A Guide to Release-Rate of lodine-131 from Stack in Normal Operation of Reactor

Abstract

For estimation of release-rate of ¹³¹I, are discussed both the effect of individual variations by age in the general population and the additional effect of ingestion of foods contaminated in the neighborhood of a reactor-site. The limiting release-rate from the 55-meter stack of the Japan Power Demonstration Reactor (JPDR) is then estimated.

The release-rate should be determined in consideration of children of ages one and two since in these subjects the positive effect from increase in breathing-rate exceeds the negative effect due to increase in thyroid-mass. The effect from ingestion with green vegetables would become comparable to that from inhalation with air, when the deposition-velocity is 2cm/sec and the intake-rate is about 100g/day. The limiting release-rate from the JPDR is about 4mc/hr under meteorologically neutral conditions with mean wind-speed of 2.5m/sec, which is the most predominant condition at the Tokai site.