Criticality and doppler reactivity worth uncertainty due to resolved resonance parameter errors; Formula for sensitivity analysis

Zukeran, Atsushi*; Nakagawa, Tsuneo; Shibata, Keiichi; Ishikawa, Makoto*; Hino, Tetsushi*

Reactivity uncertainties such as effective multiplication factor can be estimated by the sensitivity coefficients of the infinitely diluted cross section and resonance self-shielding factor to the changes of resonance parameters of interest. In the present work, the uncertainties of the resolved resonance parameters for the evaluated nuclear data file JENDL-3.2 were estimated on the basis of Breit-Wigner Multi-level formula. The resonance self-shielding factor based on NR-approximation is analytically described. Reactivity uncertainty evaluation method for the effective multiplication factor k, temperature coefficient , and Doppler reactivity worth is developed by means of the sensitivity coefficient against the resonance parameter. Final uncertainties are estimated by means of error propagation law using the level-wise uncertainties. Preliminary uncertainty of Doppler reactivity worth results about 4% at the temperature 728 K for large sodium-cooled FBR.