Operation conditions of the emergency condenser of the SWR 1000

Siemens AG is developing the innovative boiling water reactor concept SWR10 00. New features are the passive safety systems (e.g. emergency condenser, building condenser, passive pressure pulse transmitter). For the experiment al investigation of the emergency condenser effectiveness, the NOKO test fa cility has been constructed at the Forschungszentrum Julich. The facility h as an operating pressure of 10 MPa and a maximum power of 4 MW. The emergen cy condenser test bundle consists of eight tubes and is fabricated with pla nned geometry and material of the SWR1000. In more than 200 experiments, th e emergency condenser capacity was determined as a function of pressure, wa ter level and concentration of non-condensables in the pressure vessel, as well as of pressure, water level and temperature in the condenser. For the evaluation of the NOKO experiments, the program system CASH-Graphics (Compu tergestutzte Auswertung und Unsicherheitsanalyse) was developed. This evalu ation is the basis for the determination of the operation conditions of the emergency condenser. Post-test calculations of NOKO experiments were perfo rmed with an improved version of ATHLET. To calculate the heat transfer coe fficients during condensation in horizontal tubes, the module KONWAR has be en developed and implemented in ATHLET. KONWAR is based on the flow regime map of Tandon and includes several semi-empirical correlations for the dete rmination of the heat transfer coefficients. The comparison between calcula tions and experiments shows a good agreement. (C) 1999 Elsevier Science S.A . All rights reserved.