break-even Inherently-safe Dual-missioning Experimental and Test Reactor (AMBIDEXTER) nuclear energy complex. This essentially comprises two mutually independent circuits of the radiation/material transport and the heat/energy conversion, centered at the integral reactor assembly, which enables one to utilize maximum benefits of nuclear energy under minimum risks of nuclear radiation. The entire reactor system resides in a thin and large Hastelloy vessel, the internal part of which is divided into a number of equipment compartments with neither connection pipings nor active valves necessary. As the reactor operates at very low FP inventory throughout its designed lifetime and there is no primary heat transport pipings outside the reactor vessel, significant release of radioactive materials due to any equipment failure should be incredible. The nuclear-thermalhydraulic characteristics of the molten ThF₄–²³³UF₄ fuel salt extend the self-sustainability of the AMBIDEXTER fuel cycle to enhance the resource security and safeguard transparency. While maintaining the break-even conversion ratio criterion, a flexible fuel management strategy using a certain choice of denaturants should improve its own proliferation-resistance characteristics. As the core technologies associated with developing the AMBIDEXTER concept are mostly available in commercialized forms at present, investigating the integral performance of the concept should be the prime research topic in ongoing 250 MW_th prototype design studies.     

Considerations of importance to decisions on an alternate nuclear program

The nuclear power program of the United States is based on the concept that nuclear plants of the thermal converter type—primarily those cooled and moderated by light water—will fill the generating needs in the early years, and that the fast breeder will be developed on a sufficiently rapid schedule to take over the major portion of the electrical load before our reserves of moderate-cost uranium are used up. In this plan the thermal converter reactors play an important, if not altogether essential, role as producers of plutonium for the initial inventory of the breeders. To reassess this plan, in the absence of any reliable model for the long-term U.S. economy in its relationship to energy supplies and costs, we are forced to use as input some estimate of the energy demand over a period of approximately a century. This input has a profound impact on the assessment, affecting not only our estimate of the urgency of development of the breeder, but conclusions as to optimum choice of converter reactors as well. Inasmuch as the demand is not an independent variable, but will surely depend upon the cost of power, this approach has obvious deficiencies.Since, however, the objective of planning is to make things happen as one wants them to—and what we are doing here is planning—I believe we should concentrate on making available the desirable quantities of electrical energy, rather than some smaller amounts which may indeed fill the demand if our plans go awry and the power cost rises drastically.I have therefore chosen a relatively generous demand projection, which amounts to 18.3 × 10⁷ MW-yr of total electrical energy over the next century, of which it is assumed that 70% will be generated by nuclear fission. In view of the great uncertainty of projection, a simple linear growth has been assumed.When one assesses the options for the future in terms of large energy productions, it is necessary to consider separately the case in which no fast breeder is assumed to be developed and the case in which it is assumed that the fast breeder is developed to a viable commercial stage, but possibly on a delayed schedule. In the former case the important performance characteristic of the nuclear plant is the amount of energy produced per unit of natural uranium fed into the system. In the latter case one must consider the production of plutonium for the fast breeder inventory. The important characteristic then becomes the amount of net plutonium produced per unit of natural uranium fed to the system. If the growth rate of breeder capacity is limited by plutonium availability, the efficiency of use of feed uranium, in terms of energy production, has little effect on the total quantity of natural uranium required.The minimum mission for fission power plants is assumed to be the supply of 70% of the total electrical demand over the next century, a period which might be a reasonable one for the development and large scale production of some alternate energy producer. If the light water nuclear plants produced all of this energy (13 × 10⁷ MW-yr) they would require some 25 million tons of natural U₃O₈: more than our estimated resources, even including those in the cost range of $100/lb. It is concluded that, in the absence of the fast breeder, an acceptable alternative would be a reactor whose power cost sensitivity to the price of natural U₃O₈ would be less than that of the light water reactor, by something like a factor of four.If we seek, not to replace the breeder in our plan, but to find some better converter than the LWR in the interim before its large-scale production, the considerations become more complex. For minimum long-term resource requirement we must provide first for plutonium production, up to the point that plutonium availability is never a limit to breeder growth. Up to that point, the building of plants which use up natural uranium without producing net plutonium can only increase the long-term consumption of uranium, regardless of how efficient they are in producing energy. I refer you to Fig. 3 for an illustrative set of curves which show typical characteristics of a converter-breeder system in which the early growth of breeder capacity is plutonium-limited.The optimum converter mix then depends on a number of considerations which we are unlikely to predict with any accuracy: the electrical demand curve, the development schedule of the breeder, the limitations other than plutonium availability to the rate of construction of breeders, and the breeding and inventory characteristics of the breeder. From the point of view of resource conservation alone, however, we cannot go wrong with an improved converter which can be made either an efficient energy producer or an efficient producer of plutonium, simply by changing its fuel cycle. This of course suggests the heavy water reactor.From the more practical point of view we must recognize that any decision to introduce a new converter type in the United States could slow down the development of the fast breeder, not only by diverting development and production resources, but also by appearing to reduce the urgency of that development. In the long run this might overbalance any direct benefit from the alternate converter type. I believe the one thing that can be shown by analysis is that the most effective way of conserving nuclear resources is to develop, introduce, and build the fast breeder as rapidly as possible. My own opinion is that the real incentive for looking at alternates is to provide some kind of a backup against the possibility, which I hope is a very remote one, that the fast breeder development may be stopped or severely delayed for non-technical reasons.     

