Fission product release from highly irradiated LWR fuel

Commercial SNF Accident Release Fractions

“…Other results provided in NUREGICR-0722 (Loren et al 1980, InNUREGICR-5009 (Baker et al 1988, Table 3.6), the release fraction of I3'I is shown to increase with burnup and for a fuel rod with a bumup of 60,000 MWd/MTU the release fraction is stated to be 0.12, which illustrates the conservative nature of the 0.3 value on p. 25.2 of Regulatory Guide 1.25. Thus, these points illustrate the conservatism associated with the release fractions stipulated on p. 25.2 of Regulatory Guide 1.25.…”

“…Comparison between Burst Rupture and Impact Rupture Distributions Figure 8 compares the lognormal distributions produced for the burst rupture data (MMD = 150 pm, MGD = 0.715 pm and I S = 3.8) from NUREGKR-0722 (Loren et al 1980, p. 105 and Appendix C ) and the impact rupture data (MMD = 18 mm and IS = 8.18) from ANL-81-27 (Mecham et al 1981, Table 2). The resulting distributions show that, as expected, the attrition process for commercial SNF escaping through a hole in the clad produced by a burst rupture has fewer large particulates relative to the commercial SNF particulates produced by the impaction of a tup onto unclad fuel pellets.…”

A physical description of fission product behavior fuels for advanced power reactors.

“…• C. Earlier tests [69,70], conducted under similar conditions, were performed at temperatures of 500 to 1600…”

“…5.12 indicate that the theory predicts the release of 85 Kr during the HI-1 test in a flowing steam atmosphere reasonably well. [69,70,71]. The temperatures were ramped to values of 500 to 1600 • C and held for various lengths of time before test termination.…”

Nuclear Reactor Safety Research Since Three Mile Island

“…The processes for iodine retention in water are complex, involving chemical reactions and partitioning between vapor and liquid phases. The recent finding that radioactive iodine is released from the fuel at least partly in the form of CsI may be important in understanding the retention at TMI (8,9).…”