Experimental Determination of the Spent Graphite Radioactive Contamination at Plutonium-Production Reactors of the Siberian Group of Chemical Enterprises (TOMSK-7)

Spent graphite from decommissioned plutonium-production uranium-graphite reactors is contaminated with radionuclides, and this graphite represents an important fraction of the radioactive wastes accumulated by the Russian nuclear power industry. To select proper ways and dates for the management of graphite, the information regarding the composition and level of the graphite contamination is required.

In the paper, results are presented that were obtained in studies carried out at the I-1, EI-2, and ADE-3 reactors of the Siberian Group of Chemical Enterprises (Russia) in 1996-1999. The main feature of the studies is a wide-scale sampling from the graphite piles of the aforementioned reactors followed by complex assays of their radioactive contamination.

The analyses performed for the large number of graphite samples made it possible to obtain a detailed picture of the pile contamination, to study radionuclide distributions over the piles, to construct schemes for evaluation of radionuclide stockpiles, and to evaluate stockpiles of several radionuclides including ¹⁴C, ³H, ⁹⁰Sr, ²⁴¹Am, ²⁴⁴Cm, ^{238,239,240,241}Pu, ^137,134Cs, and ⁶⁰Co.