Investigations on the testing of iodine filters by different methods

The retention of 131I by a deep bed carbon filter (adsorber) of an FRG pressurized water reactor under normal conditions was determined with different test methods. These comprised in-place tests on the carbon filter with CH3131I and 131I from the plant (contained in the exhaust air) and laboratory tests on carbon samples with CH3131I. The laboratory tests with CH3131I produced results that were not conservative with respect to the organic 131I from the plant because of the occurrence of more penetrating organic 131I species in small proportions (<10%)