Pressurized water reactors enrichment

A variety of nuclear reactor designs is possible using different combinations of components and process features for different purposes (see Nuclear REACTORS, reactor types). Two versions of the lightwater reactors were favored the pressurized water reactor (PWR) and the boiling water reactor (BWR). Each requites enrichment of uranium in U. To assure safety, careful control of coolant conditions is requited (see Nuclearreactors, water CHEMISTRY OF LIGHTWATER REACTORS NuCLEAR REACTORS, SAFETY IN NUCLEAR FACILITIES). 

By contrast, uranium fuels for lightwater reactors fall between these extremes. A typical pressurized water reactor (PWR) fuel element begins life at an enrichment of about 3.2% and is discharged at a bum-up of about 30 x 10 MW-d/t, at which time it contains about 0.8 wt % and about 1.0 wt % total plutonium. Boiling water reactor (BWR) fuel is lower in both initial enrichment and bum-up. The uranium in LWR fuel is present as oxide pellets, clad in zirconium alloy tubes about 4.6 m long. The tubes are assembled in arrays that are held in place by spacers and end-fittings. 

Another reactor that was approved for development was a land-based prototype submarine propulsion reactor. Westinghouse Electric Corp. designed this pressurized water reactor, using data collected by Argonne. Built at NRTS, the reactor used enriched uranium, the metal fuel in the form of plates. A similar reactor was installed in the submarine l autilus. 

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. 

Figure 1.11 shows three possible fuel processing flow sheets for reactors cooled and moderated by light water. The specific example shown is for a pressurized-water reactor. Fuel for this type of reactor consists of UOj enriched to around 3.3 w/o in U. The expected performance of this type of reactor is described in some detail in Chap. 3, Sec. 7. After... 

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... 

Two types of light water reactors, namely, the boiling water reactor (BWR) and the pressurized water reactor (PWR) are in use in the United States of America. The fuel for these reactors consists of long bundles of 2-4 wt% of enriched uranium dioxide fuel pellets stacked in zirconium-alloy cladding tubes. 

Pressurized water reactor (PWR) USA, France, Japan, Russia 252 235 Enriched UO2 Water Water... 

Critical Experiments on Enriched Uranium Stainless Steel Water Moderated Lattices, L. M. Welshans and K, M. Johnson (MARTIN). A series of 12 cold, clean critical cores has been studied under the Army Nuclear Power Program in conjunction with the Pressurized Water Reactor Code Development task. The purpose of the experimental program Is to Supply data on highly enriched uranium, water moderated systems using stainless steel as cladding material. 

Westinghousc critical lattices with 2.75% enriched UO2 pressurized water reactor (PWR) fuel in H2O... 

In boiling water reactors as in pressurized water reactors, U-enriched UO2 fuels as well as mixed-oxide fuels are used. Fabrication of the fuel material and the fuel pellets is virtually identical for both reactor types (see Section I.I.2.). However,... 

Nuclear powered submarines, iike the USS Maryiand shown here, typicaiiy use pressurized water reactors and highiy enriched nuciear fuei to provide more power from a smaiier reactor. One steaith issue with nuciear subs is the need to cooi the reactor, which ieaves a traii of warm water that rises to the surface. 

The LWR is further classified into the pressurized water reactor (PWR) which operates at about 150 atm and 318°C with a thermal efficiency of about 34%. The other type of reactor is the boiling water reactor (BWR) which operates at 70 atm pressure and 278°C with a thermal efficiency of 33%. These reactors require fuel with enriched to about 3% to have a sufficient neutron flux for the chain reaction. The fuel, as UO2, is in the form of pellets enclosed in a zirconium alloy, Zircaloy-2. 

The two light water reactors (LWRs) are the pressurized water reactor (PWR) and the boiling water reactor (BWR). The systems are similar in that both employ light water as both moderator and coolant, which necessitates the use of fuel enriched to about 2.0 %-2.5 % due to the appreciable neutron absorption of the water in the core. They are also alike in that in both cases the core is enclosed within a single large steel pressure vessel (see Fig. 7,1). The distinction between the two designs is also illustrated in the figure. In the... 

A relatively small amount of fuel required. For example, a 500-MWei coal-fired supercritical pressure power plant requires 1.8 million tons of coal each year, but a fuel load into a 1300-MWei pressurized water reactor is 1151 (3.2% enrichment) or into a 1330-MWei hoiUng water reactor is 1701 (1.9% enrichment). Therefore this source of energy is considered as the most viable one for electrical generation for the next 50—100 years. 

Reactivity changes and plutonium isotopic compositions were first examined for a commercial pressurized water reactor (PWR) operating on a low enrichment (3.2 wt% equilibrium fuel cycle. The results aided in understanding the significance of a number of approximations made in this assessment. The results also provided some perspective on the plutonium composition in spent conunercial reactor fuels. 

Uranium Enrichment. Enrichment of uranium-235, from 0.711 percent as present in natural uranium, is essential to the economical operation of light water reactors where the fuel life is a function of the enrichment. With approximately 4.95 percent U-235 fuel, the pressurized light water reactors... 

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