Simulation of the Bundle Test QUENCH-07 with the Severe Accident Analysis Codes ASTEC V2.1 and AC~² - ATHLET-CD

摘要

During a severe accident in a light water reactor (LWR) the likely production of hydrogencan cause oxyhydrogen reactions with serious consequences. In order to gain abetter understanding of the thermal behavior, oxidation kinetics and the resulting hydrogengeneration of core materials like Zircalloy-4 (Zry-4), the QUENCH tests wereconducted.In the framework of the QUENCH-07 bundle test, the impact of absorber rod failure onhydrogen, carbon monoxide, carbon dioxide and methane generation can be determined.From the beginning of the test a mixture of overheated steam and argon with amass flow of 3 g/s each, streams through the bundle. The latter consisting of 20 heatedfuel rod simulators and one central unheated boron carbide absorber rod simulatorwith a stainless steel cladding and a Zircalloy-4 guide tube. Validation work presentedin the following shows the simulation of the bundle test QUENCH-07 with the severeaccident analysis codes ASTEC V2.1 and AC~² - ATHLET-CD. An objective of the simulationsconducted is the analysisand assessment of thecode capabilities to simulatethe most relevant phenomenain particular related to boroncarbide during the QUENCHtest. For the simulations conductedwith ASTEC an existinginput deck by L. Laborde andF. Igier for QUENCH-03 andQUENCH-11 was used as abasis and modified forQUENCH-07 [LAB14]. For thesimulations conducted withAC² - ATHLET-CD an existingversion by T. Drath was updatedto the latest code version[DRA07].