Reactor assembly

Control rods occupy alternate spaces between fuel assemblies and may be withdrawn into the guide tubes below the core during plant operation. The rods are coupled to control rod drives mounted within housings, which are welded to the bottom head of the reactor vessel. The bottom-entry drives do not interfere with refueling operations. A flanged joint is used at the bottom of each housing for ease of removal and maintenance of the rod drive assembly. 

Except for the Zircaloy in the reactor core, these reactor internals are stainless steel or other corrosion-resistant alloys. All major internal components of the reactor can be removed 

Low-pressure coolant injection inlet Core spray sparger 

Vessel support skirt Control rod drives In-core flux monitor 

INTERUEDUTE HEAT EXCHANGER U m-VESSEL TRANSFER UACHINE 

DRIVE UOTOR FOR SODIUU PUUP 10 LINER AND INSUUTION 

Grid plate The grid plate is a box-type welded structure which consists of upper and lower plates interconnected by a number of tubes called sleeves and an outer cylindrical shell. The sleeves act as tie rods between the top and bottom plate and also supports for the subassemblies. Sodium enters the grid plate through four pipes connected to the discharge of the four primary pumps. 

Core support structure The grid plate is supported on the core support structure (CSS) which also supports the shielding subassemblies via the auxiliary grid plate and the irmer vessel. It is a radially stiffened structure supported on the main vessel bottom by a cylindrical shell. 

Roof slab The roof slab forms a part of the primary containment boundary in addition to providing thermal biological shielding and support for the major components viz. 2 

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A simple, but efficient reactor concept was developed based on the insertion of metallic wires that serve as a catalyst into a micro channel. The wire extends over the channel length and can thus be contacted electrically for heating purposes. It is sealed by graphite seals at both reactor ends. In this way, an easy, flexible and cheap concept for catalyst exchange and reactor assembly is provided. 

The reactor assembly was heated by electric heaters. The maximum operating temperature Is determined by the window construction. Sapphire windows (from EIMAC), brazed into Kovar sleeves, were used the sleeves were then welded directly into the stainless steel reactor housing. We found that the cell so constructed was capable of trouble-free, continuous operation at 450°C operations at somewhat higher temperatures are probably still possible but were not explored. Sapphire was chosen as a window material because it is insensitive to water vapor and is transparent in tljie wave number range of our interest (about 2400 cm to 2000 cm in these experiments). Moreover, the thermal expansion characteristics of the reactor were found to match well with those of the window fixture. 

Figure 3.1 shows a typical laboratory flow reactor for the study of catalytic kinetics. A gas chromatograph (GC, lower shelf) and a flow meter allow the complete analysis of samples of product gas (analysis time is typically several minutes), and the determination of the molar flow rate of various species out of the reactor (R) contained in a furnace. A mass spectrometer (MS, upper shelf) allows real-time analysis of the product gas sampled just below the catalyst charge and can follow rapid changes in rate. Automated versions of such reactor assemblies are commercially available. 

Reactors Assembled cost is 5/lb. Dished bottoms, open tops, height equal to diameter, bottom surface equals 1.5 times the surface of a flat plate of the same diameter. Tanks of over 1500 gal capacity are of 1/4" plate, smaller ones of 3/16" plate. Freeboard equals volume of the dished head. 

The chemical removal of water can be done in several ways. For anionic polymerisations it is customary to rinse all the glassware repeatedly with a solution of sodium naphthalide which reacts with water to form naphthalene and NaOH, both of which are adequately soluble in the usual solvent tetrahydrofuran (THF) at the low concentrations used. This method, however, requires that the whole reactor assembly be detachable from the vacuum line so that it can be tilted around for the sodium naphtalide solution to reach all parts of the system. Care If much water is to be removed and the volume of the purging solution is too small, some NaOH may be precipitated ). 

An isothermal, plug flow, fixed bed reforming pilot plant (shown in Fig. 14) was used to generate the kinetic data. The reactor was U shaped and contained roughly 70 ml of catalyst. Five sample taps were spaced along the reactor length to determine compositions over a wide range of catalyst contact times. The reactor assembly was immersed in a fluidized sand bath to maintain isothermal conditions. 

