Hfir irradiation facilities improvements — the HIFI project

Abstract

The High-Flux Isotope Reactor (HFIR) has outstanding neutronics characteristics for materials irradiation, but some relatively minor aspects of its mechanical design severely limit its usefulness for that purpose. In particular, though the flux trap region in the center of the annular fuel elements has a very high neutron flux, it has no provision for instrumentation access to irradiation capsules. The irradiation positions in the beryllium reflector outside the fuel elements also have a high flux; however, although instrumented, they are too small and too few to replace the facilities of a materials testing reactor. To address these drawbacks the HFIR Irradiation Facilities Improvement (HIFI) Project, now under way and scheduled for completion in mid-1987, consists of modifications to the reactor vessel cover, internal structure, and reflector. Instrumentation access will be provided to the flux trap region, and the number of materials irradiation positions in the removable beryllium will be increased from four to eight, each with almost twice the available experimental space of the present ones.