Project 4.2 was designed to study direct (primary) air blast injury, in animals, from an atomic weapon in the range of 20 to 50 psi under circumstances affording protection against missiles, thermal and ionizing radiation and to estimate the probable direct air blast hazard in man. The pressure levels at which atomic weapons direct air blast injuries occur will determine, to a large extent, the number of blast casualties likely to be encountered. It is probable that fatal overpressures are not reached until well within the range at which indirect (secondary) blast, thermal and ionizing radiation are practically certain to prove fatal. Only in special situations affording partial protection from other injuries are blast injuries likely to be of practical importance. Two animal species of widely different body weights (700 rats and 56 dogs) were exposed, together with air pressure recorders, in aluminum cylinders, covered by sandbags and dirt but open at both ends, at seven stations distributed within the intended overpressure range of 20 to 50 psi of Shot 10« About 200 rats were likewise exposed in Shot 9. Unfortunately, the destructive effect of the air blast of Shot 10 was much greater than anticipated. Many of the exposure …

This document is Report No. 3 (covering the period 10/11/53 to 12/10/53) on Flat Plate Bonded Fuel Elements at the Savannah River Plant. It contains information on the fabrication and testing of the uranium components as well as the structural components (aluminium).

Attention has continued to be concentrated on routes employing either wrought uranium or powder metallurgy product for the making of flat plate fuel elements of approximately 0.180-inch uranium metal core thickness bonded to either ribbed or ribless aluminum sheaths. Intermediate goals of the program are to have elements 18 inches long for MTR irradiation tests this fall and to make sufficient advance in the overall program in 1954 so that an initial reactor charge of 15-foot long fuels can be provided as early as possible in 1955. The development of a satisfactory process tube for retaining an assembly of several fuel elements is also required. Uranium of satisfactory quality for fabrication into fuel elements appears to have been produced by the August high alpha rolling at Superior Steel, and it seems likely from the electroplating results that the metal can be employed for electroplating and bonding without such surface preparation as vapor blasting, grinding, or machining. Difficulty in obtaining aluminum components, both sheaths and process tubes, remains a bottleneck in the development program and specifically has delayed work on the wrought metal samples for MTR tests.

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The corrosion of metals by molten hydroxides is discussed, and results of corrosion tests made at several laboratories are compared. Research results are reviewed on NaOH corrosion of metals, static corrosion by molten caustic at 1500 ts F, dynamic corrosion by molten caustic at 1500 ts F, NaOH-NaH systems, corrosion by fused caustic at high temperatures, purification techniques for NaOH, mechanisms of some corrosion reactions, screening tests on metals, alloys, and ceramic materials, and static corrosion by hydroxides. The metallurgical and chemical aspects of interaction between metals and hydroxides are discussed. (C.H.)

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In fast reactors the poisoning effects of fission products are reduced because of relative low capture cross sections at high energies. In addition, in fluid fuel reactors there is the possibiity of removing them by processing. If plutonium production is of secondary importance to power production, then higher burnup of fuel is possible and dependency of reactivity on burnup becomes a problem of interest. One-group calculations are performed as a first step in understanding the relative effects of the initial breeding ratios, enrichment, and fissin product and heavy isotope concentration.

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