This report considers the theoretical evaluation of a system for gaining increased control strength and increased control lifetime and presents a theoretical model which is applicable to conventional multigroup diffusion theory.

Stability tests are to be made in the VBWR (boiling water reactor). The tests are of three types: steady state measurements, rod oscillator tests, and transient tests.

The power of nuclear track research emulsion as a fast neutron dosimeter is examined in the exposure of a human phantom to PuBe neutrons. Semiautomatic track scanning and high-speed data analysis obviate the major disadvantages of this dosimeter, and allow the following basic information to be obtained without a serious cost in time: the rulative proton recoil energy spectrum, the absolute differential proton track den sity spectrum, and the average proton recoil energy at various locations in the phantom. From this are calculated the total absorbed local tissue doze due is proton recoils, the local thermal neutron intensity, and that portion of the tissue doze due to thermal [formula] tracks.

Pulse-amplitude discriminators are useful in nuclear counting to separate signals of greater amplitude from a background of unwanted or noise signals of lesser amplitude. As used here, the term "fast" implies circuits capable of responding to pulses between a nanosecond and a microsecond in duration. An ideal discriminator would produce for any incoming signal whose amplitude is greater than a threshold bias level, an output pulse of constant amplitude, duration, and delay with respect to the input signal, regardless of the incoming duration and rate; and for signals less than the threshold, zero output.

"A survey of the current theoretical picture of plasma containment in cusped magnetic configurations is presented together with a mention of the points of contact which exist or might soon be made to exist with experiment. A theory of containment was developed which is applicable to the whole range of plasma densities from a tenuous plasma in an essentially vacuum magnetic field to a fully developed plasma which completely excludes the magnetic field from its interior. Also presented are cursory accounts of the situation with regard to stability, cyclotron radiation, and methods of creating this type of plasma configuration."

"Design and fabrication techniques were improved so that the large area image intensifier now performs well in image intensifier systems for photographing nuclear tracks. Two successful samples meeting most of the objectives were completed and started in circulation among members of the AEC Image Intensifier Committee for evaluation in systems to record nuclear tracks. Except for a reported long decay in the P-15 phosphor performance was quite good. Resolution, gain, and background requirements were met. Magnification was still high (1/6.5 compared to a design objective of 1/8) but can be lowered to 1/8 by a straightforward mechanical change. Evaporated layers of thallium activated rubidium and cesium iodide were improved and further evaluated. Improved control of color and persistence was obtained. Efficiency as high as 1/3 that of P-11 phosphor was obtained in some samples. The current test series confirmed earlier results that an increase in cesium iodide content shifts the emission spectrum towards the yellow. Burn-resistance and light output was poorer for the cesium enriched phosphors while decay time was decreased.

Abstract; This technical report describes the changes in the SM-1 incurred by the experiment, Core Temperature and Flow Instrumentation (Task XIV), and evaluates the possible hazard involved in these changes. Temperature and flow measurements will be taken on a Task XIV instrumented stationary fuel element, instrumented control rod fuel element and other selected points in the SM-1 core to provide data on the core steady state and transient performance. The hazards evaluation consists of a nuclear evaluation, thermal and hydraulic analysis, description of tests to be performed, and discussion of containment integrity and maximum accident considerations.

Abstract: This technical report describes the changes incurred in the SM-1 by the insertion of the SM-1 Core II and special components. The special components consist of impact specimens, a boron gradient rod, SM-2 elements, a PM-1-M element, and high burnup SM-1 Core I elements. The change in hazards, due to operation of SM-1 with Core II and the special components is evaluated. The analysis indicates there is no change in hazards.

Abstract: This technical report contains a description and results of a second series of critical experiments performed on the SM-2 core mock-up, as additional to the first series of experiments reported in APAE No. 54. The SM-2 core mock-up contains 36.4 kg U-235 and and estimated 67.9 gm B-10. The equivalent diameter and the active height are about 22 in.; the metal-to-water volume ration is 0.344. Data is presented on activation, reactivity, and stuck rod measurements. All measurements were conducted on the open seven control rod array employing 38 stationary fuel elements. Activation measurements consisted of neutron flux measurements using uranium fission foils for relative power distribution studies, the effect of flux suppressors on reducing power peaks, blocked coolant channel measurements, and gamma ray dose distribution. Reactivity measurements were performed to determine the effect f flow divider, flux suppressors and stimulated high temperature and pressure operation; b-10 loading in the SM-2 core; and core material coefficients. For the later, the worth in cents per gm or cents per cc was determined at simulated temperature of 510 degree F for B-10, U-235, stainless steel, and void. Stuck rod measurements were made to obtain an indication of the criticality margin in the …