Figure 17.19. Reactors for the oxidation of sulfur dioxide (a) Feed-product heat exchange, (b) External heat exchanger and internal tube and thimble, (c) Multibed reactor, cooling with charge gas in a spiral jacket, (d) Tube and thimble for feed against product and for heat transfer medium, (e) BASF-Knietsch, with autothermal packed tubes and external exchanger, (f) Sper reactor with internal heat transfer surface, (g) Zieren-Chemiebau reactor assembly and the temperature profile (Winnacker- Weingartner, Chemische Technologie, Carl Hanser Verlag, Munich, 1950-1954).

Reactor Assembly. This assembly (Fig. 3) consists of the reactor vessel, its internal components of the core, shroud, top guide assembly, core plate assembly, steam separator and dryer assemblies and jet pumps. Also included in the reactor assembly are the control rods, control rod drive housings and the control rod drives. 

Fig. 3, Reactor assembly ol contemporary boiling water reactor. (General Electric)...

Fig. 1. Flow reactor assembly for measuring extrinsic field effects.

A detailed drawing of the reactor assembly is shown in Fig. 14. It is a stainless steel, 1-L autoclave equipped with a Magnedrive stirrer and a cooling coil. A special shaft extension was made to provide extra room for insulation heating tapes. It can be operated at a high stirrer speed so as to have all phases completely backmixed. The Magnedrive is cooled by house air. 

Fig. 14. Cross-section of the adiabatic reactor assembly. (Reprinted with permission from Bhattacharjee, S., Tierney, J. W., and Shah, Y. T., Ind. Eng. Chem. Process Des. Dev. 25, 117, copyright 1986, American Chemical Society.)...

The reactor is sketched in Figure 8 where three concentric annular spaces with the six catalytic walls are shovm. The reactor is fed through the outer annular space (maximum PCE concentration) where the radiation field has ifs minimum value. Exit of reactants and products occurs from the inner annular space. All details of the reactor assembly and operating conditions are described in Table 2. For more details the reader can resort to references (Imoberdorf ef al., 2006, 2007). 

The reactor assembly is slightly different from that used to produce boron on a tungsten substrate, as pyrolytic carbon is applied online. 

The reference test was conducted in a stainless steel reactor assembly which was sized to duplicate the Kureha reactor geometry. The experimental operating conditions compared favorably with the actual plant conditions. In particular, the steam temperature, S F ratio, residence time, oil feed rate, and heat input were matched very closely. However, the reactor exit temperature was somewhat lower than that of the operating plant. The experimental gas yields for ethylene, ethane, propylene, and propadiene agreed very well with the plant. There were slightly lower experimental values for hydrogen, methane, acetylene, and total gas, which indicated a less severe crack. 

Apparatus for preparations. All reactions were performed with a stainless steel vacuum line. Preparations were carried out in Teflon reactors assembled especially for each. The reactors were joined to the metal line via flexible fluorinated ethylene propylene (FEP) tubes and a polytetrafluoroethy-lene (PTFE) valve. FEP-tube reactors were prepared by first cutting lengths to —25 cm. These tubes were softened at one end by heating in a flame, then squeezed with broad-nose pliers to seal the end. One-armed reactors consisted of one of these tubes connected directly to a PTFE valve. T-shaped reactors had two of these tubes connected to a PTFE T-joint, which itself was connected via FEP tubing to a PTFE valve. All reactors were made vacuum-tight with PTFE swage connections. 

In one trial to test film growth the temperature was controlled by use of steam on the underside of the film surface in the reactor assembly. Titanium tetraisopro-poxide [Ti(OC3H7)4] was carried by a helium stream over the condensing surface, where it decomposed to Ti02 plus gases. 

The first reactor type, which employs direct sonication, is represented by the lab scale system shown in Fig. 5. This flow reactor assembly consists of a titanium horn assembly, a piezoelectric transducer capable of variable energy output, and a flow through reaction chamber. This design provides for maximum... 

The reactor assembly consisted to two 38 mm diameter tubular sections the reactor-preheater tube and the reactor-electrobalance interface section. The reactor-preheater tube is 0.66 m in length and is constructed of fused quartz. The lower portion of this tube is packed with fused quartz rings and is used as a feed gas preheater. A thermocouple is located in the reactor directly below the metal foil and a gas sampling port is positioned immediately... 

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