The radiation stability of radioactive waste (RW) matrices containing transuranium elements (Np, Pu, Am, Cm) is one of the crucial characteristics determining their suitability for long-term storage or disposal in geological formations. Among three basic procedures for determining the stability of matrices against a decay—study of natural analogues, external ion irradiation, and internal a irradiation (from incorporated actinide isotopes) [ 1 ], the last one is most adequate. As a rule, isotopes with short half-lives are used: ~(238)Pu (T_(1/2) = 87.8 years) and ~(244)Cm (T_(1/2) = 18.1 years). As a result, the radiation dose accumulated by a matrix with real RWs after storage for ~ 10~5 years is achieved in one to two years. At the same time, the dose rates in the matrices containing these isotopes exceed by orders of magnitude the dose rates in matrices containing actinide RWs from spent nuclear fuel treatment. A more adequate situation is observed when long-lived isotopes ~(241)Am (T_(1/2) = 432.5 years) and ~(243)Am (T_(1/2) = 7370 years) are used; however, it will take 5 to 50 years to achieve comparable radiation loadings.
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