FINAL RESULTS OF CROSS-CALIBRATION MEASUREMENTS ARE MEPhI

This paper reports the results of the final part of the cross-calibration measurements for the active well coincidence counter (AWCC) carried out at the Moscow State Engineering Physics Institute (MEPhI) in the framework of the UD Department of Energy (DOE) and MEPhI joint project to establish a Master's Graduate Program in material protection control and accounting (MPC&A). The main concepts of cross-calibration and preliminary results results of passive cross-calibration measurements were reported at 1998 Institute of Nuclear Materials Management Annual Meeting. During that work, it was established that calibration curves measured at Los Alamos using available standards could be transferred to MEPhI. This paper now reports the results obtained at MEPhI from measuring the content of fissile materials in blocks of metal uranium and in fresh fuel assemblies for Russian RBMK and VVER reactors. The effects of sample geometry, self-absorption, and enrichment on the final measurement bias, and the approximations made to take these into account, will be discussed