Measurement and Evaluation of Hydrogen Production from Mixtures of Seawater and Zeolite in Decontamination of Radioactive Water

Abstract

Zeolite is used for decontamination of radioactive water containing salts from seawater in the Fukushima Dai-ichi Nuclear Power Station. Evaluation of hydrogen production by water radiolysis during the process is important for a safe operation. Thus, hydrogen production from the mixture of zeolite and seawater was studied by γ-radiolysis experiment, and the hydrogen production during the process was evaluated. The measured yield of hydrogen from seawater was comparable to the primary yield in the γ-radiolysis of water. This result indicates that oxidation of hydrogen by radical products of water radiolysis is not effective in seawater. The measured yield from the mixture decreased at a high weight fraction of zeolite. However, the measured yield was higher than that expected from the direct radiolysis of water in the mixture, which would decrease proportionally to the weight fraction of water. This result suggests that the radiation energy deposited on zeolite is involved in hydrogen formation. From the measured yields, the hydrogen production rate was evaluated to be 3.6 mL/h per ton of radioactive water before the process and 1.5 L/h per ton of the waste adsorbent after the process.