Abstract: Hydrodynamic flow studies were conducted on a full scale model of the SM-2 reactor vessel and core. Test fluid was water at 200 psi and 200 degree F. Test facilities, model, and instrumentation design are discussed. Flow distribution in the stationary fuel elements, lattices, and control rods of the second pass was investigated. Pressure losses through the various core components were measured and are compared with calculated values. Observed over-all pressure drop was 71 feet of water at 200 degree F, 31% higher than predicted, part of which was due to presence of instrument leads. Element to element flow distribution varied approximately +-8% from pass average. Channel-to-channel stationary element flow distribution varied approximately +-10% from element average and control rod flow distribution varied from +-8.9% to +-6.4 and -11.6% depending upon rod locations. These variations exceed the original goals of a +-10% and +-12% combined deviation for stationary and control rod elements respectively, but are satisfactory in relation to thermal design. There was no indication of unsatisfactory structural performance of any components under hydrodynamic loadings up to 130% of design values. The test program was terminated after determining flow distribution in the reference core design, omitting any work on …

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Abstract: "The electron paramagnetic resonance (EPR) of color centers in additively colored KCl crystals is measured to observe the effects of optical bleaching at room temperature. Earlier measurements on the F-center are confirmed and the susceptibility is measured at 78 and 300 deg K over five decades of power, including the very low power region. The width and the saturation properties of the individual multiplets are studied in detail and the technique of making EPR measurements on inhomogeneously broadened lines is discussed. A calculation is presented which shows that a slight departure from a Lorentzian multiplet shape can account for the saturation data. The bleached crystals show a resonance which has a width of 35 gauss and a different rate of saturation than the F- center. This resonance is associated with the B-band which appears in the optical absorption."

The electron paramagnetic resonance (EPR) of color centers in additively colored KCl crystals is measured to observe the effects of optical bleaching at room temperature. Earlier measurements on the F-center are confirmed and the susceptibility is measured at 78 and 300 deg K over five decades of power, including the very low power region. The width and the saturation properties of the individual multiplets are studied in detail and the technique of making E PR measurements on inhomogeneously broadened lines is discussed. A calculation is presented which shows that a slight departure from a Lorentzian multiplet shape can account for the saturation data. The bleached crystals show a resonance which has a width of 35 gauss and a different rate of saturation than the F- center. This resonance is associated with the B-band which appears in the optical absorption. (auth)

Laboratory-scale tests on methods for recovering uranium and thorium from graphite-base reactor fuel elements are reported. The 90% HNO/sub 3/ process, which involves simultaneous disintegration and leaching in 21 M HNO/sub 3/, is applicable to all fuel elenments which do not contain coated fuel particles. Leaching of irradiated (0.001% burnup) fuels containing 3 and 12% uranlum recovered approximates 99.3 and 99.9%, respectively, of the uranium in two 4-hr leaches with boiling acid. The graphite residue retained > 50% of the long-lived fission products. Three successive leaches of fuel containing uranium and thorium recovered approximates 99% of both elements. Uranium recoveries by combustion in oxygen followed by dissolution of the ash hn nitric acid or fluorlde-catalyzed nitric acid are quantitative only when the fuel is not coated, does not contain Al/sub 2/O/sub 3/-coated fuel particles, and is free from impurities such as iron. During combustion up to 95% of the Ru-106 was volatilized from irradiated specimens. Recoveries, by leaching with 70% HNO/sub 3/, from fuel specimens containing Al/sub 2/O/sub 3/-coated fuel particles were greater than 99% when the specimens were ground finer than 200 mesh to ensure crushing of the fuel particles. (auth)

A test was carried out to determine the adequacy of storage capacity and operating procedures of the radioactive waste disposal system during a normal reactor plant warmup. The capacity and operating procedures were found to be adequate. It was impossible to perform a complete material balance based on existing level instrumentation and using the data required by the test procedure. Approximately 21,290 gal. of waste were received in the system and 13,210 gal. were discharged to the river with a total activity of 1200 mu c. A quantity of 6,670 gal. of reactor coolant effluent was processed. Approximately 634 lb of combustible waste were incinerated. (M.C.G.)

Plant drawings for the final design for the Army Reactor (PL-2) are presented. Two hundred and twenty-eight figures are included. (M.C.G.)