Meeting EU's energy needs through nuclear fission: Synergy of public and private research in an international context

The availability of an affordable and sustainable energy supply is becoming a major and growing concern for world's future. It is very likely that there is not one single solution to the problem but that it is necessary to call upon a whole set of means such as energy efficiency improvement, deployment of renewable energies, clean coal technologies including CO₂ capture and storage, nuclear development. Indeed, it is more and more recognized that nuclear energy offers a very effective way to contribute to this worldwide challenge. It can be a safe, clean, reliable and cost-effective source of energy, the price of which remaining quite stable. Although the “generations” of nuclear systems are at different degrees of maturity, the scientific, technological and industrial gaps are quite well identified and assessed so that it is possible to describe a detailed roadmap of their development, including R&D needs.A significant part of these R&D needs should be addressed through cooperation involving public and private sector. It is the case for programs relating to safety, radiation protection, PRA (probabilistic risk assessment) methodology, background knowledge about ageing, fuel and fuel cycle for future light water reactors (Gen 3), pre-normative research for the purpose of harmonizing safety demonstration methodologies, Gen 4 systems with an emphasis on sodium-cooled fast breeder, large R&D infrastructures like test reactors and more generally, all obstacles to a consensual development of nuclear energy. R&D program should also be helpful in maintaining appropriate expertise and competencies.Strong cooperation between countries and between stakeholders is necessary to face all these challenges.     

Role of nuclear energy in environment, economy, and energy issues of the 21st century – Growing energy demand in Asia and role of nuclear

The economic growth of recent Asia is rapid, and the GDP and the energy consumption growth rate are about 8–10% in China and India. The energy consumption forecast of Asia in this century was estimated based on the GDP growth rate by Goldman Sachs. As a result, about twice in India and Association of South East Asian Nations (ASEAN) and about 1.5 times in China of SRES B (Special Report on Emission Scenarios) are forecasted. The simulation was done by Grape Code to analyze the impact of energy increase in Asia. As for the nuclear plant in Asia, it is expected 1500 GWe in 2050 and 2000 GWe in 2100, in the case of the environmental constrain. To achieve this nuclear utilization, there are two important aspects, technically and institutionally.

