Failure behaviour of a piping system with a circumferentially orientated flaw - Analytical and experimental investigations

Several cases of cracking in ferritic piping of power stations have initiated various investigations with regard to crack growth by the strain induced corrosion cracking (SICC) mechanism /1/ as well as to final failure behaviour by leak or break. The both phenomena were studied by a pipe failure test performed at the decommissioned Heissdampfreaktor (HDR) near Frankfurt. The test was performed in the scope of Phase II of the HDR-Safety-Program sponsored by the Ministry of Research and Technology of the FRG /2/. During the test the failure of the piping system was caused by cyclic crack growth beginning from a circumferential notch. The piping was loaded cyclically using displacement control under high pressure and temperature. The flexible installation of the piping can be considered as comparable to feedwater lines of BWR having only two fix points and no other supports ( Fig. 1 ). The loading and the corrosive environment should simulate extreme BWR operating conditions during start up or shut down of the plant. Fig. 1 Test structure A diagram of a piping system with a circumferential crack for a pipe failure test. https://www.w3.org/1999/xlink" xlink:href="#long-desc224"/> https://www.w3.org/1999/xlink" xlink:href=" https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003763246/3dd1067a-243d-4b3a-b8d3-0e516be855dd/content/pg413_1.tif "/>