Abstract
The large size of resonance parameter covariance matrices (RPCM) in the actinide region often renders them impractical for dissemination via ENDF. Therefore, a method of approximating the RPCM by a much smaller group-wise covariance matrix (GWCM) is described, implemented, and examined. In this work, 233U RPCM is used to generate GWCM's for the 44 group AMPX, 100 group GE, 171 group VITAMIN-C, and 240 group CSWEG. Each of these GWCM's is then used to compute group-wise uncertainties for the groups of the remaining group structures. The group-wise uncertainties thus obtained are compared with those obtained from a full RPCM, i.e. without the approximation. A systematic comparison of group-wise uncertainties based on GWCM's vs. RPCM, for a variety of group structures, will shed light on the validity of this approximation and may suggest which group structure(s) yield a GWCM that could be used in lieu of the RPCM.
