Possibility of determining nuclear-fuel characteristics by mass spectrometry without chemical separation of the elements

In order to correctly organize the fuel cycle of a nuclear power plant, it is necessary to know such characteristics of the spent nuclear fuel as the burnup and the content of transuranium elements in it. The authors study a sample of spent fuel, cut out of the center of a fuel cell of the RBMK-1000 reactor and dissolved in nitric acid without removing the jacket of the fuel cell. In performing the mass-spectrometric analysis, while increasing the temperature of the evaporator, the following groups of mass spectra were succesfully recorded: Cs, Ce, and Nd and their oxides, Pu, and U. The results are shown of the measurements of the isotopic composition and mass of some elements accumulating in the fuel (relative to uranium). The data was used to calculate the burnup of the nuclear fuel and the contribution of fission of heavy nuclides U 235, U 238, Pu 239, and Pu 241 to it. The same method was used to determine the characteristics of the spent mixed fuel of a BOR-60 reactor. Results are presented and it has been shown that the use of an ion source with surface ionization in a partially closed cavity enables determining the basicmore » characteristics of the spent nuclear fuel without purification and chemical separation of the fuel elements from the samples.« less