Experimental and computational studies of the coolability of heap-like and cylindrical debris beds

Eveliina Takasuo, Stefan Holmström, Tuomo Kinnunen, Pekka H. Pankakoski, Ville Hovi, Mikko Ilvonen, Saidur Rahman, Manfred Bürger, Michael Buck, Georg Pohlner

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

Abstract

The COOLOCE (Coolability of Cone) test facility has been used at VTT for experimental investigations of the coolability of porous debris beds with different geometries. The main objective of the experiments was to compare the coolability of a heap-like (conical) debris bed configuration to that of a cylindrical, top-flooded debris bed. Few previous debris coolability studies have investigated the effect of the possible ex-vessel debris bed geometries, and the experiments aimed to provide new data on this topic. In a heap-like configuration, lateral flooding through the surface of the heap (or cone) is expected to increase dryout power while the height of the configuration can reduce it, and thus decrease coolability. The experimental results suggest that the coolability of the conical debris bed is poorer than that of the cylindrical bed assuming that the formation of the first dry zone is taken as the coolability limit. Computational analysis of the experiments and prediction of dryout power has been performed using the MEWA 2D code (developed at IKE, University of Stuttgart) to verify its applicability in 2D situations. This is of high importance concerning reactor scale assessment. In addition, 3D scoping simulations of the particle bed dryout process have been done by using the two-phase flow solver PORFLO developed at VTT. The COOLOCE experiments are performed considering a fully quenched water filled bed. However, when a debris bed is formed, particles will initially be hot and dry. Therefore, it is also very important to consider quenching of an initially hot and dry particle bed because quenching versus heat-up by decay heat determines the coolability in the initial stages of reactor scenarios. In this respect, an application of the MEWA code to reactor conditions by considering an initially hot and dry conical bed formed by settling of particles from breakup of melt jets flowing into a water-filled cavity is presented. It has been observed that quenching during bed formation indicates substantial coolability margins compared to quenching of an already established dry debris bed which was considered in a previous study
Original languageEnglish
Title of host publicationERMSAR 2012 Papers (CD)
Publication statusPublished - 2012
MoE publication typeNot Eligible
Event5th European Review Meeting on Severe Accident Research, ERMSAR 2012 - Cologne, Germany
Duration: 21 Mar 201223 Mar 2012

Conference

Conference5th European Review Meeting on Severe Accident Research, ERMSAR 2012
Abbreviated titleERMSAR 2012
CountryGermany
CityCologne
Period21/03/1223/03/12

Fingerprint

experiment
geometry
two phase flow
cavity
vessel
flooding
melt
water
particle
prediction
simulation
reactor
code
test
effect
analysis

Keywords

  • Severe accident
  • debris coolability
  • conical debris bed
  • dryout experiments
  • COOLOCE facility
  • quenching simulation

Cite this

Takasuo, E., Holmström, S., Kinnunen, T., Pankakoski, P. H., Hovi, V., Ilvonen, M., ... Pohlner, G. (2012). Experimental and computational studies of the coolability of heap-like and cylindrical debris beds. In ERMSAR 2012 Papers (CD)
Takasuo, Eveliina ; Holmström, Stefan ; Kinnunen, Tuomo ; Pankakoski, Pekka H. ; Hovi, Ville ; Ilvonen, Mikko ; Rahman, Saidur ; Bürger, Manfred ; Buck, Michael ; Pohlner, Georg. / Experimental and computational studies of the coolability of heap-like and cylindrical debris beds. ERMSAR 2012 Papers (CD). 2012.
@inproceedings{098cbf985f7548ab84e03a2d91f6bbb9,
title = "Experimental and computational studies of the coolability of heap-like and cylindrical debris beds",
abstract = "The COOLOCE (Coolability of Cone) test facility has been used at VTT for experimental investigations of the coolability of porous debris beds with different geometries. The main objective of the experiments was to compare the coolability of a heap-like (conical) debris bed configuration to that of a cylindrical, top-flooded debris bed. Few previous debris coolability studies have investigated the effect of the possible ex-vessel debris bed geometries, and the experiments aimed to provide new data on this topic. In a heap-like configuration, lateral flooding through the surface of the heap (or cone) is expected to increase dryout power while the height of the configuration can reduce it, and thus decrease coolability. The experimental results suggest that the coolability of the conical debris bed is poorer than that of the cylindrical bed assuming that the formation of the first dry zone is taken as the coolability limit. Computational analysis of the experiments and prediction of dryout power has been performed using the MEWA 2D code (developed at IKE, University of Stuttgart) to verify its applicability in 2D situations. This is of high importance concerning reactor scale assessment. In addition, 3D scoping simulations of the particle bed dryout process have been done by using the two-phase flow solver PORFLO developed at VTT. The COOLOCE experiments are performed considering a fully quenched water filled bed. However, when a debris bed is formed, particles will initially be hot and dry. Therefore, it is also very important to consider quenching of an initially hot and dry particle bed because quenching versus heat-up by decay heat determines the coolability in the initial stages of reactor scenarios. In this respect, an application of the MEWA code to reactor conditions by considering an initially hot and dry conical bed formed by settling of particles from breakup of melt jets flowing into a water-filled cavity is presented. It has been observed that quenching during bed formation indicates substantial coolability margins compared to quenching of an already established dry debris bed which was considered in a previous study",
keywords = "Severe accident, debris coolability, conical debris bed, dryout experiments, COOLOCE facility, quenching simulation",
author = "Eveliina Takasuo and Stefan Holmstr{\"o}m and Tuomo Kinnunen and Pankakoski, {Pekka H.} and Ville Hovi and Mikko Ilvonen and Saidur Rahman and Manfred B{\"u}rger and Michael Buck and Georg Pohlner",
note = "Project code: 35094-1.2",
year = "2012",
language = "English",
booktitle = "ERMSAR 2012 Papers (CD)",

