Use of sensitivity and uncertainty analysis in reactor design verification Part II: Flux measurement analysis

As for any new reactor design, the ACR-1000® design has to go through a comprehensive design verification process. One of the activities for supporting the ACR physics design calculations using the ACR physics code toolset, namely WIMS-AECL/DRAGON/RFSP, is to compare the flux distributions resulting from the calculation using this toolset at various power calibration monitor (PCM) detector locations against the flux measurement data from the Japanese Advanced Thermal Reactor (ATR) FUGEN. The discussion of this particular design verification exercise will be presented in a two-part paper. The usage of data from the FUGEN reactor qualifies this exercise as design verification by alternate analysis. In order to have meaningful results at the end of the design verification process, the similarity between the ACR-1000 and FUGEN reactors has to be demonstrated. It is accomplished through the sensitivity and uncertainty analysis using the TSUNAMI (Tools for Sensitivity and Uncertainty Analysis Methodology Implementation) methodology. The results from the similarity comparison have been presented in Part I of the paper. In Part II, results from flux distribution comparison will be presented. Favourable results from this design verification exercise give a high level of confidence that using the same physics toolset in calculating the flux distribution for ACR-1000 reactor will produce results with acceptable fidelity. In addition, the results will also give an indication of expected margins in the design calculations, not only at the locations of the PCM detectors but also at the derived bundle and channel powers obtained through the flux mapping calculation.