Assay Method for MTR-Type Fuel Elements

Year
1981
Author(s)
R. Sher - Stanford University
Abstract
A calculational program for an HP-97 calculator has been written to enable IAEA Inspectors to verify unlrradiated MTR-type (plate) fuel elements by means of gamma-ray measurements with a SAM-2 instrument. The program requires operatorsupplied design data on the elements. The program calculates the expected gamma count rate if the element is actually as designed. The principal problem in the calculation is to account for gamma ray scattering in the fuel plates (\"buildup factor\"). The buildup factor was calculated as a function of uranium enrichment in typical fuel element designs, and the results were parametrized in a simple manner for use in the HP-97. Comparison of calculated and experimental data indicates that the calculations are accurate to within ± 2%. This accuracy is sufficient to detect the substitution or removal of a single plate in the element.