RELAP5 Simulation of Darlington Nuclear Generating Station Loss of Flow Event (NUREG/IA-0247)

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Publication Information

Date Published: February 2011

Prepared by:
D. Naundorf1
J. Yin1

A. Petruzzi2
A. Kovtonyuk2

1AMEC NSS Limited
700 University Avenue
Toronto, Ontario, Canada

2Nuclear Research Group San Piero A Grado
University of Pisa
Pisa, Italy

A. Calvo, NRC Project Manager

Published by:
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 International Code Assessment and Maintenance Program (CAMP)

Availability Notice


The Darlington NGS consists of four 940 MWe CANDU reactors. A detailed RELAP5 model of a Darlington NGS reactor has been created for use with RELAP5/MOD3.3. The model includes the primary heat transport system, the steam generator feedwater and main steam supply systems, the pressure and inventory control system, and the emergency coolant injection system. The modeling of Darlington required the creation of new subroutines for RELAP5 to describe the functionality of the process control systems and emergency control systems with sufficient accuracy. These controller subroutines are standalone modules that are compiled and linked together with the RELAP5 source to facilitate integration with future revisions to the code. The November 25, 1993, loss-of-flow event at Darlington was simulated using this RELAP5 model. Excellent agreement was obtained between the RELAP5 predictions and station measurements.

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