turbine is returned by the steam generator feedwater pumps. The reactor is equipped with residual-heat removal systems. The condensers are designed to condense the outlet steam from the low pressure turbine and the exhaust steam from the auxiliary turbine drive of the feedwater pump at 500 Pa, by dissipating the heat to three mechanical-draft wet cooling towers. The three main mechanical-draft wet cooling towers are each sized for one-third of the requirements. Each tower is designed to cool 13.6 m^/s of water from 48°C to 33°C when operating at a wet bulb temperature of 23°C. Each tower employs a reinforced concrete-filled structure combined with components for water distribution, fill splash service, support system, drift eliminators, louvers, and fan deck. Radioactive contaminants can come from the fuel itself or from (1) impurities in the fuel cladding, (2) activated wear products, or (3) other sources. Because several systems are contaminated, normal maintenance, operations, and leaks will lead to release of some of these elements. The mechanisms of release of these radioactive elements are primarily leakage through the building ventilation systems and dissolution in liquid effluents. Areas that have the potential for contamination are ventilated through high efficiency particulate filters, which remove more than 99.9% of the particles larger than 0.3 pm. Potentially contaminated liquid effluents are monitored or processed to remove radioactive elements by filtration and ion exchange. In each case, not all of the radioactive elements can be prevented from entering the biosphere. Consequently, radioactive elements are emitted to the biosphere by the LWR,* within the limits prescribed by the EPA and enforced by the NRC. Water consumption results primarily from cooling tower evaporative losses and cooling tower blowdown (1.42 m^/s at full power). The largest consumers of water are the mechanical-draft cooling towers (about 1 m^/s). The primary sources of liquid effluents from a LWR facility include the cooling tower blowdown stream and process water effluent. No radioactive wastes are discharged in effluent streams. These waste streams, which are processed to remove radionuclides, are then discharged under controlled conditions.** Cooling tower blowdown does not contain any radionuclide contamination but does contain chemicals added for control of corrosion and biological growth. 3.2.6 Liquid-Metal, Fast-Breeder Reactor The LMFBR plant reference design^ is a 3400-MWt loop-type, sodium- cooled fast-breeder reactor plant with a nominal electrical rating of 1250 MW. *Airborne radionuclides: total noble gases, 3 x 10^ Ci/yr; iodine, 13.1 x IO-2 Ci/yr; Mn, Fe, Co, Sr, Cs, 4.1 x IO-2 Ci/yr. **Waste-water effluents at 70% capacity factor: total suspended solids, 0.94 t/d; total dissolved solids, 2.35 t/d; organics, 210 kg/d. ^The plant design was developed by United Engineers and Constructors for the Department of Energy in the Energy Economic Data Base (EEDB) program as described in Ref. 22. Additional input was derived from Ref. 23.
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