Critical power

The "SIMON" Project ("On-line acoustic monitoring of structural integrity of critical power plant components operating at high temperatures") had a duration of 4 years (1.10.1993 -30.09.1997) the Project Consortium included CISE (Project Coordinator, I), MITSUI BABCOCK ENERGY (UK), HERIOT-WATT UNIVERSITY (IK), PROET / EDP (P) and ENEL (I). 

F. Cattaneo, C. De Michelis, S. Ghia, G.M.Piana "AEBIL a new acoustic emission system for on-line structural integrity monitoring of critical power plant components" to be presented at the 7th European Conference on Non-Destructive Testing, Copenhagen, 26-29 May 1998. 

BE-60S6 On-line acoustic monitoring of structural integrity of critical power plant comoonents oneratinn at hiah temoeratiire Mr. C G. De Michairs CISE SpA... 

Building 5—A motor control center (MCC) constructed of unreinforced masonry. An electrician spends 1 hour a day monitoring equipment in the MCC. The MCC provides power for process equipment critical to the continued operation of the facility. Critical power for safety shutdown equipment for both Process Units 1 and 2 is located in Building 5. 

Figure 5.19 Boiling length effect on critical power. (From Bertoletti et al., 1964b. Reprinted with permission of CISE, Milan, Italy.)...

In the quality flow region, where the CHF occurs at the exit of the channel, experimental results indicate that the critical power of a nonuniformly heated test section is a function of Hin, L, De, G, and p, and suggest that an approximate relationship for boiling crisis in an axially nonuniformly heated test section can be written as... 

In a test section operated in a quality region with the same H1B, L, D, G, and p, the critical powers will be approximately the same for both the uniform and nonuniform flux distributions, provided the peak-to-average flux ratio is not greater than 1.6 (Janssen and Kervinen, 1963). 

Comparisons of rod bundle data with the Columbia correlation and other existing correlations were made using COBRA-IIIC code for predictions of all correlations. The DNBR (or CHFR) reported is not the critical power ratio as used by other authors. The DNBR errors reported by Reddy and Fighetti (1983) are based on the following analysis The measured local heat flux at the experimental location of the first or higher-rank CHF indications is compared with the predicted CHF calculated using local conditions from the subchannel analysis for the... 

Using Eqs. (5-42)-(5-46) in Section 5.3.2.2 with iterative calculations, the predicted CHF were compared with Columbia University data (Fighetti and Reddy, 1983). The comparison was made by examining the statistical results of critical power ratios (DNBRs), where... 

Since the uncertainty of the CHF predictions determines the safety margin of the protection systems and control systems for limiting the operating power of a reactor, the critical power ratio evaluated in (a) or (b) represents a realistic parameter for ensuring a proper safety margin. The simple CHF ratio as defined in (c) is rather too optimistic from a reactor safety point of view. 

Lahey, R. T., Jr., and J. M. Gonzalez Santalo, 1977, The Effect of Non-Uniform Axial Heat Flux on Critical Power, Paper C29/77, Inst. Mech. Eng., London. (5)... 

Fig. 5.2. Start of filamentation in BaF2 at different values of incident laser power expressed in multiples of Pcr, the critical power for self-focusing. Vertical arrows indicate the filament start position in each case...

Conical emission, 85, 89, 93 Constructive interference, 66 Continuous wavelet transforms, 145 Contrast ratio, 142-144, 191 Conversion efficiency, 96 Corona discharges, 110 Counter-propagating laser pulses, 171 CPA, 187 Critical power, 83 Cross section, 125... 

The nonlinear modes are usually referred to as solutions to the nonlinear Helmholtz equation in the waveguide cross-section. For their investigation, power-dispersion diagrams are commonly used that give values of critical powers and are helpful in stability analysis of the fundamental mode. ... 

Below a critical power input the gas bubbles are not affected laterally but move upward with their natural buoyancy. This condition is called gas flooding of the impeller. At higher power inputs the gas is dispersed radially, bubbles impinge on the walls and are broken up, consequently with improvement of mass transfer. A correlation of the critical power input is shown as Figure 10.10. 

The nonlinear directional coupler is potentially a useful device because it has four ports, two input and two output, and because the outputs can be manipulated with either one or two inputs. Optimally the two channels are identical, and the coupling occurs through field overlap between the two channels. As a result, when only one of the channels is excited with low powers at the input, the power oscillates between the two channels with a beat length Lb, just like what occurs in a pair of weakly coupled identical pendulii. As the input power is increased, a mismatch is induced in the wavevectors of the two channels, which decreases the rate of the power transfer with propagation distance. This leads to an increase in the effective beat length. There is a critical power associated with this device, for which an infinitely long, lossless NLDC acts as a 50 50 splitter, that is, Lb oo. 

The origin of the n2 measured using the 10 ns pulses could be electronic or molecular rotation. These can be distinguished by measuring the ratio of the critical power for self-focusing for linear and circular polarised light. The observed ratio of 2.1 is consistent with a molecular rotation (11-13.161 and relates to the anisotropic polarisability of the molecule. The rotational relaxation time, calculated from the Debye formula (H), is about 0.5-2 ns, consistent with these results. 

Critical power qCTit 0.4mWkg 1 23Wkg- 230kWkg- ... 

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