Reactor Safety Issues Resolved by the 2D/3D Program (NUREG/IA-0127, GRS–101, MPR–1346)

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Publication Information

Date Published: July 1993
Reprinted: October 1993

Edited by:
P. S. Damerell, J. W. Simons,
MPR Associates, Inc.

Prepared Jointly by:
Japan Atomic Energy Research Institute
Gesellschaft fuer Anlagen-und Reaktorsicherheit
Siemens AG, UB KWU
U.S. Nuclear Regulatory Commission
Los Alamos National Laboratory
MPR Associates, Inc.

Prepared as part of:
Arrangement on Research Participation and Technical Exchange between
the Federal Minister for Research and Technology of the Federal Republic of Germany
(BMFT) and the Japan Atomic Energy Research Institute (JAERI) and the United States Nuclear
Regulatory Commission (USNRC) in a Coordinated Analytical and Experimental Study
of the Thermo-hydraulic Behavior of Emergency Core Coolant during the Refill and Reflood
Phase of a Loss-of-Coolant Accident in a Pressurized Water Reactor (the 2D/3D Program).

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

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The 2D/3D Program studied multidimensional thermal-hydraulics in a PWR core and primary system during the end-of-blowdown and post-blowdown phases; of a large-break LOCA (LBLOCA), and during selected small-break LOCA (SBLOCA) transients. The program included tests at the Cylindrical Core Test Facility (CCTF), the Slab Core Test Facility (SCTF), and the Upper Plenum Test Facility (UPTF), and computer analyses using TRAC. Tests at CCTF investigated core thermal-hydraulics and overall system behavior while tests at SCTF concentrated on multidimensional core thermal-hydraulics. The UPTF tests investigated two-phase flow behavior in the downcomer, upper plenum, tie plate region, and primary loops. TRAC analyses evaluated thermal-hydraulic behavior throughout the primary system in tests as well as in PWRs. This report summarizes the test and analysis results in each of the main areas where improved information was obtained in the 2D/3D Program. The discussion is organized in terms of the reactor safety issues investigated.

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