Preliminary environmental radiation considerations for CFETR

Abstract

Since Chinese fusion engineering test reactor (CFETR) stepped into the engineering design phase, it was significant to discuss the environmental radiation issues considering both Chinese radiation safety regulations and lessons learned from international thermonuclear experimental reactor (ITER) being constructed in France. In this study, firstly, the legal and regulatory framework of nuclear safety in China and ITER licensing process lessons were reviewed. Secondly, public dose limit was proposed for CFETR. Thirdly, safety limit and radioactive source terms were discussed and proposed for CFETR. Fourthly, public radiation dose was estimated, tritium emission limit was proposed under normal operation from the perspectives of tritium emission limit for nuclear power plants (NPPs) in China and reverse value based on public dose limit. Finally, potential consequences of environmental radiation were discussed under accidental conditions. Nuclear emergency countermeasures including no evacuation criteria needed or not were proposed. The preliminary environmental radiation considerations were proposed for CFETR: 1) It had better invite the experts from Chinese national nuclear safety administration (NNSA) to participate in the engineering design, which can make the related persons understand the fusion safety characteristics as early as possible, so as to further speed the licensing process; 2) 0.1 mSv/a was proposed as the public dose limit of CFETR under normal operation; 3) The same ITER safety limit was proposed to be set for CFETR from the consideration of both comparable size of vacuum vessel (VV) and hydrogen/dust explosion; 4) A tritium emission limit of 5–33 g/a was proposed for CFETR; 5) The “no off-site emergency response” was suggested as one of the safety goals during the design of CFETR, however, “off-site emergency measures” were still proposed to be deployed during the operation of CFETR. It was expected the environmental radiation considerations could provide a reference to speed the construction of CFETR on the premise of environment friendly and public safety.