Mechanical Behavior of Ballooned and Ruptured Cladding (NUREG-2119)

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Publication Information

Manuscript Completed: February 2012
Date Published:
February 2012

Prepared by:
Michelle Flanagan

Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001

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This report presents and discusses the results of the NRC’s integral loss-of-coolant accident (LOCA) research program. In this program, the residual bending moment and failure energy were measured using the four point bend tests for as-received and irradiated samples following exposure to LOCA conditions to determine the resistance to fracturing of ballooned cladding. The findings of this research program have been used to develop a recommendation for how to treat the ballooned region in LOCA analysis. To support the recommendation, this document will begin with a review of the regulatory history of the balloon region, present a discussion of available test methods for measuring post-LOCA cladding behavior, present the results of bend tests on as-fabricated and irradiated cladding material following exposure to LOCA conditions, and conclude with recommendations for using this information to inform regulatory decisions. The purpose of this document is to serve as the technical basis for the treatment of the ballooned and ruptured regions of a fuel rod in LOCA analysis.

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