Pressurized water reactor fuels

PARTICLE FUEL PRESSURIZED WATER REACTOR (PFPWR50)... 

The PFPWR50 is a particle fuel pressurized water reactor of 50 MW(th). 

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. 

The mathematical formulation of forced convection heat transfer from fuel rods is well described in the Hterature. Notable are the Dittus-Boelter correlation (26,31) for pressurized water reactors (PWRs) and gases, and the Jens-Lottes correlation (32) for boiling water reactors (BWRs) in nucleate boiling. 

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. 

The relative activity of americium isotopes for a typical pressurized-water reactor (PWR) fuel assembly are 1,700, 11, and 13 Ci for241 Am, 242Am, and 243Am (DOE 1999). The respective activity ratios for a typical boiling water reactor (BWR) are 680, 4.6, and 4.9 Ci. There are 78 PWR and 41 BWR reactors in the United States, several of which have ceased operation. Total projected inventories of these three radionuclides for all reactors are 2.3x10s, 1.4xl06, and 1.7xl06 Ci, respectively. The post irradiation americium content of typical PWR and BWR reactor fuel assemblies are 600 g (0.09%) and 220 g (0.07%), respectively. 

Fuel cell vehicles, 73 800-801 Fuel cell voltage equation, 72 208 Fuel cell voltages, 72 206-209 versus current densities, 72 208 Fuel cooling, in pressurized water reactors, 77 544... 

Fuel type characteristics Graphite gaseous reactor Pressurized water reactor Fast breeder reactor... 

Table 1. Chemical compositions (ivr%) of low-pressured water reactor (LWR) spent fuel and uraninite from Oldo reactors 10. 16 and Cigar Luke...

The BWR operates at constant pressure and maintains constant steam pressure similar to most fossil-fueled hollers. The BWR primary system operates at pressure about onc-half that of a pressurized water reactor primary system, while producing steam of equal pressure and quality. 

Fig. 12. Reactor core cross section of contemporary pressurized water reactor with 241 fuel assemblies. (Combustion Engineering)...

Fig. 13, Fuel assembly used in contemporary pressurized water reactor...

The control element assemblies consist of an assembly of 4. 8, or 12 fingers approximately 0.8-inch (2-centimeter) outside diameter and arranged as shown in Fig. 14. The use of cruciform control rods, as in boiling water and early pressurized water reactors, necessitates large water gaps between the fuel assemblies to ensure that the control rods will scram (prompt shutdown) satisfactorily. These gaps cause peaking of the power in fuel rods adjacent to the water channel compared to fuel rods some distance from the channel. 

Pressurized vs. boiling LWRs The pressurized water reactor (PWR) transfers its energy from the fuel to an intermediate heat exchanger to generate the steam that... 

As an example, a fuel element of the type used in a pressurized water reactor (PWR) is shown in Fig. 11.11. The fuel element has 16 x 16 positions for 236 fuel rods and 20 control rods. 

The fuel rods for boiling and pressurized water reactors are constructed similarly. They are filled with helium to improve the heat transfer from the pellets to the cladding tube and to withstand better the pressure in the reactor and contain no fuel at the top end of the fuel rods to improve fission gas retention. The latter can be ensured by holding the fuel in place with the aid of a spiral spring. Both ends of the cladding tube are welded gas tight. The fuel rods for pressurized water reactors are manufactured with a helium pressure of ca. 23 bar and ca. 5 bar for fuel rods for boiling water reactors. 

The actual fuel elements in pressurized water reactors consist of individual fuel rods and control rod tubes mounted in a self-supporting construction of spacers fitted with a top and feet. Fuel elements for boiling water reactors, by comparison, have no control rod tubes, the fuel element zirkaloy claddings being used to guide the control rods and the coolant. 

Figure 4. Fuel processing the flow sheets for lOOO-MW(e) pressurized water reactor (A) without and (B) with plutonium recycle. (After Ref. 8.)...

The Pressurized Water Reactor (PWR) reload core optimization problem, though easily stated, is far from easily solved. The designer s task is to identify the arrangement of fresh and partially burnt fuel (fissile material) and burnable poisons (BPs) (control material) within the core which optimizes the performance of the reactor over that operating cycle (until it again requires refueling), while ensuring that various operational (safety) constraints are always satisfied. 

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. 

Basis is pressurized water reactor fuel with 33,000 megawatts per day/MTlHM. Total is of all radionuclides, both selected and unselected. 

Figure 13.18 Water-dilution volumes for radionuclides in spent fuel discharged from a l-GW(f>) pressurized-water reactor as a function of decay time. After J. Choi and H.

Figure 13.19 Water-dilution volumes for radionuclides in spent-fuel reprocessing wastes formed by operating a l-GW( -) pressurized-water reactor for one year, plotted as a function of decay time. After J. Choi and H. Pigford, Water dilution volumes for high-level wastes, ANS Transactions 39, p. 176. Copyright 1981 by the American Nuclear Society,...

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