Experimental results on the breakaway oxidation of the E110 cladding alloy under high-temperature isothermal conditions

In order to evaluate the effect of zirconium breakaway oxidation on the behaviour of nuclear fuel in LOCA (Loss-of-coolant accident) conditions, high temperature (800-1200 °C) oxidation tests with E110 type cladding were performed in steam atmosphere. The onset time of breakaway oxidation was detected using an online method based on hydrogen release. The experimental results showed that the breakaway oxidation starts not earlier than 5 min after the start of the oxidation that is longer than the duration of dry phase in a design basis accident LOCA. The experiments give preliminary indication that the breakaway oxidation does not play role in design basis accident LOCA conditions with the E110 alloy. This is to be confirmed by transient oxidation tests.