Simultaneous Determination of Caesium, Neodymium, Uranium and Plutonium Isotopes in Pressurized Water Reactor Spent Nuclear Fuels by Isotope Dilution Mass Spectrometry

Abstract

An isotope dilution mass spectrometric method (IDMS) has been used for the determination of caesium, neodymium, uranium and plutonium isotopes in pressurized water reactor (PWR) spent nuclear fuels irradiated in a power reactor. The method includes the determination of Cs, Nd, U, Pu and their isotopes through thermal ionization isotope dilution mass spectrometric by using quadrupole spikes (¹³³Cs, ¹⁵⁰Nd, ²³³U and ²⁴²Pu). The measured atoms of the radioactive Cs isotopes (¹³⁴Cs, ¹³⁵Cs and ¹³⁷Cs) were corrected for the decay during and after irradiation. The total burnup (atom % fission) determined from a measurement of the Cs isotope burnup monitors (¹³³Cs and ¹³⁷Cs) was compared with those by the Nd isotope burnup monitors (¹⁴⁸Nd and ¹⁴⁵Nd + ¹⁴⁶Nd).