Overview of the Savannah River reactor surveillance program

Preliminary radiation effects studies, now nearing completion, are based upon short-term irradiations in the High Flux Isotope Reactor (HFIR) and University of Buffalo Reactor (UBR). The purpose of these studies is to assess the impact of radiation effects on the performance and service life of Savannah River Site (SRS) reactor components. The SRS reactor surveillance program was simultaneously established in order to validate the results of these short-term irradiations under conditions more applicable to the SRS reactor components. The main conditions of interest include: temperature, moderator chemistry and neutron spectrum. The materials employed in both the surveillance and short-term irradiation programs were taken from the SRS R-reactor process piping and included base, weld, and heat-effected zone metal samples in both the C-L and L-C orientations. Test specimen types include tensile, Charpy V-notch, compact tension, constant extension rate test, and wedge-opening-load. A program schedule has been established for the irradiation and testing of surveillance specimens. The surveillance capsules are currently undergoing irradiation near the center of the SRS K-rector core and will remain in this location until their total fast fluence is equal to the current maximum reactor tank wall exposure. The bulk of the specimens will then be moved tomore » blanket capsules at the edge of the core in order to track the wall exposure. A small portion of the specimens will be removed and tested, and a third group of specimens will be removed from the central core position after they have accumulated a thermal fluence 50% greater than the current maximum tank wall exposure. Specimen groups will be removed from the blanket capsules and tested periodically. Additional capsules may be inserted in order to generate flow fluence or high thermal to fast flux ratio data. 17 refs.« less