SM-2 REACTOR CORE AND VESSEL REVIEW REPORT FOR AUGUST 25, 1959 TO DECEMBER 14, 1959

The most adverse power distribution was revised based on a comparison of PDQ calculations and measurements made during the SM-2 flexible experiments. A review of the basic nuclear data and calculational models employed in the SM-2 nuclear analysis was rnade. A comparison between initial reactivily, hot-to-cold reactivity change, and xenon reactivity with experiment was rnade. Based on a revised power distribution, the core flow requirement was reestimated to be 7800 gpm. Tentative designs of the core support and fuel element structure were prepared and evaluated for pressure drop and flow distribu-tion. The ETR and MTR irradiation programs are suramarized. The TIG process for welding elements is discussed. Specimens of Eu/sub 2/O/sub 3/ dispersions in stainless steel were autoclave tested. Static deflection messurements indicated that a fuel element with cold rolled plates will have a deflection aproximately 18% lower than annealed plates. measurement of plate collapse on two elements indicated possible collapse in the range 140 to 164% of rated flow. Flow distribution and pressure drop tests were made for several core support structure configurations. Mockup experiments on the SM-2 initial cold, clean and SM-2 mid-life cores were completed. Limited power distribution and flux distributions were performed in the clean mockup. The hot-to-cold reactivily change was measured by aluminum displacement as 90. The average B/sup 10/ and U/sup 235/ worth in the clean mockup was measured as 43 and 0.157 cents /g. The reactivity effect of replacing control rod fuel assemblies by stationary fuel elements was measured in the clean mochup. Stuck rod positions were measured in the mid-life mockup. (For preceding period see APAE-memo-223.) (W.D.W.