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CSNI2003 MCCI PROJECT.
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CSNI2003 MCCI PROJECT.

MCCI PROJECT, Molten Core Concrete Interaction Project

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1. NAME

MCCI (Molten Core Concrete Interaction) Project.

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2. COMPUTERS

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Program name Package id Status Status date
MCCI PROJECT CSNI2003/01 Arrived 24-JAN-2007

Machines used:

Package ID Orig. computer Test computer
CSNI2003/01 Many Computers
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3. DESCRIPTION OF THE PROJECT

In a core melt accident, if the molten core is not retained in-vessel despite severe accident mitigation actions, the core debris will relocate to the reactor cavity region and interact with the structural concrete - potentially resulting in basemat failure through erosion or overpressurisation. This would result in the release of fission products into the environment. Although this is a late release event, the radiological consequences could be substantial enough to warrant an effective mitigation strategy for preventing such a release. The severe accident management guidance (SAMG) for operating light water reactor plants includes, as one of several strategies, flooding the reactor cavity in the event of an ex-vessel core melt release.

 

The Melt Coolability and Concrete Interaction (MCCI) Project was dedicated to provide experimental data on this severe accident phenomena and to resolve two important accident management issues:

 

  • verify that molten debris that has spread on the base of the containment can be stabilised and cooled by water flooding from the top;

  • assess the two-dimensional, long-term interaction of the molten mass with the concrete structure of the containment, as the kinetics of such interaction is essential for assessing the consequences of a severe accident.

 

To achieve these basic objectives, supporting experiments and analyses were performed at Argonne National Laboratory (ANL), with a view to providing an understanding the phenomena, and to produce a consistent interpretation of the results relevant to accident management.

 

Previously, an internationally-sponsored programme has already been carried out at ANL to address the corium coolability issue. The MCCI project aimed to complete this earlier research and achieve the following technical objectives:

 

  • resolve the ex-vessel debris coolability issue through a redirected programme which focuses on providing both confirmatory evidence and test data for the coolability mechanisms identified in previous ANL integral effect tests;

  • address remaining uncertainties related to the long-term, two-dimensional, melt-concrete interaction under dry cavity conditions.

 

The first MCCI experiments focused on water ingress mechanisms, as these are thought to be the most effective ones for cooling the melt. These experiments have demonstrated how cooling of the melt by water is affected by the concrete-melt composition and that cooling of the melt by water is reduced at increasing concrete content, i.e. cooling by water flooding is more effective in the early phase of the melt-concrete interaction. The effect of concrete type, such as siliceous and limestone types (used respectively in Europe and the United States), has also been addressed. Material properties such as porosity and permeability have been derived from these tests.

 

A first melt-concrete interaction test with siliceous concrete in 2003 produced unexpected results (a strong asymmetry in concrete ablation), although the associated analytical exercise proved very valuable in helping to understand code capabilities and shortcomings. A second test was carried out in 2004 at 30% lower power than the first on limestone concrete (instead of the siliceous concrete used in the first test). The strength of the solid upper crust, a parameter that is of great interest for modelling and understanding MCCI at plant scale, was also determined during these experiments. A third test with siliceous concrete was successfully carried out in 2005, yielding excellent data on axial and radial concrete ablation.

 

The first phase of the programme (MCCI-1) was completed in 2005. The experiments on water ingress mechanisms showed that cooling of the melt by water is reduced at increasing concrete content, implying that water flooding is more effective in the early phase of the melt-concrete interaction. The effect of concrete type, i.e. siliceous and limestone types (used respectively in Europe and the United States), was also addressed in the first phase of the programme. Material properties such as porosity and permeability were derived. Tests also showed appreciable differences in ablation rate for siliceous and limestone concrete, which is a relevant finding that requires confirmation. A workshop on the results of MCCI-1 took place on 10-11 October 2007 in Cadarache. This project was followed by the MCCI-2 project.

 

Project participants: Belgium, Czech Republic, Finland, France, Germany, Hungary, Japan, Norway, Republic of Korea, Spain, Sweden, Switzerland and the United States.

 

Project period: January 2002-December 2005

 

Project management: US Nuclear Regulatory Commision (USNRC)

 

For more detailed information visit http://www.oecd-nea.org/jointproj/mcci.html

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9. STATUS
Package ID Status date Status
CSNI2003/01 24-JAN-2007 Masterfiled restricted
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10. REFERENCES

Publications

  • M. T. Farmer, S. Lomperski, D. Kilsdonk, R. W. Aeschlimann, and S. Basu:
    A Summary of Findings from the Melt Coolability and Concrete Interaction (MCCI) Program, Paper 7544, 2007 International Congress on Advances in Nuclear Power Plants (ICAPP'07), Nice, France, 13-18 May 2007.

 

 

CSNI2003/01, included references:
Conference Proceedings:

1. M. T. Farmer, S. Lomperski, and S. Basu,'The Results of the CCI-3 Reactor
Material Experiment Investigating 2-D Core-Concrete Interaction and Debris
Coolability,' Proceedings ICAPP '06, Reno, Nevada, June 6-8, 2006.

