Radiation distribution sensing with normal optical fiber

The purpose of this study is to develop a radiation distribution monitor using a normal plastic optical fiber. The monitor has a long operating length and can obtain continuous radiation distributions. A principle of the position sensing is based on a time-of-flight technique. The monitor is sensitive to beta rays or charged particles, gamma rays, and fast neutrons. The spatial resolutions for beta-rays ( ⁹⁰Sr-⁹⁰Y), gamma-rays (¹³⁷Cs), and D-T neutrons are 30, 37, and 13 cm, respectively. The detection efficiencies for the beta-rays, gamma-rays, and D-T neutrons are 0.11%, 1.6×10 ^-5% and 1.2×10^-4%, respectively. The effective attenuation length of the detection efficiency is 18 m. In this paper, we describe the basic characteristics of this monitor     

Design and fabrication aspects of a plutonium-incineration experiment using inert matrices in a “Once-Through-Then-Out” mode

In the plutonium incineration experiment, named ‘Once-Through-Then-Out’ (OTTO), that is being prepared by JAERI, PSI and NRG, the use of highly stable inert matrices will be examined. The inert matrices MgAl₂O₄ spinel and ZrO₂ are insoluble in nitric acid and are considered as good storage media for final disposal. These inert matrices will be used in this experiment, which is representative for an OTTO scenario. A total of 7 Pu-containing targets were prepared for an irradiation in the High Flux Reactor in Petten. The objective of the irradiation is to reach a very high Pu-burnup. The main parameters to be studied are stability under irradiation, swelling, fission gas release and chemical interactions in the fuel. Four targets will be equipped with thermocouples for on-line monitoring of central temperature. Four of the targets contain MgAl₂O₄ as an inert matrix, 2 targets contain ZrO₂ and one target contains mixed-oxide (MOX) fuel for reference purposes. The fissile plutonium concentration is 0.32–0.44 g cm⁻³. Both particle-dispersed fuel and homogeneous dispersions were fabricated in order to test the effect of the size of the fissile inclusions. The design of the experiment and the fabrication of the samples are discussed.     

Current status of researches on the plutonium rock-like oxide fuel and its burning in light water reactors

Intention of the ROX-LWR system research is to provide an option for utilization or disposition of surplus plutonium. Researches on inert matrix materials and irradiation performance shows that the most favorable candidate for the ROX fuel is a particle dispersed fuel where small particles consisted of yttria stabilized zirconia, PuO₂ and some additives are homogeneously dispersed in spinel matrix. Reactor safety analyses show that the ROX fueled PWR core has nearly the same performability as the existing UO₂ fueled PWR under both reactivity initiated accidents and loss of coolant accidents.     

Mass Transfer of Lead Coolant Vapors in a BREST-OD-300 Reactor

The goal of the work reflected in this paper is to investigate the mass transfer of lead from the coolant surface in the gaseous cavities of the cooling loop of a BREST-OD-300 reactor. The theoretical and experimental investigations show that the amount of lead evaporating from the free surfaces of the first loop of the reactor is negligible.The results of this work are the recommendations that filters should be placed at locations where the pipelines of the gas system, located outside the reactor block, are connected to the reactor cover, because of the possibility of aerosols – dust-like impurities from other sources with mass flow several times greater than the rate of evaporation of lead in the unit – entering the gas system. 2 figures, 7 references.     

Some notes on the determination of moisture and volatile matter in fats and oils

Summary It has been found that the method of moisture determination introduced by Parsons and Holmberg, in which water is evolved from the sample and absorbed on CaCl₂, is absolute and is applicable to all types of oils and fats, except those containing residual solvent. It is particularly suited for the determination of very low percentages of moisture in oils and fats. Of the methods recommended by the A.O.C.S. for the determination of moisture and volatile in oils and fats, the vacuum oven was found to be the most accurate, except on high-fatty-acid coconut oil. The hot-plate method gave the highest moisture results when the test was conducted according to the procedure outlined in the methods of the A.O.C.S. When first traces of smoking were observed under a strong beam of concentrated light, resulting moistures approached those obtained by the vacuum oven. Moisture results obtained by the air oven, if corrected for peroxide absorption, approach those of the vacuum oven. The percent of residual solvent in extracted soyabean oil, independent of moisture, may be accurately determined by adsorption of solvent vapor on activated charcoal.     

Determination of air content in dry shortenings

A method of test is described for the determination of dry shortening air content. Liquid mediums are prepared which have identical specific gravity to that of the shortening which is under test. Simple calculation of specific gravity data gives the air content. A distinct advantage to the method lies in the fact that air content can be determined for any shortening sample size.     

The oven test as an index of keeping quality

The Schaal or Oven Test, originally developed by the biscuit and cracker industry to provide a relative rating for stability of various shortenings, has been generally adopted by shortening manulacturers. Advantages as well as limitations of the test are enumerated. It is possible to estimate the Oven Test by determining peroxide development in the test sample after two to four days in the oven. Oven Tests may also be conducted without having determined them organoleptically by observing the color change at the point of extreme rancidity. Peroxide formation occurring in a fat contained in biscuits or crackers when subjected to the Oven Test has been investigated and a simple and rapid method of extracting the fat, without changing its peroxide characteristics, has been devised. Lever brothers company