3. DESCRIPTION OF EXPERIMENT
The EXP-FIO-131 experiment, performed at the Chalk River Laboratories in 1983, was a part of an experimental program on fuel performance under high-temperature transient conditions such as those associated with the onset of a loss of coolant accident (LOCA).
The main purpose of the EXP-FIO-131 experiment was to provide quantitative code verification data.
An instrumented, unirradiated, Zircaloy-sheathed UO2 fuel element assembly was subjected to a coolant depressurization (blowdown) transient in the X-2 pressurized water loop of the NRX reactor. The fuel element used 1.3 wt% U235 in uranium dioxide fuel clad with Zircaloy-4 sheath material.
The fuel assembly was instrumented with one functional centreline fuel thermocouple, a peripheral fuel thermocouple, six sheath thermocouples, four coolant thermocouples, an internal gas pressure transducer, and a pressure transducer to monitor coolant pressures at the fuel assembly outlet.
Post-irradiation examination (PIE) of the fuel element assembly included visual examination, sheath profilometry measurements, neutron radiography, and metallography, including fuel grain size measurements. Chemical burnup and fission-gas measurements were not done.