Neutrons, effect

Cadmium-113 captures neutrons effectively and is suitable in the regulation of nuclear reactors. The isotope is a beta-emitter with a half-life of 10u years (record). 

Marti, K. and Lugmair, G. W., "81Kr-Kr and K-40Ar ages, cosmic-ray spallation products and neutron effects in lunar samples from Oceanus Procell arum", Proc. Second Lunar Sci. Conf., 1971, 2, 1591-1605. 

Levy, Herley and co-workers at Brookhaven National Laboratory have been studying the effects of X-ray, gamma rays and neutron radiations on AP (Refs 163,208,211,224, 228,240, 241,244,255 258). Neutron effects studies... 

Herley et al, Recent Radiation Effect Studies on Ammonium Perchlorate. Part II The Effect of Fast Neutron, Gamma Ray and Combined Radiation on the Thermal Decompositions of- Ammonium Perchlorate Powder—Aluminum Particle Mixtures , Ibid, paper 2.2b, pp 301—15 (1975) 242) W.D. Hutchinson, Neutron Effects on Solid Propellants , Ibid, paper 2.6, pp 281-99 (1975) 243) R.A. Benham F.H. Mathews,... 

Medema and Houtman (110b) used a somewhat parallel behavior of alumina toward thermal activation and neutron bombardment as measured by activity and selectivity for the isomerization of butene-1 to assign the neutron effects to the conversion of some of type A sites (110c) to type B. The neutrons were supposed to function by knocking out oxygen atoms and hydroxyl groups from the surface. This is an example of the use of information from more conventional studies to explain a result of irradiation, a frequently necessary departure from the irradiation technique presented in Section II,A. 

L. Avrami, H. Jackson, O. Sandus, Pulsed Neutron Effects on Spartun Ordnance and Explosives, Tech. Rept. 4509, Picatinny Arsenal, Dover, N.J. (1973). 

An example of crystal monochromator instrument on a continuous source is IN4 [31] at the ILL, shown in Fig. 3.30. IN4 sits at the end of a short thermal neutron guide, thus the lack of hot neutrons effectively restricts the energy transfer range to less than 800 cm". ... 

Marti K, Lugmair GW (1971) Kr -Kr and K-Ar" ° ages, cosmic ray spallation products, and neutron effects in lunar samples from Oceanus Procellaram. Proc Lunar Sci Conf 2nd 1591-1605 Marti K, Graf T (1992) Cosmic ray exposure history of ordinary chondrites. Ann Rev Earth Planet Sci 20 221-243... 

Dr. Oppenheimer stated that the visual effect of an atomic bombing would be tremendous. It would be accompanied by a brilliant luminescence which would rise to a height of 10,000 to 20,000 feet. The neutron effect of the explosion would be dangerous to life for a radius of at least two-thirds of a mile. 

No clear-cut method for estimating the neutron current leaving the thermal shield was established analytically. Therefore, the final analysis of the concrete with respect to neutron effects was held in.abeyance until certain experimental data were available from the Mock-Up. These data are principally measurenents of therma1-neutron flux and of the cadmium ratios at various points in the reactor. 

T. Plass, G.N. and Wigner, E. P., Values of the Thermal Utilization, Resonance Absorption, and Fast Neutron Effect for Oxide and Metal Spheres and Cylinders , CP-372, December 14, 1942. 

S. D. Harkness, J. A. Tesk, and C. Y. Li, An analysis of fast neutron effects on void formation and creep in metals, Nucl. Appl. Technol. 9, 24-30 (1970). 

Another type of purely neutronic effect which is important in thermal reactors arises from the heating of the moderator and consequent rise in neutron temperature. This results in a change in both the thermal diffusion length and the neutron age to thermal, thus a change in migration length and hence in neutron leakage. 

The neutronic effectiveness of a moderator material can be expressed in terms of the conversion potential of a mixture of fuel and moderators in an infinite medium. This approach has been used in a relative comparison of HjO, BeO, and C with fuel which has appeared in a progress report on BeO reactor studies (26). In this evaluation, the excess production of neutrons per neutron absorbed in the fuel has been calculated for homogeneous mixtures of fuel and moderator having different moderator/ atom ratios, i.e.,... 

Results of the eight 4 x 4x4 experiments are summarized in Tables I and n. The errors are mostly due to positioning uncertainties and control element perturbation. No attempt has been made to correct for the neutronic effect of support structure and room return. 

Boron compounds have low solubility relative to some cadmium, gadolinium, or europium compounds in nitric acid solutions, and would be more likely to precipitate from solution if high concentrations are required. Cadmium is a desirable poison however, it may be volatile at temperatures encountered in the waste conversion proqess and would therefore require an additional process for recovery. Additional requirements for, soluble poisons Include chemical stability in the solution and processing behavior similar to the fissile material. Each poison s neutron absorption rate is uniquely dependent on the neutron energy spectra of the system hence, the relative neutronic effectiveness of each poison varies from one system to another. Consequently, a mixture of poisons in a solution may be more effective than dither poison alone. ... 

Low power measurements with observation of delayed neutron effects. 

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