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10th General Assembly of the Fusion Energy Forum of Japan Award of Masaji Yoshikawa Prize for Fusion Energy | News

Update:2018年12月26日更新
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Youji Someya received the 10th Masaji Yoshikawa Prize for Fusion Energy for Early Career Research Contribution at Fusion Energy Forum

Youji Someya, Senior Researcher of Fusion Reactor Design Group in Fusion Energy Research and Development Directorate received the Masaji Yoshikawa Prize for Fusion Energy for Early Career Research Contributions at the 10th Fusion Energy Forum, held on February 24, 2017.

Youji Someyaの画像

Award title

Study on Radwaste Management Scenarios for Shallow Land Disposal in the Fusion DEMO Reactor

Description of the award-winning work

This research aims to increase the public acceptance concerning the shallow land disposal of radioactive wastes in the fusion reactor and is the only research in Japan. This award is to honoring its outstanding achievements.

There is a concern that the replacement of in-vessel components (IVCs) such as blankets and divertors, generates a considerable amount of radioactive waste. Classification for waste disposal is determined according to the evaluation of radiation exposure to the public after disposal in Japan. In the Japanese nuclear regulations, we should analyze nuclide migration by taking into account that nuclides concentration [Bq/ton] should be limited to 10 (μSv/y) in the biosphere. Our assessment indicates that radiation exposure is 2.64 μSv/y when a used blanket, the highest concentration in the IVCs, is cooled down for 10 years and is disposed of in a concrete pit near the land surface, which is lower than a criterion for shallow land disposal as L2 (10 μSv/y). The situation is the same for a used divertor as well. From this assessment, it is concluded that all rad-wastes originating from used IVCs of DEMO will be qualified to be Low Level Waste and can be disposed of in shallow land disposal.

All members of the selection committee highly appreciated him for consistently continuing a steady study on inevitable tasks.

Comment

I am very honored to be awarded the 2016 Masaji Yoshikawa Prize for Fusion Energy. First of all, I would like to take this opportunity to thank for the members of the Fusion Reactor Design Group of QST, the members of the DEMO Design Joint Special Team, and the collaborators from universities who work together and gave me advice.
Radwastes generated in a fusion reactor are not categorized as high-level waste, however, they need to be under control for the long term beyond generations. DEMO reactor which generates radwastes at every few-year periodic maintenance requires a radwaste management from the relatively early stage after the start of operation. Taking into consideration the reduction of radwastes, this affects not only building design and safety but also the concepts of reactor, IVCs and remote maintenance. I believe how to handle radwastes is an important factor which influences the social acceptance for the development of fusion reactor and I would like to go on a comprehensive study on radwaste disposal management scenario including a concept study on the equipment in order to solve the tasks.
I would greatly appreciate your continuous supports in future.