Reactor sources

Figures Comparison of nuciear reactor and pulsed spaliation sources. For reactor sources (steady-state method), a narrow band of wavelengths is seiected with a monochromator crystal and the scattering angle (26,) Is varied to scan dspacings. Pulsed sources (time-of-flight method) use almost the entire avail-abie neutron spectrum, fix the scattering angie (26,), and simultaneousiy detect a neutron while determining its time of flight.

Figure 4-18. Fixed bed (integral) reactor. (Source V. W. Weekman, Laboratory Reactors and Their Limitations/ A CbEJ, Vol. 20, p. 833, 1974. Used with permission of the AlChEJ.)...

Figure 8-38. Residence time distributions of some commerciai and fixed bed reactors. The variance, equivaient number of CSTR stages, and Peciet number are given for each reactor. (Source Wales, S. M., Chemicai Process Equipment—Seiection and Design, Butterworths, 1990.)...

Figure 12-6. Causes of runaways in industrial reactors. (Source Internal Ciba-Geigy Publication, 1984.)...

Blond, R., The Development Severe Reactor Source Terms 1957-1981, November 1982. Safety Goals for Nuclear Power Plant Operation May 1983. 

The following sources and instruments dominate studies in the area of liquids and amorphous materials. Although there are a number of sources available, each is optimized for a particular class of experiment. The sources can be split into two types pulsed neutron sources and reactor sources... 

Other reactor sources with instruments like D4C but with much lower flux, and hence longer data collection times, are the Laboratoire Leon Brillouin (LLB, Saclay, France), on the instrument 7C2, and the NFL (Studsvik, Sweden), on the instrument SLAD... 

Cells used for high-temperature measurements in furnaces often consist of silica sample tubes, supported by thin vanadium sleeves. The key to the analysis is whether it is possible to have a container that scatters in a sufficiently predictable way, so that its background contribution can be subtracted. With the current neutron flux available from both pulsed and reactor sources, sample volumes of... 

FIGURE 4-2 Schematic diagram of Foster Wheeler transpiring-wall SCWO reactor. SOURCE Eco Logic (2001a). 

In order to determine the dynamics of atoms we have to carry out an inelastic neutron scattering measurement. With a reactor source this can be done with a triple-axis spectrometer, which has an analyzer crystal. Tripleaxis refers to the three axes for the monochromator, sample, and analyzer, all moving independently and controlled by a computer. With a pulsed source we use a mechanical chopper, which is a rotating cylinder with a hole perpendicular to the rotating axis that allows neutrons with a chosen range of velocity to go through. The neutrons scattered by the sample are detected... 

As with neutron powder methods, both monochromatic and time-of-flight (Laue) techniques have been used for single-crystal neutron studies. Such studies are much less numerous, however, as a result of the difficulty of compressing suitably sized (>1 mm ) single-crystal sample to the required pressure while maintaining the crystal quality. The piston cylinder cell design of Me Whan and others [128] has been used at the ILL reactor source for a number of neutron structural studies to... 

The advantages of using polychromatic radiation from a reactor source, coupled with Laue diffraction methods, have been investigated by McIntyre et al. for high-pressure studies [194]. Using a 0.5-mm crystal in a moissanite anvil pressure cell... 

The (TiN) + clusters produced by a laser-induced plasma reactor source were investigated by means of time-of-flight mass spectrometry. The mass spectral abundance indicates that the clusters have cubic structures resembling subunits of the fee lattice of TiN. The primary stoichiometries observed are (TiN) + (n = 1-126), except for Ti N , (n = 14, 63) (36). 

FIG. 8-36 Cascade control of an exothermic chemical reactor. (Source Seborg et al., Process Dynamics and Control, 2d ed.y Wiley, New York, 2004.)... 

Figure 4-2. Jacketed batch reactor. (Source D. B. Gooch, Autoclaves Pressure—Temperature Reactions, Ind. Eng. Chem., 35, 927-946, 1943. Used with permission from the American Chemical Society.)...

Figure 8-6. Age distribution functions of ideal reactors. (Source Wen and Fan [6]).

Figure 12-33. Steps used to model compressible vapor venting from the reactor. (Source Reproduced with permission of the AlChE. Copyright 1996 AlChE. All rights reserved.)...

Fig. 19.11. Generic coal gasification reactors. (Source Electric Power Research Institute and Synthetic Fuels Associates, Inc.)...

Neutron Facilities (Reactor Sources and Spallation Sources) 3... 

NEUTRON FACILITIES (REACTOR SOURCES AND SPALLATION SOURCES)... 

Figure 2 Improvement in Neutron Fluxes (vertical axis) over time (horizontal axis). Note the predominance of fission reactor sources from 1945 to 1980 (dashed line in the middle) and the steady drift toward more intense spallation sources in more recent years (solid line to the right). (Drawn from data in Skold Price, 1986)...

Gives an overview of neutron scattering methods from both pulsed and reactor sources. Also provides some experimental examples. 

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