BURNUP DETERMINATION OF A HIGH BURNUP PWR FUEL BY NEODYMIUM AND CESIUM ISOTOPE MONITOR METHODS BASED ON ISOTOPE DILUTION MASS SPECTROMETRIC MEASUREMENTS

摘要

Destructive methods were used for the burnup determination of a PWR nuclear fuel irradiated to a high burnup in power reactors. The total burnup was determined from a measurement of the Nd and Cs isotope burnup monitors. The methods included U, Pu, ~(148)Nd, ~(145)Nd+~(146)Nd, total of the Nd isotopes, and ~(133)Cs and ~(137)Cs determinations by the isotope dilution mass spectrometric method (IDMS) by using quadrupole spikes (~(233)U, ~(242)Pu, ~(150)Nd and ~(133)Cs). The methods involved two sequential anion exchange resin (AG 1X8 and 1X4) separation procedures and a Cs purification with a cation exchange resin (AG 50WX4) separation procedure. The effective fission yield was calculated from the weighted fission yields averaged over the irradiation period. The results obtained by the Nd and Cs isotopes from the mass spectrometric measurement were compared with those by the ORIGEN code.