Study on the Behavior of Radiolytically Produced Hydrogen in a High-Level Liquid Waste Tank of a Reprocessing Plant: Hydrogen Consumption Reaction Catalyzed by Pd Ions in the Simulated Solution

It is well known that not all of the hydrogen formed in high-level liquid waste comes out in the gas phase because hydrogen is consumed by some unclarified secondary reaction. Using a simulated waste solution, it was found that the H₂ consumption reaction is not caused by radiation as was thought but is caused by a catalytic effect of Pd ions, which suggests that the same reaction proceeds in actual solution. Using the catalytic reaction rate constant measured in the simulated solution, the analysis showed that the H₂ concentration in the gas phase does not reach its explosion limit of 4% even if the sweeping air stops for a long time.