Full Scale Loop Seal experiments with TRACE V5 Patch 1 (NUREG/IA-0403)

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Publication Information

Manuscript Completed: January 2009
Date Published: December 2011

Prepared by:
Seppo Hillberg

VTT – Technical Research Centre of Finland
Nuclear Power Plant Modelling
P.O.B. 1000
02044 VTT

A. Calvo, NRC Project Manager

Prepared for:
Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001

Prepared as part of:
The Agreement on Research Participation and Technical Exchange
Under the Thermal-Hydraulic Code Applications and Maintenance Program (CAMP)

Published by:
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001

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Full scale loop seal experiments have been simulated with thermal hydraulic simulation code TRACE V5 Patch 1. Multiple nodalizations were created different geometric accuracy. The main interest in the simulations was the residual water level in the horizontal pipe. Also pressure behaviour during the air blow to the loop seal and effects of different maximum time steps and initial liquid levels were studied.

Simulations revealed differencies in results obtained with different nodalizations. Most of the nodalizations produced reasonable results except a simple 90° bend that used grav terms elevation option (namelist variable ielev=0). This model cleared too much water out of the loop seal. A very similar model using cell angle elevation option didn't suffer from this problem.

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