The Scoping Emergency Cooling Heat Transfer (SECHT) Project was an experimental project directed at scoping the parameters of bottom and top flooding modes of emergency core cooling for nuclear reactor fuel bundles. The SECHT Project consisted of four series of tests of which the third series (SECHT III tests) is described in this report. The primary objective of the SECHT III tests was to perform timely sensitivity studies by using readily available hardware. Exact scaling of a segment of a reactor core was not accomplished;therefore, the results presented in this report are more quali¬tative than quantitative. The SECHT III testing program consisted of 55 experi¬ments that were designed to form a parametric study over the range of variables thought possible at the initiation of the emergency core coolant injection in contemporary water cooled reactors. The test parameter variations included:initial bundle temperatures between 800 and 2000°F, cold flooding rates between 0.45 and 7.2 in./sec, average bundle power between 0 and 15,000 Btu/hr-ft2, and coolant inlet temperatures between 100 and 200°F. The test vessel was fitted with a constrictive device which was placed over the exit as a means of providing preliminary data on the effects of water carry-over. Specific results show that the arrest and turnaround of the bundle temperature ex¬cursion occurs more quickly in tests which have high initial temperatures and that the sensitivity of turnaround time to bundle power decreases with increasing bundle initial temperature. The effect of the constriction is shown to be strongly dependent on flow rate. The experience gained from this project in electric heater design, instrumentation, and test procedures has been valuable to the Full Length Emergency Cooling Heat Transfer (FLECHT) Project.
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