Dt=olgnDesign efforts on the MSRE continued un all :t'ronts. Although findings of continuing studies necessitated some revisions, both the goals of the experiment and the basic design of the plant remained unchanged. The re;:i.ctor is to proviU.e facilities for demonstrat.ion of safety, dependability, and. serviceability of molten-salt systems and is intended to produce information on the behavior of graphite under irradiation and in contact with molten salts.The reactor., fuel pump, and heat exchanger will be located in the reactor cell. A component and process-piping layout was completed with a check of thermal stresses in the piping. Layout of auxiliary connections is in progress. Checking of thermal stresses in the coolant piping is in progress. The drain-tank area layout is under revision following the decision to eliminate freeze flanges from the drain.lines in the initial construction.Detajl drawings of the reactor were completed. A set of five molybdenum bands was included in the midplane of the graphite core to restrain bowing of thP stringers caused by the fast-flux e;r.adient. FouL• 11 .f:lOiSon tubes;' are intended to introduce nuclear poison in the reactor to balance reactivity changes stemming from xenon sorption or potentfa,l fuel absorption in the moderator graphite. The fuel fr.action in the core was raised to 22.5%, minimizing the nuclear consequences of such eventualities. The design of the air-cooled radiator and drain tanks was completed.The off-gas system piping is designed to .accommodate either fresh or recycle helium. The xenon decay was increased to 72 days minimum so that the raclioacti vi ty of the stored helium should not exceed 15 curies. Dalt-c'.ontaining lines and components will be provided with heaters capable of heating the system to 1250°F. Heating units were designed. for the reactor, drain tanks, aud pi pine;. Specifications were prepared for the single-arm remote-maintenance manipulator. Design of individual tools and racks is in progress.Heat-balance and neutron-level meC:l.mirementc ocrve o.B the indicators of reactor power. Automatic control of reactor power appears necessary because of the sluggishness of the.system and uncertainties of graphite. The rioison tubes provide a total of 12% &/k for control purposes. Interlocking functions w.i.11 control the heat withdrawal at the radiator. vThe design of the hot-test stand for the MSRE fuel pump was completed, and fabrication was started. Design of the water test stand for the MSRE coolant pump was essentially completed.The pump containing a salt-lubricated journal bearing continues to operate satisfactorily after 7440 hr at 1225°F, including 72 stops and stFJ.:r.ts.The small frozen-lead-sealed pump failed after 22,000 hr of operation, apparently as a result of erosion of the shaft by metal oxides.Defiign and fabrication of the MSRE engineering tes.t loop were completed.Several types of end seals are •being developed for use as cold end seals for mineral-insulated sheathed thermocouples in MSRE installations.Hemote electrica...