THE NOBLE GAS PERMEABILITY CHARACTERISTICS OF GRAPHITE MATERIALS FOR USE IN GAS-COOLED REACTORS

S>The theory of gas permeation through porous materials is reviewed in brief. Experimental data are presented on the permeation of He and the fission product noble gases as a function of pressure, temperature, and time of annealing through various graphite materials of interest for use to contain or hold back volatile fission products in gas-cooled reactors. (auth

Electro-impulse de-icing testing analysis and design

Electro-Impulse De-Icing (EIDI) is a method of ice removal by sharp blows delivered by a transient electromagnetic field. Detailed results are given for studies of the electrodynamic phenomena. Structural dynamic tests and computations are described. Also reported are ten sets of tests at NASA's Icing Research Tunnel and flight tests by NASA and Cessna Aircraft Company. Fabrication of system components are described and illustrated. Fatigue and electromagnetic interference tests are reported. Here, the necessary information for the design of an EIDI system for aircraft is provided

Chemical Problems in Advanced Gas-Cooled Reactors

The chemical problems largely involve gas- and solidphase chemistry where chemical reactions and physicochemical processes occur at elevated temperatures ( approximately 4000 deg F). The high temperatures require that the fuel bodies and moderator be made of refractory materials and may preclude the use of metal cladding. Areas of concern include reactor materials and primary coolant systems, where most of the problems involve mass transfer. Reactions are discussed which can lead to carbon transfer in a gas-cooled graphite reactor. Substantial mass transfer can be expected from gas-phase diffusion across a gap caused by equilibrium concentration shifts when the gap boundaries are at different temperatures. Reactions are discussed which show how coolant impurities can lead to fuel migration. Activated charcoal appears to be a most useful agent for removing volatile-fission-product activities from-the reactor coolant. In regard to the minimization of hightemperature vaporization processes, the carbide-- graphite systems appear better than the oxide systems because the fuel material carbides are less volatile than the oxides in the presence of graphite. The vapor pressures are tabulated for gas-cooled-reactor fuel materials. (B.O.G.

Studies of thermionic materials for space power applications informal monthly report, sep. 1 - sep. 30, 1963

Thermionic materials for space power application - uranium carbide-zirconium carbide fuels and tungsten claddin

Studies of thermionic materials for space power applications informal monthly report, oct. 1 - oct. 31, 1963

Thermionic space power material - isostatic pressing, vapor deposited tungsten, high temperature properties, cesium thermionic cell life testing, and irradiation studie

Entry, Descent and Landing Systems Analysis Study: Phase 1 Report

NASA senior management commissioned the Entry, Descent and Landing Systems Analysis (EDL-SA) Study in 2008 to identify and roadmap the Entry, Descent and Landing (EDL) technology investments that the agency needed to make in order to successfully land large payloads at Mars for both robotic and human-scale missions. This paper summarizes the motivation, approach and top-level results from Year 1 of the study, which focused on landing 10-50 mt on Mars, but also included a trade study of the best advanced parachute design for increasing the landed payloads within the EDL architecture of the Mars Science Laboratory (MSL) missio