[en] Design trends and major technical issues of advanced fast breeder reactors and high temperature gas cooled reactors are discussed

[en] This paper proposes a team behavior network model that can simulate and analyze response of an operator team to an incident in a dynamic and context-sensitive situation. The model is composed of four sub-models, which describe the context of team performance. They are task model, event model, team model and human-machine interface model. Each operator demonstrates aspects of his/her specific cognitive behavior and interacts with other operators and the environment in order to deal with an incident. Individual human factors, which determine the basis of communication and interaction between individuals, and cognitive process of an operator, such as information acquisition, state-recognition, decision-making and action execution during development of an event scenario are modeled. A case of feed and bleed operation in pressurized water reactor under an emergency situation was studied and the result was compared with an experiment to check the validity of the proposed model

[en] Nuclear power is playing a key role in constraining the dependence on foreign energy sources and decreasing the emission of green house effect gases in Japan's electricity generation sector. The installed capacity are currently expected to be 45 GWe in 2000 and 70GWe in 2010. The goal of the long-term planning of Atomic Energy Commission (AEC) is to develop a nuclear energy supply system based on fast breeder reactors as well as light water reactors with closed nuclear fuel cycle in order to secure for future generations a safe, reliable and environmentally benign energy source of vast supply potential. In recent years, however, there have occurred several events which have caused strong public repercussion and alarmed the nuclear energy policy makers and administrative authorities that significant changes are occurring in the society as well as in the organizations which are responsible for the promotion of the nuclear energy utilization and that nuclear community should pursue the reform of themselves at least to improve transparency and accountability to the public and perform continuous review of the rationale for the current programs and future plan, flexibly changing or discarding programs in response to the new social and economic environments taking the choices and priorities proposed by external reviewers into consideration. (author)

[en] This paper proposes a methodology to identify causes of human error in the operation of plant systems to support the development of CAI system for operator training. The target task of this methodology is goal-driven and knowledge-based planning behaviour, the cognitive process of which is assumed to be modeled as means-end analysis. The methodology uses four criteria to classify errors in an operation into eight groups, and then asks the trainee several questions to prune the causes. To confirm the usefulness of this methodology, a prototype CAI system is developed for the operation of filling up sodium into the primary coolant system of a liquid-metal-cooled fast reactor. The experimental result indicates that the system has the capability of identifying causes of the trainee's error, and consequently of figuring out the characteristics of his/her defect. As a result of this study, several issues are identified for future research

No abstract available

[en] Evolution of laser field in a Michelson resonator FEL is studied via supermode analysis. It is found that the lasing dynamics in a Michelson FEL can be described by three dimensionless variables: cavity loss, equivalent cavity detuning and the interference parameter. Small-signal gain and temporal profile of laser pulse can be obtained as eigenvalue and eigenstates of the supermode equation. (author)

[en] Overview: - Severe accident at Fukushima Daiichi NPP - Innovative strategy for energy and the environment established in Japan - Where should global nuclear community go - Conclusion

[en] • New nuclear energy strategy is still in the process of deliberation in Japan. Though many of idled plants will be restarted after renovation of their safety features in accordance with new safety rules set by the NRA, the contribution of nuclear power in Japan will probably not return to the level before 3.11. • Japan is in the process of reviewing its strategy for SFR R&D with a view to making it compatible with the new situation to be realized under new safety regulation as well as new energy strategy to be formulated within a year. • It is contemplated that major emphasis of the SFR R&D should be on a) the completion and use of MONJU, b) FR safety and c) waste minimization, not to mention the making effective use of our knowledge basis and research and engineering capabilities cultivated through the FaCT project in the development of sustainable nuclear energy systems worldwide for future generations of mankind. • Promotion of international cooperation should be an essential ingredient of the strategy

[en] The report outlines an nuclear incident and accident evaluation system established in Japan. It sets up rankings of incidents and accidents taking place in nuclear reactor facilities, which are determined in terms of the environmental effects of radioactive substances released, unexpected exposure of workers, and deterioration in the multiple protection system in the nuclear reactor facilities. The ranking system is intended to improve the communications between the public and experts concerning the significance of an incident or accident that has occurred. Its significance for the public is determined on the basis of three factors. One of them is the estimated exposure dose at the periphery of the monitoring area of the facility. The unexpected exposure dose of plant workers has also been adopted as a measure to determine the significance of the associated incident or accident because it is likely to reflect the condition of safety management, although there has been a view that it might not serve effectively to evaluate its effect on the public. The potential hazard of a nuclear reactor facility is evaluated in terms of deterioration in deep layer protection, internal leakage of radioactive material, and damage to the fuel. (N.K.)

[en] In five years from 1991 to 1996, the energy consumption in the world increased by the yearly rate of 1.5%, and in 1996, it reached about 8.4 billion t in terms of petroleum. The proportion that nuclear energy takes in it was 7.4%, following 39% of petroleum, 27% of coal and 24% of natural gas. In electric power generation field, nuclear power took 17% in the whole world, and 30% in Japan in 1995. As of the end of 1996, the nuclear power generation facilities in the world were 434 plants of 365 GWe output, and 51 plants of 43 GWe output were in operation in Japan. As the technologies of utilizing nuclear energy, there are the utilization of nuclear fission reaction, nuclear fusion reaction and radio-isotopes. In this report, the utilization of nuclear fission reaction is taken up. Pressurized water reactor, boiling water reactor, heavy water (CANDU) reactor and gas-cooled reactor, and nuclear fuel cycle are briefly explained. As for the performance of nuclear power generation, safety, reliability and economical efficiency are reported. The factors which exert effects to the development of nuclear energy utilization are the acceptance by public, economical efficiency and environmental problems. The range of possible installation capacity and the subjects for hereafter are described. (K.I.)