The use of present fission reactors to simulate radiation damage in fusion reactor first walls

Abstract

Abstract The placement of passive shields (ISSECs) between the first wall and the source of neutrons has been considered as a mechanism for extending first wall lifetimes in fusion reactors. Solid carbon, Mo, Nb, W, and V were considered as ISSECs for tokamaks and liquid metals Li, Pb, and a Pb-Li eutectic alloy Pb4Li for laser fusion reactors. In addition to their radiation damage reducing capabilities in the first walls, it is shown that ISSECs also soften the Primary Knock-on Atom energy spectrum in the first wall to close to that found in fast or thermal fission test reactors. Such damage modifications would allow more confidence in applying data from current fission test facilities to components in future fusion devices. The appm He/dpa ratio has also been shown to be about equal in both the first wall and in fission reactors when 40-50 cm of liquid Pb or Pb4Li is used (except for Ni containing alloys in HFIR). At present, the required thicknesses for the other ISSEC materials to give the same reduct...