Analysis of LOFT Small Break Experiment L3-1 with THYDE-P Code. CSNI International Standard Problem No.9 and THYDE-P Sample Calculation Run 50

摘要

Experiment L3-1 was the first small break loss-of-coolant experiment conducted at the Loss-of-Fluid Test (LOFT) facility with the nuclear core at 48.9 +- 1.0 MW, which is about 98% of the LOFT rated thermal power of 50 MW. The break size was equivalent to a 4-inch pipe rupture, or a 2.5% break, in a commercial plant, scaled on a break area basis. This experiment was selected as OECD-CSNI International Standard Problem No. 9. The THYDE-P code is a computer code to analyze both the blowdown and refill-reflood phases of loss-of-coolant accidents (LOCAs) of pressurized water reactors (PWRs) without a change in the models and the methods and is now under verification and modification study. The present calculation was the first verification study applied to a small break LOCA and was performed as Sample Calculation Run 50 which is part of a series of THYDE-P sample calculations. The calculation was carried out from test initiation to 2000 sec after rupture since it was the period of interest in the present work. The discharge coefficient for the Moody correlation was assumed to be 0.8. The overall trend of the experiment was well simulated by THYDE-P. (Atomindex citation 14:727935)