Computational Fluid Dynamics (CFD) in Nuclear Reactor Safety (NRS)


This WGAMA activity originated as a response to an initiative of the "Exploratory Meeting of Experts to Define an Action Plan on the Application of Computational Fluid Dynamics (CFD) Codes to Nuclear Reactor Safety Problems", held in Aix-en-Provence (France) in 2002. This meeting defined an action plan containing near-term objectives that were reformulated as four CSNI-approved activities:

  1. Review existing CFD guidelines, analyse their completeness for single phase NRS applications, and make recommendations on the need to write a new guidance manual devoted to NRS.
  2. List NRS problems requiring CFD use, identify existing and needed assessment actions, and define a methodology to develop NRS-specific assessment matrices.
  3. Explore extension of CFD to two-phase problems, including classification of two-phase NRS problems requiring CFD, classification of different modelling approaches, specification and analysis of needs for physical assessment, specification and analysis of needs for numerical assessment.
  4. Establish benchmarks on turbulent and stratified flows, jet impingement, and CFD coupling to 0-D/1-D thermal-hydraulic codes.

In the first instance, three writing groups were formed at the end of 2002 to produce reports on the first three activities. Further activities have been defined in subsequent years creating task groups for organising workshops, performing code-data benchmarks and revising reports.

Reports providing guidance on CFD application to NRS

The three initial Writing Groups began to publish their work as CSNI reports in 2007. These have been subsequently updated (leading to new versions published in 2014) and a fourth one added that examines uncertainty quantification methods:

  1. Best Practice Guidelines for the use of CFD in Nuclear Reactor Safety Applications – revision, NEA/CSNI/2(2014)11;
  2. Assessment of CFD Codes for Nuclear Reactor Safety Problems – revision 2, NEA/CSNI/R(2014)12;
  3. Extension of CFD Codes Application to Two-Phase Flow Safety Problems – Phase 3, NEA/CSNI/R(2014)13.
  4. Review of Uncertainty – Quantification Methods for CFD, NEA/CSNI/R(2016)4.

CFD benchmarks

Benchmark exercises have been organised requiring identification of a suitable CFD-quality experiment, full specification of the analysis to be performed in blind conditions (i.e., no knowledge of the experimental results) then compilation of results for comparison.

  1. OECD/NEA CFD benchmark with Uncertainty Quantification (turbulent mixing based on GEMIX), exercise started in 2015;
  2. OECD/NEA-PSI CFD Benchmark Exercise (jet erosion of a stratified atmosphere based on PANDA), NEA/CSNI/R(2016)2;
  3. OECD/NEA-KAERI Rod Bundle CFD Benchmark Exercise (turbulent mixing downstream of a spacer grid), NEA/CSNI/R(2013)5;
  4. OECD/NEA-Vattenfall T-Junction Benchmark Exercise (high-cycle thermal fatigue), NEA/CSNI/R(2011)5.

CFD workshops

Biennial workshops were inaugurated in 2006 aiming to create a forum for numerical analysts and experimenters for exchanging information on nuclear safety issues covering single- and multi-phase flows. Submitted papers are peer reviewed by members of the scientific committee.

  1. CFD for Nuclear Reactor Safety Applications (CFD4NRS-6), Cambridge, MA (hosted by MIT), Sept. 2016, second announcement; website;
  2. CFD for Nuclear Reactor Safety Applications (CFD4NRS-5), Zürich, Sept. 2014, NEA/CSNI/R(2016)1;
  3. CFD for Nuclear Reactor Safety Applications (CFD4NRS-4), Daejeon, Sept. 2012, NEA/CSNI/R(2014)4;
  4. CFD for Nuclear Reactor Safety Applications (CFD4NRS-3), Bethesda, Sept. 2010, NEA/CSNI/R(2011)14;
  5. Experiments and CFD Codes Application to Nuclear Reactor Safety (XCFD4NRS), Grenoble, Sept. 2008, NEA/CSNI/R(2009)12;
  6. CFD Codes for Application to Nuclear Reactor Safety (CFD4NRS), Garching, Sept. 2006, NEA/CSNI/R(2007)3.

After each workshop a selection of papers may appear in a special issue of Nuclear Engineering and Design, e.g.:

  • Smith et al. (eds.), "Experiments and CFD Code Applications to Nuclear Reactor Safety (XCFD4NRS)", Special Issue, Nucl. Eng. Des., 240(9), 2075-2382 (2010)
  • Smith et al. (eds.), "CFD4NRS: Benchmarking of CFD Codes for Application to Nuclear Reactor Safety", Special Issue, Nucl. Eng. Des., 238(3), 443-785 (2008)

Related links

Working Group on the Analysis and Management of Accidents (WGAMA)

Committee on the Safety of Nuclear Installations (CSNI)

WGAMA / CFD members' area (password protected | reminder)

Last reviewed: 1 June 2016