Method of cleaning sodium-contaminated equipments

Purpose: To efficiently remove hydrogen resulted from chemical reaction between sodium and cleaning liquid out of a cleaning tank and regenerate the removed hydrogen as water under the safety oxidizing treatment. Constitution: Exhaust gases from a cleaning system from which alcoholic vapors have been separated are conditioned for the flow rate so that the hydrogen concentration is kept higher than 75 volume %, that is, the explosive limit and sent to a hydrogen gas processing device. The hydrogen-containing exhaust gases adjusted to such a safety flow rate are reacted in an oxidizer with oxygen contained in air supplied thereto and converted into steams. The steam, airs or the likes treated in the oxidizer are cooled in contact with a cooling pipe introduced from a cooler and only the steams are condensated and recovered as water. Then, the water is stored from the cooler to a water-store tank and the amount is monitored by a level meter disposed at the upper portion of the tank. Remaining airs are discharged by way of the cooler. (Yoshihara, H.)