SEDL / STP / STP939-EB / STP28141S

Experimental and Theoretical Results of Cladding Oxidation Under Severe Fuel-Damage Conditions

Hofmann, P
Institut für Material- und Festkörperforschung, Karlsruhe,

Neitzel, HJ
Institut für Reaktorbauelemente, Karlsruhe,

Pages: 35    Published: Jan 1987

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Abstract

Under severe fuel-damage (SFD) conditions a combined external and internal oxidation of the fuel-rod cladding occurs due to a reaction with steam or oxygen on the outside surface and the UO² fuel on the inside surface. These reactions result in the formation of oxygenstabilized α-Zr(O) phases, ZrO², and a (U,Zr) alloy. The reaction kinetics have been studied with isothermal and transient temperature experiments above 900°C. The tests were performed using short LWR fuel-rod sections in an (Ar + 25 vol% O²) environment. The numerical model PECLOX, which solves the Fick and Stefan equations, has been developed. It predicts the formation, growth, and disappearance of the various interaction layers and the corresponding oxygen profiles as functions of temperature and time.