A simple method is described for producing parabolic mirrors by revolving a horizontal pan of liquid plastic and allowing it to harden into the parabolic shape which has been assumed by the liquid platic. This surface can be plated without further polishing into a mirror of a quality suited to various laboratory and industrial applications.

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Equipment required to provide production capacity of 525 tons per month of I & E fuel elements ``O,`` ``C,`` and ``K`` sizes in the 313 Building is specified in this document.

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The activation cross section of sodium in the range from thermal energy through the 3-kev resonance is generally assumed to be given by the one-level BreitWigner formula, the GAMMA /sub gamma / being selected to describe correctly the known thermal absorption cross section. The contribution of this resonance to the resonance activation integral then turns out to be 0.12 barns. This somewhat indirectly inferred value is considerably larger than the value given by Dancoff et al., in an old paper, the latter value being based on experimental work. It is shown in the present memo, that Dancoff's actual measurements are quite consistent with the Breit-Wigner formula and the above mentioned GAMMA /sub gamma /. The discrepancy is a result of Dancoff's transition from the actual measurements to the resonance integral, this transition being based on data that is now obsolete. (auth)

In 1954 the Oak Ridge Nationai Laboratory operated, for demonstration purposes, a high-temperature circulatingfuel reactor, employing as fuel enriched uranium fluoride dissolved in molten fluorides of other cations. A BeO moderator was used. At a maximum power of 2.5 Mw, 100 Mw hr were obtained. A negative temperature coefficient resulting largely from fuel expansion yielded exceptional stability of the reactor, and made the reactor a slave of the power demand. Xe/ sup 135/ and some of the other fission fragments are not retained in the fuel; hence, there is no xenon poisoning and relatively little danger of spreading of gaseous fission fragments in case of an accident. The advantages of liquid-fuel reactors (elimination of radiation dnmage and thermal stresses in solid fuel elements, ease of fabrication and fuel reprocessing) are combined with low pressures at very high temperatures. (auth)

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The benefits of the poison spline system as developed and partially tested by the Facilities Engineering Operation are considered over a two year period. The full pile operational charge-discharge installation at the end of that time could make the poison spline system a marginal operation. This document list the production gains that are possible, how these gains compare with the cost of the poison spline system, and how this system compares with other available supplementary reactivity control systems.

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This document is a supplementary operating guide to document HW-44064, ``Process Specifications for Critical Mass Control -- Purex Plant.`` It is primarily intended that this document illustrate the actual operational means of conforming to the limits of critical mass control as presented in HW-44064.

A metbed was introduced for combining the techniues of classical Lanchester theory of combat with those of game theory toward the end of selecting optimal strategies in combat with special weapons. In the application of this method to the example in which only the defender had atomic weapons,. it was showm that the attacker always chose either to disperse his troops the maximum amount or not to disperse his troops at all. The defender always chose to employ a mixed strategy consisting of the weapon systems of either two intermediate weapons or four small weapons. If both the defender amd attacker hnd access to atomic weapons, then the opticmal strategy for the attacker was to employ the weapon system consisting of four small weapons and to use a mixed stratregy for the dispersion of his troops. On the other hand, the defender never dispersed his troops amd always used a mixed strategy for tee - weapon systems. In the example where the defender has a fixed weapon system and chooses to optimize his aiming procedure, it was shown that the optimal aiming procedure does not involve only the aimimg procedures which are optimal against each of the fixed dispersion patterns …

This report, from the Chemical Processing Department at HAPO, discusses the following: Production operation, purex operation, redox operation, finished products operation, power and general maintenance operation, financial operation, facilities engineering operation, research and engineering operation, and employee relations operation.

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This document summaries the amounts of radioactive contamination discharged to ground from separation facilities through December 1956. Detailed data for individual disposal sites is presented on a month basis for the period of July through December 1956. Previous publications of this series may be referred to for specific information on measurements and radioactivity totals prior to July 1956. Tables I and II list the major disposal sites in separation facilities, total volume of waste discharged to each location, and the gross amounts of plutonium and beta particle emitters discharged to ground since startup. Tables III through XXXVI present this same data on a month to month basis and also include information on the source of the waste stream and the settling facility used. Isotopic data are included for all disposal sites from which the waste was analyzed for specific contaminants. Estimates of contamination and volumes discharged to the swamps are also included.

The fission cross section of Pu/sup 240/ was determimed from Pu/sup 240/U/sup 235/ ratio for neutron energies between threshold and 8.1 Mev. U/sup 235/ cross section values were essentially those given in a recent compilation in ''Progress in Nuclear Energy.'' The technique used was to mount the two foils back-to-back in a double ionization chamber and to irradiate them in a neutron flux of variable energy. (A.C.)

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This report presents the results of initial experiments concerning the protection afforded by the Panellit system against hazards associated with the inadvertent plugging of a process tube.

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Critical experiments are described, and the hazards attpendant to these experiments are evaluated for a reflector-controllped boiling-peterogeneous- reactor design. The proposed reactor design is water moderated and reflected. However, to provide maximum flexibility and safety, the critical asspembly is a thermal reactor moderated and reflected with plastic having appropriate voids to simulate water. A spection of the plastic reflector is movable to represent changes in the waterrelector level. The data obtained using this reflectorcontrolled assembly is then suppliped to an electronic reactor simulator which is connected to a full-scale mock-up of the proposed hydraulic control system. In this manner, thpe characteristics of thpe complete system are determined. The fuel-element assemblies are composed of strips of aluminum and Teflon-coated uranium sandwiched with plastic and pecased in aluminum boxes. One- half of the core is on a movable table, while the other half is on a fixed table. Primary control and safety of the asspembly is achieved by inserting or withdrawing sandwiched stainlpess steel-cadmium rpegulating and safety plates and by increasing or decreasing the distance between the two core halves. For safety, the maximum normal rate of reactivity addition has been limited to an pestimated 0.04 per cent per sec for control-rod …

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The failure of the valve bellows would appear to be due to a combination of stress corrosion nnd crevice corrosion. Stress corrosion occurred as evidenced by the transgranular branched cracking found in the bellows and in the base which was joined to the bellows. It seems probable that chlorides were present, which, along with the residual stresses present in the bellows assembly, created the necessary conddtions for stress corrosion to occur. Crevice corrosion occurred probably due to heavy deposits of solids at the base of the bellows, which created a condition of oxygen impoverishment. While the crater in the base may have been related to a galvanic effect created by the gold gasket, the contour of the crater would suggest that the cause of the crater was due more to crevice corrosion. (auth)

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