Abstract. If a pile rod gets bowed within its cooling tube it becomes warmer on the side which approaches the tube wall, and thermal expansion tends to warp it in the same direction as the original displacement. This was discussed roughly in N-601, and it was there concluded that the mechanism was not important for an isolated short slug. In connection with current development of continuous jacket (cartridge) assemblies, it seems desirable to look at this question again. In this case it is possible that the effect may be of some concern.

From introduction: "The purpose of the present report is to describe briefly certain improvements that have been made in the experimental facilities and to present the results of further measurements on critical masses and spatial neutron flax distributions in Be reflected reactors having square and thin slab geometries."

The monitoring of thermal and resonance neutron flux in a thermal reactor having high flux over periods of time from 1 to 12 months using think Co foils is considered. Special attention is paid to the many correction factors to be applied to the activation data; neutron temperature, effective cadmium cutoff energy, burnout of Co59 and Co60, and decay of Co60. Results on a homogeneity test of 10 mil, 0.08% Co-A1 alloy foils is given.

This report describes a specific apparatus used to monitor the intensity of gamma radiation. The report includes a diagram of the apparatus.

This technical report presents measurements of the thermal expansion of five titanium carbide type cermets from 68 to 1800F. These cermets are designated by Kennametal, Inc., as K 138A, K 150A, K 152B and K 162B. They contain from 64 to 80 weight percent titanium carbide, 10 to 30 weight percent metal binder and 6 to 10 weight percent other carbides. The metal binders are cobalt, nickel, and nickel and molybdenum. An attempt was made to calculate the thermal expansion of each type cermet from thermal expansions of the constituents. The expansion of the mixture was computed by weighting and expansions of the constituents according to (1) weight percent of the constituents, (2) volume percent of the constituents and (3) according to a value developed for mixtures by P. S. Turner. It was found that expansions computed according to volume percent and by Turner's method agreed with measured values with +- 5 percent. The values calculated by weight percent were from 5 to 11 percent higher than the observed values. The thermal expansions of these cermets are compared with the expansions of a group of metals and alloys.

Molecular sieves are synthetic zeolites which, when dehydrated, contain a network of empty pores and cavities that constitute almost 50% of the total volume of the crystals. They have the unique property of adsorbing within these cavities only those molecules that are small enough to pass through the pores of the crystals, Molecular sieves have a very strong affinity for water and other polar molecules. It is this selective property plus their stability and reasonable cost that make them of interest for the application described herein.

The increasing popularity of liquid-hydrogen targets in physics research has emphasized the need for containers with maximum beam transparency (i.e., thin walls and low Z) and suitable strength at cryogenic temperatures. Fabrication of a Mylar container satisfying these requirements is described here.

A need for a small vertical cylinder-type furnace arises frequently in the Chemistry Department at the Lawrence Radiation Laboratory (LRL). Adequate heat is the major requirement; close control or calibration is not usually necessary. A heating unit of this type can either be used for quickly concentrating solutions in centrifuge cones or, by the addition of a refractory pedestal--can be made into a crucible furnace for size 0 and 00 crucibles. Because much of the chemistry done at LRL is with radioisotopes, disposal of contaminated equipment is an important consideration. In general, furnaces are difficult to decontaminate, hence there was a need for a disposable type. Because nothing meeting the requirements seemed to be commercially available, the Health Chemistry Department made up a simple furnace that has proved useful.

Facilities shall be provided in the 221-U Building for removing fuel elements from the casks as placed in the railroad tunnel from the transfer facility and moving the elements to modified existing 10' X 16' X 14' storage tanks in ten existing cells where they will be stored, until scheduled for processing.

A number of Pu-Al and UO2-PuO2 Zircaloy clad capsules have been fabricated for irradiation in the MTR. In addition, a four rod cluster containing Al 8 w/o Pu and Al 12 w/o Si 8 w/o Pu cores has been successfully irradiated and discharged from Loop 3 of the KER. A second four rod cluster is awaiting irradiation and design and fabrication of a seven rod cluster test element is underway.

Basic Studies. Sinterability studies on the isomorphous system UO2-PuO2 have continued. One-half inch diameter X 3/8'' long compacts containing physical mixtures of the two components have been heated in hydrogen. Sintered density as a function of time and temperature has been determined for times of one and eight hours up to 1600 C. In general, there seems to be minima on isothermal plots of density versus composition in the intermediate range 20-40 w/o PuO2. At concentrations greater than 40 w/o PuO2, density increases rapidly with increasing PuO2. In every case pure PuO2, (produced by decomposing plutonium oxalate at at 300 C) sintered to a greater density that ball ball milled PWR grade UO2. The data, for a one hour soak time, and tabulated in percent of the theoretical crystallographic density, can be seen below:

This report covers the S-I-5-B-M fuel irradiation in the GETR Maritime Loop during the final quarter of fiscal year 1962 plus the month of July 1962 to conclude the irradiation program. The data are summarized in Section II.

The following is taken from ORNL-2257, Instantaneous Velocity Profile Measurement by Photography, by R. E. Lynch, L. D. Palmer, and G. M. Winn. This report is in in preparation status; and errors, inconsistances, and omissions in he language, as well as in the technical aspects, may exist. The technique of using phosphorescent particles to enable photographic determination of qualitative and quantitative instantaneous velocity profiles is covered by AEC Patent Application No. SN-710, 371 issued to F. E. Lynch, L. D. Palmer, H. F. Poppendiek, and G. M. Winn and entitled " A Method of and Means for Visualizing Fluid Flow Patterns.