Gaseous systems decontamination

It will have become apparent that the decontamination applications for gaseous systems are very important, and can involve very large flow volumes. The applications include ... 

Metal parts and dunnage are decontaminated to a 5X level, and gaseous effluents from the hydrolysis processes are treated in the gas-phase chemical reduction (GPCR ) system. 

Cyclone. The first element in the system for DTS gaseous effluent is the cyclone provided to separate large particulate matter that could rapidly plug the downstream candle filters. This element is not required in the system for MPT gaseous effluent. Separated particulate matter is discharged into a steel container through a rotary air lock. The particulates are processed in the MPT to ensure 5X decontamination. 

The PRH hydrolysate is discharged to a stirred tank, where the hydrolysis of agent is completed. Air is drawn through the PRH to remove volatile materials, and the gaseous effluent is passed through a CATOX, scrubber, and carbon filters prior to release to the plant s HVAC system. The solids, consisting of the washed munitions parts, go into the HDC that treats metal parts from the projectile agent removal system (Step 16), where they are decontaminated to a 5X level. 

Under the 10 and last Decommissioning Permit, the remaining auxiliary systems (sodium washing plant, ventilation plant, liquid effluent system, gaseous effluent system, etc.) are to be dismantled and any buildings remaining are to be decontaminated, measured for clearance, and then demolished, if necessary. Then the site is to be recultivated. 

Numerous fuel reprocessing plants have been operated (or planned) that included iodine removal systems on the gaseous effluent streams (CEC, 1982a). Table 6.1 lists several reprocessing plants along with type of iodine removal system used at each and the overall stack decontamination factor. Overall stack DFs can vary considerably compared to the theoretical efficiency of the individual systems because of routing in the plant of streams that may contain iodine. 

The estimated total accumulated amount of I that will be produced in U.S. nuclear power reactor fuels through the year 2000 is about 2500 curies. If reprocessing resumes and decontamination factors of 500 exist for gaseous effluent treatment systems, only about 5 Ci of this total will have been released to the environment from fuel reprocessing plants. The remainder will be incorporated into solid wastes appropriately isolated from the biosphere. 

---