Pool boiling defined

Effect of Multicomponent Mixtures in Nucleate Pool Boiling. For a binary liquid mixture of composition xu we may define a heat transfer coefficient h as... 

A number of empirical and semiempirical methods have been developed to predict the changes in heat transfer coefficient in pool boiling. Stephan and Korner [128] define an effective temperature driving force for use instead of (Tw -r ) inEq. 15.111 ... 

Virtual Sources The previous equations apply to point source releases. Real releases, such as a boiling pool of liquid or a streaming jet of flashing hquid, involve a more complex geometiy One approach Guideline.s for Chemical Proce.s.s Quantitative Risk Analy.sls, AIChE, 1989, p. 87) is to define a virtual source upwind from the ac tual source such that the computed plume matches the real plume. However, to achieve this, a concentration at a centerhne point directly downwind must be known. 

For BWRs, the radiologically representative design basis accidents have not been defined as precisely as for PWRs. However, the possible events are phenomenologically quite similar (with the exception of the steam generator tube rupture accident, which does not apply for BWRs) and there are no significant differences to be expected in radionuclide behavior. Consequently, equivalent requirements are applied to the design of both PWR and BWR plants. This means that in most cases the radiochemistry principles discussed in what follows will apply mutatis mutandis to boiling water reactors as well. In the event of a loss-of-coolant accident, the BWR pressure suppression pool represents an effective retention system the behavior of the fission products in this pool will be discussed in Section 7.3.2.4. 

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