Determination of Zr and Mo isotopes in spent nuclear fuel solution by isotope dilution inductively coupled plasma mass spectrometry for validation of calculated values

Asai, Shiho; Hanzawa, Yukiko  ; Konda, Miki; Suzuki, Daisuke   ; Magara, Masaaki  ; Kimura, Takaumi 

Isotopes of Zr and Mo including both radio and stable isotopes can be found in spent nuclear fuel. Of these isotopes, Zr and Mo which have long half-lives of 1.61 10 y and 4 10 y, respectively, are of great importance from the viewpoint of managing high-level radioactive wastes in a long-term basis. In this study, contents of Zr and Mo isotopes in spent nuclear fuel solution were determined by isotope dilution inductively coupled plasma mass spectrometry. The sample solution was prepared by dissolving a Japanese PWR irradiated UO fuel with a burnup of 51 GWd/t. The measured contents of Zr, Zr, Zr, Zr, Zr, and Zr in the sample were agreed well with the predicted values obtained through a burnup calculation code ORIGEN2. For Mo, the contents in the sample were approximately 30% less than the predicted values, indicating that part of Mo exists in the insoluble residue.