Nuclear Science and Techniques

《核技术》(英文版) ISSN 1001-8042 CN 31-1559/TL     2019 Impact factor 1.556

Nuclear Science and Techniques ›› 2009, Vol. 20 ›› Issue (5): 312-316 doi: 10.13538/j.1001-8042/nst.20.312-316

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Effect of water injection on hydrogen generation during severe accident in PWR

TAO Jun* CAO Xuewu   

  1. School of Mechanical and Power Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
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TAO Jun, CAO Xuewu. Effect of water injection on hydrogen generation during severe accident in PWR.Nuclear Science and Techniques, 2009, 20(5): 312-316     doi: 10.13538/j.1001-8042/nst.20.312-316

Abstract:

Effect of water injection on hydrogen generation during severe accident in a 1000 MWe pressurized water reactor was studied. The analyses were carried out with different water injection rates at different core damage stages. The core can be quenched and accident progression can be terminated by water injection at the time before cohesive core debris is formed at lower core region. Hydrogen generation rate decreases with water injection into the core at the peak core temperature of 1700 K, because the core is quenched and reflooded quickly. The water injection at the peak core temperature of 1900 K, the hydrogen generation rate increases at low injection rates of the water, as the core is quenched slowly and the core remains in uncovered condition at high temperatures for a longer time than the situation of high injection rate. At peak core temperature of 2100–2300 K, the Hydrogen generation rate increases by water injection because of the steam serving to the high temperature steam-starved core. Hydrogen generation rate increases significantly after water injection into the core at peak core temperature of 2500 K because of the steam serving to the relocating Zr-U-O mixture. Almost no hydrogen generation can be seen in base case after formation of the molten pool at the lower core region. However, hydrogen is generated if water is injected into the molten pool, because steam serves to the crust supporting the molten pool. Reactor coolant system (RCS) depressurization by opening power operated relief valves has important effect on hydrogen generation. Special attention should be paid to hydrogen generation enhancement caused by RCS depressurization.

Key words: Pressurized water reactor (PWR), Severe accident, Core damage state, Depressurization, Water injection, Hydrogen generation, Steam starvation