OBSERVATIONS CONCERNING LICENSEE PRACTICES IN ERROR PROPAGATION

This paper describes some of NUSAC's observations concerning licensee error propagation practice. NUSAC's findings are based on the results of work performed for the NRC whereby NUSAC visited seven nuclear fuel fabrication facilties, four processing low enriched uranium (LEU) and three processing high enriched uranium (HEU), in order to develop a detailed evaluation of the processing of material accounting data by those facilities. Discussed is the diversity that was found to exist across the industry in material accounting data accumulation; in error propagation methodology, for both inventory difference (ID) and shipper/receiver difference (SRD); as well as in measurement error modeling and estimation. Problems that have been identified are, in general, common to the industry. The significance of nonmeasurement effects on the variance of ID is discussed. This paper will also outline a four-phase program that can be implemented to improve the existing situation.