-19a substantially higher g/T level than the present standard production; and the aéceptence of this level will make it possible to produce the high quality material in addition without too much trouble. It will not be necessary to undettake newprocess plant. constructioti beyond that now planned, The requirement for high quality material will not be met in. 1955,.and probablynot in 1956, but will be in 1957. | ‘There was some consideration of whether still higher quality plutonium would be needed, as suggested in Dr. Bradbury's letter. Dr, Mark summarized the situation by saying that material of better than 200 g/T quality was not needed for present designs, but that its lack would place a limitation on future design possibilities, | U-233 Dr. Pittman reviewed the U~233 situation, According to a recent - study, the cost of U-233 would be comparable to that of 20 n/g-sec plutonium. It was planned to commence some. production by loading an enriched Savannah River reactor with thorium next year. There is some indication that the supply of thorium metalwill be a bottleneck. For a separation plant; a Savannah River Purex plant will probably be converted to the Thorex process, | | Upgrading plutonium by isotope separation did not appear economically Piutonium advantageous, under any conditdons, in comparison to U~233. Isotope Separa- tion (Dr. Pittman referred the Committee to an Operations Analysis report by Mr. Herron, which compared low g/T, isotope separation, and U-233. report was not available during the meeting.) However, the | The lithiun-6 production plans had not been altered, and the plan to Li-6 construct a second plant was going along. LOH to LAD might be a bottleneck, The capacity for converting |

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