Parametric study of an autoclave test for nodular corrosion

The use of a steam corrosion autoclave test as a quality control tool for Zircaloy products has been practiced for many years. The most common form of the test is exposure to steam at 672k, 10.3 Mpa (7500F, 1500 psi) for three days. Some years ago it was found that this test did not predict susceptibility to the occurrence nodular corrosion in boiling water reactors (BWR). A number of investigators found that a test at 723 to 773 K would produce nodular corrosion on Zircaloy products and therefore used the test as an index for research work on Zircaloy materials. More recently the test has been proposed as a quality control test on each lot of material. This study of test parameters and interlaboratory variability was undertaken as a necessary part of establishing an ASTM standard for such a test. Temperature of the test was found to be the most significant variable studied, and interlaboratory variation was relatively high when compared with the common 672 K test