MASS SPECTROMETRIC DETERMINATION OF BURNUP BY URANIUM ISOTOPIC RATIO METHODS

The mass spectrometric determinations of burnup in rich uranium fuels by uranium isotopic ratio methods were described in this paper: First, the burnup-values B_(U1)(%) were calculated from uranium isotopic ratios R_(6/5) before and after irradiation in rich-uranium fuels and α_(5·) Second, the α_(5·8)-values were obtained from B_(U1)(%), B_(U0)(%) (~(148)Nd -spent-uranium concentrations method), and R_(5/8), R_(6/8) before and after irradiation of 3—4 pieces of uranium fuel. Third, the correlative curves of α_(5·8) versus burnup-values B_U(%)in irradiated fuels were drawn, α_(5·8)=F (B_U(%)) also were induced from this curves. FinaIy, the burnup-values B_(U2)(%) were counted from α_(5·8) and R_(5/8), R_(6/8), before and after irradiations, the burnup-values of B_(U1)(%) and B_(U2)(%) were in good agreement。 The B_(U1+2)(%) and B_(U0)(%) were agreed within 2.5%.