Two xenon extraction runs were made this month. It appears that a small design change in Trap #2 will be necessary so that a dry ice-trichloroethylene slurry can be used for coolant rather than liquid freon. For each of the runs this month the enriched generator was exposed for four hours in the est pile operating at 100 watts. A period of eight hours for cooling and xenon builidup was allowed before the collection and separation runs were started.

Examination of Al- 1.65w/o Pu and Al- 12 w/o Si- 1.65 w/o Pu capsules irradiated 55- 60% burnout of the plutonium atoms revealed a 1.4% volume increase and no apparent microstructural changes. A four rod cluster containing Al-8 w/o Pu and Al-12 w/o Si-8 w/o Pu alloy cores is currently under irradiation in Loop 3 of KE Reactor at a water temperature of approximately 230C. A second cluster has been fabricated an is scheduled for charging late in 1958. Two seven-rod clusters for irradiation in KER are also being fabricated.

This is the sixteenth quarterly report of the research and development activities of the Radiological Sciences Department, Hanford Atomic Products Operation, as before, includes some items charged to control but included for general interest. Such are identified as "not charged to research."