}

Takasuo, E, Holmström, S, Kinnunen, T, Pankakoski, PH, Hovi, V, Ilvonen, M, Rahman, S, Bürger, M, Buck, M & Pohlner, G 2012, Experimental and computational studies of the coolability of heap-like and cylindrical debris beds. in ERMSAR 2012 Papers (CD). 5th European Review Meeting on Severe Accident Research, ERMSAR 2012, Cologne, Germany, 21/03/12.

Experimental and computational studies of the coolability of heap-like and cylindrical debris beds. / Takasuo, Eveliina; Holmström, Stefan; Kinnunen, Tuomo; Pankakoski, Pekka H.; Hovi, Ville; Ilvonen, Mikko; Rahman, Saidur; Bürger, Manfred; Buck, Michael; Pohlner, Georg.

ERMSAR 2012 Papers (CD). 2012.

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

TY - GEN

T1 - Experimental and computational studies of the coolability of heap-like and cylindrical debris beds

AU - Takasuo, Eveliina

AU - Holmström, Stefan

AU - Kinnunen, Tuomo

AU - Pankakoski, Pekka H.

AU - Hovi, Ville

AU - Ilvonen, Mikko

AU - Rahman, Saidur

AU - Bürger, Manfred

AU - Buck, Michael

AU - Pohlner, Georg

N1 - Project code: 35094-1.2

PY - 2012

Y1 - 2012

N2 - The COOLOCE (Coolability of Cone) test facility has been used at VTT for experimental investigations of the coolability of porous debris beds with different geometries. The main objective of the experiments was to compare the coolability of a heap-like (conical) debris bed configuration to that of a cylindrical, top-flooded debris bed. Few previous debris coolability studies have investigated the effect of the possible ex-vessel debris bed geometries, and the experiments aimed to provide new data on this topic. In a heap-like configuration, lateral flooding through the surface of the heap (or cone) is expected to increase dryout power while the height of the configuration can reduce it, and thus decrease coolability. The experimental results suggest that the coolability of the conical debris bed is poorer than that of the cylindrical bed assuming that the formation of the first dry zone is taken as the coolability limit. Computational analysis of the experiments and prediction of dryout power has been performed using the MEWA 2D code (developed at IKE, University of Stuttgart) to verify its applicability in 2D situations. This is of high importance concerning reactor scale assessment. In addition, 3D scoping simulations of the particle bed dryout process have been done by using the two-phase flow solver PORFLO developed at VTT. The COOLOCE experiments are performed considering a fully quenched water filled bed. However, when a debris bed is formed, particles will initially be hot and dry. Therefore, it is also very important to consider quenching of an initially hot and dry particle bed because quenching versus heat-up by decay heat determines the coolability in the initial stages of reactor scenarios. In this respect, an application of the MEWA code to reactor conditions by considering an initially hot and dry conical bed formed by settling of particles from breakup of melt jets flowing into a water-filled cavity is presented. It has been observed that quenching during bed formation indicates substantial coolability margins compared to quenching of an already established dry debris bed which was considered in a previous study

AB - The COOLOCE (Coolability of Cone) test facility has been used at VTT for experimental investigations of the coolability of porous debris beds with different geometries. The main objective of the experiments was to compare the coolability of a heap-like (conical) debris bed configuration to that of a cylindrical, top-flooded debris bed. Few previous debris coolability studies have investigated the effect of the possible ex-vessel debris bed geometries, and the experiments aimed to provide new data on this topic. In a heap-like configuration, lateral flooding through the surface of the heap (or cone) is expected to increase dryout power while the height of the configuration can reduce it, and thus decrease coolability. The experimental results suggest that the coolability of the conical debris bed is poorer than that of the cylindrical bed assuming that the formation of the first dry zone is taken as the coolability limit. Computational analysis of the experiments and prediction of dryout power has been performed using the MEWA 2D code (developed at IKE, University of Stuttgart) to verify its applicability in 2D situations. This is of high importance concerning reactor scale assessment. In addition, 3D scoping simulations of the particle bed dryout process have been done by using the two-phase flow solver PORFLO developed at VTT. The COOLOCE experiments are performed considering a fully quenched water filled bed. However, when a debris bed is formed, particles will initially be hot and dry. Therefore, it is also very important to consider quenching of an initially hot and dry particle bed because quenching versus heat-up by decay heat determines the coolability in the initial stages of reactor scenarios. In this respect, an application of the MEWA code to reactor conditions by considering an initially hot and dry conical bed formed by settling of particles from breakup of melt jets flowing into a water-filled cavity is presented. It has been observed that quenching during bed formation indicates substantial coolability margins compared to quenching of an already established dry debris bed which was considered in a previous study

KW - Severe accident

KW - debris coolability

KW - conical debris bed

KW - dryout experiments

KW - COOLOCE facility

KW - quenching simulation

M3 - Conference article in proceedings

BT - ERMSAR 2012 Papers (CD)

ER -