Determination of Pd in Pd recovered from spent nuclear fuel solution by laser induced photoreduction

Asai, Shiho; Yomogida, Takumi   ; Saeki, Morihisa*; Oba, Hironori*  ; Hanzawa, Yukiko  ; Horita, Takuma ; Kitatsuji, Yoshihiro  

Pd is a long-lived radionuclide that can be found in HLW. The estimation of the amount of Pd in HLW is considered crucial for long-term safety evaluation of HLW. However, experimentally determined concentrations of Pd in HLW has not been reported due to the difficulty in recovering significant amount of Pd from HLW which has high radioactivity. In this study, we have focused on remotely operated separation technique based on laser-induced photoreduction, which allows to keep the distance from samples. To validate the applicability of the proposed method, spent nuclear fuel with a traceable irradiation history was employed instead of HLW. The resulting Pd precipitate contained almost no impurities, such as actinides (U, Np, Pu, Am, Cm), major fission products (Zr, Mo, Tc, Ru, Rh, Ba, Cs, Ce), resulting in the interference-free measurement of Pd with ICP-MS. The amount of Pd per 1 mg of U in the sample was 2399 ng/mg-U.