An investigation was made of high-energy neutron damage in Cu and Nb irradiated with approximately 15 MeV neutrons at the Oak Ridge Isochronous Cyclotron. The neutrons were generated by bombarding a thick Be target with 40- MeV deuterons resulting in a high energy neutron spectrum broadly peaked at 15 MeV. Single crystals of Cu and Nb were irradiated at room temperature to fluences of approximately 2 x 10$sup 17$ n/cm$sup 2$. The resulting loop-type defect clusters in the crystals were characterized using x-ray diffuse scattering and transmission electron microscopy. The cluster size distributions were found to be generally similar to those characteristic of fission neutron irradiations in these materials and no multiple clusters or sub-clusters were observed. Additional comparisons with fission reactor irradiations in Cu and Nb indicate that the retained displacement damage in these crystals is approximately 3 times greater for the high-energy neutrons than for an equivalent fluence of fission neutrons. This result is consistent with detailed damage energy calculations for the Be(d,n) neutron spectrum. (auth)

The $sup 252$Cf Activation Analysis Facility at the Savannah River Laboratory (SRL) is used routinely for multielement analyses of a wide variety of solid and liquid samples (e.g., metal alloys, fly ash and other airborne particles, rocks, and aqueous and nonaqueous solutions). An automated absolute activation analysis technique, developed to use neutron transport codes to calculate multienergy group neutron spectra and fluxes, converts counting data directly into elemental concentrations expressed in parts per million. The facility contains four sources of $sup 252$Cf totaling slightly over 100 mg. A pneumatic ''rabbit'' system permits automatic irradiation/decay/counting regimes to be performed unattended on up to 100 samples. Detection sensitivities of less than or equal to 400 ppb natural uranium and less than or equal to 0.5 nCi/g for $sup 239$Pu are observed. Detection limits for over 65 elements have been determined. Over 40 elements are detectable at the one part per million level or less. Overall accuracies of +- 10 percent are observed for most elements. (auth)

A pulsed dc power system provides 120 kA excitation current for the ORMAK toroidal field coils. A drive potential of 1000 volts brings the coils up to full current in about 0.5 seconds. Constant current is maintained for 0.25 seconds, then approximately 20 x 10$sup 6$ joules of stored energy is dumped in a free-wheeling diode and resistance network. The power system contains 8 each, 30 kA, 500 V thyristor controlled dc power modules in a series/parallel combination. A control computer generates thyristor trigger pulses in a programmed sequence as required for the desired duty cycle. A feedback network including current sensing and computer software permits trigger timing adjustments as necessary for constant current operation. (auth)

This paper describes a new rf heating system which has just been completed and is now operational on the ATC machine. The system utilizes four UHF TV klystrons to generate at least 200 kW of power at a frequency of 800 MHz. Pulse widths can be varied from 20 $mu$sec up to 20 msec. A radar type floating deck modulator along with photo-optical transmitting and receiving devices have been incorporated into the system to provide the pulse fidelity and versatility which characterizes this equipment. Modular construction was emphasized in the design, when possible, to reduce maintenance and down time in the advent of component falilure. Hybrid combining techniques are utilized in order to provide two 100 kW feeds into the machine. (auth)

The AMPX system was used to generate a P$sub 3$ 218 neutron group master cross-section library from ENDF/B-IV data for the fuel, structural, and neutron- absorbing materials tabulated. The library is the data base for the generation of broad-group cross sections for shipping cask calculations and other criticality safety analyses using codes such as KENO and ANISN. Selection of the fine-group energy structure for the 3-eV to 20-MeV energy range included consideration of the resonance structure of prominent nuclei, the thresholds of important reactions, and the fission spectra. For 10$sup -5$ less than or equal to E/sub n/ less than 3 eV, 78 closely spaced thermal groups were chosen to examine the effects of low-energy resonances and thermal-neutron upscatter. Distribution of the 218 groups within the Hansen-Roach 16-group boundaries is shown. Adequacy of the group structure and validity of selected data sets from the library were tested by P$sub 3$S$sub 8$ XSDRNPM calculations of k-eff for two benchmark critical experiments; first, the 4.9 percent-enriched UO$sub 2$F$sub 2$- H$sub 2$O solution critical sphere experiment of Johnson and Cronin was analyzed, and, second, the 93.2 percent-enriched UO$sub 2$F$sub 2$-H$sub 2$O solution critical sphere experiment of Fox was analyzed. (auth)

The feasibility of constructing a radioisotope scanner using a Ge(Li) detector with adequate efficiency for clinical use is discussed. (WHK)

Small-angle neutron scattering techniques have been used to study the angular distribution of the critical scattering from cobalt above T/sub c/. These measurements have been put on an absolute scale by calibrating the critical scattering directly against the nuclear incoherent scattering from cobalt. In this way the interaction range r$sub 1$, which appears in the classical and modified Ornstein--Zernike expressions for the asymptotic form of the spin pair correlation function and is related to the strength of the spin correlations, has been determined. We obtain r$sub 1$/a = 0.46 +- 0.03 for the ratio of the interaction range to the nearest-neighbor distance in cobalt. This result is in good agreement with theoretical predictions. Lack of agreement among previous determinations of the ratio r$sub 1$/a made in iron failed to provide a definitive comparison with theory. (auth)

