Test and Calculation of the Emergency Condenser of the SWR 1000

The Siemens AG is developing the new innovative boiling water reactor
concept SWR1000. New features are the passive safety systems (e.g.
emergency condensers, building condensers, passive pressure pulse
transmitters, gravitydriven core flooding lines).

For the experimental investigation of the emergency condenser effectiveness,
the NOKO test facility has been constructed at the Forschungszentrum Jülich
in cooperation with Siemens. This test facility has an operating pressure of
10 MPa and a maximum power of 4 MW for steam production. The emergency
condenser bundle consists of eight tubes and is fabricated with planned
geometry and material of the SWR1000. In more than 200 experiments, the
emergency condenser capacity was tested as a function of pressure, water
level and concentration of noncondensables in the pressure vessel as well
of pressure, water level and temperature in the condenser.

Post test calculations of NOKO experiments were performed with an improved
version of ATHLET. To calculate the heat transfer coefficients during
condensation in horizontal tubes the module KONWAR has been developed
and implemented in ATHLET. KONWAR is based on the flow regime map of
Tandon and includes several semiempirical correlations for the determination
of the heat transfer coefficients. The comparison between calculations and
experiments shows a good agreement.