The deposition of film was studied in irradiated circulating loops, in which both grounded and insulated plates were in the irradiated coolant volume; the purpose of these tests was to determine the effect on rate of film formation of charges generated on particulate matter or coolant molecules in the radiation field. Heavier deposits were found on the grounded plates and currents up to 30 microamp were measured flowing to this plate. Tests in the rocking cell showed that techniques are now available whereby this apparatus can be used with confidence to screen film-forming characteristics of coolant compositions. It was demonstrated that iron percarbide (Fe/sub 20/C/sub 9/) could be made under conditions comparable to those in the OMRE. It was made from an iron chelate by carbon monoxide reduction and emphasizes the possible importance of oxygen containing chelate in the transport of iron and deposition of film. The nature of the impurities occurring in commercial Santowax was examined and some highly colored, oxygenated material isolated. The hexaphenyls produced in irradiation of m- and p-terphenyls and in the reaction of polyphenyls with hydrogen atoms was studied. Further work was initiated in the area of synthesis of reference hexaphenyls, but synthesis of new …