AREVA NP MR Cladding benefits for proposed US NRC RIA and LOCA requirements
- AREVA NP, 10, Rue Juliette Recamier, 69456 Lyon (France)
- AREVA NP, Route de Nantes BP 3021, 44560 Paimboeuf (France)
- AREVA Inc., 3315 Old Forest Road, Lynchburg, VA (United States)
- AREVA GmbH, Paul-Gossen-Strasse 100, 91052 Erlangen (Germany)
M5 is the reference alloy of AREVA NP for PWR cladding applications. It is a zirconium-based alloy containing 1% niobium, no tin, and well-controlled oxygen, iron, and sulfur contents. It has a fully recrystallized microstructure. The absence of tin in M5 results in a very low corrosion rate and hydrogen pick-up during normal operation, even at high burn-up and in high duty irradiation conditions. Due to this low hydrogen pick-up under irradiation (typically less than 100 ppm, End of Life), M5 retains a very good strength and an exceptional residual ductility during and after the accident. This allows utilities implementing M5 to simplify the safety analysis and to demonstrate significant margins regarding fuel related criteria. Simplified methods are easier for plants to implement and maintain for future plant operations and core design management. This paper specifically presents 3 examples on the safety improvement brought by M5 cladding. First, during a reactivity-induced accident (RIA), the properties of M5 are such that bounding analyses for future cycles are significantly simplified, in particular by demonstrating that fuel dispersal will not occur. The major aspects of the AREVA NP RIA methodology are presented. A second focus is made on the low hydrogen embrittlement of M5 and on its high ductility after quenching during a loss-of-coolant accident (LOCA). In a third part, the breakaway oxidation testing program currently under development in Paimboeuf (France) is described, including details about the testing devices and qualification. The tests have demonstrated that M5 cladding does not have breakaway at least up to 5000 s oxidation duration at 1000 C. degrees, which is much higher than the LOCA duration.
- Research Organization:
- American Nuclear Society - ANS, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
- OSTI ID:
- 22750138
- Resource Relation:
- Conference: Top Fuel 2016: LWR fuels with enhanced safety and performance, Boise, ID (United States), 11-15 Sep 2016; Other Information: Country of input: France; 24 refs.; Related Information: In: Top Fuel 2016 Proceedings| 1670 p.
- Country of Publication:
- United States
- Language:
- English
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