Applying Nuclear Safety Requirements for Limited Life Activities

摘要

On April 10, 2003, the National Nuclear Security Administration (NNSA) was required to meet 10 CFR 830,Subpart B, Safety Basis Requirements (ref. 1). This law was approved and applicable for all nuclear facilities atNNSA sites. The Nevada Test Site (NTS) is a NNSA Defense Programs’ site established to support national securitymissions, including the Stockpile Stewardship Program for weapons certification by conducting undergroundnuclear tests. The NTS has met the Stockpile Stewardship Program mission by primarily detonating physicssubcritical experiments (SCEs) consisting of high explosives (HE) mated to special nuclear material (SNM) in anunderground environment at the U1a Complex or in vertical holes at the NTS. SCEs are short-lived activities;therefore, the U1a Complex is not considered a nuclear facility. To meet 10 CFR 830, Subpart B requirements, anSCE is considered a “limited life” nuclear activity. The safety basis for the SCE effort at NTS is primarily governedby a safe harbor found in 10 CFR 830, Subpart B for limited life activities, NV Order 450.X5 (ref. 2), and NV Order450.X6 (ref. 3). Approval of the approach to implement 10 CFR 830 for the SCE by preparing this document inaccordance with DOE-STD-3011-94 (ref. 4) was given in a memorandum from NNSA/HQ to National NuclearSecurity Administration Nevada Site Office (NNSA/NSO) in June 2002. The safety of SCE operations is addressedthrough a systematic process whereby the concept of operation is considered; attendant risks are identified,analyzed, and evaluated; and appropriate controls are identified and implemented. The complete safety basis for aparticular SCE consists of documents prepared for each phase of the operation which occur at different locations,including assembly operations performed at the Device Assembly Facility (DAF), on-site transportation, andoperations at the U1a Complex. A separate safety document is required for each of these operations/locations. Whenconsidered as a complete package, these documents provide the overall SCE safety basis for execution of a SCE atNTS for NNSA/NSO. This paper will discuss how the Subcritical Experiment Bounding Hazard Analysis (SCEBHA) is used as a basis document for linking all the safety documents for an SCE together. The safety basis for SCEoperations includes both the SCE BHA and a SCE Input Document for the particular SCE. The SCE BHA hasreduced both the effort in producing the safety basis document for individual SCEs and the time during the review ofthe SCE input document.