Milestone 1.2.9: Radiolytic Gas Generation Measurements from Helium Backfilled Samples of AA1100 and AA6061 Coupons

S&T Accomplishment Report · Mon Nov 15 04:00:00 EST 2021

OSTI ID:1882587

Horne, Gregory P ^[1]; Conrad, Jacy Kathleen ^[1]; Pilgrim, Corey David ^[1]; Pu, Xiaofei ^[1]; Copeland-Johnson, Trishelle Marie ^[1]; Khanolkar, Amey Rajendra ^[1]; Parker-Quaife, Elizabeth H ^[2]; Wilbanks, Joseph Richard ^[1]; Rae, Cathy ^[3]

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1. Idaho National Laboratory
2. NNL
3. INL

Nearly 18 metric tons of aluminum-clad spent nuclear fuel (ASNF) is safely managed by the U.S. Department of Energy (DOE). These assemblies are currently in interim storage, with the intention of extended storage (>50 years) until final disposal. Strategies for the continued safe storage of this material are under evaluation, of which a key criterion is the extent of molecular hydrogen gas (H2) formation from the radiolysis of hydrated (oxy)hydroxide aluminum corrosion layers arising from in-reactor and wet storage conditions. Radiation-induced H2 formation has the potential to compromise cladding and storage canister integrity, in addition to promoting the formation of unfavorable gaseous environments. Consequently, understanding this radiation-induced phenomenon is essential for the development of predictive modeling capabilities to support technical considerations and the identification of radiation related challenges for the extended storage of ASNF. Here, we report radiolytic H2 yields (G-values, G(H2)) from the gamma irradiation of ‘pristine’ and pre-corroded aluminum coupons in helium (He) environments as a function of alloy composition (AA1100 and AA6061), relative humidity, and absorbed gamma dose. Measured yields were lower than corresponding values reported for argon environments, a positive result for proposed extended dry storage strategies that would employ helium as a backfill gas. Interestingly, the presented G(H2)He values are comparable to those previously measured in nitrogen environments, suggesting a He mediated H2 inhibition process, attributed here to Penning ionization.

• Research Organization: Idaho National Laboratory (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE Office of Environmental Management (EM)
• DOE Contract Number: AC07-05ID14517
• OSTI ID: 1882587
• Report Number(s): INL/EXT-21-65356-Rev000
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
Aluminum-clad Spent Nuclear Fuel
Gamma Radiolysis
Molecular Hydrogen Production