The purpose of the Argonne National Laboratory Building 200 M-Wing Hot Cells Decontamination Project was to practically eliminate the radioactive emissions of Rn-220 to the environment and to restore the hot cells to an empty restricted use-condition. About 96.2 TBq (2,600 curies) per year of Rn-220 was being emitted at the start of the project fro the radioactive contaminants left in the hot cells at the end of the Argonne Proof-of-Breeding program work in 1985.

Four of the five project Hot Cells (M-1, M-3, K-1, and K-3) had been used for Proof-of-Breeding research on irradiated thorium rods from the U.S. Navy’s Shippingport Atomic Power Station thorium core breeder reactor research. The research involved precise shearing of the rods in Hot Cell M-3, dissolving of the samples in concentrated acids in Hot Cell M-1, preparing dissolver solution samples for radioassay in Hot Cell K-3, and pumping the waste dissolver solution to waste cementing stations in Hot Cell K-1. Extensive equipment and structures in the hot cells needed to be removed as radioactive waste.

Hot Cell A-1 had been used for pulverizing irradiated reactor fuel specimens from the Zion Nuclear Power Station in Illinois for analyses to quantify breeding of fissile isotopes.

All five of the hot cells required remote disassembly and decontamination work prior to protected entry decontamination. Two pairs of heavy duty manipulators were procured to facilitate the remote disassembly and decontamination work. An existing radio-controlled rail cart system was used for moving remote-handled (>200 mrem/hr) radioactive waste.

The project was carried out by Argonne personnel during the period of June 1992 to April 1996 (46 months) at a cost of $5.8 million. The total radiation dose to project personnel was about 74.5 person-mSv (7.45 person-rem). This was 80.1% of the total dose forecasted in the project Action Description Memorandum. All radiation exposures were maintained below regulatory guidelines in all aspects.

The five hot cells were emptied and decontaminated for restricted use. the goal of practically eliminating radioactive emissions from the five hot cells was achieved by the project team. A total of 23.4 metric tons (25.8 tons) of radioactive waste was generated. Approximately 7.7 metric tons (8.5 tons) of radioactively contaminated lead shielding bricks were taken to Argonne Waste Management for decontamination and recycling. Ten 208-l (55-gal) drums of remote-handled waste were shipped to the Department of Energy disposal site by shielded cask truck transport. The contact-handled radioactive waste was shipped in steel bins by truck transport to the Department of Energy disposal site. The radioactivity in the waste totaled 110 curies, primarily of mixed fission products.