Occupational radiation exposures associated with alternative methods of low-level waste disposal

The Low-Level Radioactive Waste Policy Amendments (LLRWPA) Act of 1985 assigns the responsibility for disposal of low-level radioactive wastes to individual states. The Act also mandates that the US Nuclear Regulatory Commission (NRC), in consultation with states and other interested parties, identify disposal methods other than shallow land burial (SLB), the method currently used at the three low-level waste (LLW) disposal sites operating in the United States. The NRC contracted with Pacific Northwest Laboratory (PNL) to compare projected occupational exposures associated with the SLB method and five alternative disposal methods, including below ground vaults (BGV), above ground vaults (AGV), earth mounded concrete bunkers (EMCB), augured holes (AH) and minded cavities (MC). This report is intended to inform state and local governments about these projected exposures in anticipation of their participation in siting new low-level waste disposal facilities. The results of this study suggest that, with the design and operation assumptions made in this study, occupational dose equivalents for the five methods examined in detail would be highest for the EMCB method (1.81 person-mrem/m3 of waste disposed). The lowest occupational dose equivalents would occur for the AH method (1.29 person-mrem/m3). Projected occupational dose equivalents for SLB, BGV, and AGV disposal methods are 1.38, 1.47, and 1.61 person-mrem/m3, respectively. Based on simularities between the reference BGV and MC facilities, it was projected that the occupational dose equivalents for a MC facility would be 40% higher than for the reference BGV facility. 17 refs., 15 figs., 13 tabs