ANALYSIS OF BURNUP DATA FROM PRTR Pu-Al FUEL ELEMENT No. 5075

Burnup experiments are being performed in the Plutonium Recycle Test Reactor (PRTR) on modified fuel elements to obtain data useful in checking physics models in fuel cycle analyses. The irradiated element reported on is a standard Pu--Al PRTR element removed from the reactor because of a faulty end spider. The element is a l9-rod cluster of Pu--Al rods clad with Zircaloy. The element had received approximately 50 Mwd of exposure, which is approximately 20% burnup of the initial plutonium. The data obtained from ths element, the laboratory procedures used, some of the difficulties encountered, comparison of the data with burnup calculations, and derivation of cross-section ratios from the data are discussed. (M.C.G.)