A. Development of the CANDLE core and/or the Breed and Burn core.

B. The establishment of the stable nuclear fuel supply system like “Asian nuclear fuel supply organization”.

Isotope separation methods for self-consistent nuclear energy system

It is known that for transmutation of fission products(FPs) in the concept of self-consistent nuclear energy system(SCNES) based on fast neutron reactor it is necessary to apply isotope separation of some FPs to keep neutron balance (to decrease parasitic capture of neutrons by stable isotopes). It is a question whether such FPs isotope separation can be feasible or not within amount of nuclear fission energy production. So it is necessary to consider isotopic content of FPs after fast reactor and to choose energetically appropriate isotope separation method for each radioactive FPs taking into account safe radioactivity level of FPs. In this paper we discuss about isotope separation method for SCNES. Isotopic composition of FPs was calculated using tables of fission yields from ²³⁹Pu fission. It isshown that concentrations of radioactive isotope in the main FPs to be isotopically separated are significant and vary from 2% in ruthenium up to 74% in iodine. We consider new isotope separation methods developed recently such as plasma separation process (PSP) based on selective ion cyclotron resonance heating and atomic vapor laser isotope separation (AVLIS) as a possible candidates. It seems to be energetically profitable to combine various methods to achieve desired separation characteristics. Since the most of FPs have a high initial concentration of radioactive isotope, PSP method seems to be a good candidate for first stages of separation process. We consider the main parts of energy expenditure in one PSP module and its separation characteristics. Estimations of energy consumption in multistage isotope separation process of FPs give maximum value 100keV/fiss. using PSP only and 3MeV/fiss. using AVLIS only. We can significantly decrease these values using AVLIS after PSP when concentration of target isotope in separation cascade will become sufficiently low. We can affirm that energy consumption in isotope separation of FPs is less than 60 MeV of electricity per one fission in nuclear reactor.     

Plutonium use in nuclear power in Russia

Conclusions The following concept of plutonium utilization based on the evolutionary development of the traditional technology in our country arises: The main problem of any short-term program of dealing with plutonium must be solved — reliable and safe storage of separated energy plutonium and freed weapons plutonium before utilization in reactors. Plutonium (mainly energy plutonium) is utilized primarily in BN-800 fast reactors and the development of technology using weapons plutonium in BN-600 reactors starts. In the future attention should be focused on nuclear-power centers patterned after the Industrial Association “Mayak” (RT-1 plant, Complex 300, BN-800) with reliable nonproliferation of weapons plutonium. It is extremely important to speed up work on the completion of Complex 300: This work must be completed before BN-800 is ready. In the future efforts must be concentrated on the following: development and implementation, in BN-800, of an economically more efficient plutonium-burning core; the possibility of building light-water reactors with the required degree of safety for effective plutonium utilization must be justified (including a “cold” core based on cermet fuel); and, development and implementation of technology for a safe and an ecologically acceptable closed nuclear fuel cycle based on plutonium and²³³U with burnout of Am, Np, and Cm. Ministry of Atomic Energy of the Russian Federation. Institute of Physics and Power Engineering. A. A. Bochvar All-Union Scientific-Research Institute of Standardization in Machine Building. Special Design Office for Machines. Translated from Atomnaya énergiya, Vol. 76, No. 4, pp. 326–332, April, 1994.     

Space nuclear power systems with turbomachine energy conversion

The expansion of space exploration requires the development of sufficiently powerful and reliable power facilities which can operate for a long time. Such facilities could be nuclear power systems and nuclear-powered propulsion systems with turbomachine energy conversion. The development of such systems at the present time is based on the results of work performed as part of the nuclear rocket motor program. The data presented in this article attest to the fact that our country plays a leading role in the construction of such of reactors. To maintain our leading position in space nuclear technologies, it is important to use and further develop the existing unique engineering and technological bases. __________ Translated from Atomnaya énergiya,Vol. 103, No. 1, pp. 48–50, July, 2007.     

The role of nuclear power in the sustainable energy future of Korea

The purpose of this study is to analyze the role of nuclear power in the sustainable energy supply future of Korea. For this purpose, an energy-economy interaction model of the computational general equilibrium (CGE) approach, the Korean Energy and Environmental Policy model(KEEP) was adapted. The model is a non-linear optimization model that maximizes the discounted value of Korean economic utility. The model operates over the time horizon of 1995–2040 in annual steps.

Some scenarios are established in accordance with three possible nuclear growth rate and the strength of the carbon tax imposed. At first, business as usual(BAU) nuclear growth scenario was set up and maintaining the current installed capacity and phasing out the nuclear power options are considered. After that, the investigation has been done on each scenario in the case that a tax for CO₂ emission regulation was imposed.

Results show that limiting CO₂ emissions with a nuclear phase out scenario will have the most serious impact on the economic welfare compared with the other scenarios. If the CO₂ emission target will be imposed in Korea in the foreseeable future, nuclear power will play an important role in mitigating the economic impacts.

This analysis gives us a chance to consider the trade-offs between the most important energy issues of today-concerns with the risk of nuclear power, those involving future climate change, and energy security.