Nuclear criticality safety standard for a fuel reprocessing plant assuming burnup credit published by the atomic energy society of Japan - 14591
In this paper an outline of the standard published in April 2015 by the Atomic Energy Society of Japan (AESJ) is presented. The standard gives basis of nuclear safety management of a spent fuel reprocessing plant that assumed burnup credit in nuclear criticality safety evaluation. Ten years ago the AESJ published Basic Items of Criticality Safety Control: 2004, AESJ-SC-F004:2004, which prescribed basic ideas, requirements and methods on nuclear criticality safety controls of facilities handling with nuclear fuel materials in general for preventing a nuclear criticality accident. However, it did not include any specific procedures for adopting burnup credit. Therefore, a new standard was envisaged as the first Standard for fuel reprocessing plants, which clarified the specific procedures to apply burnup credit to designers, operators, maintenance persons and administrators. The Standard, Procedures for Applying Burnup Credit to Criticality Safety Control of a Reprocessing Facility: 2014, AESJ-SC-F025: 2014, was developed by the AESJ after vital discussions of the Working Group on Nuclear Criticality Safety Control, which were followed by critical reviews of the Special Committee on Nuclear Fuel Cycle and those of the Standard Committee, where both committees were established under the AESJ. The followings are some features of the standard: 1. In many countries, application of burnup credit has been considered especially in transportation and storage of spent fuel. The standard applies to a reprocessing plant, especially to the Rokkasho Reprocessing Plant in Japan. The present edition of the Standard assumes the first phase of burnup credit, i.e., burnup credit considering reduction in {sup 235}U, production of {sup 239}Pu and changes in other actinides, but not considering neutron absorption effect of fission products. 2. This standard covers nuclear criticality safety management including safety design and safety control stages. It prescribes each procedure of nuclear safety management with emphasis on its necessity rather in detail. Attached to the standard are seven appendices, which give reference to it, and explanations, which provide supplemental information to the readers. Future needs of AESJ standards in the field of nuclear criticality safety will be discussed in the presentation. (authors)