Absolute determination of power density in the VVER-1000 mock-up on the LR-0 research reactor

• Net peak area of 92Sr induced in selected VVER-1000 mock-up pins is measured.
• Determination of absolute power density in VVER-1000 mock-up.
• Calculations of NPA using various nuclear data.
• Discrepancies between calculation and experiment for pins adjacent to baffle model.

The work presents a detailed comparison of calculated and experimentally determined net peak areas of selected fission products gamma lines. The fission products were induced during a 2.5 h irradiation on the power level of 9.5 W in selected fuel pins of the VVER-1000 Mock-Up. The calculations were done with deterministic and stochastic (Monte Carlo) methods. The effects of different nuclear data libraries used for calculations are discussed as well. The Net Peak Area (NPA) may be used for the determination of fission density across the mock-up. This fission density is practically identical to power density.