>The basic fuel element consisted of a uniform dispersion of fuel in a 1 1/2 inch diameter graphite sphere. Ceramic coatings for the retention of fission products were studied. It was found-that molecularly deposited'' ceramics such as alumina, siliconized silicon carbide, and pyrolytic carbon were excellent barriers to fission product leakage. The most advantageous location for ceramic coatings was found to be on the individual fuel particles, where the coating was subject to smaller forces and where a larger thickness-todiameter ratio could be used than if the coating were on the surface of the graphite sphere. Fuel elements were irradiated to burnups ranging up to about 6 at.% U/sup 235/. In all specimens containing a uniform dispersion of fuel, the graphite spheres were found to retain their structural properties after irradiation. Data are given on fuel particle coatings of A1/sub 2/O/sub 3/, pyrolytic carbon, and metals: surface coatings of siliconized silicon carbide, pyrolytic carbon, and metal carbides; properties of and the effects of irradiation on graphite spheres; the use of natural graphite in preparing a high-density matrix material; graphite fueling by thorium nitrate infiltration; subsurface metal and metal carbide coatings for graphite; and an in-pile loop program on the behavior …

The physical and mathematical reactor models which are used in Program ODD are discussed. In addition, the FORTRAN II source program listings, decimal data input sheets, and input and output for a sample case are given. Program ODD was designed to raake use of the Revised Nuclear Data System at ANPD which consists of twenty-five energy group cross-section data including high energy inelastic scattering matrices, resonance parameters for the resolved resonances, and thermalization scattering matrices for the near thermal energy region. The most unique aspect of the program is the mathematical technique employed for eliminating inner iterations and slow convergenc rates occasioned by the up- scattering'' in the thermalization region of the energy lattice. Direct inversion of the energy matrix coupling the thermal and last four epitherma groups provides simultaneous consistent solutions for thes groups within each power iteration. (auth)

A critical experiment program is carried out in a configuration similar to the BONUS reactor. The results give information concerning: the effects of different boilersuperheater geometries; the reactivity changes associated with superheater voiding or flooding; power regulation between the boiler and superheater regions; epithermal transmission probabilities for B-stainless steel and Cd control rods; the power flattening characteristics; and void simulation properties. The calculational methods used in the study predict the measured reactivity and power distribution to within the limits of experimental accuracy. (T.F.H.)

Drawings andd specifications for the PL reactor core are given. The requirements for the material procurement, fabrication, testing, and inspection of one P L-2 reactor core and spares are listed. (M.C.G.)

tems were cast and cured. Results of chemical tests on aa epoxy curlang exudate are included. Comparison of solvent effects on retention of radioelements by stainless steel was started and data are tabulated for Ac/sup 227/, Th/sup 227/, a nd Ra/sup 22//sub 3/. Work on protactinium was resumed after suspension of this project in 1960. Methods for preparation of small quantities of highly enriched U isotopes are being examined. Included in the survey are chemical exchange, electromagnetic separation, gaseous and liquid thermal diffusion, gas centrifugation, and photochemical techniques. Continued investigation of viscosities of La and Pr for use in Pu alcontinued along with studies of Pu bearing glass fibers. (J.R.D.)

Apparatus for the performanee testing of SNAP 10A thermoelectric elements was designed, constructed, and is now in operation. Elements may be tested for any desired length of tfme up to 1400 deg F and in a vacuum of 1 x 10/ sup -5/ of Hg. The equipment used for these tcsts may also be utilized for measuring Seebeck coefficient and resistance as a function of temperature. Element performance is derived from the data on voltages and temperatures. The performance variables which are reported in graphic form are as follows: loaded output voltage at any desired DELTA T; open circuit output voltage at any desired DELTA T; power output under optimum load conditions; current produced under matched load conditions; and internal resistance of the element. (auth)

A detailed analysis was made of the power distributions in the SM-2 experimental core at 68 deg F and the SM-2 reference core at 510 deg F. This analysis supersedes the power distribution calculations presented in APAE No. 69. The calculated distributions for the experimental core were normalized to measured data wherever possible in order to obtain corrections factors for application to the reference core. The over-all power distributions were calculated by synthesis of one-dimensional axial calculations with twodimensional radial calculations. The variation of the power distribution with fuel burnup is also presented. In order to improve the agreement between measured and calculated axial power distributions, flux-weighting the nuclear parameters in the rods-in and rods-out regions was investigated. (auth)

Specifications for the plant equipment for a P L-2 nuclear power plant are given. (M.C.G.)