The effect of finite resistance in the vacuum-tank walls on the longitudinal stability of an intense beam of particles in an accelerator is investigated theoretically. We show that even if the particle frequency is an increasing function of particle energy, the wall resistance can render the beam unstable against longitudinal bunching. In the absence of frequency spread in the unperturbed beam, the instability occurs with a growth rate that is proportional to (N/{sigma}){sup 1/2}, where N is the number of particles in the beam and {sigma} is the conductivity of the surface material. By means of the Vlasov equation a criterion for beam stability is obtained. In the limit of highly conducting walls the criterion involves the frequency spread in the unperturbed beam, the number of particles N, the beam energy, geometrical properties of the accelerator, but not the conductivity {sigma}. A numerical example presented indicates that certain observations of beam behavior in the MURA 40-Mev-electron accelerator may be related to the phenomenon we investigated.

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Discussed topics on current reactor production fuels include: uranium core production data, uranium specifications, induction heat treating, fuel performance, residual stress measurements, AlSi process development, thoria program, and self-support program. The N-reactor fuels production is discussed. And concerning N-Reactor fuels development, process development and irradiation experience are discussed.

The objective of this supplement to Production Test IP-550-I is to include the K reactors in the program for routinely monitoring graphite oxidation rates. This supplement does not initiate a new program; it continues one which has been in existence for some time. Oxidation of the reactor graphite weakens its structural capacity. At some degree of oxidation, sufficient loss of strength will occur to significantly affect the ability to maintain and operate the reactors. For this reason it is necessary to control and to monitor the rates of oxidation in realtor. It is difficult to accomplish the latter in a truly representative fashion. A number of methods of obtaining information on this subject must be used; one of these is to expose small samples to the reactor atmosphere under operating conditions and then determine the average rate at which the samples have changed weight. This method has been employed in one fashion or the other for some time. Until June, 1962, the program was authorized by Production Test 105-532-E; from June, 1962, until January 26, 1964, the program was authorized by PITA IP-20-I{sup 4} at the K reactors.

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This report addresses the desgin and performance analysis of a pressure control system for the test cell A feedsystem.

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Diffusion of beryllium-7 through polycrystalline unirradiated specimens of BeO was studied as a preliminary step to a study of diffusion in irradiated material. Beryllium-7 was deposited on one end of cylindrical specimens by exchange and adsorption from aqueous solution. The depth of penetration perpendicular to the surfaces of deposition was determined after annealing the specimens at pre-determined conditions. A simple lapping device of high precision was developed to determine penetration depths. For the polycrystalline cold-pressed and sintered BeO studied, the diffusion behavior between 1150 and 1800 deg C is described by the empirical relation: D = 2.49 x 10/sup -3/ exp -- (62.5 x 10/sup 3//RT) cm/sup 2//sec. A diffusion model is proposed based on vacancy migration which suggests identical activation energies for diffusion in both a and c directions in single crystals and predicts an activation energy of the correct order oi magnitude. Furthermore, the model p dicts that the frequency factor in the direction pexpendicular to the c axis should be about 50% higher than that parallel to the c axis. (auth)

The salivary gland chromosomes of Chironomus tentans larvae collected from White Oak Creek, an area contaminated by radioactive waste from the Oak Ridge National Laboratory, and from six uncontaminated areas were examined for chromosomal aberrations. White Oak Creek populations were exposed to absorbed doses as high as 230 rads per year or about 1000 times background. Chromosomal maps were constructed to make a general comparison of the banding pattern of the salivary chromosomes of the C. tentans in the East Tennessee area with those of Canada and Europe. These maps were used as a reference in scoring aberrations. Fifteen different chromosomal aberrations were found in 365 larvae taken from the irradiated population as compared with five different aberrations observed in 356 larvae from six control populations, but the mean number of aberrations per larva did not differ in any of the populations. The quantitative amount of heterozygosity was essentially the same in the irradiated and the control population, but there were three times the variety of chromosomal aberrations found in the irradiated area. From this evidence it was concluded that chronic low-level irradiation from radioactive waste was increasing the variability of chromosomal aberrations without significantly increasing the frequency. It was …

A method is presented for designing a two-layer pressure vessel wherein contact between the layers is produced by controlled yielding of the inner vessel by internal pressure. The amount of prestress depends upon the dimensions of the vessel, the properties of the material of construction, and the prestressing pressure. The method takes into account the actual stress-strain curve of the material and satisfies the rules of plastic flow with work hardening. (auth)

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This report summarizes the results of the fifth of a series of tests completed in the A-11 test program.

This letter provides information on a proposed peaceful use of nuclear explosives (Project Sulky)with regard to nuclear excavation for an Isthmian canal. Nuclear explosion detection, radioactivity release, details of the changes in the experimental plan, and Pike venting analysis are included.

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