QUARTERLY STATUS REPORT ON LAMPRE PROGRAM FOR PERIOD ENDING MAY 20, 1961

LAMPRE-L The reactor was started up and held st 160 deg C and at hot critical for various measurements. Some of the 160 deg C measurements included rod worth, temperature coefficient, and shim-down extrapolated mass. In the approach to hot critical, multiplication was measured during the temperature increase from 160 to 500 deg C and found to increase markedly when the core meltsd. Reactivity changes due to jarring of the fuel capsules to remove bubbles and voids in the melted fuel were observed. Zero measurements made at 48O deg C are reported. Power coefficient measurements at 0 to 46 kw and power demand experiments were made, and the 50-kw transfer function is plotted. Shielding inadequacies are discussed briefly. The results of a fuel pin scan are given. Observations on the performance of the sodium system are discuaaed. Type 17-4 PH stainless steel was found to undergo additional grain boundary precipitution during long-term exposure to temperatures below the hardening temperature, and measurements of its properties are reported. fuel and Container Development. Impurities in the LAaMPRE-1 fuel which has a corrosive effect on the fuel container are discussed. Observations in the Pu -Ce-Co phase diagram are reported. Different types of LAMPRE-1 capsule failure are discussed. Work on improving the corrosion resiatance of Ta revealed Y and W to be beneficial additives. Sodium Test Facility. The test facility was opersted nearly continuously. with test equipment pieces receiving total operating times as high as 10,400 hr. The He cover gas in the primary and secondary loops was analyzed for buildup of O/sub 2/, H/sub 2/, and CH/sub 4/. (D.L.C.