Water-Cooled Support Systems

This section emphasizes water-cooled supports for skid rails and other conveying systems, but much of the information herein can be adapted to water-cooled doorframes and other equipment that needs cooling. 

In furnaces with bottom zones, such as pusher or walking beam steel reheat furnaces, each skid rail, on which the loads rest or slide, consists of a schedule 160 pipe, 6.625 (0.1683 m) OD with 0.718 (18.24 mm) wall thickness, through which cooling water is circulated. A solid skid wear bar is securely welded onto the top surface of the pipe. The skid wear bars are often small diameter bars of heat-resisting, wear-resisting material. Their small diameter allows less contact area with the load pieces, thereby minimizing heat loss from the loads. 

The water-cooled skid rail pipe supporting the skid wear bar is insulated with one or two different insulating materials to reduce heat gain (as these are subject to the same hot furnace gas heat transfer as are the loads). A group of crosswise water-cooled support pipes (crossovers) support the skid rail pipes from below and are attached to the furnace sidewalls. Vertical pipes (risers) support the crossover pipes. The outer surfaces of all the skid and supporting pipe stmcture must be capable of withstanding physical and thermal shock as well as chemical attack from the bottom-zone furnace gases. 

Recirculating water-cooling systems should have water treatment to control hardness to near zero and to prevent oxygen corrosion. If there is a steam boiler nearby, a common water treatment may be possible, but this should be explored with care. The cooling-water temperature rise should not exceed 20°F (11°C), and steaming 

Load support system designers must realize that skids will never form an absolutely level pass line, nor will the loads be perfectly straight therefore, the entire weight of any load piece may be on just two skids, the entire load weight of which might be on only two crossovers, the entire load weight of which may be on only two risers. 

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Function event trees include primarily the engineered safety features of the plant, but other systems provide necessary support functions. For example, electric power system failure amid reduce the effectiveness of the RCS heat-removal function after a transient or small UJ( A. Therefore, EP should be included among the systems that perform this safety function. Siipfiort systems such as component-cooling water and electric power do not perform safety functions directly. However, they significantly contribute to the unavailability of a system or group of systems that perform safety functions. It is necessary, therefore, to identify support systems for each frontline ssstcm and include them in the system analysis. 

Nuclear power plant systems may be classified as "Frontline" and "Support. . iccurding to their. service in an accident. Frontline systems are the engineered safety systems that deal directly with an accident. Support systems support the frontline systems. Accident initiators are broadly grouped as loss of cooling accidents (LOCAs) or transients. In a LOCA, water cooling the reactor is lost by failure of the cooling envelope. These are typically classified as small-small (SSLOCA), smalt (SLOCA), medium (MLOCA) and large (LLOCA). 

Plant design differences (primarily in support systems such as cooling water, electrical power, ventilation, and air systems)... 

Figure 1. Diagrammatic presentation of the experimental arrangement, a, dial gage h, water-cooling system clt c2 supporting pistons d, seal e, high pressure cylinder /i,/2, load-applying pistons g, steel shell h, specimen i. thermostat k, stirrer, /, ring m, baseplate n, steel block o, asbestos insulation, p, heating element.

Figure 13.1 Schematic diagram showing various components of a CVD system (1 reactor 2 heating element 3 reaction tube 4 water-cooled end flanges 5 power controller 6 pressure indicator 7 temperature sensor 8,10,11. -precursor gas tanks, 9 metal halide (liquid) vaporizer 12 particulate trap 13 gas scrubber 14 flow meter 15 flow meter valves 16 gas tank regulators 17 substrate support 18 substrates).

When evaporation is complete, raise the flask from the bath, switch the motor off, open the vacuum inlet tap to allow air into the system and allow the flask to cool. Support the flask with your hand, take off the plastic joint clips, put the flask on one side and only then turn off the water pump. Turn off the water supply to the condenser. 

The nickel base plate (6) supports water-cooled electrodes made of nickel (7), a thermocouple (8), and a pipe leading to a manometer (9) and to a vacuum pump system (10). 

In the separation of the major systems of control and instrumentation for the reactor and.the reactor heat removal processes, two major control and instrument centers are provided. These major control centers are located in the Reactor Building and in the Process Water Building. The reactor is controlled from the former, while the latter center, which is primarily for the control and instrumentation of process-water flow through the reactor, includes the instrumentation of the locally controlled reactor cooling-air system. A number of the supporting process systems are like the cooling-air system in that they have- locally controlled equipment but have some instrumentation extended to one or both of the major control centers. 

In general, the indicating and recording instruments on the panel are associated with the principal processes, i..e., the process-water and cooling-air systems of the reactor. Some of these instruments and a number of the annunciators are associated with the supporting processes and the effluent control systems. 

The supercritical-water-cooled reactor (SCWR) ( Fig. 58.21) system features two fuel cycle options the first is an open cycle with a thermal neutron spectrum reactor the second is a closed cycle with a fast-neutron spectmm reactor and full actinide recycle. Both options use a high-temperature, high-pressure, water-cooled reactor that operates above the thermodynamic critical point of water (22.1 MPa, 374°C) to achieve a thermal efficiency approaching 44%. The fuel cycle for the thermal option is a once-through uranium cycle. The fast-spectrum option uses central fuel cycle facilities based on advanced aqueous processing for actinide recycle. The fast-spectrum option depends upon the materials R D success to support a fast-spectrum reactor. 

The RCP shaft seal and supporting systems provide improved RCP seal integrity. For example, to maintain seal injection under SBO conditions, the System 80+ standard design incorporates an on-site alternate AC (AAC) power source. As described in CESSAR-DC Section 8.1.4.2, the installation and design of the AAC source is in compliance with the intent of Regulatory Guide 1.155 (Reference 3). The AAC would be used to power the charging pumps which supply seal injection water to cool the RCP shaft seals. 

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