Experimental investigation and flow visualization of steam condensation in a scaled IRWST-ADS simulator

Suleiman Al Issa, Rafael Macian-Juan, Gonzalo Jimenez, Cesar Queral, Javier Montero-Mayorga

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations

Abstract

The use of suppression pools to limit the pressure increase in nuclear power plant containments has been a common strategy since the development of the first BWR designs more than 50 years ago. In the new Generation III+ PWR reactors design, suppression pools design has been also incorporated; AP1000 (Westinghouse), EPR (AREVA) and APR1400 (KEPCO). In particular, in an AP1000 design the steam is directly released to the suppression pool from the pressurizer in case of an Automatic Depressurization System (ADS) actuation. The thermal-hydraulic behavior of the pool is quite complex under accidental conditions: the pool receives steam at high velocity and temperature from the reactor cooling system (RCS), the pool is the heat sink of the Passive Residual Heat Removal (PRHR), and eventually, it is the source for the low pressure safety injection. In order to study the behavior of the AP1000 IRWST during a steam discharge from the ADS at different stages of a SBLOCA, an experimental test rig was constructed in cooperation with the Technical University of Munich (TUM) within the frame of the Spanish Ministry of Economy and Competiveness research project (Integrated Safety Assessment methodology applied to advanced reactors (ISAMAR)). The experimental test rig consists of a transparent 2.5m vertical channel with a rectangular 15×15 cm cross-section with steam injected vertically from a single injection nozzle near the bottom of the channel. The temperature was monitored at the center of the channel and at different axial locations. Special image-processing programs were implemented to generate 2D time-averaged void fraction distributions at different stages of the experiment. Experiments were performed starting from room temperature until reaching saturation at the top of the channel. The results show that a full condensation occurs as T < 101.1 ± 1.9°C near the injection. Exceeding this limit, steam bubbles starts to reach the top of the channel, and eventually a local flashing occurred at the last 40 cm of the channel. This implies that a special care should be taken to prevent a large-scale flashing event at the IRWST. The resulting 2D void distributions provide a valuable source for a planned CFD validation.

Original languageEnglish
Title of host publicationInternational Topical Meeting on Nuclear Reactor Thermal Hydraulics 2015, NURETH 2015
PublisherAmerican Nuclear Society
Pages8561-8574
Number of pages14
ISBN (Electronic)9781510811843
StatePublished - 2015
Event16th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2015 - Chicago, United States
Duration: 30 Aug 20154 Sep 2015

Publication series

NameInternational Topical Meeting on Nuclear Reactor Thermal Hydraulics 2015, NURETH 2015
Volume10

Conference

Conference16th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2015
Country/TerritoryUnited States
CityChicago
Period30/08/154/09/15

Keywords

  • ADS
  • AP1000
  • Flow visualization
  • IRWST
  • SBLOCA
  • Two-phase flows

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