Failure Rate Data Transfer

Chapter 7—Failure Rate Data Transfer Provides a form to facilitate the transfer of plant-specific data to the CCPS Data Base or to combine it with other generic data. 

Figure 7.1 Example Failure Rate Data Transfer Form.

When plant-specific data are required. Chapter 6 discusses how to collect and treat the data so that the resulting failure rates can be used in a CPQRA or be combined with the data in the CCPS Generic Failure Rate Data Base. Chapter 7 provides a form that can be used to transfer these data to CCPS s Generic Failure Rate Data Base. 

Under accident conditions of transport, irradiated fuel pins may fail, with subsequent radioactive release into the package containment system. Data on the fuel fission product inventory, possible failure rate of pin cladding and the mechanism of activity transfer from the failed pin into the containment system are therefore required to enable the package leaktightness to be assessed. 

Simplified thermal-hydraulic analyses, which were benchmaiked against GT-MHR data, indicated that for a fixed core outlet temperature of 1000°C for the coolant, the peak fuel temperature in the AHTR during normal operation will be 110-130°C cooler than for the prismatic helium-cooled NGNP design, and the average fuel temperature at the core outlet will be 30-50°C cooler. This is a direct result of the superior heat transfer properties of the molten salt relative to helium. This is significant because the failure rate of the coated particle fuel increases with increasing temperature. 

Yokoyama and Frank, Frank et Brain, and Egle largely overlooked this flow-dependent relationship, because they did not normalize their retention data into the average-transfer-coefficient form. In fact, failure to do this led Yokoyama and Frank to the erroneous conclusion that the uptake of O3 was inversely rated to flow."... 

Comparative responses obtained with quercetin and narlngenin are shown in Traces D and E, respectively. Quercetin and narlngenin, at concentrations that completely inhibited photophosphorylation, inhibited the ADP-stimulated rate of 0 utilization 70 and 82%, respectively. FCCP restored the rate to 12 and 42% of the original rate for quercetin and narlngenin, respectively. The failure to obtain complete recovery can be attributed to interference with a component of the electron-transport pathway, at these same concentrations, as evidenced by data presented in Table II. Similar results were obtained with the remainder of the representative compounds. The results reinforce the postulate that the primary effect Imposed by the allelochemlcals on thylakolds is energy transfer inhibition with a secondary effect imposed on the electron-transport pathway. 

Two separate models based on Dow Advanced Continuous Simulation Language (DACSL) were used in these studies. The first model used laboratory data and parameter estimation to determine the Arrhenius constants for two desired and eight undesired reactions in a process. The second model used the Arrhenius constants, heats of reaction, different physical properties, and reactor parameters (volume, heat transfer properties, jacket control parameters, jacket inlet temperature) to simulate the effect of reaction conditions (concentration, set temperature, addition rate) on the temperature of the reaction mixture, pressure and gas flow rates in the reactor, yield, and assay of the product. The program has been successfully used in two scale-ups where the optimum safe operating conditions, effect of various possible failures, and control of possible abnormal conditions were evaluated. 

Data available on the first failure did not permit an estimate of the water leak rate. For the second leak, however, sufficient data were available to permit an estimate of the leakage rate during the final heat-transfer run. Estimates of this leakage rate were made from data both on the pressure rise and on the increase in sodium impurity content. These estimates indicated an average leak rate of approximately 0.01 pound per minute. 

Finally, the relative rates of the vanadium catalyzed oxidation of some nucleophilic substrates by r-BuOOH in ethanol at 25 °C were found to be ( -Bu)2S(100) > PhS(n-Bu)(58)>(n-Bu)2SO(17)> cyclohexene (0.2). These data suggest strongly that electropositive oxygen is being transferred from the metal-activated hydroperoxide to the substrate. Thus, a polar mechanism can be advanced. A radical mechanism is ruled out by the observation of reproducible kinetics, the simple rate law, the failure of radical traps to influence rate, and by the absence of products expected to arise from radical intermediates. 

This synthesised survey data indicates LCR compliance based on the first litre sample and non-compliance from the third litre on-wards, consistent with the trend shown in Figure 7.1 for site 01. The failure profile based on 90th percentile concentrations can be compared (Table 7.2) to the two other case studies and their plumbosolvency characteristics, as observed or predicted and quantified by M (the initial mass transfer rate in pg/m /s) and E (the equilibrium concentration in pg/1). 

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