Towards an European consensus on possible causes of MCCI ablation anisotropy in an oxidic pool

M Cranga, C Spengler (Corresponding Author), K Atkhen, A Fargette, M Fischer, J Foit, R Gencheva, E Guyez, J F Haquet, C Journeau, B Michel, C Mun, P Piluso, Tuomo Sevon, B Spindler

Research output: Contribution to journalArticleScientificpeer-review

14 Citations (Scopus)

Abstract

One of the most disputed issues raised by molten corium concrete interaction (MCCI) is how the 2D cavity ablation in an oxidic pool evolves: why is the ablation anisotropic with siliceous concretes and isotropic with carbonaceous concretes. The work performed in the frame of the SARNET2 WP6 group during the last 4. years has enabled significant progress on this topic. This paper summarizes this progress using the analysis of recent 2D real material experiments in an oxidic pool and from analytical simulant experiments on 2D heat convection in a bubbling pool, including calculations and recalculations with MCCI codes available in Europe.Firstly, the effective heat transfer coefficients from the bulk pool to the bottom and lateral pool interfaces deduced from MCCI experiments lead to a range of a few 100W/m2/K. By contrast, a detailed review of possible 2D convection mechanisms shows that the individual heat convection mechanisms (without taking a crust into account) such as gas bubbling convection and solutal convection overestimates the overall heat transfer coefficient, and does not account for the main trends of 2D ablation deduced from MCCI tests, which are very dependent on the composition of concrete components and aggregates. This fact, in turn, points to the effect of more complex pool/concrete interface structures. On the basis of a thorough interpretation of the experimental database and of a detailed comparison of MCCI code predictions, a set of the most realistic and consistent assumptions are identified and major remaining uncertainties are listed.
Original languageEnglish
Pages (from-to)72-88
Number of pages16
JournalAnnals of Nuclear Energy
Volume74
DOIs
Publication statusPublished - 2014
MoE publication typeA1 Journal article-refereed

Fingerprint

Ablation
Molten materials
Anisotropy
Concretes
Heat convection
Heat transfer coefficients
Experiments
Chemical analysis
Gases

Keywords

  • molten corium concrete interaction
  • ablation
  • nuclear accidents
  • nuclear energy
  • severe accidents

Cite this

Cranga, M., Spengler, C., Atkhen, K., Fargette, A., Fischer, M., Foit, J., ... Spindler, B. (2014). Towards an European consensus on possible causes of MCCI ablation anisotropy in an oxidic pool. Annals of Nuclear Energy, 74, 72-88. https://doi.org/10.1016/j.anucene.2014.07.017
Cranga, M ; Spengler, C ; Atkhen, K ; Fargette, A ; Fischer, M ; Foit, J ; Gencheva, R ; Guyez, E ; Haquet, J F ; Journeau, C ; Michel, B ; Mun, C ; Piluso, P ; Sevon, Tuomo ; Spindler, B. / Towards an European consensus on possible causes of MCCI ablation anisotropy in an oxidic pool. In: Annals of Nuclear Energy. 2014 ; Vol. 74. pp. 72-88.
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abstract = "One of the most disputed issues raised by molten corium concrete interaction (MCCI) is how the 2D cavity ablation in an oxidic pool evolves: why is the ablation anisotropic with siliceous concretes and isotropic with carbonaceous concretes. The work performed in the frame of the SARNET2 WP6 group during the last 4. years has enabled significant progress on this topic. This paper summarizes this progress using the analysis of recent 2D real material experiments in an oxidic pool and from analytical simulant experiments on 2D heat convection in a bubbling pool, including calculations and recalculations with MCCI codes available in Europe.Firstly, the effective heat transfer coefficients from the bulk pool to the bottom and lateral pool interfaces deduced from MCCI experiments lead to a range of a few 100W/m2/K. By contrast, a detailed review of possible 2D convection mechanisms shows that the individual heat convection mechanisms (without taking a crust into account) such as gas bubbling convection and solutal convection overestimates the overall heat transfer coefficient, and does not account for the main trends of 2D ablation deduced from MCCI tests, which are very dependent on the composition of concrete components and aggregates. This fact, in turn, points to the effect of more complex pool/concrete interface structures. On the basis of a thorough interpretation of the experimental database and of a detailed comparison of MCCI code predictions, a set of the most realistic and consistent assumptions are identified and major remaining uncertainties are listed.",
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Cranga, M, Spengler, C, Atkhen, K, Fargette, A, Fischer, M, Foit, J, Gencheva, R, Guyez, E, Haquet, JF, Journeau, C, Michel, B, Mun, C, Piluso, P, Sevon, T & Spindler, B 2014, 'Towards an European consensus on possible causes of MCCI ablation anisotropy in an oxidic pool', Annals of Nuclear Energy, vol. 74, pp. 72-88. https://doi.org/10.1016/j.anucene.2014.07.017

