Coolant Water Instrumentation

Ohere are many miscellaneous pressure gauges In the control room vhlch Indicate the pressures at various points In the primary secondary and last ditch coolant systems. Included In these measurements are top of riser pressure crossheader pressures, top of downcomer pressure, control rod coolant pressures, and high tank level and pressure. 

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Coolant water temperature > design instrument fault/low coolant flowrate/high coolant inlet temperature/cooling tower fault/excess condenser area. 

The use of appropriate instruments to monitor equipment operation and relevant process variables will detect, and provide warning of, undesirable excursions. Otherwise tliese can result in equipment failure or escape of chemicals, e.g. due to atmospheric venting, leakage or spillage. Instruments may facilitate automatic control, emergency action such as coolant or pressure relief or emergency shutdown, or the operation of water deluge systems. 

These meters have been very useful for handling liquid metal coolants where the conductivity is high though they have now been developed for liquids such as tap water which have a poor conductivity. Designs are now available for all sizes of tubes, and the instrument is particularly suitable for pharmaceutical and biological purposes where contamination of the fluid must be avoided. 

Check Accuracy of Tester. Test the instrument with solutions of known freezing protection. A 33% solution of ethylene glycol engine coolant in water protects to 0°F (—18°C) and a 50% solution should indicate —34°F (—37°C) protection. 

Once a set of premises is available for each failure, the list of possible overpressure causes can be narrowed down. A possible cause can be eliminated from the list if it is certain that its relief requirement is lower than or identical to the relief requirement of another source. For instance, when coliunn pressure is controlled by manipulating cooling water to the condenser, failure of the pressure controller may have identical consequences to coolant failure. In this case, failure of the pressure controller can be eliminated from the list. Another example is a column whose heat-input control valve and all feed control valves fail shut, while cooling is likely to continue normally during an instrument air failure in this case, the relief load is likely to be small (if any) upon instrument air failure, and this cause can be eliminated from the list. 

It was the only accident the cause of which is concerned with LBC using. As a result of low studying physical and chemical coolant operation processes, the substantiated specifications on impurity compositions in coolant, instrumentation for coolant quality control and equipment to provide the maintenance of required coolant qualities in the course of operation have been lacked. This level of LBC knowledge can be compared with that of water coolant when it was allowed to convey water from the water pipeline into the steam boiler. 

Reactor Process Control Instrumentation provides information only on the status of the reactor mainly during plant operation. However, when discussing instrumentation regarding coolant flow, one must remember that the water plant must maintain swiequate coolant to the reactor ICX) percent of the time. 

The HPI system at TMI-2 correctly came into operation because the system was undergoing a loss of coolant accident (LOCA) because of the stuck open relief valve. But at the time, the operators did not know that yet. They had neither diagnosed a LOCA nor its cause, because the control room pressurizer water level instrumentation indicated a level that was higher than normal. 

The temperature of the instrument is maintained at the desired level by circulating water from a thermostat. For electrophoresis at a field strength greater than lOVcm, the temperature of the coolant might be 10-14°C, depending on the humidity of the air. For a field strength below lOVcm, a temperature of 16-20°C is adequate. A variety of suitable instruments are commercially available. 

PRISM employs passive safety, digital instrumentation and control, and modular fabrication techniques to expedite plant construction [1-4]. PRISM has a rated thermal power of 840 MW and an electrical output of 311 MWe. Each PRISM module has an intermediate sodium loop that exchanges heat between the primary sodium coolant from the core with water/steam in a sodium-water steam generator (SG). The steam from the sodium-water SG feeds a conventional steam turbine. A diagram of the PRISM nuclear steam supply system (NSSS) is shown in Figure 6.2. 

During the process of heating the coolant and fuel to operating coolant temperature, it is necessary to withdraw 5.I per cent k of control rods. Thus, sufficient horizontal control rods are available to counteract the reactivity increase due to flooding. Flow monitoring instruments on each process tube would sense any gross water loss to the reactor core and would scram the horizontal control rods in 1.2 seconds. For a leakage rate equal to the normal flow to one process tube, 15O seconds would be required... 

Most of the heat generated by the reactor Is removed by the primary loop cooling water. In order to ensure efficient 1 safe, heat removal, reliable Instrumentation for measurement and control of the flow, temperature and pressure of the coolant have been provided. 

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