Thermal effects in the matrix with the rare earth fraction

Separation of high-level waste (HLW) onto fractions simplifies their isolation in matrices and disposal. One of these fractions consists of rare earths (REE) and minor actinides (MA = Am, Cm). Among the rare earth elements there are isotopes 144Ce, 147Pm, 151Sm, and 154,155Eu with half-lives of up to 93 years, decay of the nuclides will cause heating of the matrices with HLW. It has been shown that preliminary storage of the REE–MA matrix for 10 years or more will reduce the content of REE radioisotopes and their contribution to temperature increase in geological repository.