Development of exhaust air filters for reprocessing plants

Work completed: 1. An iodine and aerosol test rig was built jointly with GWK in a caisson in WAK and accepted by the TUeV (Technical Inspectorate). An in-line iodine measuring probe was installed in the dissolver off-gas line. 2. Sampling systems for the dissolver and vessel off-gas were designed and built for examination of the gaseous components. 3. High loading level and desorption tests were carried out in the laboratory with AC 6120/H1 as the iodine sorption material. 4. The flowsheet for PASSAT and all the technical criteria for delivery and acceptance and specifications for the components and examination of the bids were begun. 5. Fabrication and partial testing of a prototype iodine filter (box design) were completed. Results: Ad. 1. In principle, iodine measurements can be performed with the existing iodine measuring system. Improvements were achieved and tested in prolonging the service life of the system. Also a parallel development seems to be successful. Ad 2. First samples were taken to determine the concentration of organic constituents in the vessel off-gas of the WAK facility. Ad 3. In the case of iodine concentration peaks of > 10 g I2/m3 of offgas there is physical adsorption on the iodine sorption material in addition to chemisorption. The optimization of a sweep phase for further transport of the adsorbed iodine up to the point of binding by chemisorption in deeper layers of the filter will be the object of further studies. Ad 4. The assembly structure to accomodate the whole system has been set up. Technical discussions about the adjudication of the contract for the plant have in part been finished. Ad 5. Partial testing of the prototype iodine filter (box design) produced good results in long time and handling tests. (orig./RW)