The shutdown system for the Clinch River Breeder Reactor (CRBR) includes two independent systems--a primary and a secondary system. The Secondary Control Rod System (SCRS) is a new design which is being developed by General Electric to be independent from the primary system in order to improve overall shutdown reliability by eliminating potential common-mode failures. The paper describes the status of the SCRS design and fabrication and testing activities. Design verification testing on the component level is largely complete. These component tests are covered with emphasis on design impact results. A prototype unit has been manufactured and system level tests in sodium have been initiated.

A two year design study has been completed for medical ion accelerators with beams of sufficient range and intensity for therapy. The particles of main interest were ions between carbon and neon, but the generation of proton and neutron beams was studied also. Cyclotrons appear to be good injectors for a heavy ion medical synchrotron, particularly if neutron and/or isotope production is desired as well. They also offer a competitive solution for proton beams of 250 MeV. A superconducting cyclotron design for 380 MeV/u carbon was worked out, but a synchrotron for heavy ion beams of 400 to 600 MeV/u and 5 x 10/sup 9/ particles/sec was found to be more economical and flexible.

Lead-tin plating can be rapidly and uniformly applied to a 0.25 in. square copper conductor. Such plating can be used as solder with a minimum flux requirement. In the range studied, the tin content of the coating can be controlled. It varies directly with the tin content of the bath and amperage and inversely with the temperature.

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