Calculations of the photonuclear giant resonance according to the Wilkinson model are presented in this report. In this model the giant resonance in the cross section for absorption of gamma rays by nuclei is ascribed to the excitation of large numbers of nucleons in closed shells. The model generally predicts correctly the integrated cross section for the giant resonance, bu the resonance energy is too low. Results are presented in a series of tables and formulas so that the integrated cross section may be calculated for any given nucleus.

Abstract: "Measurements have been made of the cross sections for the reactions Id-6(n, dn)He-4 and Li-7(n, tn)He-4 over an incident neutron energy range of 5 - 14 MeV. The energy and angular distributions of all reaction products were determined."

Work performed during the quarter is summarized by: direct measurement of fission gas pressure, loop operations, performance of UO2 fuel, UO2 grain growth and melting studies.

The Program fuel element has continued under irradiation in the Vallecitos Boiling Water Reactor, thermal energy group transfer cross sections for UO2 have been computed, and data have been reduced from the resonance wire activations performed last quarter. Future plans are included.

The following report is part of a series of quarterly reports discussing investigations on the development of zirconium-base alloys having corrosion resistance and strength superior to Zircaloy-2 and/or development of materials of equivalent corrosion resistance by exhibiting enhanced strength. This report covers the period between May 29 and June 18 of 1958, made by the United States and the European Atomic Energy Community (EURATOM).

"Short-range order coefficients were measured at 300 and 400°C for iron-aluminum alloys containing 14.8, 18.2, and 20.0 atomic per cent aluminum. These alloys exhibited a strong preference for unlike near neighbors. The short-range order was greater at the lower temperature and increased as the Fe 3Al composition was approached."

"Theoretical calculations have been carried our for the two ordering phases which occur in the FeAl system. The statistical treatment involves first and second neighbor interaction parameters as well as a magnetic interaction between first neighbor iron atoms. The phase diagram and the amount and type of long range order for slowly cooled alloys are calculated. Further calculations include short range order for the disordered phase at three compositions and two temperatures. As expected, the short range order increases as a critical temperature is approached either in composition of in temperature."

The Fuel Cycle Program is an integrated program of investigation in the Vallecitos Boiling Water Reactor (VBWR) and other facilities to improve the technological limits of boiling water reactors in several areas. This report presents updates on tasks related to those areas.

"Contact conductances for three semi-smooth and rough stainless steel contacts involving six steels are determined. The procedure and equipment used are fully described, and the results are given. Graphs display thermal conductance and conductivity versus pressure and temperature."

This report contains technical specifications and supporting data for the Critical Experiment Facility, information to justify operation of the facility, procedural control to be used to ensure safe operation, changes in neutron instrumentation and safety system, an evaluation of the safety of the Facility. It also contains descriptions of the site, the facility and the Critical Assemblies, operating standards and procedures. Amendment no.18 to license application for Critical Experiment Facility is also attached.

"A series of glass compositions containing uranium oxide was investigated to determine fiberizability and physical properties of resultant fibers. The basic properties to be determined were the maximum U/sub 3/O/sub 8/ content in a fiberizable glass and the maximum service temperature of the fibers. Glasses containing 60 wt% U/sub 3/O/sib 8/ were fiberizable; the fibers had strengths of 100,000 psi at 1600 deg F. Fiber-forming equipment was installed at Moun Laboratory to produce glass fibers containing PuO/sub 2/. Fibers were successfully formed in the first trials. For additional work a series of base glasses were provided affording a wider range of both PuO/sub 2/ solubility and physical properties."

It is shown that under very simple and general assumptions the existence of an antiunitary reflection transformation and the charge gauge group implies the existence of an antiparticle corresponding to a given charged particle. Similar consequences follow on replacing the charge gauge group by the baryon gauge group. No assumptions as to specific wave equations, or indeed the existence of local fields, are made.

This paper discusses a group of high-speed switching circuits using the basic current-switching mode of operation. The first part of the paper presents a dynamic analysis of the basic current-switching mode and the second part is the dynamic and steady-state analysis of a current-switching flip-flop.

"The behavior of charged particles in a plasma-free cusp field, or in a cusp field where there is very little plasma, is studied. The numerical computations described may provide a valid picture of the behavior of particles outside such a body of plasma or in the early stages of creation of such a cusped plasma in the low- beta limit. The computations provide a striking illustration of orbits which neither have constant magnetic moment nor behave so irregularly as to defy explanation."

