１F accident left various lessons & learn for "nuclear power generation." Lessons from safety assurance in the design and operation of power plants were immediately addressed, and new regulatory standards set requirements and criteria that are said to be "the strictest in the world." In nuclear disaster prevention, we propose the following efforts. Take countermeasures based on "indoor evacuation" in principle. The prefecture governor has the responsibility and authority for crisis management, and operates i...
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New Crisis management on Nuclear Accident

In JNFL, Corrective Action Program (hereinafter, CAP) system will be applied as activity to improve the safety. The CAP system is one of the activities based on new inspection system to be enforced in 2020, JNFL has already started the CAP system as trial in 2018....
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Current situation of corrective action program in Japan Nuclear Fuel Limited

Under the new inspection system for nuclear facilities introduced in April 2020, SDP (Significance Determination Process) is applied to an inspection finding to determine its safety significance. Regarding nuclear fuel facilities, the features of them are hardly incorporated into the current evaluation method of SDP, because the evaluation method was basically developed for nuclear power plant. In order to solve this challenge, we are developing evaluation method of SDP for nuclear fuel facilities....
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Progress report of evaluation method of SDP for Nuclear Fuel Facilities

Spent fuel storage pools keep pool water by lining plate installed in inner surface. For the continuous maintenance method of those lining plate, the necessity occurs to quickly develop underwater repair welding technology. So, we are decided to develop new underwater welding method that is able to conquer those problems. In this paper, we report the concept of new welding method and results of confirmation examination for formation of new welding method by practical use conditions....
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Development of High Reliable Welding Method with Underwater Laser Welding Technology for Stainless Steel Made Structures Installed in Underwater

There are various conditions (radiation controlled area, special equipment, special rule and so on) in nuclear related facilities. When we work there, we are always required to achieve high level of safety, reliability and efficiency. We self-manufacture tools to eliminate unreasonableness (Muri), unprofit (Muda), unevenness (Mura) and also improve efficiency. Always aiming the improvement of safety and productivity is one of the important missions as a cooperating company. In this report, we introduce seve...
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Kaizen effort of maintenance in nuclear related facility by tool production

The reactor core cooling was lost due to the attack of huge Tsunami and the reactor building was severely damaged by the hydrogen explosion at units of Fukushima Daiichi NPS. Significant amount of radioactivity was released to the environment and broader and longer evacuation of the general public in the vicinity of the NPS was carried out to the extent much more than expected by the former Nuclear Safety Commission. Coupled by the effects of earthquake and tsunami, considerable number of indirect disaster ...
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Failure of Emergency Response around Fukushima NPS and the Further Improvement of Revised Response Procedures

The processes and inclusions of reprocessing plants are diverse and exposed to various corrosive environments as chemical plants. There are facilities in reprocessing facilities that have been used for more than 20 years, and corrosion and erosion events caused by the aging of equipment and structures, utility equipment, etc. have become apparent in recent years. To investigation of causes and understanding of mechanisms are essential for preventive maintenance against corrosion events, it is useful to obta...
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Effort on Maintenance cooperated with specialist of Corrosion engineering

The evaporation to dryness due to the loss of cooling functions is an event that leads to boiling and dryness if the cooling function to remove decay heat of solution is lost. We clarify a phenomenon that is caused by the result of the course of the evaporation to dryness, and we will prepare some countermeasures against these clarified phenomenon. And furthermore, we prepare the design condition for these countermeasures....
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A phenomenon of the course of the evaporation to dryness and the design condition for countermeasures

Trial cases against operation of nuclear power plants are studied from the view point of nuclear science and engineering. At present both administrative litigations and civil litigations are allowed to take place in Japan, where the latter method is mainly aims to relieve cases of immature legal regulation. Problems of civil litigation in the nuclear reactor regulation of very well adjusted and established....
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Administrative Litigation and Civil Litigation

On evaluation of internal exposure in the radiation workers involved in maintenance and operation, calculation from work environment measurement, extracorporeal measurement methods and bioassay analysis method are adopted in Rokkasho Reprocessing Plant from its features. In addition, we proceed to improve efficiency of analysis work by implementing pretreatment of samples promptly and safety with mass analysis method as which ICP-MS, inductively coupled plasma mass spectrometers is used. We report overview ...
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Improvement of periodical bioassay analysis by mass spectrometry in Rokkasho Reprocessing Plant