Comparisons of HELIOS, ORIGEN2, and Monteburns calculated Am-241 and Am-243 concentrations to measured values for PWR, BWR, and VVER spent fuel

A study was performed at Los Alamos National Laboratory to explore the accu racy of several reactor analysis codes in calculating Am-241 and Am-243 con centrations in light water reactor spent fuel. Calculated higher-actinide c oncentrations were compared to measured values from the literature for thre e reactor fuels. The fuel samples were taken from the Mihama Unit 3 pressur ized water reactor, the Garigliano boiling water reactor, and a VVER-440. T he Am-241 and Am-243 concentrations were calculated using the HELIOS-1.4 la ttice-physics code, the ORIGEN2 burnup code, and a linked MCNP/ORIGEN2 code named Monteburns 3.01. Comparisons were made between the calculated and me asured values. It was determined that all codes performed consistently well for the Mihama Unit 3 measurements (within +/- 5% for Am-241 and +/- 20% f or Am-243) and the Garigliano measurements (within +/- 12% for Am-241 and /- 12% for Am-243). It was determined that the ORIGEN2 pressurized water re actor libraries are insufficient for the VVER-440 measurements, The HELIOS and MONTEBURNS codes both demonstrated good ability to calculate these isot opes for VVER-440 fuel (+/- 10% for Am-241 and +/- 12% for Am-243). The acc uracies of these codes and the associated radiochemical measurements of the se higher-actinide isotopes may be insufficient for safeguards and fuel man agement purposes; thus, development, of new methods and modification to exi sting data libraries may be necessary in order to enable cost-effective saf eguarding of these higher-actinide materials.