Recently released JENDL-5 data are extensively tested for U-235, Pu-239 and U-238 above the resolved energy region. For this purpose, a sequence of effective multiplication factors along with some spectral indices for well documented bare and reflected cores of fast systems having a hard spectrum and exhibiting larger sensitivity to data of these actinides, 40 parameters in total, are computed by means of a stochastic technique based upon the Serpent code. This approach is then used along with consistent JENDL-5 covariance data to perform adjustments in conjunction with the Asymptotic Generalized Linear Least-Squares (AGLLS) and Asymptotic Progressing nuclear data Incremental Adjustment (APIA) assimilation methodologies. In the provided example the adjustment largely relies on fission reaction rates per atom for Pu-239 relative to the fission of U-235 measured at core center for Godiva and Jezebel and one effective multiplication factor for an intermediate enrichment uranium system. The latter is sensitive to U-238 data.
Despite the good performance of the JENDL-5 library, the illustrative adjustment provides overall improvements of the calculation results in terms of decreased mean χ² and especially reduced variance of the individual χ² s. More precisely, the posterior mean χ² of the 40 parameters is close to one as aimed for. This outcome along with the lowered variance signalize a better consistence of the posterior as compared to the prior results despite the small-size assimilation database.