Two-Phase Natural-Circulation Experiments in a Test Facility Modeled after Three Mile Island Unit-2. Final Report

摘要

A series of natural circulation experiments was conducted in a test facility that was configured after the primary and the secondary cooling systems of TMI-2. Results support the feasibility of core residual heat removal by two-phase natural circulation. Tests with noncondensable gas in the primary system indicate that two-phase natural circulation is quite tolerant of the presence of noncondensable gas. The different modes of natural circulation were discovered. Mode 1, during which only saturated steam flows in the hot leg, accomplishes the heat removal via phase changes in the vessel and in the steam generator tubes. Mode 2, during which a percolating flow exists in the hot leg, removes the heat by means of a much faster circulation in the primary loop. (ERA citation 07:004272)