Reactor orders

Optimism about economic growth in the period 1960—1975 led to a large number of reactor orders. Many of these were canceled even after partial completion in the period after the 1974 oil crisis, as the result of a reduction in energy demand. Inflation, high interest rates, long constmction periods, and regulatory delays resulted in severe cost overmns. Moreover, the reactor accidents of TMI and, later, Chernobyl produced an atmosphere of pubHc concern. 

Problems P5-3. P5-5, P5-7, and P5 18 all involve batch reactor experiments to find] the reactor order and specific reaction rate. The students can use differed techniques to differential the data or can use regression. These problems cat be alternated from year to year. 

In the U.K. electricity industry, there were dramatic reductions in nuclear research and development (R D) funding—cuts of well over 50% in six years. This was primarily associated with the fact that no new reactor orders are anticipated at present in the U.K. However, the observed cuts in R D expenditures could reduce the levels of expertise available to deal with critical safety problems that may arise. For example, the reduced funding could result in R D staffing levels falling below a critical mass, or lead to attrition of the most talented researchers. The U.K. nuclear power industry also experienced problems with loss of specialized skills among the technical support staff. 

Because the location and operations perfonned at K-Reactor in Cold Standby and L- and P> Reactor Disassembly Basins vdll lemain the same as previously petfonned during routine reactor operations, the cuirent site and reactor order compliance statfis is applicable to the continued use of K-Reactor to store and handle unirradiated fUd and irradiated compcments and to store and process contaminated moderator and the continued use of L- and P-Reactor Disassembly Basins to store and handle inadiated components. 

The current site and reactor order compliance status is applicable to the continued use of K-Reactor in Cold Standby for the storage and handling of unirradiated fuel and irradiated components and the storage and processing of contaminated moderator. Also the current site and reactor order compliance status is applicable to the L> and P>Reactor Disatuembly Basins in the continued use of the basins to store and handle irradiated components. 

PTC 32.2 Report— 1979(R1992) Methods of Measuring the Performance of Nuclear Reactor Fuel in Li t Water Reactors Order No. C00045 23.00... 

Reactor order for sulfur and hydrogen, respectively Average molar weight, g/gmol Reaction order for nickel and vanadium Number of moles of species i, mol,... 

Having made a choice of the reaction path, we need to choose a reactor type and make some assessment of the conditions in the reactor. This allows assessment of reactor performance for the chosen reaction path in order for the design to proceed. 

Cfeed = molar concentration of FEED in the reactor di, 0-2 = constants (order of reaction) for primary and secondary reactions... 

In general terms, if the reaction to the desired product has a higher order than the byproduct reaction, use a batch or plug-flow reactor. If the reaction to the desired product has a lower order than the byproduct reaction, use a continuous well-mixed reactor. 

Figure 2.3 Choice of reactor type for mixed parallel and series reactions when the parallel reaction has a higher order than the primary reaction.

In the preceding section, the choice of reactor type was made on the basis of which gave the most appropriate concentration profile as the reaction progressed in order to minimize volume for single reactions or maximize selectivity for multiple reactions for a given conversion. However, after making the decision to choose one type of reactor or another, there are still important concentration effects to be considered. 

Some guess for the reactor conversion must be made in order that... 

Multiple reactions. For multiple reactions in which the byproduct is formed in parallel, the selectivity may increase or decrease as conversion increases. If the byproduct reaction is a higher order than the primary reaction, selectivity increases for increasing reactor conversion. In this case, the same initial setting as single reactions should be used. If the byproduct reaction of the parallel system is a... 

This might he worthwhile if the FEED-BYPRODUCT separation is expensive. To use a purge, the FEED and BYPRODUCT must be adjacent to each other in order of volatility (assuming distillation is used as the means of separation). Of course, care should be taken to ensure that the resulting increase in concentration of BYPRODUCT in the reactor does not have an adverse effect on reactor performance. Too much BYPRODUCT might, for example, cause a deterioration in the performance of the catalyst. 

Reactor diluents and solvents. As pointed out in Sec. 2.5, an inert diluent such as steam is sometimes needed in the reactor to lower the partial pressure of reactants in the vapor phase. Diluents are normally recycled. An example is shown in Fig. 4.5. The actual configuration used depends on the order of volatilities. 

Also, if there are two separators, the order of separation can change. The tradeoffs for these two alternative flowsheets will be different. The choice between different separation sequences can be made using the methods described in Chap. 5. However, we should be on guard to the fact that as the reactor conversion changes, the most appropriate sequence also can change. In other words, different separation system structures become appropriate for different reactor conversions. 

If a fluid is placed between two concentric cylinders, and the inner cylinder rotated, a complex fluid dynamical motion known as Taylor-Couette flow is established. Mass transport is then by exchange between eddy vortices which can, under some conditions, be imagmed as a substantially enlranced diflfiisivity (typically with effective diflfiision coefficients several orders of magnitude above molecular difhision coefficients) that can be altered by varying the rotation rate, and with all species having the same diffusivity. Studies of the BZ and CIMA/CDIMA systems in such a Couette reactor [45] have revealed bifiircation tlirough a complex sequence of front patterns, see figure A3.14.16. 

The Stainicaibon process is described in Figures 3—7. The synthesis section of the plant consists of the reactor, stripper, high pressure carbamate condenser, and a high pressure reactor off-gas scmbber. In order to obtain a maximum urea yield pet pass through the reactor, a pressure of 14 MPa (140 bar) and a 2.95/1 NH —CO2 molar ratio is maintained. The reactor effluent is distributed over the stripper tubes (falling-film type shell and tube exchanger) and contacted by the CO2, countercurrendy. This causes the partial NH pressure to decrease and the carbamate to decompose. 

Industrial appHcations often require that bulk materials or Hquids be weighed in hoppers, silos, tanks, or reactor vessels, referred to collectively as vessels. Because they come in such a wide variety of si2es, shapes, and capacities, scales using these vessels as load receivers are not typically available as standard products. Vessels are usually custom-fabricated to suit a particular appHcation, then mounted on a scale. Some can be mounted on a standard scale such as a bench, portable, or floor scale. More typically, a number of weigh modules are used to support the vessel. This offers the scale designer great flexibiHty but certain precautions are necessary in order to constmct an accurate scale. Some of the more important factors associated with the design of vessel scales are discussed herein. 

A fixed-bed reactor for this hydrolysis that uses feed-forward control has been described (11) the reaction, which is first order ia both reactants, has also been studied kiaeticaHy (12—14). Hydrogen peroxide interacts with acetyl chloride to yield both peroxyacetic acid [79-21-0] and acetyl peroxide... 

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