Two promising reactor Generation IV designs employ nuclear graphite as their moderator and reflector. To this end, new graphite grades are being developed which will require their suitability for reactor design to be established. Understanding graphite irradiation behavior, especially dimensional change, is critical when selecting a particular nuclear graphite grade. This is usually established by fast neutron irradiation experiments in a material test reactor (MTR). However, due to the limited accessibility to MTR irradiation facilities, cost, and the time required for such experiments to be carried out, the development of new nuclear graphite grades is somewhat limited. Here. a novel approach is proposed to enable suitable grades to be selected from a number of candidates before an MTR program is implemented. This is done by estimating the irradiation-induced dimensional change behavior of several nuclear graphite grades based on the bending of graphite foils under ion irradiation. The method is capable of efficiently distinguishing the most dimensionally stable graphite grades in the laboratory without the need to irradiate many samples in an MTR program.

 

Figure : Estimating the dimensional change behavior of nuclear graphite with heavy-ion irradiation-induced bending