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The changes in fuel and poison distributions and the changes in flux shape which accompany the consumption of fuel are studied. The technique employed is a perturbation calculation based on a one-velocity group treatment of the neutrons. The geometry is a spherical core surrounded by an infinite reflector. The programming forms for the IBM-650 which performs the computations using the Wolontis interpretative system are included. Two sample calculations were worked out using the code described and the results are plotted. (M.H.R.)

Digital-computer shielding-nuclear analysis programs are described. Each description includes (1) the purpose of the program, (2) the theoretical or physical assumptions, and (3) the major computer equipment required by the program. (auth)

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In a series of 1850 exposures with a modified 24-in. carbon arc searchlight, the influence of two cotton poplin fabrics alone and in combination with underwear material on the energy required to produce 2+ cutaneous burns in swine were studied. Impregnation of both khaki and green poplin with flre retardant material reduced the amount of energy necessary to produce a 2+ burn below that required with the untreated material, when the fabrics were spaced 2 and 5 mm from the skin. As a fabric is separated from the skin, the amount of absorbed energy required to produce a 2+ sub-fabric burn increases in a linear relationship with the amount of spacing. Maximum protection was provided by a two layer combination of poplin and underwear separated by a 5 mm air space. The energy required to produce a 2+ burn beneath two fabric layers separated by 5 mm decreased as the exposure time increased. With two layers spaced 2 mm, the requirements were the same. (auth)

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A preliminary study of molten salt pcwer reactors was made. The most promising fuel carrier salts were the fluorides and chlorides of the alkali metals, zirconium, and beryllium. The chlorides were found to have lower melting points but were less stable and more corrosive than the fluorides. A Li/sup 7/ F- - BeF/sub 2/ mixture with ThF/sub 4/ and UF/sub 4/appeared to perform best. Of the numerous alloys tested as container material, Inconel and a nickel-- molybdenum alloy INOR-8 appeared to be the most resistant to corrosion. To study the performance, safety, economics, and construction costs of a typical molten salt reactor, a reactor of specific type and size was chosen for study. The reference design reactor was a two-region homogeneous converter with a core salt of 70 mole% Li/sup 7/F and 30% BeF/sub 2. ThF/sub 4/ and enough VF/sub 4/ for criticality were added. Study in- dicated that a molten salt reactor would prcduce economical power, but the problem of developing a salt core and a container metal which would last for mamy years of operation needed further study. (M.C.G.)

The action and emission spectra of the delayed light emission from Chlorella, Nostoc, and spinach chloroplasts have been measured. The action spectra for Chlorella and for spinach chloroplasts are quite similar to the absorption spectra of these materials. The action spectrum for Nostoc, on the other hand, shows a relatively low activity for chlorophyll and carotenoids and a high activity for phycocyanin. The emission spectra of these materials demonstrates that the luminescence is the result of a transition between the first excited singlet state and the ground state of chlorophyll. Low-temperature studies suggest that the triplet state of chlorophyll is not involved at all in the luminescence of spinach chloroplasts. There is some indication that part of the light emitted from Nostoc is due to a phycocyanin transition.

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A study of nucleate boiling of subcooled water in forcedconvection source-vortex flow in small diameter horizontal tubes is described. A measured heat flux of ll,000,000 Btu/hr ft/sup 2/ was attained, a value 5 times greater than any previously reported for comparable conditions. (T.R.H.)

Radioactive debris from nuclear detonations may fall out over an extensive area. A rapid evaluation of the distribution of such surface contamination cam be obtained by an aircraft mounted detector. The gamma field measured in the aircraft can be related to the intensity on the ground. The HASL Top Hat'' system measures the radiation intensity, in an aircraft, at any altitude up to 1500 feet. The data are continuously compensated to the reading that would be obtained if the measurements were taken at three feet from thc ground surface. It will record the ground radiation field intensities from 0.01 mr/hr to 1000 r/hr. The Telepulse Coding Unit converts this information to a signal suitable for transmission to a plotting center via a standard voice radio transmitter. The transmitted signal is decoded by a Telepulse Receiving Unit and is automatically recorded on a strip chart. The radiation data must be correlated with the aircraft position to determine the location amd intensity distribution of the contaminated area. (auth)