Abstract. A fast-slow coincidence scintillation spectrometer for gamma-gamma cascade measurements following thermal neutron absorption in nuclei is now in operation at the Livermore 1-megawatt pool-type reactor. Design features of the spectrometer and experimental techniques in its use are discussed with particular emphasis on the application of the recently introduced sum-coincidence method for analysis of capture-gamma double cascades. A new technique for the determination of added neutron binding energy is presented and various types of coincidence data from appropriate experiments are illustrated.

The magnetic properties of core materials ae investigated for a pulse width of 30 nanoseconds. Methods of testing which are necessitated by the sort pulse width are explained and the design of the pulser which is capable of 0.2 megawatt peak power is described. The data obtained if evaluated and presented for the various materials which were tested.

"Additional mixtures of polymers and multi-unsaturated monomers have been prepared, irradiated and the gel content determined. The gel content determination of crosslinked polyolefins has been investigated in detail. The multi-unsaturated monomers used and radiation conditions applied up to this time have not given significant gel contents for polypropylene. the polypropylene resin used has been characterized by differential extraction."

The response of a two silicon p-n junction diodes has been measured for protons up to 13.3 Mev. In one case the dependence of depletion layer thickness with bias voltage was found to be T or V(0.46). The observed resolution, made up of contributions from crystal noise, beam width, and scatterer thickness, was about 1% for 9-Mev protons.

When light propagates with the wave normal in the direction of an optic axis of a biaxial crystal, the usual ray theory breaks down. This phenomenon can be analyzed by means of an asymptotic solution of Maxwell's equations. The intensity is governed by a partial differential equation within the phase surfaces, instead of ordinary differential equations along rays. This example slows that light does not always propagate along rays. A similar phenomenon occurs in hydromagnetics.

With the development of the zircaloy-2 clad uranium fuel element, it was necessary to develop a method of closing the end of the element after the extruded tubes were cut to the desired length. Regardless of the ultimate design of the closure, a satisfactory zircaloy-2 fusion welding technique had to be worked out. The first fully successful welding was performed with electron beam welding in a vacuum chamber. To make satisfactory welds, the electron beam welding involved time and equipment, plus undue maintenance on the equipment.

The work described was undertaken to provide data for nuclear safety studies concerning NPF reprocessing equipment. The original objective was to determine the uranium density and water (hydrogen) content of UO2-H2O mixtures ranging from compact centrifuge cakes to dilute slurries. The scope was later expanded to include mixtures of UO2 with hydrocarbon oil and mixtures of UO3-H2O.

At present, emphasis is being given the application of nondestructive testing to the inspection of nuclear fuel in conjunction with complete product specifications. The objective is to quantitatively specify fuel quality parameters, and to measure the entire fuel production against these specifications nondestructively. Under this concept the acceptability of a given fuel element becomes a well-defined factor readily determined by appropriate nondestructive tests.