Saclay Nuclear Research Center, Atomic Energy Commission, Gif-sur-Yvette,
Pages: 24 Published: Jan 1983
Research on irradiation embrittlement in modern pressure vessel steels was initiated at the French Atomic Energy Commission ten years ago. During this period many steels and welds were irradiated in the Triton and Siloe reactors; research was undertaken both independently and within the framework of research programs coordinated by the International Atomic Energy Agency.
Mainly through tests of tensile and Charpy impact properties, the effects of chemical composition were studied, confirming the influence of copper and phosphorus and uncovering the surprisingly detrimental effect of nickel content. At the same time, new fracture mechanics testing procedures for irradiated materials were developed.
Today the major part of these programs is complete and future activities will probably be reduced on pressure vessel steels. The main topics for forthcoming studies are the effect of flux or irradiation rate on embrittlement and elastic-plastic fracture mechanics. A review of past activities and a preview of forthcoming research is given.
During the period covered by these studies, many pressurized water reactors were built in France that are now starting to operate, with each reactor containing irradiation surveillance capsules. This important program, which is described in the second part of the paper, will lead in the next ten years to an increased knowledge of radiation embrittlement on a more statistical basis, taking into account results obtained on a reference plate.
pressure vessel steels, irradiation embrittlement, surveillance programs
Paper ID: STP31846S