Voids have been produced by 1.2-MeV proton irradiation at 500 C in Type 316 stainless steel containing 2 appm helium. The proton fluence was 6×1018 p/cm2. Observations of electron microscope foils obtained at various positions along the proton path length have shown that the volume swelling increased with increasing number of atom displacements. Calculated volume swelling ranged from 0.2 to 5 percent. In addition to voids, irradiation produced dislocation loops and small precipitate particles on dislocations have been observed.

With the Molten-Salt Reactor Experiment (MSRE) operating a t 5 Mw, sawtooth pressure perturbations were introduced into the fuel-pump bowl to determine the amount of helium gas entrained i n the circulating fuel. The pressure and neutron flux signals were simultaneously amplified and recorded on magnetic tape. Then the signals were analyzed using auto-power spectral density, cross-power spectral density, cross-correlation, and direct Fourier transform techniques to obtain the neutron-fl ux-to-pressure frequencylesponse function. An analytical model, developed previously to a i d i n the interpretation of the fluctuations of the neutron flux i n an unperturbed system, was used t o infer from the exprimental data the amount of helium void (interpreted as a void fraction) entrained i n the fuel salt. A description of the analytical model and i t s experimental verification are included i n this report. The v o i d fraction w a s determined to be between 0.023 and 0.045%. The uncertainty of this inference i s attributed to assumptions made i n the model.

A novel method for monitoring air or dilute air-fuel mixture flow is initially developed and tested. Although many flow sensors are commercially available, none appear to have the combination of harsh environment durability (>600°C), fast response, bidirectional flow sensitivity, and low pressure drop desired for the application in hybrid power generation systems. The flow sensor described here uses the ions produced in a hydrocarbon flame to seed the gas flow, and then detects the current resulting from the flow induced drift of charged species in two directions from the flame source. Initial results show that the sensor is sensitive to flow reversal, but suffers from difficulties with flame blowout at high gas velocities.

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Presented h e r e i n i s t h e development of a program for t h e IBM 7090 f o r t h e purpose of obtaining t h e surface temperature d i s t r i b u t i o n , t h e gas bulk temperature, and t h e pressure d i s t r i b u t i o n for any of t h e 234 channels i n t h e EGCR. The program i s designed for any a r b i t r a r y power d i s t r i b u t i o n yielding a constant gas o u t l e t temperature o r a given maximum surface temperature, and includes t h e e f f e c t s of thermal radiat i o n on surface and bulk gas temperatures.