Phenomena-based validation matrix for ex-vessel (containment) models and codes (Containment-CVM)

The objective of the validation matrix to be compiled is to define a basic set of available experiments for comparison of measured and calculated parameters covering the full range of ex-vessel phenomena expected in the course of light water reactor severe accidents.

Expected products

The outcome of this task is a summary report as a supplement to the existing reports 'Separate Effects Test Matrix for Thermal Hydraulic Code Validation, OECD/GD(94)82, September 1993 and 'In-Vessel Core Degradation Code Validation Matrix, OECD/GD (96)14, 1996.

The report provides an overview of the ex-vessel phenomena involved in severe accidents. The existing experimental facilities with data on overall dimensions, compartmentalisation, facility specifics and the extent of instrumentation are described.

The available experimental database is then summarised, with test conditions, phenomena, processes covered and parameter ranges presented in concise, standard tabular formats to aid comparison between the different experimental series. These data are then cross-referenced against the phenomena identified earlier, judging the results against a set of criteria for selection and identifying key tests of particular value.

While computer codes are used to simulate containment behaviour during a severe accident, they must be validated against relevant experiments to warrant reliable predictions. As successful validation needs a sound and comprehensive experimental basis, test matrices were elaborated for in-vessel thermal hydraulics and core degradation phenomena in the framework of OECD co-operation. This work intends to close the still existing gap for ex-vessel phenomena and processes.

The first step in this direction was the 'State-of-the-Art Report on Containment Thermal Hydraulics and Hydrogen Distribution, NEA/CSNI/R(99)16, published in June 1999, in which the most important phenomena for simulating containment thermal hydraulics and hydrogen distribution during the core damaged phase of a PWR severe accident were cross-referenced to internationally-available experiments, mostly integrated ones.

The scope of the validation matrix includes requirements for both, mechanistic and parametric modelling codes and considers phenomena and processes relevant to pressurised water reactor (PWR) and boiling water reactor (BWR) designs of Western origin, as well as VVER types.

The variety of phenomena extends from thermal hydraulics, including hydrogen distribution and combustion processes, aerosol and fission product behaviour, including iodine chemistry, up to the melt behaviour in the containment including fuel-coolant-interactions.

Safety significance

This activity aims at a significant improvement of the reliability of severe accident containment models/codes including the influence of accident management procedures. The result is an increased understanding of the related phenomena and demonstrates where experimental gaps are still existing.

Use and users of the results

The validation matrix is of use to code developers in listing key phenomena/processes and experiments in which these phenomena/processes are explored, and to code users who wish to be trained in the performance of a code using a selected set of experiments independent of those used in its development. The emphasis of the report is towards the latter application. Integral experiments are preferred, where interactions of phenomena as well as the phenomena themselves are considered as being more representative of these conditions expected during plant transients. Separate effect tests are also of value, in order to ensure that the full set of phenomena/ processes and their associated parameter ranges are adequately covered.

Lead organisation

The lead organisation is GRS - Gesellschaft für Anlagen und Reaktorsicherheit mbH.


Major experimental research efforts for ex-vessel model/code validation are performed at facilities in Canada, Finland, France, Germany, Japan, Switzerland, and the USA.

Expected contributions

NUPEC B-1-3 B-2-2 B-2-6 B-3-6 B-5-3 B-6-1 B-8-3 B-9-4 B-11-4
IRSN TOSQAN ISP-47   (spray test with light gas)
H2PAR test 
ENACCEF uniforme mix. 13 % H2
                    positive H2 gradient
                    negative H2 gradient
Proposed experiments for the H2-ISP

KALI      (2 to 3 tests)
GRS HDR V44 (ISP-16)
HDR T31.5 (ISP-23)
HDR T31.5 Phases 1 + 2
HDR T11.1
HDR E11.4
HDR E11.2 (ISP-29)
              VANAM M3 (ISP-37)
ThAI       ISP-47
             TH2 and 7
MUSCET at 9 %, 12 %, 16 %
    without obstacles (no)
    with obstacles (T1)
FZK   12 m tube
HYCOM   MC 003
HYCOM   MC 018
HYCOM   R 0498 09
HYCOM   MC 043
HYCOM   MC 020 
RUT         HYD32
German matrix
BMC   Kx19            Ex17
           1x2                Ex29
           1x7                Kx23
HDR    E12.3.2
AECL   / interconnected vessel case 11
AECL   Local air cooler test 2/50
             Dousing spray test No. 1
             Large scale gas mixing test
             GMB T001 / GMU S001
AECL   LSVC S01 and S03
               Phases A, C, E, F

Last updated: 22 February 2007