Working reservoir

This provides personnel radiation protection and permits isolation and repair. To prevent leakage of radioactive water from around the shafts, demineralized water under pressure can be added at the shaft seal. However, allowing the active water to leak into drainage to the retention basin is not serious. 

3 Working Reservoir. The purpose of the working reservoir is to supply water at a constant head to the reactor active lattice. In the event of electrical or mechanical failure of the water pumping, system, the reserve of an overhead water supply is most advantageous. If local boiling would not occur in the active lattice and/or if a continual full water flow were not required, the pumps could deliver water directly to the reactor as is done at Hanford. 

The height of the working reservoir is based on. the allowable internal pressure for which the aluminum reactor tank is designed. Thus the working reservoir is 170 ft above a horizontal centerline through the active.lattice. This elevation permits an increase of the process-water flow rate.to the highest value attainable with the present reactor tank and fuel elements. 

The size of the working reservoir is based on a full process-water flow of 20,000 gpm for 7.5 min. The 150,000-gal capacity of the reservoir can provide this flow. There are several reasons that such a large reserve capacity is desired. It is conceivable that an emergency condition may not be recognized or acted upon for several minutes. Also, during an electrical outage the flow does not cease for half a minute and it takes another halfminute to close the main water valve. In either of these situations an appreciable quantity of reserve water may be lost. In addition, the reactor must be cooled after it is shut down, and by allowing a 1000-gpm flow to the reactor for this purpose, about half the reserve can be lost in an hour. 

Protection of personnel against radiation during reactor operation is provided by a fence.around the base of the working reservoir. Since approach 

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As schematized in Fig. 2.11, a chosen initial system (a) might later be enlarged to include a work reservoir, a heat reservoir, or a mass reservoir, thus giving a larger system (b). 

A work reservoir is similarly defined as any body or combination of bodies, used as part of the surroundings, whose only interaction with the system is one that may be described in terms of work. We may have a different type of reservoir for each mode of interaction other than thermal interaction. A work reservoir then is used to perform work across the boundary separating the reservoir and the thermodynamic system and to measure these quantities of work. In the following we are, in order to simplify the discussion, primarily concerned with mechanical work, but this limitation does not alter or limit the basic concepts. A reservoir for mechanical work may be a set of weights and pulleys in a gravitational field, an idealized spring, or a compressible fluid in a piston-and-cylinder arrangement. In any case the reservoir must... 

We return to the piston-and-cylinder arrangement discussed in Section 2.3. In that discussion we did not completely describe the process because we were interested only in developing the concept of work. Here, to complete the description, we choose an isothermal process and a gas to be the fluid. We then have a gas confined in the piston-and-cylinder arrangement. A work reservoir is used to exert the external force, Fe, on the piston this reservoir can have work done on it by the expansion of the gas or it can do work by compressing the gas. A heat reservoir is used to make the process isothermal. The piston is considered as part of the surroundings, so the lower surface of the piston constitutes part of the boundary between the system and its surroundings. Thus, the piston, the cylinder, and the two reservoirs constitute the surroundings. 

The gas is compressed under the conditions that the work reservoir exerts the pressure Px on the piston. The work done on the gas and associated with the pressure of the gas is... 

The net work, W, done on the heat engine by the work reservoir is equal to the sum of the work done in each of the steps (a negative quantity) the area ABCD represents this net work. The net heat absorbed by the system is the sum (Q2 + Qi). The result of the cycle is illustrated in Figure 3.5, in which the squares represent the heat reservoirs and the circle represents the heat engine. A quantity of heat, Q2, is absorbed by the fluid from the heat reservoir at the higher temperature, a smaller quantity of heat, — Qu is rejected by the fluid to the heat reservoir at the lower temperature,... 

In Section 3.3 we concluded that an isolated system can be returned to its original state only when all processes that take place within the system are reversible otherwise, in attempting a cyclic process, at least one work reservoir within the isolated system will have done work and some heat reservoir, also within the isolated system, will have absorbed a quantity of heat. We sought a monotonically varying function that describes these results. The reversible Carnot cycle was introduced to investigate the properties of reversible cycles, and the generality of the results has been shown in the preceding sections. We now introduce the entropy function. 

We continue with a reversible heat engine operating in a Carnot cycle, but center our attention on the working substance rather than on the entire system consisting of the heat engine, the work reservoir, and the two heat reservoirs. For such a cycle we can write... 

The expansion of an ideal gas in the Joule experiment will be used as a simple example. Consider a quantity of an ideal gas confined in a flask at a given temperature and pressure. This flask is connected through a valve to another flask, which is evacuated. The two flasks are surrounded by an adiabatic envelope and, because the walls of the flasks are rigid, the system is isolated. We now allow the gas to expand irreversibly into the evacuated flask. For an ideal gas the temperature remains the same. Thus, the expansion is isothermal as well as adiabatic. We can return the system to its original state by carrying out an isothermal reversible compression. Here we use a work reservoir to compress the gas and a heat reservoir to remove heat from the gas. As we have seen before, a quantity of heat equal to the work done on the gas must be transferred from the gas to the heat reservoir. In so doing, the value of the entropy function of the heat reservoir is increased. Consequently, the value of the entropy function of the gas increased during the adiabatic irreversible expansion of gas. 

Work source. When a work reservoir which is able to release work of the quantity W shown in Fig.. 6 is regarded as a process, the following equations are obtained. 

The objective here is to show that the reaction equilibrium criteria (7.6.3) are a consequence of the more general equilibrium criterion (7.1.40) that applies to any NPT system, including reacting systems. Consider a system of C species confined to a closed vessel and maintained at constant T and P by contact with an external heat and work reservoir. The species may undergo 51 independent chemical reactions. Since T and P are fixed for the entire system, the NPT criterion for equilibrium (7.1.40) applies that is, when all reactions are complete and equilibrium is reached, the system s total Gibbs energy will be a minimum,... 

Ifoter supplies and treatment. Two deep wells are located on the site each one is capable of delivering the normal site demands. Water passes through reservoir tanks and is pumped from there to the Demineralizer Building. Here one portion is demineralized, another chlorinated, and a third softened and chlorinated. The reactor uses demineralized water in a recirculating cooling system. An overhead working reservoir in this loop provides the flow... 

I. WORKING RESERVOIR LEVEL INSTRUMENT AIR PRESSURE REACTOR DISCHARGE AIR PRESSURE ALARM... 

EJECTOR 4 evaporator TEMPERATURES WORKING RESERVOIR LEVEL... 

The head losses between the working reservoir and the exit of the reactor tank are due almost entirely to the velocity head and friction losses across the active and beryHium sections, with relatively small losses contributed by the conveying pipe line There are block valves and a flow control valve in the inlet line to the reactor, but there are no obstructions inthepipe line from the reactor to the seal tank. 

Water in the seal tank is drawn into the flash evaporators by means of the partial vacuum existing there. The water, in being flashed at a pressure that yields lOO F effluent, falls from the flash evaporators into the sump tank below. From the sump tank the water is once more pumped up to the working reservoir to complete the process water cooling cycle. The reactor heat, liberated in the flash evaporators, is carried away by the cooling tower water circulated through the condenser tubes in the evaporators. 

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