Report of long term foreign stay (Nuclear Research and Consultancy Group, the Netherlands). The first half of irradiation tests and post irradiation examinations of the FUJI project

Japan Nuclear Cycle Development Institute has been conducting the collaboration on the research and development of advanced sphere-pac fuel (under the name of 'FUJI project') with Paul Scherrer Institut (PSI) in Switzerland and Nuclear Research and Consultancy Group (NRG) in the Netherlands. The main target of this collaborative study is the comparative irradiation of sphere-pac, vipac and pellet fuel fabricated in PSI. This irradiation is performed in High Flux Reactor (HFR) in Petten, the Netherlands. Through this collaborative study, the fabrication techniques of sphere-pac fuel in Switzerland is introduced to Japan, and the fuel performances evaluated with the comparative irradiation in the Netherlands are reflected to the estimation of the fuel cycle costs. The author stayed at NRG from October 2003 to June 2004 as an assignee for the project. The author participated in the irradiation tests and the post irradiation examinations (PIE), and analyzed the data obtained in the experiments. The communication and the discussion on the irradiation were also performed among related organizations. As a result, the first and second irradiation tests and their post irradiation examinations were completed. The irradiation condition data, which is necessary to validate fuel design codes, were estimated with the on-line data of the irradiation and the PIE data. The knowledge on the fuel restructuring of sphere-pac and vipac fuel at the beginning of irradiation was obtained according to the analysis of the PIE data. (author)