The Use of Polytetrafluoroethylene (Teflon®) Containing Filter/ Moderators for Epithermal Neutron Beam Production

We have investigated the suitability of fluorinated hydrocarbon polytetrafluoroeth-ylene (PTFE) for application in the filter/moderator of an epithermal beam. We show that the neutronics performance, cost, and fabricability of Al and PTFE compares favor- ably with other good filter/moderator materials such as Al/Al2O3, Al/C, and Fluental ®. In this study, we have carried out irradiation tests to evaluate the performance of PTFE in the mixed gamma and fast neutron environment expected for the MIT Fission Con- verter epithermal neutron beam application. The irradiation stability was found to be more than adequate for the planned application.