2. S. Basu, M. T. Farmer, and S. Lomperski,'Significance of the OECD-MCCI
Program in Relation to Severe Accident Uncertainties Evaluation,' CSNI Workshop
on Evaluation of Uncertainties in Relation to Severe Accidents and Level 2
Probabilistic Safety Analysis, Aix-en-Provence, France, 7-9 November, 2005.

3. M. T. Farmer, S. Lomperski, and S. Basu,'The Results of the CCI-2 Reactor
Material Experiment Investigating 2-D Core-Concrete Interaction and Debris
Coolability,' 11th International Topical Meeting on Nuclear Reactor
Thermal-Hydraulics (NURETH-11), Avignon, France, October 2-6, 2005.

4. M. T. Farmer, S. Lomperski, and S. Basu,'Status of the Melt Coolability and
Concrete Interaction (MCCI) Program at Argonne National Laboratory,'
Proceedings ICAPP '05, Seoul, Korea, May 15-19, 2005.

5. M. T. Farmer, S. Lomperski, and S. Basu,'Results of Reactor Material
Experiments Investigating 2-D Core-Concrete Interaction and Debris
Coolability,' Paper 4102, Proceedings ICAPP '04, Pittsburgh, PA USA, June 13-17,
2004.

MCCI-Program Technical Reports:

1. M. T. Farmer, S. Lomperski, D. J. Kilsdonk, and R. W. Aeschlimann,'OECD
MCCI Project Final Report,' OECD/MCCI-2005-TR06, February 28, 2006.

2. M. T. Farmer, S. Lomperski, D. J. Kilsdonk, and R. W. Aeschlimann,'OECD
MCCI Project 2-D Core Concrete Interaction (CCI) Tests: Final Report,'
OECD/MCCI-2005-TR05, February 28, 2006.

3. M. T. Farmer, S. Lomperski, D. J. Kilsdonk, R. W. Aeschlimann,'2-D Core
Concrete Interaction (CCI) Tests: CCI-3 Test Data Report-Thermalhydraulic
Results,' Rev. 0, OECD/MCCI-2005-TR04, October 15, 2005.

4. S. Lomperski, M. T. Farmer, D.J. Kilsdonk, and R. W. Aeschlimann,
'Small-Scale Water Ingression and Crust Strength Tests (SSWICS) SSWICS Final
Report: Thermal Hydraulic Results,' OECD/MCCI-2005-TR03, June 2005.

5. S. Lomperski, M. T. Farmer, D. J. Kilsdonk, and R. W. Aeschlimann,'Project
Small-Scale Water Ingression and Crust Strength Tests (SSWICS) SSWICS Final
Report: Crust Strength Measurements,' OECD/MCCI-2005-TR02, June 2005.

6. S. Lomperski, M. T. Farmer, D. J. Kilsdonk, and R. W. Aeschlimann,
'Small-Scale Water Ingression and Crust Strength Tests (SSWICS); SSWICS-7 Test
Data Report:  Thermalhydraulic Results,' Rev. 0, OECD/MCCI-2005-TR01, January
11, 2005.

7. M. T. Farmer, S. Lomperski, D. J. Kilsdonk, R. W. Aeschlimann, and S. Basu,
'2-D Core Concrete Interaction (CCI) Tests: CCI-2 Test Data
Report-Thermalhydraulic Results,' Rev. 0, OECD/MCCI-2004-TR05, October 15, 2004.

8. S. Lomperski, M. T. Farmer, D. J. Kilsdonk, and R. W. Aeschlimann,
'Small-Scale Water Ingression and Crust Strength Tests (SSWICS); SSWICS-6 Test
Data Report:  Thermalhydraulic Results,' Rev. 0, OECD/MCCI-2004-TR03, March 22,
2004.

9. M. T. Farmer, S. Lomperski, D. J. Kilsdonk, R. W. Aeschlimann, and S. Basu,
'2-D Core Concrete Interaction (CCI) Tests: CCI-1 Test Data
Report-Thermalhydraulic Results,' Rev. 0, OECD/MCCI-2004-TR01, January 31,
2004.

10. M. T. Farmer, D. J. Kilsdonk, S. Lomperski, R. W. Aeschlimann, and S. Basu,
'2-D Core Concrete Interaction (CCI) Tests: CCI-2 Test Plan,' Rev. 0,
OECD/MCCI-2004-TR02, January 31, 2004.

11. S. Lomperski, M. T. Farmer, D. J. Kilsdonk, and R. W. Aeschlimann,
'SSWICS-5 Test Data Report - Thermalhydraulic Results,' Rev. 0,
OECD/MCCI-2003-TR06, October 22, 2003.

12. M. T. Farmer, D. J. Kilsdonk, P. Pfeiffer, and S. Lomperski,'Crust Failure
Test Design Report,' Rev. 0, OECD/MCCI-2003-TR05, March 31, 2003.

