Method and system for regenerating dehumidifier for use in charcoal adsorber

A method and system for continuously regenerating dehumidifiers of a charcoal adsorber system are provided. Off-gas, including radioactive noble gases, such as xenon and krypton, is physically adsorbed in charcoal adsorbers and discharged to the atmosphere after its radioactivity has decayed. Before passing to the charcoal adsorbers, the off-gas is subjected to dehumidifiers consisting of a molecular sieve or some other desiccant. A couple of dehumidifiers is alternately used because periodic regeneration for the dehumidifier is necessary to recover moisture adsorption ability of the desiccant. The regeneration for the dehumidifier is completed by the steps of purging the dehumidifier with fresh air, and thereafter circulating the fresh air within a closed loop including a heater, dehumidifier, cooler condenser, and blower. Moisture absorbed in the dehumidifier is carried away by circulating heated fresh air and separated from the fresh air by cooling condensers. After completion of the regeneration, the fresh air is returned to the charcoal adsorber system for further treatment. By employing fresh air as regeneration gas, the regeneration for dehumidifiers can be completed faster and with less contamination as compared with a conventional method of employing off-gas for regeneration.