[en] In order to study the initiation and progression of damage during core degradation, especially the hydrogen source term during the reflood of a degraded core the QUENCH program is performed at Forschungszentrum Karlsruhe. Major objective of the QUENCH-09 bundle experiment was to provide data on the degradation of B₄C control rods, on the formation of gaseous reaction products during this degradation, and on the impact of control rod degradation on surrounding fuel rods. The test conduct was broadly similar to previous QUENCH experiments, but with the inclusion of a phase with steam starvation conditions before cooldown, thus widening the database and providing closer comparison with the planned PHEBUS FPT3 experiment. Significant release of gaseous reaction products from the B₄C oxidation and small amount of methane was only detected in the cooldown phase. From the large hydrogen release during the cooldown phase, it is conjectured that the long period of steam starvation caused regions of the bundle to be particularly susceptible to further oxidation. Much information can be drawn from the test and new aspects of the bundle behavior under such conditions have arisen. (author)