Search for Solving the Problem of Conditioning the Reactor Graphite

Abstract

Spent reactor graphite constitutes a significant part of the accumulated solid radioactive wastes, and a search for its isolation from the biosphere is a topical task. Radioactive nuclides are listed in the paper, the activity of which determines the degree of contamination of the graphite stack and other construction elements of decommissioned uranium-graphite reactors. The suggested technical solutions must be based on a differentiated approach to various kinds of a graphite waste, which differ in the specific activity and spectrum of radionuclides. A preliminary fractionation (assortment) will make it possible to many times diminish the amount of waste delivered to the point of deep burial. A search for approaches to graphite processing must be subordinate to the problem of finding the less expensive technologies. Any procedure aimed to process graphite to remove 14C and 36Cl into a separate product will only make larger the total waste volume and require an additional expenditure. The development of even the most effective methods cannot provide the economic effect that can be obtained if the regulations on the content of impurities in graphite are reconsidered and a safe burial of the reactor graphite in near-surface storages is substantiated.