Experimental Evaluation of hydrogen Concentration Reduction Performance of the presently developed Particle Recombination Catalyst

Abstract

The long-term safety storage of fuel debris is required for decommissioning of the Fukushima Daiichi nuclear power station scheduled for the end of 2021. When the fuel debris contains water, hydrogen is generated by radiolysis, and it is necessary to keep the hydrogen concentration in the fuel debris storage container below 4% using Passive Auto Catalytic Recombiner (PAR). In the present study, hydrogen concentration reduction experiments were conducted using spherical PAR with a diameter of 20 mm, and the effects of controlling factors such as the quantity of PAR and the hydrogen gas flow rate on the hydrogen concentration reduction were quantitatively evaluated. Moreover, numerical simulations were performed to confirm physical phenomena expected by the experimental results. It was confirmed that the hydrogen concentration could be kept below 4% as the hydrogen explosion lower limit by PAR and the fuel debris storage container with PAR was effective.