ISSN Online: 2379-1748
ISBN Flash Drive: 978-1-56700-469-4
ISBN Online: 978-1-56700-470-0
Second Thermal and Fluids Engineering Conference
Experimental Study For The Reflood Behavior of Nuclear Reactor In Medium And High Pressure Conditions Using 3×3 Heater Bundle
Abstract
For a loss-of-coolant accident (LOCA) conditions in a pressurized-water reactor (PWR), the coolant level
decreases and then fuel core is uncovered. The cladding temperature of uncovered fuel increases until the reflood
phase, which is a process to refill coolant into the core, and the cladding ballooning can be made at high
temperature position. The ballooned claddings block a coolant flow path in the fuel assembly and this flow
blockage is one of the major concerns associated with the coolability of partially blocked regions. Several
experimental programs had been devoted to perform the coolability after ballooned cladding. However, the
previous experimental programs did not consider the ballooned cladding in medium and high pressure conditions.
So, the coolability in partially blocked core in medium and high pressure conditions is one of the unresolved
thermal-hydraulic safety issues. In the present experimental program at Korea Atomic Energy Research Institute,
the reflood tests will be performed to investigate the effects of clad ballooning on the coolability of partially
blocked rod bundle in medium and high pressure conditions. The first phase of this experimental program is the
reflood test using intact rod bundle, which has 3×3 array intact heater rods, for reference conditions. And the
second phase is the reflood test using nine partially ballooned heater rods. In the present research, the first phase experiments had been performed and analyzed. The peak cladding temperatures, quenching temperatures and
quenching times were analyzed for various conditions.