Special Analysis of Transuranic Waste in Trench T04C at the Area 5 Radioactive Waste Management Site, Nevada Test Site, Nye County, Nevada, Revision 1
This Special Analysis (SA) was prepared to assess the potential impact of inadvertent disposal of a limited quantity of transuranic (TRU) waste in classified Trench 4 (T04C) within the Area 5 Radioactive Waste Management Site (RWMS) at the Nevada Test Site (NTS). The Area 5 RWMS is a low-level radioactive waste disposal site in northern Frenchman Flat on the Nevada Test Site (NTS). The Area 5 RWMS is regulated by the U.S. Department of Energy (DOE) under DOE Order 435.1 and DOE Manual (DOE M) 435.1-1. The primary objective of the SA is to evaluate if inadvertent disposal of limited quantities of TRU waste in a shallow land burial trench at the Area 5 RWMS is in compliance with the existing, approved Disposal Authorization Statement (DAS) issued under DOE M 435.1-1. In addition, supplemental analyses are performed to determine if there is reasonable assurance that the requirements of Title 40, Code of Federal Regulations (CFR), Part 191, Environmental Radiation Protection Standards for Management and Disposal of Spent Nuclear Fuel, High-Level, and Transuranic Radioactive Wastes, can be met. The 40 CFR 191 analyses provide supplemental information regarding the risk to human health and the environment of leaving the TRU waste in T04C. In 1989, waste management personnel reviewing classified materials records discovered that classified materials buried in trench T04C at the Area 5 RWMS contained TRU waste. Subsequent investigations determined that a total of 102 55-gallon drums of TRU waste from Rocky Flats were buried in trench T04C in 1986. The disposal was inadvertent because unclassified records accompanying the shipment indicated that the waste was low-level. The exact location of the TRU waste in T04C was not recorded and is currently unknown. Under DOE M 435.1-1, Chapter IV, Section P.5, low-level waste disposal facilities must obtain a DAS. The DAS specifies conditions that must be met to operate within the radioactive waste management basis, consisting of a performance assessment (PA), composite analysis (CA), closure plan, monitoring plan, waste acceptance criteria, and a PA/CA maintenance plan. The DOE issued a DAS for the Area 5 RWMS in 2000. The Area 5 RWMS DAS was, in part, based on review of a CA as required under DOE M 435.1-1, Chapter IV, Section P.(3). A CA is a radiological assessment required for DOE waste disposed before 26 September 1988 and includes the radiological dose from all sources of radioactive material interacting with all radioactive waste disposed at the Area 5 RWMS. The approved Area 5 RWMS CA, which includes the inventory of TRU waste in T04C, indicates that the Area 5 RWMS waste inventory and all interacting sources of radioactive material can meet the 0.3 mSv dose constraint. The composite analysis maximum annual dose for a future resident at the Area 5 RWMS was estimated to be 0.01 mSv at 1,000 years. Therefore, the inadvertent disposal of TRU in T04C is protective of the public and the environment, and compliant with all the applicable requirements in DOE M 435.1-1 and the DAS. The U.S. Environmental Protection Agency promulgated 40 CFR 191 to establish standards for the planned disposal of spent nuclear fuel, high level, and transuranic wastes in geologic repositories. Although not required, the National Nuclear Security Administration Nevada Site Office requested a supplemental analysis to evaluate the likelihood that the inadvertent disposal of TRU waste in T04C meets the requirements of 40 CFR 191. The SA evaluates the likelihood of meeting the 40 CFR 191 containment requirements (CRs), assurance requirements, individual protection requirements (IPRs), and groundwater protection standards. The results of the SA indicate that there is a reasonable expectation of meeting all the requirements of 40 CFR 191. The conclusion of the SA is that the Area 5 RWMS with the TRU waste buried in T04C is in compliance with all requirements in DOE M 435.1-1 and the DAS. Compliance with the DAS is demonstrated by the results of the Area 5 RWMS CA. Supplemental analyses in the SA indicate there is a reasonable expectation that the TRU in T04C can meet all the requirements of 40 CFR 191. Therefore, inadvertent disposal of a limited quantity of TRU in a shallow land burial trench at the Area 5 RWMS does not pose a significant risk to the public and the environment.