Condenser Air Removal System

An increase in radioactivity indicated by condenser air removal system monitors, and blowdown system monitors will reveal reactor coolant leakage through steam generators tubes to the secondary side. Routine analysis of steam generator secondary water samples will also indicate increasing leakage of reactor coolant into the secondary system. 

Air in-leakage and noncondensable gases removed from the condenser air removal system and the gland seal system are routed to the turbine island vents, drains and relief system, where they are... 

There are no design requirements on this system associated with maintaining safety functions. 6.6.6 Condenser Air Removal System... 

Failure of the condenser air removal system for one of the main condenser shells would result in a gradually increasing back pressure in that particular condenser shell. Eventually, if not resolved by the operators, this would result in a turbine trip (Section 10.4.2.2.1 of Reference 6.1). 

The following design requirement for the condenser air removal system supports safe operation of the plant under normal conditions ... 

Air inleakage and noncondensable gases contained in the turbine exhaust steam naturally aceumulate in the condenser and must be removed. This is achieved by the condenser air removal system (Section 6.6.6). 

In addition, in direct cycle reactors, provision should be made for monitoring of the condenser air removal system. In PWRs this is also useful for the detection of ruptures of steam generator tubes. In gas cooled reactors, provision should be made to sample and monitor all operational discharges of the reactor coolant. 

Acid cleaners based on sulfamic acid are used in a large variety of appHcations, eg, air-conditioning systems marine equipment, including salt water stills wells (water, oil, and gas) household equipment, eg, copper-ware, steam irons, humidifiers, dishwashers, toilet bowls, and brick and other masonry tartar removal of false teeth (50) dairy equipment, eg, pasteurizers, evaporators, preheaters, and storage tanks industrial boilers, condensers, heat exchangers, and preheaters food-processing equipment brewery equipment (see Beer) sugar evaporators and paper-mill equipment (see also Evaporation Metal surface treati nts Pulp). 

Other Considerations Leakage of cold air into a settling chamber can cause local gas quenching and condensation. Condensation can cause corrosion, dust buildup, and plugging of the hopper or dust removal system. The use of thermal insulation can reduce heat loss and prevent condensation by maintaining the internal device temperature of the above the dew point (EPA, 1982). No pretreatment is necessary for settling chambers. 

Cracking imposes an additional penalty in a vacuum unit in that it forms gas which cannot be condensed at the low pressures employed. This gas must be vented by compressing it to atmospheric pressure. This is accomplished by means of steam jet ejectors. Ideally, it would be possible to operate a vacuum pipe still without ejectors, with the overhead vapors composed only of steam. In practice, however, leakage of air into the system and the minor cracking which occurs make it necessary to provide a means of removing non-condensibles from the system. In addition to the distillation of atmospheric residuum, the lube vacuum pipe still is also used for rerunning of off specification lube distillates. 

For a steam coil to operate efficiently, it must have all the latent heat in the steam. This is achieved by the use of a steam trap. The correct trap type must be selected for the particular application in order to prevent waterlogging. All condensate, air, or other noncondensable must be removed from the system without delay otherwise,... 

When the ejector system consists of one or more ejectors and intercondensers in series, the volume as pounds per hour of mixture to each succeeding stage must be evaluated at conditions existing at its suction. Thus, the second stage unit after a first stage barometric intercondenser, handles all of the non-condensables of the system plus the released air from the water injected into the intercondenser, plus any condensable vapors not condensed in the condenser at its temperature and pressure. Normally the condensable material tvill be removed at this point. If the intercondenser is a surface unit, there wall not be any air released to the system from the cooling w ater. 

Filters in air-conditioning systems do not remove all the dirt from the air, and this will settle on duct walls. There is an increasing awareness that ducting systems can harhour a great deal of dirt, and that this dirt will hold bacteria, condensed oils such as cooking fats and nicotine, fungi and other contaminants. 

Moisture may be removed from air by passing it over a surface which is colder than its dewpoint (see Figure 24.9). In air-conditioning systems this is a continuous process, providing that the moisture condenses out as water and can be drained away. If the apparatus dewpoint is beIowO°C, the moisture will condense as frost, and the process must be interrupted from time to time to defrost the evaporator. 

Steam traps are installed in condensate, mechanical return systems and are a frequently overlooked item for reducing operating costs. Large industrial process plants typically have many hundreds of steam traps installed to recover low-energy condensate and remove (potentially corrosive) air and carbon dioxide. 

Repeated pulsing can be used to provide efficient removal of non-condensable gases. The system is evacuated to a pressure lower than 50 mbar. Steam is then injected to return the system to atmospheric pressure. The system is then re-evacuated prior to injecting the steam for sterilization. This pulsing can be repeated several times to achieve improved air removal. 

In vacuum processes which use inlet condensers to remove substantial amounts of vapour, the associated pumping system is used to maintain the required working pressure by removing any uncondensed vapour and permanent gas from air in-leakage, usually leaving the condenser. A typical system is shown in Figure 6.2. 

The new air-conditioning system is a two-step process. The first, a continuous one, reduces the temperature to about 0° C., removing water by condensation. The... 

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