Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Modelling of pool stratification and mixing induced by steam injectionthrough blowdown pipes
KTH, School of Engineering Sciences (SCI), Physics, Nuclear Power Safety.
KTH, School of Engineering Sciences (SCI), Physics, Nuclear Power Safety.
KTH, School of Engineering Sciences (SCI), Physics, Nuclear Power Safety.
2018 (English)In: Annals of Nuclear Energy, ISSN 0306-4549, E-ISSN 1873-2100, Vol. 112, p. 624-639Article in journal (Refereed) Published
Abstract [en]

Containment overpressure is prevented in a Boiling Water Reactor (BWR) by condensing steam into thepressure suppression pool. Steam condensation is a source of heat and momentum. Competition betweenthese sources results in thermal stratification or mixing of the pool. The interplay between the sources isdetermined by the condensation regime, steam mass flow rate and pool dimensions. Thermal stratificationis a safety issue since it limits the condensing capacity of the pool and leads to higher containmentpressures in comparison to a completely mixed pool with the same average temperature. The EffectiveHeat Source (EHS) and Effective Momentum Source (EMS) models were previously developed for predictingthe macroscopic effect of steam injection and direct contact condensation phenomena on the developmentof stratification and mixing in the pool. The models provide the effective heat and momentumsources, depending on the condensation regimes. In this work we present further development of theEHS/EMS models and their implementation in the GOTHIC code for the analysis of steam injection intocontainment drywell and venting into the wetwell through the blowdown pipes. Based on thePPOOLEX experiments performed in Lappeenranta University of Technology (LUT), correlations arederived to estimate the steam condensation regime and effective heat and momentum sources as functionsof the pool and steam injection conditions. The focus is on the low steam mass flux regimes withcomplete condensation inside the blowdown pipe or chugging. Validation of the developed methodswas carried out against the PPOOLEX MIX-04 and MIX-06 tests, which showed a very good agreementbetween experimental and simulation data on the pool temperature distribution and containmentpressure.

Place, publisher, year, edition, pages
Elsevier, 2018. Vol. 112, p. 624-639
Keywords [en]
thermal stratification, GOTHIC, chugging, frequency and amplitude, time average, effective momentum source
National Category
Energy Engineering
Research subject
Energy Technology
Identifiers
URN: urn:nbn:se:kth:diva-217309DOI: 10.1016/j.anucene.2017.10.019ISI: 000419409100053Scopus ID: 2-s2.0-85032947808OAI: oai:DiVA.org:kth-217309DiVA, id: diva2:1155323
Note

QC 20171108

Available from: 2017-11-07 Created: 2017-11-07 Last updated: 2018-11-09Bibliographically approved
In thesis
1. Steam condensation in a water pool and its effect on thermal stratification and mixing
Open this publication in new window or tab >>Steam condensation in a water pool and its effect on thermal stratification and mixing
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The Pressure Suppression Pool (PSP) of a Boiling Water Reactor (BWR) is a large heat sink designed to limit the containment pressure by condensing steam released from the primary coolant system. The development of thermal stratification is a safety concern since it leads to higher containment pressures than in completely mixed conditions, and can affect the performance of systems such as the emergency core cooling and containment spray, which the use PSP as a source of water.The goal of this thesis is to develop and validate models for the prediction of the PSP behavior during a steam injection in a Nordic BWR. The framework of the Effective Heat Source and Effective Momentum Source (EHS/EMS) models is used to provide the integral heat and momentum sources induced by the steam condensation. The EHS/EMS can be implemented in a containment thermal-hydraulic or a CFD code, where the pool is modelled with a single-phase liquid solver.EHS/EMS models are developed for the low steam mass flux regimes appearing in (i) large diameter blowdown pipes connecting the drywell to the wetwell pool; and (ii) multi-hole sparger pipes connecting the primary system to the pool.Empirical correlations are developed to predict the effective momentum induced by chugging in the blowdown pipes. The correlations are implemented in GOTHIC, where a containment model is proposed to enable capturing the feedback between pool conditions and drywell pressure. Validation is performed against the PPOOLEX experiments.Conceptual designs are proposed for a set of large-scale pool experiments with spargers in the PPOOLEX and PANDA facilities. Correlations are proposed for the erosion velocity of a cold layer, and ranges are estimated for the angle, profile and turbulence of the momentum sources created by steam injection. CFD simulations of the experiments is done to calibrate the momentum sources in the oscillatory bubble regimes. A concept of the Separate Effect Facility (SEF) is proposed to provide a measurements of the effective momentum. Empirical correlations for the bubble radius, velocity, heat transfer coefficient, etc. are also developed and compared to available data from the literature.Application of the developed CFD and EHS/EMS models to full-scale containment behavior shows that thermal stratification can occur during prototypic steam injection conditions. Recommendations are given on how to avoid this.

Place, publisher, year, edition, pages
Sweden: KTH Royal Institute of Technology, 2018. p. 69
Series
TRITA-SCI-FOU ; 2018:48
Keywords
Steam injection, EHS/EMS, blowdown pipes, spargers, chugging, oscillatory bubble, CFD, condensation pool, stratification, mixing
National Category
Energy Engineering
Research subject
Engineering Mechanics
Identifiers
urn:nbn:se:kth:diva-238732 (URN)978-91-7873-028-5 (ISBN)
Public defence
2018-12-07, FB54, AlbaNova University Centre, Rogslagstullbacken 21, 114 21 Stockholm, 14:00 (English)
Opponent
Supervisors
Funder
Swedish Radiation Safety Authority
Note

QC 20181109

Available from: 2018-11-09 Created: 2018-11-09 Last updated: 2018-11-12Bibliographically approved

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full textScopus

Search in DiVA

By author/editor
Gallego Marcos, IgnacioVillanueva, WalterKudinov, Pavel
By organisation
Nuclear Power Safety
In the same journal
Annals of Nuclear Energy
Energy Engineering

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 159 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf