Mass transfer of 316L steel in Pb17Li CLIPPER loop after 12000 hour running

An examination of the large 316L CLIPPER loop has been done after 12 000 h running with Pb17Li, the hot part being at 400deg C and the cold part at 340deg C. The morphology and the chemical composition of the ferritic layer formed on the tubes at 400deg C are the same as already observed, but its thickness is less than expected from previous shorter tests. This feature can be explained by a partial scaling of the layer. Deposits are located in the cold part of the main circuit and in the cold trap. Their mean density in these zones is about 0.4 mg cm-2 and increases where hydraulic perturbations take place. Temperature lowering favours the formation of chromium, nickel and manganese compounds to the detriment of iron. (orig.)