In a gas-cooled reactor operating at very high power density the thickness of the reflector may be determine by the requirement that the steel pressure vessel be protected from an excessive dose of fast neutrons, rather than by the usual requirements of neutron economy and power distribution. It is important the the reflector not be made thicker than necessary, since an increase in pressure vessel diameter can result in a marked increase in cost, as well as a decrease in the permitted gas pressure level.

The report summarizes results obtained since September, 1951, by total neutron yield experiments using 190 Mev deuterons and the MnSo4 tank method (UCRL-1375 and UCRL-1480). A new method of beam monitoring has resulted in establishing firmly the absolute yield for solid uranium and thorium primary targets backed by a solid uranium secondary. The beam monitoring was done by using a primary target built into a faraday cup. This method circumvents errors caused by recombination in the ionization chambers used previously.

From abstract: "Rats have been fed active strontium which was adsorbed on clay, while their controls were fed the same amount of active strontium in aqueous solution. There was no significant difference in the amount deposited in the skeleton between the two groups, and it is concluded that if ions are adsorbed on inert material, they will be eluted during their passage through the gastrointestinal tract."

In order to test the operation of a freeze jacket in air with the process fluid closely following the conditions found in the high pressure circulation loop of a homogeneous reactor, or, 2000 psi and 300C, a test loop was built and used in conjunction with existing refrigeration equipment. The freeze jacket was made of 5/16-in. type 346 stainless steel tubing wrapped around and welded to a 1/2-in. stainless steel process line. It was concluded that for these reactor operating conditions, only a small leak rate, 11 cc/min, could be frozen off. It is recommended that, at the beginning of the the freezing operation, the temperature of the secondary refrigerant entering the freeze jacket be at least -40C and that the freeze jacket be made as long as practical.

This report deals with the (1.1) physical properties of graphite, (1.2) effects of pile irradiation on the properties of graphite, (1.3) effect of irradiation on "ceramic" materials, (1.4) effects of radiation on ice -- the x-ray induced luminescence of ice, (1.5) investigation of color centers and other optical properties of single crystals. (2.1) radiation chemistry of liquids, (2.2) application of mass spectrometry to chemical problems, (2.3) vapor pressure and heat of vaporization of uranium, (3.1) nuclear properties of Zr93 and Nb93m from fission, (3.2) mass distribution in the spontaneous fission of Cm242, (3.3) Upper limit to the lifetimes of the first excited states of Th236, U234, and Pu236, (3.4) on the one-body model of alpha radioactivity, (4.1) spectrographic analysis, (4.2) chemical analysis, (5.1) paramagnetic resonance measurements, and (5.2) the 60-inch cyclotron.

This report deals with the (1.1) physical properties of graphite, (1.2) effects of pile irradiation on the properties of graphite, (1.3) effect of irradiation on "ceramic" materials, (1.4) effects of radiation on ice -- the x-ray induced luminescence of ice, (1.5) investigation of color centers and other optical properties of single crystals. (2.1) radiation chemistry of liquids, (2.2) application of mass spectrometry to chemical problems, (2.3) vapor pressure and heat of vaporization of uranium, (3.1) nuclear properties of Zr93 and Nb93m from fission, (3.2) mass distribution in the spontaneous fission of Cm242, (3.3) Upper limit to the lifetimes of the first excited states of Th236, U234, and Pu236, (3.4) on the one-body model of alpha radioactivity, (4.1) spectrographic analysis, (4.2) chemical analysis, (5.1) paramagnetic resonance measurements, and (5.2) the 60-inch cyclotron.

It is the purpose of this memo to clarify and revise burnup calculations for the APPR irradiation program and to present a proposed irradiation schedule. the report will also be in the nature of a review of the program.

Abstract: "Blacosolv, trichloroethylene, is used in degreasing uranium metal. Tests were made under possible industrial conditions to determine whether a hazardous reaction between uranium and Blacosolv could occur. Temperature-rise measurements showed that there was no reaction of the metal, in various states of subdivision, with Blacosolv at temperatures up to 850 F. However, a reaction was observed in tests under which the finely divided metal, wet with solvent, was subjected to a severe impact."

Short reports to the members of the Nuclear Cross Section Advisory Group from three groups: (1) High voltage group; (2) Fast chopper time-of flight spectrometer; and (3) Electronuclear research division.

Work during this report period includes a continuation of the study of the effect of krypton 85 on the polymerization of styrene; an attempt at evaluation of the polymers produced; and the effect of krypton radiation on the electrical properties of gases, such as the rare gases, and nitrogen, and oxygen. the results obtained are summarized in the report.

This report is a comparative cost study of radioactive waste disposal for the Lawrence Radiation Laboratory (UCRL). In particular, it compares the costs of sea disposal in depths of 1000 fathoms and of 2000 fathoms off the California coast with land burial of the wastes at the Hanford Atomic Products Operation (HAPO), Richland, Washington, at the National Reactor Testing Station (NRTS), Idaho Falls, Idaho, or at the Nevada Test Site (NTS), Nevada. In the comparison, the cost of utilizing a commercial waste-disposal firm is also shown as well as a tentative cost of using the Military Sea Transport Service (MSTS).

In H measurements, the measured flux-linkage change represents twice the value of H to be plotted. In B measurements the bucking coil links flux equal to the air-flux in the B-measuring coils. The measured flux change therefore corresponds to twice the flux of intrinsic magnetization in the sample.

Sheline and Johnson made Mg28 through the reactions Si30(γ,2p)Mg28 and Mg26(α,2p)Mg28 in order to characterize and determine a decay scheme for the new nuclide. Lendner separated a magnesium fraction from the spallation products of the irradiation of chlorine, as sodium chloride, with 340-MeV protons. The 21-h activity that was present was deduced to be Mg28 from the 2.3-m half-life of the Al28 that was milked from it, as Sheline and Johnson had done.