13. S. Lomperski, M. T. Farmer, D. J. Kilsdonk, and R. W. Aeschlimann,
'Small-Scale Water Ingression and Crust Strength Tests (SSWICS); SSWICS-4 Test
Data Report:  Thermalhydraulic Results,' Rev. 0, OECD/MCCI-2003-TR04, March 21,
2003.

14. S. Lomperski, M. T. Farmer, D. J. Kilsdonk, and R. W. Aeschlimann,
'Small-Scale Water Ingression and Crust Strength Tests (SSWICS); SSWICS-3 Test
Data Report:  Thermalhydraulic Results,' Rev. 0, OECD/MCCI-2003-TR03, February
19, 2003.

15. S. Lomperski, M. T. Farmer, D. J. Kilsdonk, and R. W. Aeschlimann,
'Small-Scale Water Ingression and Crust Strength Tests (SSWICS); SSWICS-2 Final
Data Report,' Rev. 0, OECD/MCCI-2003-TR02, February 12, 2003.

16. S. Lomperski, M. T. Farmer, D. J. Kilsdonk, and R. W. Aeschlimann,
'Small-Scale Water Ingression and Crust Strength Tests (SSWICS); SSWICS-1 Final
Data Report,' Rev. 1, OECD/MCCI-2003-TR01, February 10, 2003.

17. M. T. Farmer, S. Lomperski, D. J. Kilsdonk, and R. W. Aeschlimann,
'Long-Term 2-D Molten Core Concrete Interaction Test Design Report,' Rev. 0,
OECD/MCCI-2002-TR05, September 30, 2002.

18. S. Lomperski, M. T. Farmer, D. J. Kilsdonk, and R. W. Aeschlimann,
'SSWICS-1 Test Data Report - Thermalhydraulic Results,' Rev. 0,
OECD/MCCI-2002-TR04, September 20, 2002.

19. S. Lomperski, M. T. Farmer, D. J. Kilsdonk, and R. W. Aeschlimann,
'SSWICS-2 Test Data Report - Thermalhydraulic Results,' Rev. 0,
OECD/MCCI-2002-TR06, September 20, 2002.

20. M. T. Farmer, S. Lomperski, D. J. Kilsdonk, and R. W. Aeschlimann,'Melt
Eruption Test (MET) Design Report,' Rev. 2, OECD/MCCI-2002-TR03, April 15, 2003.

21. M. T. Farmer, S. Lomperski, D. J. Kilsdonk, R. W. Aeschlimann, and P.
Pfeiffer, 'Small-Scale Water Ingression and Crust Strength Tests (SSWICS)
Design Report,' Rev. 2, OECD/MCCI-2002-TR01, October 31, 2002.

22. S. Lomperski,'Enhancing Instrumentation for Reactor Material Experiments,'
OECD/MCCI-2002-TR02, September 3, 2002.

NRC-Sponsored Technical Reports and Conference Proceedings:

1. M. T. Farmer,'Phenomenological Modeling of the Melt Eruption Cooling
Mechanism During Molten Core-Concrete Interaction,' Proc. ICAPP '06, Reno,
Nevada, June 6-8, 2006.

2. M. T. Farmer, J. J. Sienicki, and A. Kovtonyuk,'OECD MCCI Analytical
Support (Stand Alone Task): Water Ingression Modeling of the OECD/MCCI SSWICS
Tests,' NRC/MCCI/2003-TR01, October 15, 2003.

3. H. Ley,'MELCOR Parameter Studies for 2-D Molten Core Concrete Interaction
Experiments,' September 30, 2002.
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11. HARDWARE REQUIREMENTS

Any computer able to read Adobe Acrobat files and import text files of up to 5 MB.

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12. PROGRAMMING LANGUAGE(S) USED
No specified programming language
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13. SOFTWARE REQUIREMENTS

Must be able to import tab-delimited ASCII files (programs such as Microsoft Excel).

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15. NAME AND ESTABLISHMENT OF AUTHORS

S. Basu
Project Manager
U.S. Nuclear Regulatory Commission
MS-T10K8
11545 Rockville Pike, Rockville, MD 20852 U.S.A.

 

Mitchell T. Farmer
Manager, Engineering and Development Laboratory
Argonne National Laboratory
Argonne, IL 60439 USA

 

Stephen W. LOMPERSKI
Reactor Engineering Division
Argonne National Laboratory
Argonne, IL 60439 USA

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16. MATERIAL AVAILABLE
CSNI2003/01
Data files
Design reports, Data reports, and final reports (PDF)
7 small-scale water ingression and crust strength (SSWICS) tests
3 large-scale core/concrete interaction (CCI) tests
1 melt eruption (MET) test
Videos recorded by the lid camera looking down onto the melts during
the large scale tests CC1-1,-2,-3 and MET-1
Readme file
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17. CATEGORIES
  • Y. Integral Experiments Data, Databases, Benchmarks

Keywords: core concrete interactions, experiment, nuclear reactor safety, reactor materials, severe accidents.