Natural Circulation Assessment of a PWR Loss of Off-site Power with RELAP5/MOD 3.2 (NUREG/IA-0538)

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Publication Information

Manuscript Completed: March 2021
Date Published: February 2023

Prepared by:
R. MartĂ­, O. Parera

Av. de la Fama, 11-15
CornellĂ  de Llobregat 08940, Spain

K. Tien, NRC Project Manager

Division of Systems Analysis
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

Availability Notice


The work presented corresponds to the assessment of a PWR Loss of Off-Site Power with RELAP5 [1]. The RELAP5 input deck has been obtained from the existing RELAP5 input deck with some modifications. The calculated results were compared against the plant data. The results show that RELAP5 is capable of reproducing the phenomena with a good level of satisfaction. However, some discrepancies between the predicted variables and the plant data suggest further investigation of the RELAP model.

The simulations were prepared by IDOM Nuclear Services. A Spanish NPP provided the input model, the plant data, and transient available data and associated information.

The report is focused on the transient calculations and the modifications and conclusions obtained from them. The purpose of this work is to detect possible errors in the existing plant model and provide the modifications for the input model.

The work to which this report refers, falls within the framework of the CAMP/SPAIN Project. The objectives being those referred to in the CAMP Program itself, in particular, achievement of the capacity required to apply calculation tools supporting the quantitative analysis of transients and operation procedures, as well as joint participation in the international efforts aimed to validate and experience the use of appropriate calculation codes.

Page Last Reviewed/Updated Thursday, March 02, 2023