Evaluation of covariances for resolved resonance parameters of sup 2 sup 3 sup 5 U, sup 2 sup 3 sup 8 U, and sup 2 sup 3 sup 9 Pu in JENDL-3.2

Evaluation of covariances for resolved resonance parameters of sup 2 sup 3 sup 5 U, sup 2 sup 3 sup 8 U, and sup 2 sup 3 sup 9 Pu was carried out. Although a large number of resolved resonances are observed for major actinides, uncertainties in averaged cross sections are more important than those in resonance parameters in reactor calculations. We developed a simple method which derives a covariance matrix for the resolved resonance parameters from uncertainties in the averaged cross sections. The method was adopted to evaluate the covariance data for some important actinides, and the results were compiled in the JENDL-3.2 covariance file.