Co-60 Transport from Steel Creek as a Result of L-Reactor Restart

摘要

A total of 66 Ci of Co-60 have been discharged to SRP streams since startup. About 26.6 Ci of Co-60 have been released to Steel Creek from L (14.9 Ci) and P (11.7 Ci) areas. Due to radioactive decay only about 2.1 Ci of the initial 26.6 Ci of Co-60 remains today (halflife 5.26 years). If all of the released Co-60 remained in the Steel Creek system the 2.1 Ci Co-60 inventory is significantly less than the Cs-137 inventory of 67 Curies. The concentration and dose from the possible remobilization of this Co-60 is calculated. Co-60 has a strong affinity for sediments. Co-60 has been measured in the Steel-Creek system by aerial survey, and in the sediments. The aerial survey measured distribution of Co-60 is considerably less than the Cs-137 distribution. The highest Co-60 exposure rate isopleth range in the Steel Creek system is about 20% of the Cs-137 range. Co-60 activity is about one tenth the Cs-137 in the sediments of the Steel Creek system. (ERA citation 08:057637)