Effects of gamma-induced displacements on HFIR pressure vessel materials

Analysis of HFIR Dosimetry Experiments Performed in Cycles 400 and 401

“…[3][4][5][6][7][8]. Figure 3 schematically shows the HFIR surveillance keys and displays the locations of the DOS capsules in Key 7 and Key 3.…”

“…In 1993, research into the cause of the higher-than-expected radiation damage rates identified gamma radiation as the reason for additional damage. 3 In late 1990, an initiative to increase the diameter of horizontal beam line 2 (HB-2) and HB-4 was launched, with the provision that the increase would not reduce PV lifetime excessively. A new PV lifetime study 4 , using techniques proposed in 1993, 5 indicated that by updating criteria and methods of analysis 50 EFPY(100MW) could be achieved; however, another modification of the PV surveillance program was necessary, and installation of dosimeters sensitive to both neutron and gamma rays was required to determine the radiation damage rates.…”

Neutron and Gamma Fluxes and dpa Rates for HFIR Vessel Beltline Region (Present and Upgrade Designs)

“…In this analysis, the published dpa rates from the above measure-based analyses 2 were used to normalize the calculated dpa rates at the appropriate key and position locations. The normalization factor, which is the ratio of the measured to the calculated value, is used as a correction factor to obtain the best estimate dpa rate at any location.…”

“…A recent evaluation has shown that gamma contributions are significant and must be included in the vessel damage assessment. 2 The motivation for the calculations is two-fold. First, it is necessary to specifically assess the impact of the enlargement of HB-2 and HB-4.…”

A Review of Proposed Upgrades to the High Flux Isotope Reactor and Potential Impacts to Reactor Vessel Integrity

“…The prior dosimetry measurements conducted for HFIR by Remec et al (1994) provide a solid basis for validating and normalizing the neutron and gamma flux calculations. This renormalization appears to be appropriate at locations where previous measurements have been performed when the locations are well removed from the proposed beam tube modifications.…”