Boiling Reactor Experiments

Under the USAEC program, the following reactors were built Boiling Reactor Experiment V (BORAX—V, started operation in December of 1962), BOiling NUclear Superheater (BONUS, started operation in December of 1964), and Pathfinder (started operation in July of 1966). The main parameters of these reactors are listed in Tables A5.1 and A5.2 (Novick et al., 1965). 

USAEC Report (MaANL-6302), 1961. Design and Hazards Summary Report—Boiling Reactor Experiment V (Borax-v). Argonne National Laboratory. 

During the period of construction and operation of HRE-1, conceptual design studies were completed for a boiling reactor experiment (BRE) operating at 150 kw of heat and a 58-Mw (heat) intermediate-scale homogeneous reactor (ISHR). Further work on these reactors was deferred late in 1953, however, when it became evident from HRE-1 and the associated development program that construction of a second homogeneous reactor experiment would be a more suitable course of action. 

R. N. Lyon, Preliminary Report on the 1953 Los Alamos Boiling Reactor Experiments, USAEC Report CF-53-11-210, Oak Ridge National Laboratory, Nov. 30, 1953. 

Herein reactors are described in their most prominent appHcation, that of electric power. Eive distinctly different reactors, ie, pressurized water reactors, boiling water reactors, heavy water reactors, graphite reactors, and fast breeder reactors, are emphasized. A variety of other appHcations and types of reactors also exist. Whereas space does not permit identification of all of the reactors that have been built over the years, each contributed experience of processes and knowledge about the performance of materials, components, and systems. 

The 1,356 MWe Advanced Boiling Water Reactor was jointly developed by General Electric, Hitachi, and Toshiba and BWR suppliers based on world experience with the previous BWRs. Tokyo Electric Power operates two ABWRs as units 6 and 7 of the Kashiwazaki-Kariwa Nuclear Power Station. Features of the ABWR are (Wilkins, 19921 ... 

The addition of dimethylamine is usually completed within 3 hours. The reaction mixture is then stirred under nitrogen for an additional 3 hours while the system warms slowly to room temperature. The reflux condenser on the exit side (the right) of the reactor is quickly replaced by a distillation apparatus suitable for fractionation. The reaction mixture is then distilled under dry nitrogen at a pressure of 1 atmosphere. The fraction boiling at 149 to 151°/745 mm. is collected as product. In a typical experiment, this fraction weighed 304.8 g. or 94% of theory based on the dimethylamine used. Anal. Calcd. for (CH3)2NPC12 C, 16.46 H, 4.14 N, 9.60 Cl. 48.58. Found C, 16.39 H, 4.16 N, 9.30 Cl, 48.68. 

In various experiments, it was shown that the use of microwave technology leads to a significant decrease in the reaction time and in some cases also to less by-product and a higher yield. This technology allowed us to optimize the reaction with focus on work-up and purification, independent of reaction temperature and boiling point of the solvent. In most cases the reaction conditions, applied on 15 ml scale in the Emrys Optimizer, were transferred without further optimization to the microwave reactors tested and led to comparable results. Additional optimization in a few cases was limited to small adjustments in reaction temperature or reaction time. A number of scale-up experiments were conducted using a Synthos 3000 reactor and we showed that a scale-up to 100 g is feasible. 

In Advanced Gas Cooled (AGR), Pressurised Water (PWR) and Boiling Water (BWR) reactors, and in the Russian RMBK, the fuel is U02. Experiments in the UK and USA, reviewed by Farmer Beattie (1976), showed less than 1% release of fission product iodine and caesium from punctured U02 fuel cans at about 1000°C in air or steam, rising to 10-50% release at 1800°C. At 2800°C, the U02 melted and there was nearly complete release of volatile nuclides (I, Te, Cs, Ru) but only small release of refractory alkaline earth and rare earth nuclides. 

Kinetics studies were conducted at 55°C in a jacketed batch reactor. Shredded wastepaper (10 g / L) was added to 500 mL or 1L of citrate buffer, pH 4.8, and heated to the assay temperature. A specified quantity of either soluble or immobilized cellulase was added to the reactor to initiate hydrolysis. Samples were collected at regular intervals over 30-60 min, and centrifuged to separate solids. The DNS assay (4) was used to detect sugars formed during hydrolysis experiments. The supernatant from the centrifuge tube and the DNS solution were mixed and cooked for exactly 5 min in boiling water. Finally, the sample was transferred to a methacrylate cuvet, and its absorbance was measured at 540 nm. 

The main advantages of a batch reactor are as follows. It is simple and allows rapid measurements. Many experiments can be performed in a short period of time. It is convenient when using pure, expensive, corrosive, or high boiling temperature chemicals. Its use is recommended if the catalyst is sensitive to traces of poisons since there is no accumulation effect. In principle, by varying the stirring conditions it is possible to investigate the influence of heat and mass transfer processes. 

In the United States, experiments at Argonne National Laboratory in Illinois indicate that a new generation of breeder reactors can be developed that will be inherently safer than the pressurized boiling-water reactors now in use. This research also shows that these reactors can be cost-competitive with coal-... 

The form of the radial temperature profile in a nonadiabatic fixed-bed reactor has been observed experimentally to have a parabolic shape. Data for the oxidation of sulfur dioxide with a platinum catalyst on x -in. cylindrical pellets in a 2-in.-ID reactor are illustrated in Fig. 13-9. Results are shown for several catalyst-bed depths. The reactor wall was maintained at 197°C by a jacket of boiling glycol. This is an extreme case. The low wall temperature resulted in severe radial temperature gradients, more so than would exist in a commercial reactor, where the wall temperature would be higher. The longitudinal profiles are shown in Fig. 13-10 for the same experiment. These curves show the typical hot spots, or maxima, characteristic of exothermic reactions in a nonadiabatic reactor. The greatest increase above the reactants temperature entering the bed is at the center,... 

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