Overview and status of domestic and international standards for nuclear criticality safety

For many years, the United States (US) and international consensus standards for nuclear criticality safety (NCS) have provided guidance for those with hands-on operations involving fissionable materials. These consensus standards have been crucial to reducing the number of criticality accidents in process facilities. The last known criticality accident inside the United States was in 1978 (nearly 41 years ago) at the Idaho Chemical Processing Plant, and outside the United States, an accident occurred at Tokai-Mura, Japan, in 1999 (20 years ago). The domestic consensus standards for NCS include the American Nuclear Society (ANS) standards. The ANS Standards Board, the NCS Consensus Committee, and the ANS-8 Subcommittee oversee the development and maintenance of these standards. Currently there are 18 standards in the ANS-8 series: 6 are in revision mode and 12 are in maintenance mode. The international consensus standards for NCS calculations, procedures, and practices are maintained and developed within the International Organization for Standardization, Technical Committee 85 on Nuclear Energy, Subcommittee 5 on Nuclear Fuel Technology, and Working Group 8, 'Nuclear Criticality Safety'. Eight standards are currently available, three standards are in revision mode, and four proposed standards are at various stages of development. This paper provides the NCS community with an overview and status report on domestic and international NCS consensus standards to stimulate interest and to support their continued development. (author)