Nuclear reactor analysis

Duderstadt and L. J. Hamilton, Nuclear Reactor Analysis. Wiley, New York, 1976. 

LIBS is used in industry, biomedical applications, analysis of materials in hazardous environments, such as inside nuclear reactors, analysis of materials underwater, and for the ranote detection of hazardous materials, including explosives. Samples may be solids, liquids, gases, slurries, sludges, and other mixtures. Applications for LIBS (courtesy of Applied Photonics Ltd.) include the following ... 

Qualification of Computer Codes for Nuclear Reactor Analysis—II... 

Our approach in this chapter will begin with an overview in Section 21.1 of the common physical and mathematical aspects that are important to the study of criticalities, and then follow this in Sections 21.2 and 21.3 with the particular concepts, analytical approaches, tools, and data that are used in the disciplines of nuclear reactor analysis and nuclear criticality safety analysis, respectively. 

The first part of this chapter involves nuclear reactor analysis, so we can avoid duplication by building on those ideas. 

Cacuci, D. G. 2010. Handbook of Nuclear Engineering. New York Springer. This four-volume e-book provides thorough coverage of all areas of nuclear engineering. Volume 1 focuses on the fundamentals of nuclear engineering volumes 2, 3, and 4 discuss nuclear reactor analysis, power reactors, experimental reactors, and the nuclear fuel cycle, respectively. Other topics include radioactive waste disposal, safeguards, and nuclear nonproliferation. 

Duderstadt, J. J. and L. J. Hamilton. 1976. Nuclear Reactor Analysis. New Yoik John Wiley Sons. Designed for the nuclear engineering student, this book provides the basic scientific principles of nuclear fission chain reactions and applications in nuclear reactor design. References and problems are included at the end of each chapter along with appendices, which include selected nuclear data, selected mathanatical formulas, and nuclear power reactor data. 

A. F. Henry, Nuclear Reactor Analysis, M.I.T. Press, Cambridge, Massachusetts (1975). 

R. Boer and H. Finnemann, Past Analytical Flux Reconstruction Method for Nodal Space-Time Nuclear Reactor Analysis, Annals of Nuclear Energy, Vol. 19, 617-628 (1992)... 

Powder diffraction studies with neutrons are perfonned both at nuclear reactors and at spallation sources. In both cases a cylindrical sample is observed by multiple detectors or, in some cases, by a curved, position-sensitive detector. In a powder diffractometer at a reactor, collimators and detectors at many different 20 angles are scaimed over small angular ranges to fill in the pattern. At a spallation source, pulses of neutrons of different wavelengdis strike the sample at different times and detectors at different angles see the entire powder pattern, also at different times. These slightly displaced patterns are then time focused , either by electronic hardware or by software in the subsequent data analysis. 

Neutron Activation Analysis Few samples of interest are naturally radioactive. For many elements, however, radioactivity may be induced by irradiating the sample with neutrons in a process called neutron activation analysis (NAA). The radioactive element formed by neutron activation decays to a stable isotope by emitting gamma rays and, if necessary, other nuclear particles. The rate of gamma-ray emission is proportional to the analyte s initial concentration in the sample. For example, when a sample containing nonradioactive 13AI is placed in a nuclear reactor and irradiated with neutrons, the following nuclear reaction results. 

The concentration of Mn in steel can be determined by a neutron activation analysis using the method of external standards. A 1.000-g sample of an unknown steel sample and a 0.950-g sample of a standard steel known to contain 0.463% w/w Mn, are irradiated with neutrons in a nuclear reactor for 10 h. After a 40-min cooling period, the activities for gamma-ray emission were found to be 2542 cpm (counts per minute) for the unknown and 1984 cpm for the standard. What is the %w/w Mn in the unknown steel sample ... 

All the techniques discussed here involve the atomic nucleus. Three use neutrons, generated either in nuclear reactors or very high energy proton ajccelerators (spallation sources), as the probe beam. They are Neutron Diffraction, Neutron Reflectivity, NR, and Neutron Activation Analysis, NAA. The fourth. Nuclear Reaction Analysis, NRA, uses charged particles from an ion accelerator to produce nuclear reactions. The nature and energy of the resulting products identify the atoms present. Since NRA is performed in RBS apparatus, it could have been included in Chapter 9. We include it here instead because nuclear reactions are involved. 

Since the recognition in 1936 of the wave nature of neutrons and the subsequent demonstration of the diffraction of neutrons by a crystalline material, the development of neutron diffraction as a useful analytical tool has been inevitable. The initial growth period of this field was slow due to the unavailability of neutron sources (nuclear reactors) and the low neutron flux available at existing reactors. Within the last decade, however, increases in the number and type of neutron sources, increased flux, and improved detection schemes have placed this technique firmly in the mainstream of materials analysis. 

Within nuclear reactors, neutrons are a primary product of nuclear fission. By controlling the rate of the nuclear reactions, one controls the flux of neutrons and provides a steady supply of neutrons. For a diffraction analysis, a narrow band if neutron wavelengths is selected (fixing X) and the angle 20 is varied to scan the range of values. 

Kelly, B.T. and Burchell, T.D., The analysis of irradiation creep experiments on nuclear reactor graphites. Carbon, 1994, 32, 119 125. 

Solomon, K. D. and W. G. Kastenburg, 1985, Estimating the Planning Zones for the Shoreham Nuclear Reactor, A Review of Four Safety Analysis, Rand note N-2353-DOE September. 

The purpose of this analysis was to assess the risk of operating Limerick Station, specifically with regard to its location near a high population density area. These risks were evaluated to determine whether they represent a disproportionately high segment of the total societal risk from postulated nuclear reactor incidents. 

This can result in a radioactive product from the A(n, t)A reaction where A is the stable element, n is a thermal neutron, A is the radioactive product of one atomic mass unit greater than A, and y is the prompt gamma ray resulting from the reaction. A is usually a beta and/or gamma emitter of reasonably long half-life. Where access to a nuclear reactor has been convenient, thermal neutron activation analysis has proven to be an extremely valuable nondestructive analytical tool and in many cases, the only method for performing specific analyses at high sensitivities... 

All the references to burn-out have thus far been concerned with uniformly heated channels, apart from some of the rod bundles where the heat flux varies from one rod to another, but which respond to analysis in terms of the average heat flux. In a nuclear-reactor situation, however, the heat flux varies along the length of a channel, and to find what effect this may have, some burn-out experiments on round tubes and annuli have been done using, for example, symmetrical or skewed-cosine axial heat-flux profiles. Tests with axial non-uniform heating in a rod bundle have not yet been reported. 

Reviews of analytical methods for impurities in alkali metals are largely devoted to Na and K owing to their use as liquid coolants in fast-breeder nuclear reactors ". These methods may be extended to Rb and Cs except the analysis for oxygen. In analytical work with the alkali metals, care is necessary during sampling and handling to avoid contamination in transit. The impurities usually considered are O, C, N, H and metals. 

What convinces scientists that sustained fission once occurred at Oklo is the presence of characteristic fission products in the ore. Elements of mass numbers between 75 and 160 occur in the ore in larger amounts than elsewhere. Furthermore, mass analysis of the elements in Oklo ore shows that they are distributed in the characteristic pattern shown in Figure 22-12. This isotopic signature, which is not found in any other naturally occurring materials, is so characteristic that it has convinced most scientists that the ore deposits at Oklo once formed a huge nuclear reactor. 

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