Validation of calculations for systems using soluble boron for criticality control

To support the operation of nuclear fuel dissolution systems using soluble boron as a neutron poison and to establish the system safety margin, a series of critical experiments performed at the Los Alamos Critical Assemblies Facility was analyzed. The experimental solutions were analyzed by analytical laboratories at Los Alamos National Laboratory and Westinghouse Idaho National Company for excess acid, uranium, and boron. The system was modeled with the MONK6.2 code along with its associated cross-section library and the system k/sub eff/ calculated from the experimental critical heights to validate calculations for the fluorinel dissolution process at the Idaho Chemical Processing Plant. The results of the chemical analysis are shown. Boron enriched to 50.55 (wt%) in 10B was used to achieve a wide range of neutron-absorbing conditions without encountering solubility problems with the boric acid in the uranyl nitrate core solution. The k/sub eff/ values obtained for the experiments show a general positive bias. The positive bias result supports the conservatism of the fluorinel dissolution process calculations with no bias adjustments necessary. Work is in process to try to determine whether the observed bias can be attributed to the cross-section libraries or calculational methods