Benchmarking and modification of FRAPCON2 V1MOD5

The FRAPCON2 V1MOD5 computer program has been benchmarked against precharacterized fuel rods from irradiation surveillance programs of commercial pressurized water reactor (PWR) and boiling water reactor (BWR) fuel types as well as instrumented test rods irradiated at Halden. Five 15 x 15 PWR rods from assembly C64 irradiated for five cycles in Zion 1 and 2 were analyzed. After five cycles of irradiation, these rods had accumulated ∼ 60 GWd/tonne uranium peak local exposure. Three 8 x 8 BWR fuel rods from bundle MTB099 irradiated at Monticello, as well as two 8 x 8R BWR rods from the Peach Bottom lead test assembly program, were also analyzed. These rods achieved peak local exposures of 55 and 41 GWd/tonne uranium, respectively, at discharge. The FRAPCON2 V1MOD5 predictions were compared with fuel profilometry, oxide film thickness, fission gas release, fuel swelling, and other parameters measured either at the end of each fuel cycle or in hot cell examinations. In addition, 17 instrumented rods from IFA 429, 431, and 432 irradiated in the Halden reactor were examined to provide comparisons of predicted versus measured fuel temperatures and fission gas release. It has been demonstrated that FRAPCON2 V1MOD5, with the modifications described, provides a best-estimate calculation of fuel thermal mechanical behavior for current PWR and BWR fuel types