[en] Secondary ion mass spectrometry (SIMS) has been used to investigate changes that occur in an advanced Ir-0.3W alloy during high temperature aging. This alloy is used to clad ²³⁸PuO₂ heat sources used in thermoelectric generators for deep space reconnaissance satellites. Long-term direct contact with PuO₂ at 1400⁰C leads to physical and chemical changes within the cladding alloy that affect its metallurgical properties. SIMS was used to show that Cr, Fe, Ni, and in some cases O, diffuse from the PuO₂ into the alloy. Thorium and aluminum diffuse out of the alloy in these same regions. This SIMS study suggests that inward O diffusion and subsequent formation of ThO₂ on grain boundaries may stabilize the alloy against enhanced grain growth

[en] An ultrasonic technique developed at Mound to nondestructively inspect an assembly weld critical to the fabrication and production of MC2893 heat sources is described. Prior to transferring the assembly technology to Los Alamos National Laboratory (LANL), the ultrasonic technique was used at Mound as a 100% in-line inspection tool

[en] This technical monthly report covers studies related to the use of ²³⁸PuO₂ in radioisotope power systems. Most of the studies discussed here are ongoing. Results and conclusions described may change as the work continues

[en] The second in a series of quarterly reports for Technology and Space Applications materials programs conducted by the Metals and Ceramics Division of Oak Ridge National Laboratory for the Nuclear Research and Applications Division of ERDA is presented. These quarterly reports replace the monthly and annual reports previously issued on this work. The areas of research covered include high-temperature alloys for space isotopic heat sources, physical and mechanical metallurgy of heat source containment materials, isotope Brayton system materials support, and space nuclear flight systems hardware

[en] The micro-watt thermoelectric generator, e.g. for a cardiac pacemaker, consists essentially of two subassemblies. One subassembly contains an outer casing and an arrangement of insulating foils between the casing and a core casing with a getter of barium pellets. The other subassemby is made up of the fuel capsule with Pu-oxide, a thermopile arrangement of semiconductor material like Bi₂Te₃, Sb₂Te₃, Bi₂Se₃ and mixtures thereof, as well as a base plate. This subassemby is highly vacuum-tightly sealed against the outer casing by means of a terminal plate. The terminal plate consists of niobium, tantalum, or a tantalum alloy. A ring-shaped plug of aluminium oxide is inserted in it through which an electric connection consisting of niobium is tightly conducted. The inner and outer surface of the plug are alloyed with molymanganese. By brazing with silver-copper or gold-copper, the niobium parts are connected with the aluminium oxide plug. (DG)

No abstract available

[en] A method of adhering and fixing a promethium-147 layer onto a desired portion of a semi-conductor element is disclosed in which electroplating is conducted in a plating bath consisting of 0.01-0.5 mol of an aqueous solution of antimony citrate or antimony tartrate and 0.1-3.0 mol of an aqueous solution of promethium-147-nitrate. Employing platinum as a cathode and the desired portion of the semi-conductor as an anode results in an extremely pure, uniform promethium-147 layer being electroplated onto the semi-conductor surface at the required portion thereof. The plated layer will not easily separate from the semi-conductor and long life is assured owing to the thinness of the layer. Small dimensions are obtainable without sacrificing capacity. (Owens, K.J.)

[en] In preparation for the Lincoln Laboratory's LES 8/9 space mission, a series of tests was performed to evaluate the nuclear safety capability of the Multi-Hundred Watt (MHW) Radioisotope Thermoelectric Generator (RTG) to be used to supply power for the satellite. One such safety test is Test No. S-6, Launch Pad Abort Sequential Test. The objective of this test was to subject the RTG and its components to the sequential environments characteristic of a catastrophic launch pad accident to evaluate their capability to contain the ²³⁸PuO₂ fuel. This sequence of environments was to have consisted of the blast overpressure and fragments, followed by the fireball, low velocity impact on the launch pad, and solid propellant fire. The blast overpressure and fragments were subsequently eliminated from this sequence. The procedures and results of Phase II of Test S-6, Solid Propellant Fire are presented. In this phase of the test, a simulant Fuel Sphere Assembly (FSA) and a mockup of a damaged Heat Source Assembly (HSA) were subjected to single proximity solid propellant fires of approximately 10-min duration. Steel was introduced into both tests to simulate the effects of launch pad debris and the solid rocket motor (SRM) casing that might be present in the fire zone. (TFD)

[en] The Final Environmental Statement on Routine Use of Plutonium-Powered Cardiac Pacemakers (FES) was issued in July 1976. Supplement 1, prepared in 1978, updates the FES with respect to power sources for pacemakers. Particular attention is given to the non-nuclear lithium batteries as alternatives to 238-Pu power sources in pacemakers. Supplement 1 also considers the current extent of pacemaker use and makeup of the patient population and concludes that the FES' conclusion is still valid that distribution of 238-Pu powered pacemakers for routine use should be authorized subject to specific conditions

[en] Electrical degradation experienced during production of the MC2730 Radioisotopic Thermoelectric Generator has led to a study of the cause of the degradation and review of the procedures used to clean the thermopiles. By comparing data obtained electrically with that obtained by scanning Auger microprobe analysis, a surface carbon layer was identified as the cause of the degradation. Ion sputtering removal of the carbon layer resulted in recovered electrical properties. Chemical, UV and plasma cleaning were studied to determine their effectiveness in removing photoresist from the thermopiles. The most effective procedure was a combination of chemical and UV cleaning. This procedure was shown to be far more effective than chemical cleaning by itself and was able to reduce the carbon levels to levels which were nearly nondetectable by Auger electron spectroscopy