A CIIIE (enriched) element, one of two elements which failed April 5, 1962 in tube 2955C, was shipped to the Radiometallurgy Laboratory for detailed examination. The element was 21st from the downsteam end. A more severe rupture which occurred in the 19th piece from the downsteam end was believed to have caused the initial rupture indication. After a hot startup a heat cycle developed in the part of the reactor containing tube 2955 increasing the bulk water temperature about 20 per cent. At about the same time the temperature rise was noted, the first rupture indication was seen. The reactor was shutdown 40--45 minutes later, tube 2955 was pushed, and the two ruptures were found. The element was classed as a ``hot spot`` failure. Detailed examination was requested to determine the cause of failure and characterize the nature of any observed corrosion.

Recent developments in the classical theory of fully ionized gases and strong electrolyte solutions are reviewed, and are used to discuss the equation of state at high temperatures and low densities. The pressure is calculated using the ring-integral approximation, and quantitative estimates of higher correction terms are given. The effect of short range repulsive forces is shown by comparing the results with two kinds of potential functions hard spheres of diameter a, and soft'' spheres for which the short range potential cancels the Coulomb potential at the origin, and decreases exponentially with distance. It is found that the use of either type of potential extends the range of validity of the ring-integral approximation to considerably higher densities and lower temperatures. Since there is little difference in the results for the hard spheres and the soft spheres in this range, the latter system is investigated more extensively since it is more, easily handled by analytical methods. The expressions derived for the free energy of a system of charged particles can also be used in ionization equilibrium calculations, and the effect of electrostatic interactions on the equilibrium concentrations of various kinds of ions is indicated. 60 references. (auth)

Declassified 26 Nov 1973.<><DSN>29:026171<ABS>The rotating fluidized bed reactor concept is outlined and its application to rocket propulsion discussed. Experimental results obtained indicate that minimum fluidization correlations commonly in use for 1-g beds can also be applied to multiple-g beds. It was found that for a low thrust system STA90,000N (20,000 lbf)! the fuel particle size and/or particle stress play a limiting role on performance. The superiority of /sup 233/U as a fuel for this type of rocket engine is clearly demonstrated in the analysis. The maximum thrust/weight ratio for a 90,000N thrust engine was found to be approximately 65N/kg. (19 references) (auth)

The effect of temperature on the nature of oxide formed from uranium oxidizing in air is pronounced, there being an increase in particle size wtth increasing temperatare over the range 400 to 800 deg C. At 1000 deg C and above the oxide formed remains largely intact, giving rise to few-micron size particles during the heating period. In relating these facts to fission product release, it would be anticipated that the effect of air velocity on the release of fission products would be more pronounced at lower temperatures. Only a fraction of those oxide particles of apparert entrainable size become airborne, emphasizing the possible effects of fuel elemert geometry and orientation. This stability of a mass of fine particles is an importart factor to consider in a system where localized high air velocities or explosions might occur. This material once dispersed by a sudden rise in air stream velocity could remain suspended for extended periods of time. Deposition of uranium oxide and fission products on experimental apparatus points out the importance of the location of the fuel element during an overheating incident. In conclusion, particulate entrainment and deposition, fuel element geometry, oriensations and location are variables which may have an …