Thermal Behavior of Advanced UO{sub 2} Fuel at High Burnup
- Commissariat a l'Energie Atomique, Centre d'etudes de Cadarache, DEN/DEC, F-13108 St Paul lez Durance (France)
- Commissariat a l'Energie Atomique, Centre d'etudes de Saclay, DEN/DRSN, F-91191 Gif-sur-Yvette (France)
- AREVA, AREVA NP, 10 Rue Juliette Recamier, F-69456 Lyon Cedex 06 (France)
- EDF/SEPTEN, 12 Avenue Dutrievoz, F-69628 Villeurbanne (France)
To improve the fuel performance, advanced UO{sub 2} products are developed to reduce significantly Pellet-Cladding Interaction and Fission Gas Release to increase high burnup safety margins on Light Water Reactors. To achieve the expected improvements, doping elements are currently used, to produce large grain viscoplastic UO{sub 2} fuel microstructures. In that scope, AREVA NP is conducting the qualification of a new UO{sub 2} fuel pellet obtained by optimum chromium oxide doping. To assess the fuel thermal performance, especially the fuel conductivity degradation with increasing burnup and also the kinetics of fission gas release under transient operating conditions, an instrumented in-pile experiment, called REMORA, has been developed by the CEA. One segment base irradiated for five cycles in a French EDF commercial PWR ({approx} 62 GWd/tM) was consequently re-instrumented with a fuel centerline thermocouple and an advanced pressure sensor. The design of this specific sensor is based on the counter-pressure principle and avoids any drift phenomenon due to nuclear irradiation. This rodlet was then irradiated in the GRIFFONOS rig of the Osiris experimental reactor at CEA Saclay. This device, located in the periphery of the core, is designed to perform test under conditions close to those prevailing in French PWR reactor. Power variations are carried out by translating the device relatively to the core. Self - powered neutron detectors are positioned in the loop in order to monitor the power the whole time of the irradiation. The re-irradiation of the REMORA experiment consisted of a stepped ramp to power in order to point out a potential degradation of the fuel thermal conductivity with increasing burnup. During the first part of the irradiation, most of the measurements were performed at low power in order to take into account the irradiation effects on UO{sub 2} thermal conductivity at high burnup in low range of temperature. The second part of the irradiation consisted in power cycling with one steady-state at several powers (290 W/cm and 360 W/cm) to assess both the thermal conductivity at higher temperature (until 1600 deg. C) and the fission gas release kinetic. This paper summarizes and discusses the main results assessed for this advanced UO{sub 2} fuel: on the one hand, the thermal performances indicate that the fuel thermal conductivity is similar to the one of the standard UO{sub 2} fuel type (the thermal conductivity damage under irradiation can be modelling alike) and, on the other hand, the test results show low fission gas release in comparison with UO{sub 2} standard fuel. (authors)
- Research Organization:
- American Nuclear Society, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
- OSTI ID:
- 21229260
- Resource Relation:
- Conference: 2007 LWR Fuel Performance Meeting / TopFuel 2007, San Francisco, CA (United States), 30 Sep - 3 Oct 2007; Other Information: Country of input: France; 7 refs; Related Information: In: Proceedings of the 2007 LWR Fuel Performance Meeting / TopFuel 2007 'Zero by 2010', 683 pages.
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
BURNUP
CEA SACLAY
CHROMIUM OXIDES
CLADDING
FISSION PRODUCT RELEASE
FUEL PELLETS
IRRADIATION
KINETICS
MICROSTRUCTURE
NUCLEAR FUELS
PERFORMANCE
PWR TYPE REACTORS
SAFETY MARGINS
SELF-POWERED NEUTRON DETECTORS
SIMULATION
STEADY-STATE CONDITIONS
THERMAL CONDUCTIVITY
THERMOCOUPLES
URANIUM DIOXIDE