TARGET, reactor

Notes 1, All tests are at 3400 psi. 2. Ethanol (EtOH) is oxidized with approxiately stoichiometric oxygen in the reactor to bring the preheated stream up to the target reactor temperature. ... 

The target reactor for this purpose should be transportable, long-life, safe, simple (easy maintenance and operation), and proliferation-resistant. However, some of these characteristics are tightly related to each other. By investigating these characteristics, it appears that only long-life core and small-size are basic characteristics and that other characteristics can be derived from these two. 

Calculations of the temperature fields for the target reactor power of 500 kW of thermal energy were performed to scope the differences between cooling at the reactor core boimdary and cooling at the external boundary of the reflector. These scoping calculations were performed for the preliminary core size of 100-cm-diam by 100-cm-long cylinder with a 15-cm-thick reflector on all surfaces. Two computational approaches were used to model the reactor—a simplified infinite-cylinder 1-D model and a detailed 3-D finite element. 

Although the composite curves can be used to set energy targets, they are not a suitable tool for the selection of utilities. The grand composite curve is a more appropriate tool for understanding the interface between the process and the utility system. It is also, as is shown in later chapters, a useful tool for study of the interaction between heat-integrated reactors and separators and the rest of the process. 

Once a design is known for the first two layers of the onion (i.e., reactors and separators only), the overall total cost of this design for all four layers of the onion (i.e., reactors, separators, heat exchanger network, and utilities) is simply the total cost of all reactors and separators (evaluated explicitly) plus the total cost target for heat exchanger network and utilities. 

World reactor-related requirements are expected to increase from 57,182 t U in 1992 to about 75,673 t U by the year 2010. Some utiUties are expected to continue to meet their requirements by purchasing or drawing on excess inventory. Annual uranium production should remain below actual requirements until some target level of stocks is reached (27). 

The analysis of steady-state and transient reactor behavior requires the calculation of reaction rates of neutrons with various materials. If the number density of neutrons at a point is n and their characteristic speed is v, a flux effective area of a nucleus as a cross section O, and a target atom number density N, a macroscopic cross section E = Na can be defined, and the reaction rate per unit volume is R = 0S. This relation may be appHed to the processes of neutron scattering, absorption, and fission in balance equations lea ding to predictions of or to the determination of flux distribution. The consumption of nuclear fuels is governed by time-dependent differential equations analogous to those of Bateman for radioactive decay chains. The rate of change in number of atoms N owing to absorption is as follows ... 

Methanol. Methanol is produced by stoichiometric reaction of CO and H2. The syngas produced by coal gasification contains insufficient hydrogen for complete conversion to methanol, and partial CO shifting is required to obtain the desired concentrations of H2, CO, and CO2. These concentrations are expressed in terms of a stoichiometric number, ((H2 — CO)/(H2 + CO2), which has a desired value of 2. In some cases CO2 removal is required to achieve the stoichiometric number target. CO and H2 are then reacted to form methanol in a catalytic methanol synthesis reactor. 

Production in Target Elements. Tritium is produced on a large scale by neutron irradiation of Li. The principal U.S. site of production is the Savaimah River plant near Aiken, South Carolina where tritium is produced in large heavy-water moderated, uranium-fueled reactors. The tritium may be produced either as a primary product by placing target elements of Li—A1 alloy in the reactor, or as a secondary product by using Li—A1 elements as an absorber for control of the neutron flux. 

Production-Scale Processing. The tritium produced by neutron irradiation of Li must be recovered and purified after target elements are discharged from nuclear reactors. The targets contain tritium and He as direct products of the nuclear reaction, a small amount of He from decay of the tritium and a small amount of other hydrogen isotopes present as surface or metal contaminants. 

These results can be used to construct the solution as shown in Fig. 7.14. The target for minimum CE discharge through segregation, mixing and direct recycle is 0.488 X 10 kg/s (about 15 kg/yr). The solution indicates that the optimal policy is to segregate the effluents of the two scrubbers, pass the effluent of the first scrubber to the reactor, recycle the aqueous effluent of the reactor to the hrst scrubber and dispose of the second scrubber effluent as the terminal wastewater stream. 

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