Reduction of the source term of an assumed criticality accident in a fuel fabrication facility with solution system

Abstract A reasonable source term of a hypothetical criticality accident in a fuel fabrication facility with a solution system has been proposed. The public exposure must not exceed the limitation of 5 mSv during an accident. Then, we proposed as a reasonable source term of the first burst peak due to the hydrogen gas generation by radiation decomposition of water. With the criticality control system composed of the Criticality Accident Alarm System (CAAS) and a soluble neutron absorber, safety is ensured by the reduced fission number. We confirmed the effect by environmental impact assessment during a criticality accident by using the site condition of a fuel fabrication facility in Tokai-mura, Japan. As a result, the public exposure was reduced at a site boundary from 68 mSv to 0.6 mSv which is under the current regulatory guideline.