Protection of reactors

The high level of self-protection of reactors considered makes expedient their use for nuclear transmuting NP long-lived radioactive waste. 

Cathodic protection is widely used in classic and atomic power plants, oil refineries, chemical works, and for the protection of gas and water pipelines and other metal structures. Excellent results are obtained by this method during anticorrosion electrochemical protection of reactors, tanks, pipelines (external and internal surfaces), pumps, coolers, heat exchangers, etc. Con-... 

In addition to secondarv resistance control, other devices such as reactors and thyristors (solid-state controllable rectifiers) are used to control wound-rotor motors. Fixed secondary reactors combined with resistors can provide veiy constant accelerating torque with a minimum number of accelerating steps. The change in slip frequency with speed continually changes the effective reac tance and hence the value of resistance associated with the reactor. The secondaiy reactors, resistors, and contacts can be varied in design to provide the proper accelerating speed-torque curve for the protection of belt conveyors and similar loads. 

Low ambient tern- Monitor temperature perature resulting. adequate heating in embrittlement and/or mechanical design system to accommodate minimum failure of reactor. expected temperature Provide freeze protection/heat tracing CCPS G-23 CCPS G-29 Lees 1996... 

To protect the reactor and the regenerator against a flow reversal, pressure differential controllers are used to monitor and control the differential pressures across the slide valves. If the differential pressure falls below a minimum set-point, the pressure differential controller (PDIC) overrides the process controller and closes the valve. Only after the PDIC is satisfied will the control of the slide valve return to the process. 

Although the problems associated with the corrosion and protection of jointed structures have been recognised since the early days of structural fabrication, they have taken on a special significance in the past 15 years. The motivation for the increased impetus is mainly one of concern over possible costly, hazardous or environmentally unfriendly failures particularly those concerned with offshore constructions, nuclear reactors, domestic water systems, food handling, waste disposal and the like. 

Considering the formation of saturated five-membered heterocycles with two heteroatoms, it is worth to note the possibility to prepare 1,3-dioxolanes, dithiane, oxathianes 148 [93] and dioxolanones 149 [94] by condensation of the corresponding carbonyl compounds under microwave irradiation in acid medium (Scheme 52). The reaction, which is very useful for the protection of carbonyl compounds or for the preparation of useful synthetic intermediates, has also been carried out under batch conditions over Montmorillonite KIO clay in more than 150 g scale, using a 1 L quartz reactor [95]. 

The protection of components against nuclear radiation is a critical factor in the design of nuclear-fission components.P CVD is used extensively in this area, particularly in the coating of nuclear fuel particles such as fissile U-235, U-233, and fertile Th-232 with pyrolytic carbon. The carbon is deposited in a fluidized-bed reactor (see Ch. 4). The coated particles are then processed into fuel rods which are assembled to form the fuel elements. 

Among several types of reactors investigated, the microstructured reactor was successfully applied to the synthesis of a pharmaceutical intermediate via a fast exothermic Boc protecting reaction step. The reaction temperature was isothermally controlled at 15°C. By using the microstructured reactor the heat of reaction was completely removed so that virtually no byproducts were produced during the reaction. Conversions as high as 96% were achieved. The micro-reactor operation can be compared with other reactors, however, which need to be operated at 0°C or -20°C to avoid side reactions. 

The protecting reaction of the enamino pyrrolidinone with t-butoxycarbonyl anhydride was carried out by mixing 4-(N-/-butoxycarbonyl)-4-aminomethylene-pyirolidin-3-one (Boc-AMP) with 1.2 molar equivalents of t-butoxycarbonyl anhydride (/-BoczO) to make l-(N-f-butoxycarbonyl)-4-(N-t-butoxycarbonyl)-ammomethylene-pyrrolidin-3-one (B0C2-AMP). Several types of reactors, including batch reactors, a continuous stirred tank reactor (CSTR),... 

Petrozzi, S., Kut, O. M., and Dunn, I. J., Protection of Biofilms Against Toxic Shocks by the Adsorption and Desorption Capacity of Carriers in Anaerobic Fluidized Bed Reactors, Bioproc. Eng., 9 47 (1993)... 

The scope of this book includes several aspects of safe process design and operation, such as the choice of reactor type, safe operating conditions, and the selection of protective systems, primarily related to chemical reactivity. However, even in a process plant where these aspects have been carefully considered and thoroughly applied, there are still numerous events that can occur and can lead to hazardous incidents. Examples of such events are ... 

Beveridge, H.J.R. and Jones, C.G., Shock effects on a bursting disk in a relief manifold, in The Protection of Exothermic Reactors and Pressurised Storage Vessels, I Chem E Symposium Series No. 85, pp. 207-14 (1984). 

A unique feature of the Foster Wheeler SCWO reactor is its full-length transpiring-wall liner, shown in Figure 4-2. Foster Wheeler claims that this liner design protects the reactor walls from corrosion and salt deposition. The reactor liner is fabricated from multiple layers of Inconel 600 assembled in sheets of what the technology provider refers to as platelets to produce transpiration pores. Deionized water is added to the SCWO reactor through transpiration pores in the liner... 

A poor surface morphology is a major concern in device fabrication and substantial efforts have been made during the last years to resolve this issue. Different concepts have been developed, such as effective encapsulants (primarily AIN) for protection of the SiC surface [8] and annealing in CVD-reactors using Si overpressure [9]. These concepts appear to be quite successful, at least up to 1,700°C, and are reviewed in Section 4.3.1. 

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