AbstractThe interaction between Pb17Li and water, as a consequence of a localized tube microcrack, has been studied. Two experiments were performed in which a low quantity of steam was injected into the lithium lead. The artificially machined microcracks, simulating a real microcrack in an AISI 316 heat exchanger tube, had a maximum area of 0.003 mm2. No blockage of the microcrack was observed during the tests. No significant damage was observed on the microcracks geometry, probably because of the short test time. A layer of reaction products having a high melting point was formed around the test section. First analytical results seem to confirm the presence of lithium hydroxide in the reaction products.