Power density distribution

Deposition rate and ESCA results on blanks placed at various sites in the plasma reactor may therefore be used as a probe of the power density distribution in a given reactor with a glow discharge fed by tetrafluoroethylene. 

Zhao et al. (2001) examined a model for computing the electromagnetic field and power-density distribution in a cavity, and their effects on cure of a thin epoxy-resin layer during a novel microwave rapid-prototyping process. 

To shape power density distribution to maximize power output... 

To point to the importance of using improved methods of fuel and poison management, we shall discuss qualitatively the multiple drawbacks of the simplest method, which is batch irradiation of fuel initially uniform in composition, with spatially uniform distribution of boron control poison and with complete replacement of fuel at the end of its operating life. An example of this would be a PWR charged with fuel of uniform enrichment containing 4 percent and 96 percent and controlled by adjusting the concentration of boric acid dissolved in the water coolant to keep the reactor just critical at the desired power level. When this reactor starts operation, the compositions of fuel and poison are uniform throughout the core, and the flux and power density distribution are very nonuniform. 

Figure 3.5 Power density distribution in 1060-MWe PWR at beginning of period, with uniform poison, moderator, and fuel containing 3.2 w/o U.

Taking into account the radial distributions of the optical power density and the dye density, the functions of power density distribution W (r) and the dye density distribution 0 (r) are defined as... 

The power density distribution is controlled by the 12 LAC and 24 LS rods. The average power control system is used as standby in the 20-100% power range and is switched on automatically when the LAC system malfunctions. The automatic control system holds reactor power to within 1 % of the required output in the range 20-100% full power and to within 3% in the range 3-5-20% full power. 

Computer codes must be qualified. The adequacy of the nodalization should be demonstrated as recommended, for instance, in Ref. [15], Integrated computer codes are preferable. For instance, analyses of reactivity initiated accidents with spontaneous control rod withdrawal should employ a three dimensional (3-D) neutronic code with a built-in multichannel thermohydraulics code in order to determine the distortion of the neutron field and the redistribution of thermohydraulic parameters in the group of fuel channels affected by the distorted power density distribution. 

In order to obtain the most uniform possible power density distribution, the spherical fuel elements pass through the core approximately 15 times before reaching their final bum-up. 

POWER DENSiTY DISTRIBUTION WITH BURNUP AT THE BEGINNING OF FUEL CYCLE FOR CASE 023S78 WITH INTERNAL HETEROGENEOUS BLANKET... 

FIG. XXIV-19. Power density distribution with bum-up in the core for reference core configuration (Table XXIV-5) at the beginning of cycle. 

The fluxes with energies greater than 0.1 MeV make up 90% of the total flux Shape distribution follows the power density distribution of the fuel The peak E>0.1MeV fluences at 15MW-yrs (n/cm ) range from ... 

Power density distribution (with no loops) Maximum (center) 220 kw/liter... 

Eigure 4.4 illustrates the horizontal power density distribution through the vertical center of the core. The peak power density at the center of the core divided by the minimum power density at the center of the fuel tubes near the vertical faces of the core boundary is 2.3. The peak-to-average core power distribution was determined to be 2.09. 

The heat transfer analyses were based upon the material and geometry specifications described in Sects. 2 and 3. However, because the fission/power density distribution was not available at the onset of these analyses, the following simplistic bounding parametric assumptions were specified ... 

Fig. 8. Power density distribution in rz geometry. 100% nominal power. 7/12 of central control rods within the core.

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