Abstract: COST ANALYSIS FOR CONTROL MEASURES OF 131I　RELEASEXie Yunmian Yin Yuanshu(China Institute of Atomic Energy, Beijing 102413)ABSTRACT131I quantity in/on the leaves of plants around CIAE was found exceeding the GB 5481 limit in 1979, so experiments are performed to investigate the causes and some measures for reducing 131I release are suggested, such as improving the production process, adopting a highlevel 131I liquid waste smallstorage tank at site for delay release, and installing a small charcoal fillter in the offgas discharge pipe of the 131I production shop. The cost for these measures are analysed. The 7year operating results indicate that the release quantity of 131I has been effectively reduced to 18％ of the GB 5481 limit, although the total 131I production is on the increase year by year. It is concluded that these measures meet well the ALARA rule.Key words 131I control measures of 131I release cost analysis