INVESTIGATIONS ON THE PARTITIONING OF I-129 FROM SILVER-IMPREGNATED SILICA IN PREPARATION FOR FUTURE TRANSMUTATION

According to the current state of the art in reprocessing technology, the I-129 contained in spent fuel elements can be completely transferr ed to the dissolver off-gas and efficiently adsorbed on AgNO3-impregna ted silica (AC 6120). For future transmutation, the I-129 should again be separated selectively and as completely as possible (>99%) from th e AC 6120 adsorption matrix. Experimental studies show that a quantita tive recovery of the iodine is possible by wet chemical and thermal pr ocesses. Extraction experiments using iodine-loaded AC 6120 with sodiu m sulfide solution provide recovery rates of 99 +/- 1%. Reduction with hydrogen at 500 degrees C, in which gaseous HI was liberated, provide d recovery rates of >99%. After the separation of iodine, the reduced AC 6120 can be used again as an adsorbent for molecular iodine.