Pressurized water reactors nuclear power plants

Figure 21.19 Basic design of a pressurized water reactor nuclear power plant. 

The Westinghouse Pressurized Water Reactor Nuclear Power Plant. Copyright 1984. 

Westinghouse Electric Corporation, 1984. The Westinghouse Pressurized Water Reactor Nuclear Power Plant. http //www4.ncsu.edu/ doster/NE405/Manuals/PWR Manual.pdf. 

Fig. 1. Pressurized water reactor (PWR) coolant system having U-tube steam generators typical of the 3—4 loops in nuclear power plants. PWR plants having once-through steam generators contain two reactor coolant pump-steam generator loops. CVCS = chemical and volume-control system.

The Electric Power Research Institute (EPRI 1981) conducted a survey of transuranic radionuclides in the terrestrial environs of nuclear power plants in the United States in 1978-1979. The plants included two pressurized water reactors (PWRs) and two BWRs that were of modem design and had been in operation at least 3 years. The 241 Am air concentrations around all of the power plants were extremely low and indistinguishable from fallout background... 

The nuclear plants now operating in the U.S. are light water reactors, which use water as both a moderator and coolant. These are sometimes called Generation II reactors. In these Generation II Pressurized Water Reactors, the water circulates through the core where it is heated by the nuclear chain reaction. The hot water is turned into steam at a steam generator and the steam is used by a turbine generator to produce electric power. 

All over the world, 432 nuclear power reactors are under operation and more than 36 GW of electricity could be produced as of December 31, 2001. There are several types of reactors such as boiling water reactor (BWR), pressurized water reactor (PWR), Canada deuterium uranium (CANDU), and others. In these reactors, light water is normally used not only as a coolant, but also as a moderator. On the contrary, in CANDU reactors, heavy water is taken. It is widely known that the quality control of coolant water, the so-called water chemistry, is inevitably important for keeping the integrity of the plant. 

France owns a major nuclear power plant program for electricity production (more than 70% of total production). Both reactors for civil and defence programs are pressurized water reactors, with similar fissile materials. 

Radioactive waste treatment applications have been reported [3-9] for the laundry wastes from nuclear power plants and mixed laboratory wastes. Another interesting application of reverse osmosis process is in decontamination of boric acid wastes from pressurized heavy water reactors (PHWRs), which allows for the recovery of boric acid, by using the fact that the latter is relatively undissociated and hence wdl pass with water through the membrane while most of the radioactivity is retained [10]. Reverse osmosis was evaluated for treating fuel storage pool water, and for low-level liquid effluents from reprocessing plants. 

Nuclear power plants in the United States use light water moderated nuclear reactors (LWR) that produce the steam to generate electricity. The fuel elements for boiling water reactors and pressurized water reactors (PWR) are nearly the same. The fuel is uranium dioxide enriched with 3 % and this produces a nearly uniform spent fuel, which would be the feed for domestic fuel reprocessing. 

To relate these resource estimates to nuclear electric generation, it may be noted that a 1000-MWe pressurized-water reactor operating at 80 percent capacity factor without recycle, on uranium enriched to 3.3 w/o (weight percent) U in an enrichment plant stripping natural uranium to 0.3 w/o U, consumes around 200 MT of uranium per year. Thus the U.S. resource estimate of 1758 thousand MT available at less than 50/lb UgOg would keep a 300,000-MWe nuclear power industry in fuel for... 

It has been proposed that some of the natural uranium needed to fuel a pressurized-water nuclear power plant be obtained by extracting uranium from seawater used to cool the plant. If the seawater temperature rise is lO C and the reactor and fuel-cycle conditions are as given in Frg. 3.31, how many kilograms of uranium per year could be recovered at 80 percent yield from cooling water What fraction is this of the armual fuel requirement of the reactor ... 

A concept of an evolutionary reactor is pursued with the joint French / German European Pressurized Water Reactor , EPR, a 1525 MW(e) plant with evolutionary steam generating system and innovative double-walled containment [20]. A three years basic design phase as a prerequisite for the beginning of the licensing procedure was finished in 1997. The characteristic feature is a core catcher to restrict a possible core melt to the power plant itself. The joint effort by Germany ind France, however, finds in both countries a situation where no further base load is required. The EPR, confirmed as a future standard in France, is projected to substitute decommissioned nuclear plants. 

The partial meltdown of the reactor core at Three Mile Island nuclear power plant was mainly due to human error (Heppenheimer, 2002). On March 28, 1979, maintenance workers were cleaning sludge from a small pipe when they inadvertently blocked the flow of cooling water. Heat in the core flashed some water into steam and the resulting pressure surge popped a relief valve. Emergency pumps started up to restore water flow, but two valves to the reactor core had been left closed. The water poured, instead, out of the relief valve. Unaware of the open valve, and... 

An example is the SCC of stainless steel at 200 °C in a caustic solution or in aerated chloride solution where no traces of dissolution are visible on the crack face. The three conditions, namely, tensile stress, susceptible sample material, and a corrosive environment are the conditions necessary for stress corrosion to take place (73, 90). For instance, SCC of metals has been by far the most prevalent cause of failure of steam generator components in pressurized water reactors (PWRs) to an extent of 69% of all cases, piping in boiling water reactors (59.7%) and PWRs (23.7%). More than 60% of inspected steam turbines in nuclear power plants have disks with stress corrosion cracks (91). 

The total cost of electricity sold in the United States in 1998 was 3.24 million gigawatt hours at a cost to consumers of 218.4 billion. The electricity generation plants use fossil fuel, nuclear, hydroelectric, cogeneration, geothermal, solar, and wind energies. The major players are fossil and nuclear steam supply systems. The two types of nuclear reactors are boiling water and pressurized water reactors. Some relevant data on the costs of corrosion estimated in 1998 are as follows nuclear facilities 1,546 billion fossil fuel sector 1,214 billion transmission and distribution 607 million hydraulic and other power 66 million. The total cost of corrosion in the electrical utilities industry in 1998 is estimated at 6,889 billion/year. 

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