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| Program name | Package id | Status | Status date |
|---|---|---|---|
| IFPE/IFA-650.9-10-11 | NEA-1921/01 | Arrived | 08-APR-2024 |
Machines used:
| Package ID | Orig. computer | Test computer |
|---|---|---|
| NEA-1921/01 | Many Computers |
Moves to high burnup fuel design and introduction of new cladding materials have generated a need to re-examine and verify the validity of the safety criteria for Loss of Coolant Accidents (LOCA). LOCA tests at Halden are integral in-pile, single rod tests and they address various LOCA issues.
IFA-650.9
The test conditions were planned to meet the following primary objectives:
- to maximise the ballooning size to promote fuel relocation and to evaluate its possible effect on the cladding temperature and oxidation.
- to investigate the extent (if any) of - "secondary transient hydriding" - on the inner side of the cladding around the burst region.
The LOCA run in IFA-650.9 was carried out in April 2009. The tests address the LOCA performance of high burnup fuel irradiated in commercial nuclear power stations, showing considerable ballooning, fuel fragmentation and relocation when subjected to LOCA. Due to fuel relocation, the temperature measured with the lower cladding thermocouple approached 1200°C, and the test was terminated to avoid even higher temperatures. Cladding failure occurred at about 800°C, 130 seconds after the start of blow-down. A special feature of this experiment is the strong fuel fragmentation, relocation and dispersal.
IFA-650.10
The test was carried out using low fission power (2.5 kW/m) to achieve the desired conditions for high temperature, ballooning and oxidation. A heater surrounding the rod and operating at 1.2 kW/m was used for simulating the heat from adjacent rods.
The LOCA run in IFA-650.10 was carried out in May 2010 using a high burn-up PWR rod provided by EDF (56 MWd/kgU). The target peak cladding temperature was 850°C, and the hold time was ~169 seconds (from burst to scram). Rod overpressure at hot conditions was ~70 bar. Cladding failure occurred ~249 seconds after blow-down at ~755°C. The average cladding temperature increase rate during the heat -up was around 8°C/s. The results from the in-pile measurements and the gamma scanning indicate modest deformations and negligible fuel relocation.
IFA-650.11
The test was carried out using low fission power (2.4 kW/m) to achieve the desired conditions for high temperature, ballooning and oxidation. A heater surrounding the rod and operating at 1.6 kW/m was used for simulating the heat from adjacent rods.
The LOCA run in IFA-650.11 was carried out in November 2010 using a high burn-up VVER rod manufactured by JSC TVEL and supplied by Fortum Nuclear Service (51 MWd/kgU). The target peak cladding temperature was 1000°C, and the hold time was ~204 seconds (from burst to scram). Rod overpressure at hot conditions was ~55.7 bar. Cladding failure occurred ~207 seconds after blow-down at ~839°C. The results from the in-pile measurements and the gamma scanning indicate the fragmentation pattern together with a small burst opening (of about 3 mm long and max. 1 mm wide), which supported the fact that no fuel was detected at the bottom of the pressure flask.
OECD Halden Reactor Project
Institutt for Energiteknikk
P.O. Box 173
1751 Halden
Norway
Compilation: M. Veshchunov (IAEA)
These data have been released within the IAEA Coordinated Research Project FUMAC: International Atomic Energy Agency, Fuel Modelling in Accident Conditions (FUMAC), IAEA-TECDOC-1889, IAEA, Vienna (2019).
Keywords: cladding, experimental data, fuels, loss-of-coolant accident, thermal.
