GAS-COOLED REACTOR PROJECT QUARTERLY PROGRESS REPORT FOR PERIOD ENDING MARCH 31, 1961

Reactor Physics. Criticality calculations wee made for the EGCR without experimental loops and for various enrichments, and the results were used to derive the base value for the EGCR fuel enrichment. Reactor Design Studies. Studies of the performance of EGCR fuel and control rods were made. The moderator temperature distribution and the required coolant flow were determined. Investigations of structural integrity were made for the EGCR pressure vessel, through-tubes, and graphite colunm. The results of a preliminary study of the EGCR containment system and of the possibility of a runaway graphite fire are discussed. Decontamination studies of EGCR components are reported. Heat Transfer and Fluid Flow. Studies of fluid flow asymmetries, surface-temperature profiles, and heat transfer coefficients are reported. The application of mass transfer measurements to predictions of heat transfer in seven-tube clusters is concluded to be valid. Velocity contours were mapped for EGCR channels. Pressure-drop and gas-mixing measurements in EGCR fuel assemblies are reported. Materials Development. Fabrication of dense UO/sub 2/ grains and discs is described. Measurements of Xe/sup 1//sup 3//sup 3/ release rates from UO/sub 2/ pellets and powders at 400 to 1600 deg C are reported. Fabrication studies were carried out on fueled BeO. The phases present in BeO-- ThO/sub 2/-- UO/sub 2/ bcdies were identified to be pure BeO, a ThO/sub 2/-- UO/sub 2/ solid solution, and a small amount of pure UO/sub 2/. Evaluation of UO/sub 2/ spheres coated with pyrolytic carbon by thermal cycling and leaching tests is reported, Evidence of a reaction between UC and Be was found after a 66-hr test at 1100 deg C. Inspection results are presented for coatings on EGCR graphite support sleeves. Measurements of the mechanical properties of AGOT graphite are reported. Axial elongation of EGCR fuel elements in thermal cycling experiments was studied. Oxidation and carburization of 304 stainless steel by CO --CO/sub 2/ mixtures were studied. The thermal stability of Sb/sub 2/O/sub 4/ was studied at 400 to 1000 deg C. Oxidation of Be by dry CO/sub 2/ and H/sub 2/O vapor was studied. Studies on joining Be and fabrication of Be-clad fuel elements were made. Inpile Testing. Irradiations of a large number of fuel specimens and structural materials were carried out and the results of postirradiation examimations and property measurements presented. Out-of-pile Testing. Static and convection loop tests in hot helium were carried out with graphite and metal specimens, and carburization reactions in these systems were studied. The degassing behavior of graphite was studied, and porosity determinations are reported. The results of investigations of the removal of fission gases from He and other gases are discussed. Abnor mal emf drifts of thermocouples in He are discussed. Development of Test Loops and Components. Testing and development of the following components are discussed: EGCR through-tube nozzles, microswitch, globe valves, GCR-ORR loop No. 2, and loop compressors. (D.L.C.