Condensation heat transfer analysis of the passive containment cooling system of the Purdue University Multi-dimensional Integral Test Assembly.

摘要

The development of a reliable containment cooling system is one of the key areas in advanced nuclear reactor development. There are two categories of containment cooling: active and passive. The active containment cooling consists usually of systems that require active participation in their use. The passive systems have, in the past, been reliant on the supply of electrical power. This has instigated worldwide efforts in the development of passive containment cooling systems that are safer, more reliable, and simpler in their use.;The passive containment cooling system's performance is deteriorated by noncondensable gases that come from the containment and from the gases produced by cladding/steam interaction during a severe accident. These noncondensable gases degrade the heat transfer capabilities of the condensers in the passive containment cooling systems since they provide a heat transfer resistance to the condensation process.;There has been some work done in the area of modeling condensation heat transfer with noncondensable gases, but little has been done to apply the work to integral facilities. It is important to fully understand the heal transfer capabilities of the passive systems so a detailed assessment of the long term cooling capabilities can be performed. The existing correlations and models are for the through-flow of the mixture of steam and the noncondensable gases. This type of analysis may not be applicable to passive containment cooling systems, where there is no clear passage for the steam to escape. This allows the steam to accumulate in the lower header and tubes, where all of the steam condenses.;The objective of this work was to develop a condensation heat transfer model for the downward cocurrent flow of a steam/air mixture through a condenser tube, taking into account the atypical characteristics of the passive containment cooling system. An empirical model was developed that depends solely on the inlet conditions to the condenser system, including the mixture Reynolds number and noncondensable gas concentration. This empirical model is applicable to the condensation heat transfer of the passive containment cooling system. This study was also used to characterize the local heat transfer coefficient with a noncondensable gas present.