Journal of Nuclear Fuel Cycle and Waste Technology

In this work 14C and 3H distribution characteristics of spent resins from nuclear power plants(NPPs), pressurized water reactors(PWRs), was investigated . It was found that the recovery percent of 14C by the wet oxidation-acid stripping was 81%～100% for the added activity range of 14C, 0.72 Bq～460 Bq, and it was not affected by the kinds of stripping acids, 3 N-HCl, 3 N-HNO3 and 3 N-H2SO4. And the recovery percent of 3H by distillation using the same apparatus was 81%～101% for the added activity range of 3H, 0.60 Bq～435 Bq. Among the tested stripping acids, 3 N-HCl, 3 N-HNO3 and 3 N-H2SO4, only the trapped 3H solution by distillation in 3 N-H2SO4 was compatible with the 3H scintillator, Ultimagold XR. Neither of the 14C and 3H trapping solutions from the spent ion exchange resin samples by the wet oxidation-3 N-H2SO4 stripping contained gamma nuclides. However, some gamma nuclides, 60Co, 134Cs, 137Cs and 54Mn, were found in the trapped 3H solutions of the spent resins by the wet oxidation-3 N-HCl stripping. It was the same for the 3H trapping solutions of the spent resins by Sample Oxidizer(PACKARD MODEL 307). Meanwhile only two nuclides, 134Cs, and 137Cs, were found in the 14C trapping solutions of the spent resins by Sample Oxidizer(PACKARD MODEL 307). It was found that most of the 14C in the spent resins existed as inorganic carbon form, more than about 70% of the total 14C content. Among the analyzed 30 spent ion exchange resin samples, the average concentration of 14C and 3H for the high radioactive samples, 8 samples, was 19000 Bq/g±41000 Bq/g, 670 Bq/g ±460 Bq/g and that for the low radioactive samples, 22 samples, was 4.2 Bq/g±4.3 Bq/g, 6.0 Bq/g±5.3 Bq/g, respectively. And the average 14C/3H ratio for the high radioactive samples, was higher, 28, than that of low radioactive samples, 0.70. Some linear relationship trend was found between the activity concentrations of 14C and 3H.

Keywords

Wet oxidation-acid stripping,14C,3H,spent resin