International Agreement Report – Analysis of the OSU-MASLWR 001 and 002 Tests by Using the TRACE Code (NUREG/IA-0466)

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Publication Information

Manuscript Completed: October 2015
Date Published: August 2016

Prepared by:
Fulvio Mascari, Felice De Rosa, Brian G. Woods*, Kent Welter**, Giuseppe Vella***, Francesco D'Auria****

ENEA- Via Martiri di Monte Sole 4, Bologna, Italy

*Department of Nuclear Engineering and Radiation Health Physics
116 Radiation Center, Corvallis, OR 97331-5902, USA.

**NuScale Power Inc., 1100 NE Circle Blvd, Suite 200, Corvallis, OR 97330, USA.

***Dipartimento dell'Energia, Università degli Studi di Palermo,90128 Palermo, Italia

****San Piero a Grado, Nuclear Research Group (SPGNRG), University of Pisa

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 Oregon State University (OSU) has constructed, under a U.S. Department of Energy grant, a scaled integral test facility to examine natural circulation phenomena characterizing the Multi-Application Small Light Water Reactor (MASLWR) design. The MASLWR is a small modular PWR relying on natural circulation during both steady-state and transient operation, which includes an integrated helical coil steam generator within the reactor pressure vessel. Testing has been conducted in order to assess the operation of the prototypical MASLWR under normal full pressure and full temperature conditions and to assess the passive safety systems performance. The experimental data produced are useful also for the assessment of the computational tools necessary for the operation, design and safety analysis of nuclear reactors.
This report describes the assessment of TRACE code predictions, conducted under the NRC CAMP program, against the MASLWR tests OSU-MASLWR-001 and the OSU-MASLWR-002, respectively. This activity has been conducted in collaboration with the Italian National Agency for the New Technologies, Energy and Sustainable Economic Development (ENEA), the Department of Energy of the University of Palermo, the Gruppo di Ricerca Nucleare San Piero a Grado (GRNSPG) of University of Pisa, the Department of Nuclear Engineering and Radiation Health Physics at OSU and NuScale Power Inc. In particular the OSU-MASLWR-001 test, an inadvertent actuation of one submerged ADS valve, investigates the primary system to containment coupling under design basis accident conditions; the OSU-MASLWR-002 test, a natural circulation test, investigates the primary system flow rates and secondary side steam superheat for a variety of core power levels and feed water flow rates. The assessment against experimental data shows that the TRACE code predicts the main phenomena of interest of the selected tests reasonably well for most conditions.

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