Determination of critical assembly absolute power using post-irradiation activation measurement of week-lived fission products

The work presents a detailed comparison of calculated and experimentally determined net peak areas of longer-living fission products after 100 h irradiation on a reactor with power of ∼630 W and several days cooling. Specifically the nuclides studied are 140Ba, 103Ru, 131I, 141Ce, 95Zr. The good agreement between the calculated and measured net peak areas, which is better than in determination using short lived 92Sr, is reported. The experiment was conducted on the VVER-1000 mock-up installed on the LR-0 reactor. The Monte Carlo approach has been used for calculations. The influence of different data libraries on results of calculation is discussed as well. - Highlights: • Measured and calculated net peak areas of selected longer living isotopes. • Determination of absolute reactor power. • Discrepancies between calculation and experiment. • Effect of data libraries on calculational results