Foreign research and power reactors are tabulated. Nuclear power buildup goals are given for each nation on which information is available. (J.H.D.)

An estimate of the critical current for the case of breakup by an arc has been obtained. It is shown that the same technique allows a quick estimate of the critical current in the case of no arc, using neutral and plasma breakup instead. (auth)

The Early Program is designed to compute the peak power and total energy release vhich will occur in a reactor due to a step increase of reactivity. These excursions may be terminated by one of several automatic shutoff mechanisms caused by the power excursion itself. The calculation assumes no thermodynanaic delays and assumes void formation is due to heat conduction from the cladding to the moderator. (W.D.M.)

The early program is designed to compute the peak power and total energy release which will occur in a reactor due to a step increase of reactivity. The calculation assumes no thermodynamic delays and assumes void formation is due to heat conduction from the cladding to the moderator. For periods in the 1 to 10 msec. range, the calculation yields results which are in excellent agreement with SPERT experimental results. (W.D.M.)

The monocarbide and the mononitride of uranium are potentially useful ceramic nuclear fuel materials. This paper reports the results of exploratory investigations of the reactions of uranium monocarbide and uranium mononitride with boiling water. Uranium dioxide, chemically stable in deoxygenated boiling water, was used as a control.

Judging scratch depth or surface roughness by unaided visual inspection under controlled conditions, while rapid and popular, is not quantitative. Comparison methods improve reproducibility but are generally not applicable to evaluation of depths of single widely spaced scratches. Stylus-type contour recorders yield valuable scratch contour data but may themselves plow through soft materials and fine details. Depth measuring microscopes are particularly applicable to measurement of pinhole depth but do not graphically reveal profiles and provide only a small field of view. The comparatively large field of view and graphic display of contour provided by profile microscopes make them particularly suitable for evaluation scratch depth as well as surface roughness. A HAPO-constructed instrument has demonstrated an accuracy of +/- 50 micro inches in the range of 50 to 15,000 micro-inches scratch depth. It is a pocket-sized, portable, and can be used on horizontal and vertical surfaces by untrained persons with only brief instruction.

Data obtained in test of Bureau of Mines electrocerium are presented. The cerium was subjected to spectrochemical analysis, x-ray diffraction analysis, thermal analysis, metallographic tests, and high-pressure experiments.