Experimental results of the bundle test QUENCH-19 with FeCrAl claddings

The QUENCH-19 test objective was the comparison of FeCrAl(Y) and ZIRLO™ claddings under similar electrical power and gas flow conditions, simulating an early phase of hypothetical severe accident. In common with the previous QUENCH-15 experiment (performed with ZIRLO™ claddings), the electrical power was the same during pre-oxidation and transient stages. After reaching of the maximum power of 18.12 kW the power value was kept constant during about 2000 s. At the end of this phase the maximal peak cladding temperature of about 1500 °C was reached. Much lower heating rate in comparison to QUENCH-15 was measured. Exceeding 1400 °C sharp increase of hydrogen release rate was observed. The test was terminated with reflood by injecting of about 48 g/s of water from the bundle bottom. The temperatures at all bundle elevations decrease immediately after water injection. The total hydrogen release during the whole test was 9.2 g compared to 47.6 g in the QUENCH-15 test with much shorter high electrical power phase. The videoscope observation showed the damage of several claddings at the bundle elevations between 850 and 1000 mm. The claddings were failed either due to melting (mostly) or by spalling of small annular cladding parts.