SGTR and SGTL

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SGTR and SGTL
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Overview

• Background to SGTR and SGTL
• Present status of cooperation on SGTL between KTH
  and JRC
• SGTR experiments to be executed at FZK on behalf
  of JRC
• Conclusions

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Pool design and SGTR, SGTL
15..25 MPa, 330..500 oC
Steam Generator Tube Rupture (SGTR) SGTR at PWR
103104 liter/hour Steam Generator Tube
Leakage (SGTL) SGTL Rate 10 - 103
liter/day Leakage less than 1 liter/day
allowed in normal operation of PWR
SGTR SGTL
0.3 MPa, 400..500 oC
From P. Kudinov
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Liquid fraction
liquid water
Water injection (at 30 MPa, 335 oC) into lead
at 0.8 MPa

• Beznosov et al (2005)

a steamwater mixture, and 100350C, 125 MPa
steam were bubbled through 0.62 mm in diameter
openings (tube 14x2 mm), under a layer of lead
ranging in thickness from 100 to 3000 mm, at
temperatures 350600C
Limited expansion.
No explosion reported.
From P. Kudinov
A.V. Beznosov, Experimental Studies of the
Characteristics of Conatct Heat Exchange between
lead Coolant and the Working Body, Atomic
Energy, 98(3), 2005
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Size distributions of water/steam droplets
Beznosov et al, 2005
From P. Kudinov
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Life time of small droplet
From P. Kudinov
Time scale is 10s of seconds for droplets 1mm
in diameter
Guido Bleiker and Eckehard Specht Film
evaporation of drops of different shape above a
horizontal plate International Journal of Thermal
Sciences, Volume 46, Issue 9, September 2007,
Pages 835-841
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Vapor bubbles formation

• Evaporation of water droplet in a bubble will
  lead to growth of bubble diameter.
• Big bubbles most likely will not be stable due to
  high We number and high turbulence level.
• As a result we will have larger number of middle
  size bubbles up to 10 mm in diameter.

From P. Kudinov
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Vapor bubbles formation and transport phenomena
Terminal speed of rising bubbles with dmax10mm
is 0.2-0.3 m/s Importance of resolution of 3D
structure of the coolant flow for reliable
prediction of void flux into the core
Mendelson
Lehrer
From P. Kudinov
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Stream lines and flow field
Stream lines during normal operation
Flow field during normal operation
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Following calculation step

• Small leakage is assumed in this study.
• Next step will be to introduce individual steam
  bubbles at different locations in the HX. These
  bubbles will be followed along their
  trajectories.
• Different sizes of bubbles will be studied.
• The probability that bubbles reach the core will
  be estimated.

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SGTR experiment
The bunker (at FZK funded by JRC) where the
experiment be performed
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Experimental facility
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Experiments to be performed

1. Steam of 200 bar pressure released into water
   simulating break of 8 pipes will be performed
   during summer of 2008
2. Injection of 3 liters of superheated steam (25
   bar, 160?C) into Pb of 340?C.
3. Injection of 3 liters supercritical steam (240
   bar, 400?C into Pb of 480?C. Simulating break of
   8 pipes of the EFIT or ELSY design.

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Summary

• Cooperation between KTH and JRC concerning
  studies on small leakages. Results from this
  study expect this autumn.
• SGTR experiments will be performed at FZK. The
  first one will be performed this summer.