Power plant reactor

Nuclear Power Plant reactor building and cooling tower (left). (Field Mark Publications... 

Eisler, R. 2003. The Chernobyl nuclear power plant reactor accident ecotoxicological update. Pages 703-736 in D.J. Hoffman, B.A. Rattner, C.A. Burton, Jr., and J. Cairns, Jr., eds. Handbook of Ecotoxicology, Second Edition. I.ewis I ublishers, Boca Raton, Horida. 

J R Mossop, D A Thornton, and T A Lewis, Vahdation of neutron transport calculations on Magnox power plant. Reactor Dosimetry, ASTM STP1228, H Farrar, E P Lippincott, J G Williams and D W Vehar, eds, American Society for Testing and Materials, Philadelphia, PA, 1994,384-391. 

In the case of nuclear power plants, reactor sizes kept increasing to take advantage of the economy of size, until the size reached what were deemed physical manufacturing, construction, or shipping limits. Even then, improvements continued to be made in the heat removal capabilities, resulting in higher volume power densities from the same size plants. 

Preparation of uranium metal. As discussed previously, some nuclear power plant reactors such as the UNGG type have required in the past a nonenriched uranium metal as nuclear fuel. Hence, such reactors were the major consumer of pure uranium metal. Uranium metal can be prepared using several reduction processes. First, it can be obtained by direct reduction of uranium halides (e.g., uranium tetrafluoride) by molten alkali metals (e.g., Na, K) or alkali-earth metals (e.g.. Mg, Ca). For instance, in the Ames process, uranium tetrafluoride, UF, is directly reduced by molten calcium or magnesium at yoO C in a steel bomb. Another process consists in reducing uranium oxides with calcium, aluminum (i.e., thermite or aluminothermic process), or carbon. Third, the pure metal can also be recovered by molten-salt electrolysis of a fused bath made of a molten mixture of CaCl and NaCl, with a solute of KUFj or UF. However, like hafnium or zirconium, high-purity uranium can be prepared according to the Van Arkel-deBoer process, i.e., by the hot-wire process, which consists of thermal decomposition of uranium halides on a hot tungsten filament (similar in that way to chemical vapor deposition, CVD). 

WASH-1400] "An assessment of accident risks in US Commercial Nuclear Power Plants Reactor Safety Study" US Nuclear Regulatory Authority, 1975... 

If the central off-site workshop is used for maintenance of large components, the operating organization should ensure that the same quality assurance requirements are applied at snch a facility as at the nuclear power plants. Reactor components shipped to a central facility may need more stringent standards of decontamination and, when such components are dismantled, appropriate off-site radiological controls shonld be provided. 

A total of four reactors were built at the Chernobyl site, in what is now the northern edge of Ukraine, a mere 20 km south of the Belarus border. These plants were located on the banks of a man-made lake that had been created by blocking the Pripyat river. The lake provided cooling water for all four of the power plant reactors, and provided a convenient media in which to inject the reactor s waste heat. 

The pubhc perceives the risk of nuclear power to be much greater than that deterrnined by experts (4). Among explanations for the discrepancy are the behef in the possibiUty of a disaster and the association of reactors with weapons. Living 50 years within five miles of a nuclear power plant has been shown to be comparable in terms of risk to smoking 1.4 cigarettes during the same period (5). 

Demand. The demand for uranium in the commercial sector is primarily determined by the requirements of power reactors. At the beginning of 1993, there were 424 nuclear power plants operating worldwide, having a combined capabity of about 330 GWe. Moderate but steady growth is projected for nuclear capacity to the year 2010. The capacity in 2010 is expected to be about 446 GWe (29). 

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.

One was a water-moderated and water-cooled pressurized reactor the other was a Hquid-metal-cooled iatermediate neutron energy reactor. A land-based prototype submafine power plant called Mark I was built and tested at the National Reactor Testing Station. Argonne National Laboratory provided scientific data and Bettis Laboratory of Westinghouse Electric Corp. suppHed engineering expertise. 

The Westinghouse Pressuricyed Water Reactor Nuclear Power Plant, Westinghouse Electric Corp., Water Reactor Divisions, Pittsburgh, Pa., 1984. 

Reactor Safety Study An Assessment of Accident Risks in U.S. Commercial Nuclear Power Plants, Report WASH-1400 (NUREG-75/014), U.S. Nuclear Regulatory Commission, Washington, D.C., Oct. 1975. 

As of 1996, the bulk of spent fuel from nuclear power plants has been stored in specially designed water-filled holding pools at the reactor site. 

The demand for uranium ia the commercial sector is primarily determined by the consumption and inventory requirements of nuclear power reactors. In March 1997, there were 433 nuclear power plants operating worldwide with a combined capacity of about 345 GWe (net gigawatts electric)... 

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