Development of mathematical model for optimization of sodium leak collection tray
ABSTRACT Sodium leaks and resultant fire containment play an important role in the safe operation of a fast breeder reactor. Leak collection tray (LCT) is a passive device which is used to collect the highly reactive liquid sodium in the case of an accidental leakage. The consequences of sodium fire are mitigated by oxygen starvation in the vessel which collects the liquid sodium after leakage. The current paper deals with the optimization of the LCT geometry based on the hydrodynamic characteristics of the leaked liquid sodium. Isothermal numerical simulations have been performed to understand the interfacial dynamics of the hot liquid sodium flow in the top tray part and the variation of sodium draining rate into the holdup vessel for various drainpipe diameters and leak rates. Since the numerical simulations involve very high computational effort, an equivalent semi-analytical sloshing/draining model has also been developed which emulates the flow process in the LCT. The predictions of transient mass distributions in the top part and in the holdup vessel for the semi-analytical model are in close match with the results obtained from the detailed numerical study. The results reveal critical geometric parameters at which the un-burnt sodium collected in the LCT will be maximum.
- SourceAvailable from: vt.edu[Show abstract] [Hide abstract]
ABSTRACT: We recorded electroencephalogram (EEG) and electrocardiogram (ECG) from 20 infants monthly between 5 and 10 months of age during baseline and during performance on the looking A-not-B task of infant working memory. Analyses of baseline data showed age-related increases in EEG power (medial frontal, central, temporal, medial parietal, lateral parietal, and occipital electrode sites) and coherence (frontal pole-medial frontal, medial frontal-lateral frontal, medial frontal-medial parietal, and medial frontal-occipital electrode pairs), and decreases in heart rate (HR). Patterns of age-related change were similar for EEG power, EEG coherence, and HR. Analyses of task data relative to baseline revealed task-related increases in EEG power (all electrode sites), but no task-related changes in EEG coherence (medial frontal pairings) and HR. There was some evidence of localized task-related changes in EEG power by 10 months of age. These data highlight age-related changes in EEG and ECG, as well as the functional significance of these psychophysiological measures during baseline and during cognitive processing in the first year.International journal of psychophysiology: official journal of the International Organization of Psychophysiology 02/2011; 80(2):119-28. · 3.05 Impact Factor