Towards an European consensus on possible causes of MCCI ablation anisotropy in an oxidic pool. / Cranga, M; Spengler, C (Corresponding Author); Atkhen, K; Fargette, A; Fischer, M; Foit, J; Gencheva, R; Guyez, E; Haquet, J F; Journeau, C; Michel, B; Mun, C; Piluso, P; Sevon, Tuomo; Spindler, B.

In: Annals of Nuclear Energy, Vol. 74, 2014, p. 72-88.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Towards an European consensus on possible causes of MCCI ablation anisotropy in an oxidic pool

AU - Cranga, M

AU - Spengler, C

AU - Atkhen, K

AU - Fargette, A

AU - Fischer, M

AU - Foit, J

AU - Gencheva, R

AU - Guyez, E

AU - Haquet, J F

AU - Journeau, C

AU - Michel, B

AU - Mun, C

AU - Piluso, P

AU - Sevon, Tuomo

AU - Spindler, B

PY - 2014

Y1 - 2014

N2 - One of the most disputed issues raised by molten corium concrete interaction (MCCI) is how the 2D cavity ablation in an oxidic pool evolves: why is the ablation anisotropic with siliceous concretes and isotropic with carbonaceous concretes. The work performed in the frame of the SARNET2 WP6 group during the last 4. years has enabled significant progress on this topic. This paper summarizes this progress using the analysis of recent 2D real material experiments in an oxidic pool and from analytical simulant experiments on 2D heat convection in a bubbling pool, including calculations and recalculations with MCCI codes available in Europe.Firstly, the effective heat transfer coefficients from the bulk pool to the bottom and lateral pool interfaces deduced from MCCI experiments lead to a range of a few 100W/m2/K. By contrast, a detailed review of possible 2D convection mechanisms shows that the individual heat convection mechanisms (without taking a crust into account) such as gas bubbling convection and solutal convection overestimates the overall heat transfer coefficient, and does not account for the main trends of 2D ablation deduced from MCCI tests, which are very dependent on the composition of concrete components and aggregates. This fact, in turn, points to the effect of more complex pool/concrete interface structures. On the basis of a thorough interpretation of the experimental database and of a detailed comparison of MCCI code predictions, a set of the most realistic and consistent assumptions are identified and major remaining uncertainties are listed.

AB - One of the most disputed issues raised by molten corium concrete interaction (MCCI) is how the 2D cavity ablation in an oxidic pool evolves: why is the ablation anisotropic with siliceous concretes and isotropic with carbonaceous concretes. The work performed in the frame of the SARNET2 WP6 group during the last 4. years has enabled significant progress on this topic. This paper summarizes this progress using the analysis of recent 2D real material experiments in an oxidic pool and from analytical simulant experiments on 2D heat convection in a bubbling pool, including calculations and recalculations with MCCI codes available in Europe.Firstly, the effective heat transfer coefficients from the bulk pool to the bottom and lateral pool interfaces deduced from MCCI experiments lead to a range of a few 100W/m2/K. By contrast, a detailed review of possible 2D convection mechanisms shows that the individual heat convection mechanisms (without taking a crust into account) such as gas bubbling convection and solutal convection overestimates the overall heat transfer coefficient, and does not account for the main trends of 2D ablation deduced from MCCI tests, which are very dependent on the composition of concrete components and aggregates. This fact, in turn, points to the effect of more complex pool/concrete interface structures. On the basis of a thorough interpretation of the experimental database and of a detailed comparison of MCCI code predictions, a set of the most realistic and consistent assumptions are identified and major remaining uncertainties are listed.

KW - molten corium concrete interaction

KW - ablation

KW - nuclear accidents

KW - nuclear energy

KW - severe accidents

U2 - 10.1016/j.anucene.2014.07.017

DO - 10.1016/j.anucene.2014.07.017

M3 - Article

VL - 74

SP - 72

EP - 88

JO - Annals of Nuclear Energy

JF - Annals of Nuclear Energy

SN - 0306-4549

ER -