Radiation resistance of weld joints of type 316 stainless steel containingabout 10 appm He

Welding is supposed to be an important method for making joints in the pipe s conducting the heat agent when replacing divertor and first wall elements . Embrittlement through helium accumulation within the ITER components repa ired by welding during maintenance is one of the factors limiting the mater ials lifetime. To investigate this problem, a set of the 316 RF type steel specimens was saturated by He up to 50 appm at 80 degreesC. Another part wa s irradiated in the SM-2 reactor up to 0.1 dpa at 80 degreesC. Afterwards, they were subjected to e-beam welding and are welding, respectively. A part of each specimen underwent LCF bending; another part was tested to tension . These tensile and LCF tests of the specimens showed that neutron irradiat ion of the weld joints leads to their embrittlement and rapidly reduces the number of cycles to failure. (C) 2000 Elsevier Science B.V. All rights res erved.