Analysis of the Three Mile Island Submerged Demineralizer System Vessel Burial Data: Fiscal Year 1989.

摘要

The Submerged Demineralizer System (SDS) was used during the Three Mile Island (TMI) nuclear reactor cleanup to remove cesium and strontium from contaminated water. The SDS vessels are 2-ft-in diameter and 4-ft tall stainless steel cylinders containing up to 60 kCi of radioactive cesium and strontium loaded on damp zeolite. The water in the damp zeolite absorbs some of the ionizing radiation and decomposes to hydrogen and oxygen by a process called radiolysis. Gas generation rates approaching 1 L/h (Quinn et al. 1984) have been calculated and measured for some of these loaded vessels. Each of the SDS vessels contains a catalyst bed to recombine the available hydrogen and oxygen back to water. Tests have proven this hydrogen control method to be highly effective, even under very wet (but unsubmerged) conditions. Nineteen SDS vessels, packaged one at a time in a shielded and licensed shipping cask, were shipped to Rockwell Hanford Operations (Rockwell). Collectively, these vessels contain approximately 7,500 kCi of radioactive material. Sixteen vessels were transloaded into concrete overpacks and buried at the Hanford Site. The contents of the other three vessels were vitrified at Pacific Northwest Laboratory. Subsequent to placement of the SDS vessels in the burial grounds, DOE Order 5820.2A (DOE 1988) was issued in September 1988. This order requires wastes to be evaluated against 10 CFR 61.55 for radioactivity above greater-than-class C(GTCC) limits. Fourteen of the sixteen vessels buried at the Hanford Site have been determined to be GTCC waste. 5 refs., 3 figs., 3 tabs.