PWR RESEARCH AND DEVELOPMENT PROGRAM. TEST REPORT. GAMMA SCANNING SPENT SM-1 CORE I FUEL ELEMENTS. TEST 318

A test was designed and performed to experimentally determine fuel burnup distribution in the SM-1 Core I spent fuel elements. It was believed to be feasible if the spatial distribution of the gamma rays emitted from a long- lived, unsaturated fission product could be measured. However, scintillation spectra indicated an intense peak between 0.7 and O.8 Mev, primarily attributed to the 63day Zr/sup 95/ fission product and 35-day Nb/sup 95/. The magnitude of this peak nullified the possibility of distinguishing a long-lived fission product that could be used for scanning purposes. The stationary elements of one quadrant of the core were scanned using the Zr/sup 95/-Nb/sup 95/ peak as the energy interval. The results represent a fair approximation of the power distribution in SM-1 Core I during the latter portion of operating history. Results of the experiment are presented with a description of the techniques and test equipment used. (auth