Technical Report NTB 04-04

Comparison of ORIGEN2.1 with Selected Computer Codes

Codes used to calculate radionuclide inventories have been compared with the aim of testing the predictive capability of the ORIGEN2.1 code. A suite of safety relevant radionuclides were examined and differences in the output of the codes were used as an indication of uncertainty in the ORIGEN2.1 output.

It was found that the activities of most of the safety relevant nuclides can be reliably predicted by ORIGEN2.1 calculations. However, for 9 out of the 64 radionuclides considered in this work, ORIGEN2.1 predicted activities that cannot be considered reliable. The origin of the discrepancies between the codes for these 9 nuclides will be further investigated by Nagra.

It was also shown that the agreements and the deviations noted for the safety relevant nuclides do not change significantly for a variation of the key parameters burnup, enrichment and power level.

The calculations give fair estimates of appropriate error bars that should be assigned to all of the obtained activities within ORIGEN2.1 calculations.