Irradiation performance of fast reactor MOX fuel pins with ferritic/martensitic cladding irradiated to high burnups

• Published in: Journal of nuclear materials 2011-05, Vol.412 (3), p.294-300
• Main Authors: Uwaba, Tomoyuki, Ito, Masahiro, Mizuno, Tomoyasu, Katsuyama, Kozo, Makenas, Bruce J., Wootan, David W., Carmack, Jon
• Format: Article
• Language: English
• Subjects: ALLOYS; Applied sciences; Controled nuclear fusion plants; CREEP; Energy; Energy. Thermal use of fuels; EVALUATION; Exact sciences and technology; FAST NEUTRONS; fast reactor; FAST REACTORS; ferritic/martensitic; FFTF REACTOR; FISSION; Fission nuclear power plants; FUEL PINS; Fuels; HT-9; Installations for energy generation and conversion: thermal and electrical energy; IRRADIATION; irradiation test; MOX fuel; NEUTRON FLUENCE; Nuclear fuels; PIE; SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; STRAINS; SWELLING
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2011.02.052

The ACO-3 irradiation test, which attained extremely high burnups of about 232 GWd/t and resisted a high neutron fluence (E > 0.1 MeV) of about 39 × 10 26 n/m 2 as one of the lead tests of the Core Demonstration Experiment in the Fast Flux Test Facility, demonstrated that the fuel pin cladding made of ferritic/martensitic HT-9 alloy had superior void swelling resistance. The measured diameter profiles of the irradiated ACO-3 fuel pins showed axially extensive incremental strain in the MOX fuel column region and localized incremental strain near the interfaces between the MOX fuel and upper blanket columns. These incremental strains were as low as 1.5% despite the extremely high level of the fast neutron fluence. Evaluation of the pin diametral strain indicated that the incremental strain in the MOX fuel column region was substantially due to cladding void swelling and irradiation creep caused by internal fission gas pressure, while the localized strain near the MOX fuel/upper blanket interface was likely the result of the pellet/cladding mechanical interaction (PCMI) caused by cesium/fuel reactions. The evaluation also suggested that the PCMI was effectively mitigated by a large gap size between the cladding and blanket column.