Impacts of atmospheric tritium releases from solid waste storage areas

Burial sites for low-level radioactive wastes are situated on the Oak Ridge National Laboratory (ORNL) reservation. Releases of radioactive material from these sites into the ground- and surface waters, thus affecting nearby residents, has long been a concern. Such releases are considered the primary pathway of concern from low-level burial sites in humid regions. However, recent publications indicate that the atmospheric pathway, through which tritiated water vapor, /sup 14/C, /sup 85/Kr, /sup 222/Rn, and possibly other gases are emitted the trenches, dispersed downwind, and inhaled, may be an important impact from some low-level burial sites. This paper represents an attempt to estimate the atmospheric contribution from the ORNL burial grounds, specifically the Solid Waste Storage Areas (SWSAs), to the total dose commitment resulting from ORNL burial ground operations. The results of this study indicate that tritium released from the ORNL SWSAs is not a significant contributor to the offsite dose received as a result of ORNL operations. The assumptions used in this study are conservative, but some additional work may be required before the problem can be dismissed. 8 refs

HTGR severe accident sequence analysis

Thermal-hydraulic, fission product transport, and atmospheric dispersion calculations are presented for hypothetical severe accident release paths at the Fort St. Vrain (FSV) high temperature gas cooled reactor (HTGR). Off-site radiation exposures are calculated for assumed release of 100% of the 24 hour post-shutdown core xenon and krypton inventory and 5.5% of the iodine inventory. The results show conditions under which dose avoidance measures would be desirable and demonstrate the importance of specific release characteristics such as effective release height. 7 tables