When the construction of the confinement facilities for Hanford production reactors is completed, the potential for contaminating the environment with accidentally released fission products will be greatly reduced. This was demonstrated already when rupture debris burned in the rear face area of one of the reactors in which the fog spray was installed and ready for service. The fog spray effectively prevented the spread of contamination to the ventilation equipment downstream of the rear face enclosure. Also, the commercially- available absolute filters and charcoal beds will significantly decontaminate the exhaust air, stream of all fission products except the noble gases. Laboratory studies indicate that the filter system should remove at least 50 percent of all fission product halogen vapors and over 90 percent of the particulate matter released from a nuclear incident. In addition, the charcoal beds should provide an additional 90 to 95 percent decontamination of the halogens that manage to pass through the filter. It is not expected that any of the noble gases released will be removed by this system. Laboratory studies, in general, substantiate previous estimates on the release of fission products from overheated uranium fuels. The theoretical estimates are quite accurate for the volatile and …