Quarterly report documenting progress on a project to determine an improved zirconium alloy for service in superheated water and steam. This report describes the results of approximately 75 compositions that were prepared prior, and presently are being arc-melted and fabricated into corrosion specimens, continuing the investigations of the effect of zirconium purity and heat treatment on corrosion and resistance.

The spin of neodymium-141 was measured by the method of atomic beams and found to be 3/2. A lower limit placed on the hyperfine separation of the states with total angular momentum [formula] by second-order perturbation theory shows [formula]. A prerequisite for the determination of the nuclear spin from hyperfine-structure measurements is the knowledge of the electronic structure. The ground-state configuration of neodymium is known and the value is used throughout this work.

Even in its present primitive stage the molecular beam method promises to open up many opportunities for detailed studies of reactive collisions. The early results described here have revealed several features inaccessible to the traditional methods of kinetics. We hope this program of beam studies will ultimately provide the basis for constructing a theory of the molecular mechanics of reactions. By borrowing what are now everyday techniques in nuclear physics (modulation of the beams; mass analysis and counting of detected ions) it appears possible to gain from four to six orders of magnitude.

A better understanding of the maximum operating characteristics that can be achieved with the use of UO2 as a reactor fuel is the primary purpose of this program for Euratom and the Atomic Energy Commission. During this program work will be undertaken in two areas that have been of concern to the reactor core designer for a long time, viz. fission gas release and central melting in fuel rods.

A displacement of energy levels has been observed in the K=O band of odd-odd deformed nuclei. It is shown that this shift is due to a particular type of scattering in which the final state is obtained from the initial state by a rotation of 180'. This circumstance allows one to state certain selection rules on the parts of the n-p residual interaction responsible for the shift. The Wigner component of the force cannot contribute to the shift. In certain cases the contribution of all central forces will be strongly damped allowing observation of the tensor force scattering contribution. Numerical results are presented.

It is shown that the annihilation rates of positrons in metals can be correlated to a good degree by a simple model of the annihilation process based on an assumption that the fractional number of electrons available for annihilation varies as the inverse of the atomic volume of the metal.

Facilities are to be designed for installation at Hanford for the reprocessing of irradiated, low enrichment fuels from non-production reactors, see Reference 1 and 2. The initial design of the processing facilities is to be based on processing the fuels discharged from the Dresden, Yankee, Piqua, Pathfinder and Shippingport (blanket elements only) reactors. Properties of the fuels and cladding make it impossible to completely process them in existing equipment, although the separation and decontamination can be performed in existing facilities once the fueks have been placed in solution form.

The concept of thermonuclear explosives as a potentially cheap and almost inexhaustible energy source for mankind's non military needs has for several years been under active consideration at the Lawrence Radiation Laboratory. Many of the proposed peaceful applications involve underground nuclear explosions, and several experiments at the AEC Nevada Test Site have provided valuable insight into the phenomenology of such explosions. Among the possible uses currently under consideration are excavation, heat production, isotope production, mining, recovery of oil from shales and tar sands, improvements of ground water supplies, and the construction of earth fill dams. In addition a program of experimental research in the laboratory and in the field is under way. Sometime in 1961 Project Gnome if approved will be conducted in New Mexico. The purpose of Gnome, a contained nuclear explosion in a salt deposit, is to study the feasibility of heat recovery and isotope production, neutron scattering experiments will also be included. Other proposed nuclear projects will involve the creation of a small harbor near Cape Thompson, Alaska as the result of an experiment designed to investigate the cratering effects of nuclear explosives; a proposal to investigate the recovery of oil from Canadian tar sands using thermonuclear …

The Hanford water treatment plants were operated for a number of years with alum as a coagulant and activated silica as a coagulant and a polyacrylamide as a filter conditioning agent. (other polyelectrolytes may be used.) Sufficient time has elapsed to make a comparison of the two methods of operation valid and useful. Such a comparison is the purpose of this paper.

This paper describes the measurement of control rod strength in the PCTR. The first section outlines the theory and method of such a measurement, and the second section presents the results of the measurement of the Experimental Gas Cooled Reactor (EGCR) control rod strength. The reactor parameter actually inferred is the difference in the infinitive multiplication factor for a control rod supercell with and without the control rod in place in the supercell. These measurements are, therefore, very closely related to the measurement of k∞ for an ordinary lattice cell.