Transmutation and He Production in W and W-alloys
W and W-alloys are among the primary candidate materials for plasma facing components in the design of Fusion reactors, particularly in high heat flux regions such as the divertor. Under neutron irradiation W, like all other elements, undergoes transmutation to its near-neighbours in the periodic table. Additionally He (and H) is produced as a by-product of certain threshold reactions, and this is particularly significant in fusion research since the presence of helium in a material can cause both swelling and a strong increase in brittleness. In this report we present the results of inventory calculations on pure W and give quantitative estimates for He production rates. We also investigate transmutation reactions in certain alloys, which are being considered in an attempt to reduce the brittleness of pure W.