Failure behavior of SiC/SiC composite tubes under strain rates similar to the pellet-cladding mechanical interaction phase of reactivity-initiated accidents

Journal Article · Thu Nov 15 00:00:00 EST 2018 · Journal of Nuclear Materials

DOI:https://doi.org/10.1016/j.jnucmat.2018.11.023· OSTI ID:1505329

Cinbiz, M. Nedim ^[1]; Koyanagi, Takaaki ^[1]; Singh, Gyanender ^[2]; Katoh, Yutai ^[1]; Terrani, Kurt A. ^[1]; Brown, Nicholas R. ^[3]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2. The Univ. of Tennessee, Knoxville, TN (United States)
3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); The Pennsylvania State Univ., University Park, PA (United States)

The mechanical response of a nuclear-grade silicon carbide fiber-reinforced silicon carbide matrix (SiC/SiC) composite was investigated under mechanical loading conditions mimicking the pellet-cladding mechanical interaction (PCMI) phase of a reactivity-initiated accident (RIA). In a RIA, cladding deformation and failure can be induced by the rapid thermal expansion of the nuclear fuel. A pulse-controlled modified-burst test was used to investigate RIA-like PCMI scenarios on SiC/SiC composite samples at pulse widths from 12 to 100 ms.The strain-driven nature of the cladding sample deformation was due to the rapid internal pressurization and subsequent expansion of a secondary tube. A digital-image correlation technique was used to measure strains from the speckle-painted outer surface of the tubes. The failure strains of samples tested at slower rates, such as RIA event durations of 52 and 100 ms, showed good agreement with the literature-reported values for similar composites tested at slow strain rates. Additionally, the failure strain showed good agreement with reference expansion-due-to-compression tests at slow strain rate. However, a decrease in the failure strain was determined for the fast-rate (12 ms) tests. This indicated that the failure strain of these composites might be influenced by the strain rate during RIA-like events. In conclusion, the failure strains observed in the tests corresponded to local energy depositions of approximately 50 cal/g UO₂ from hot zero power, with an initial condition of pellet–cladding gap closure prior to the event. In-pile transient testing of these concepts that would result in hoop strain due to PCMI in the range of 0.5–1.0% is recommended.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE; USDOE Office of Nuclear Energy (NE)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1505329
• Alternate ID(s): OSTI ID: 1636123; OSTI ID: 22886802
• Journal Information: Journal of Nuclear Materials, Journal Name: Journal of Nuclear Materials Journal Issue: C Vol. 514; ISSN 0022-3115
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Accident-tolerant fuel
Medium-strain rate
Modified burst test
Pellet–clad interaction
Reactivity-initiated accident
SiC/SiC composites
Strain rate