QUARTERLY PROGRESS REPORT ON THE CREEPDOWN AND COLLAPSE OF ZIRCALOY FUEL CLADDING PROGRAM SPONSORED BY THE NRC DIVISION OF REACTOR SAFETY RESEARCH FOR JANUARY-MARCH 1976

摘要

The creepdown and collapse study on Zircaloy fuel cladding is concerned with the deformation behavior of cladding under normal and near-normal reactor operating conditions. Efforts this past quarter have continued on two phases of the program:(1) completion of collapse testing and (2) development and fabrication of deformation-monitoring equipment.nSufficient collapse testing has been done to complete the analysis of the test data for nearly perfect tubing. It is apparent that all three of the independent variables used in this study (pellet-to-pellet gap, pellet-to-cladding gap, and temperature) play major roles in the collapse phenomenon. A collapse model is presented that describes the collapse pressure as a function of temperature, room temperature, mid-wall hardness, and pellet-to-pellet gap.nThe instrumentation for deformation monitoring has been developed and provision has been made for automatic control of the data gathering system and for protection of the monitoring coils from damage caused by collapse of the specimen tube. Calibration of the instrumentation is still in progress.