Expert Group on Reactor Core Thermal-Hydraulics (EGRCTH)

McMaster Core Thermal-Hydraulics Benchmark

OECD Nuclear Energy Agency (NEA), McMaster University, CANDU Owners Group (COG)

Building on the OECD-NEA BFBT and PSBT benchmarks, McMaster University, in collaboration with North Carolina State University, has launched a CANDU thermalhydraulic benchmark under the WPRS Expert Group on Uncertainty Analysis in Modelling. CANDU Owners Group (COG) had provided full-scale experimental data for a 28-element CANDU fuel assembly including pressure drop and detailed pin temperatures for single-phase and boiling conditions.


The purpose of this benchmark is to:

  • Provide data for validation of numerical models that predict single and two-phase pressure drop;
  • Provide data over a wide range of geometrical and operating conditions for validation of single and two-phase heat transfer models;
  • Provide CHF data over a wide range of flows, pressures and temperatures and under full scale reactor conditions for code testing and model development. Of particular importance are the tests where aged reactor conditions are represented and hence the geometry deviates from nominal conditions;
  • Provide novel “dry patch” mapping data wherein the post-CHF characteristics like dry-area fraction and post-dryout temperatures can be compared to code predictions.

Reference systems and scenarios

A unique aspect of these data are the traversing thermocouples which provide axial and azimuthal sheath temperatures along every fuel element for both pre and post-CHF conditions. A wide range of test conditions (inlet pressure, mass flows and inlet temperatures) will be provided to the participants along with the temperature scans, CHF location and power, and post-dryout sheath temperatures. Similar to the BFBT and PSBT benchmarks, the complete set of data will be made available to participants after completion of the benchmark.


Details can be found in the working area. (password protected | reminder)

Phase I: Pre-CHF Benchmark

  • Exercise 1: Single and two-phase pressure drop benchmark
  • Exercise 2: Single-phase heat transfer benchmark
  • Exercise 3: Two-phase heat transfer benchmark

Phase II: CHF Benchmark

  • Exercise 1: Steady-state CHF benchmark under nominal geometrical conditions.
  • Exercise 2: Steady-state CHF benchmark under aged channel conditions.
  • Exercise 3: Transient heat transfer and CHF benchmark
  • Exercise 4: Post-dryout sheath temperature benchmark


Coordinator: D.R.Novog (

History / Workshops:

The Second meeting will be held in conjunction with UAM-14

  • UAM-14 (hosted by N.IN.E), Sicily, Italy, 17-23 May 2020

The first meeting was held in conjunction with UAM-13

  • UAM-13 (hosted by ORNL), ORNL, USA, 13-17 May 2019

The benchmark proposal was accepted at the 2018 WPRS-EGUAM meeting and a kickoff meeting was held in conjunction with UAM-12.

  • UAM-12 (hosted by N.IN.E.), Lucca, Italy, 14-18 May 2018

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Last reviewed: 7 November 2019