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Application of the power iteration method to the multigroup response matrix equations reduces them to a series of one-group problems. Applying acceleration techniques to each of these monoenergetic problems results in substantial reductions in computational effort. The use of point over-relaxation methods in the solution of these equations is described. Over-relaxation is also applied to the outer-iteration eigenvalue and source estimations with considerable success. 10 references. (auth)

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Acoustic sounder measurements of a vertical profile of the abrupt transition from a laminar to a turbulent atmospheric boundary layer were compared with meteorological measurements made at 10 m and 137 m on an instrumented tower. Sounder data show that conditions necessary for onset of the momentum burst phenomenon exist sometime during a clear afternoon when heat flux changes sign and the planetary surface cools. Under these conditions, the lowest part of the atmospheric boundary layer becomes stable. Prior to this situation, the entire boundary layer is in turbulent motion from surface heating. The boundary layer is then an effective barrier for all fluxes, and as the maximum flux Richardson number is reached at some height close to but above the surface, turbulence is dampened and a laminar layer forms. The profile of this layer is recorded by the sounder. Surface temperature drops, a strong wind shear develops, and the Richardson number decreases below its critical value (Ri/sub CR/ less than 0.25). Subsequently, the laminar layer is eroded by turbulence from above, and with a burst of momentum and heat, it eventually reaches the ground.

A feasibility study has been conducted to evaluate the potential use of acoustic emission to monitor thermal-shock damage in direct electrical heating of UO$sub 2$ pellets. In the apparatus used for the present tests, two acoustic- emission sensors were placed on extensions of the upper and lower electrical feedthroughs. Commercially available equipment was used to accumulate acoustic- emission data. The accumulation of events displayed on a cathode-ray-tube screen indicates the total number of acoustic-emission events at a particular location within the pellet stack. These tests have indicated that acoustic emission can be used to monitor thermal-shock damage in UO$sub 2$ pellets subjected to direct- electrical heating. 8 references. (auth)

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A description is given of a basic supercritical refrigerator. The present status of the cable enclosure and the types of cooling schemes being considered are presented with some examples of laboratory results and computer analysis. (MOW)

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The advantages and disadvantages of neutron scattering for protein crystallography, scattering from oriented systems, and solution scattering are summarized. Techniques for minimizing the disadvantages are indicated. (JSR)

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Radiation damage in the actinide dioxides is examined with respect to point defect ingrowth and annealing behavior. In $alpha$ decay, the $alpha$ particle is shown to contribute 19 percent of the total damage. Experimental results for $alpha$ bombardment, $alpha$ decay, and fission are compared to displacement theory results. A large difference for ingrowth of damage is demonstrated, but isochronal annealing curves are similar for all three damage types. (auth)

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Recent experimental data obtained from PLT has shown that equivalent beam theory is inadequate for predicting the deformation of large circular toroidal field coils. The PLT coils are much more flexible than equivalent beam theory predicts. The latest analyses have shown that shear plays an important role in the deformation of the PLT TF coils. This situation has indicated the need to analyze in explicit detail, the layer to layer behavior of simple laminated structures. The progress made to date in analyzing a laminated beam is summarized. By using variational techniques, the deflections and stresses in each layer of a laminated beam are modeled. To date, reasonable results have been obtained for either deflection or stress separately but a single model that simultaneously gives good agreement for both deflection and stress has not yet been determined. Brief descriptions of the mathematical models used and the results obtained with each are presented. (auth)

Applications of an Eulerian code to predict the response of LMFBR containment and primary piping systems to hypothetical core disruptive accidents (HCDA), and to analyze sodium spillage problems, are described. The computer code is an expanded version of the ICECO code. Sample problems are presented for slug impact and sodium spillage, dynamics of the HCDA bubbles, and response of a piping loop. (JWR)

Various parameters which are relevant to an understanding of radiation effects in metals have been evaluated utilizing available neutron spectrum information for several existing sources, e.g., EBRII, HFIR, and LAMPF, as well as the hypothetical spectrum at a fusion reactor first wall, and measured Li(d,n) spectra. Recoil energy distributions were calculated for several metals including Al, Cu, and Nb. The recoil energy range was divided into groups, and the fraction of recoils occurring in each energy group was compared with the fraction of the damage energy contributed by that group. From this comparison it was possible to conclude that the significant recoil range differs by about an order of magnitude between fission and fusion sources. The analysis further confirms that basic defect production characteristics depend upon the neutron spectrum, and that integral calculations of radiation-effect parameters do not provide a complete description of the dependence. This is equally true for comparisons between fusion-related spectra or fission-reactor spectra independently. Four recoil-dependent parameter functions which describe different aspects of radiation damage were used in the calculations. The relative effectiveness of neutron sources was found to depend upon the choice of parameter function. Fission-reactor spectra comparisons are relatively insensitive to the parameter functions …

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