REACTOR DEVELOPMENT Modifications to the Initial Engine Test (IET) facility to accommodate the HTRE-3 are to be completed in the late summer of 1958. Construction work continued on the Flight Engine Test (FET) facility and the Shield Test Pool Facility (STPF). , Indirect cycle approach, Primary emphasis in the indirect cycle effort continued on determining the feasibility of a lithium-cooled, llguid cycle reactor. Tests carried out on the compatibility of various reactor materials to Hthtum continued to indicate that niobium, molybdenum, zirconium, and titanium offer the promise of containing lithium at temperatures. required by aircraft reactor operations. However, zirconium and titanium Jack structural strength at high temperatures, and will probably be used only as alloying agents. Tests have shown that fron base alloys do not have sufficient promise to justify their consideration as materials for containing Hthium in aircraft reactors. Twelve isostatically pressed, stainless stee)-UO, fuel pin specimens were examinedafter they were irradiated in the Materials Testing Reactor at temperatures up to 1,600 degrees Fahrenheit and fuel burnups of approximately 6 percent. Fuel element development work was being converted from stainless steel to niobium as rapidly as possible. Irradiation of the first niobium clad specimens was planned for the summer of 1958. Kuclear Propzision for Unmanned Vehicles Nuclear rocket propulsion (Project ROVER). Fabrication and assembly were on schedule for Kiwi A, the first of a series of experimental reactors designed to provide data for the demonstration of feasibility of nuclear rocket propulsion under realistic operating conditions, Kiwi A is a nonflyable 100,000-kilowatt reactor using graphite plate fuel elements. At the end of the April-June quarter the pressure shell, loaded fuel plates, and other components were completed and were being assembled at the Los AlamosScientific Laboratory (LASL). Plans called for the following schedule: shipment of Kiwl A, less the control assembly, to the Nevada Test Site (NTS) in July, the shipment of the control assembly to NTS in August; a detailed check of the complete reactor and control system in September and October; the initiation of zero power experiments in mid-November; and the beginning of power experiments in January 1959. Cozstraction of facilities continued at NTS in preparation for testing Kiwi A and other nuclear rocket devices. Roads, utilities, support facilities, and the control building were completed, and construction of the test cell, propellant tank farm, and the assembly-disassembly building was showing satisfactory progress. Development of refractory metal fuel elements continued at LASL, and preliminary design work W2S bezun on Dumbo A,the initial refractory metal reactor test device. Dumbo A,the second experimental reactor in the test series, is also to be a nonflyable test reactor with a i nate ent ne towta thiltinshiged vated ‘ * ‘ |. duet . <enpdan bse: 7 oo power level of about 500,000 kilowatts. Molybdenum is to be used as the fuel element base material, zirconium hydride as the moderator, and beryllium as the reflector material. Nuclear ramjet propulsion (Project PLUTO). Technical work on PLUTO was on schedule at the University of California Radiation Laboratory (UCRL) at Livermore and Atomics International. Construction work was started on the PLUTO facilities at the Nevada Test Site, and on the critical test cell and assembly building at UCRL. Early in May the Marquardt Aircraft Company, at the invitation of the Air Research and Development Command, USAF, briefed those aircraft companies interested in conducting a study of a low altitude nuclear ramjet missile on the parametric aspects of a nuclear ramjet engine. At the end of June the Air Force wzs evzluating proposals for such a study received from eight companies. Systems for Nuclear Auxiliary Power (SNAP). Performance specifications for SNAP TI (500-watt radioisotope unit) and environmental specifications of SNAP I and SNAP Tl (3-Kilowatt ’ 16 Beer