PWR ZIRCALOY CLADDING CORROSION BEHAVIOR - QUANTITATIVE-ANALYSES

The causes of accelerated corrosion of Zircaloy-4 fuel cladding at hig h burnups in PWRs have been reviewed and, among these causes, the effe ct of hydriding has been investigated using out-of-pile corrosion test results and quantitative analyses. The review shows that the lithium effect and the microstructural change of Zircaloy-4 have potential to accelerate the corrosion rate. However, consistent data base applicabl e to quantitative analyses of PWR corrosion is not enough. On the othe r hand, the out-of-pile corrosion data shows that hydriding could acce lerate the corrosion rate by a factor of up to 4. A new corrosion mode l which can take account of hydrogen movement showed hydriding is a pl ausible factor to determine the high burnup corrosion behavior. (C) 19 97 Elsevier Science B.V.