Testing of the KERENA Containment Cooling Condenser, a passive low pressure cooling system

摘要

KERENA is an innovative boiling water reactor concept with passive safety systems (Generation Ⅲ+) of AREVA. The reactor is an evolutionary design of operating BWRs (Generation Ⅱ). In order to verify the functionality and performance of the KERENA safety concept required for the transient and accident management, the test facility "Integral Teststand Karlstein" (INKA) was built at the Components Qualification Department of AREVA GmbH at Karlstein (Germany). It is a mock-up of the KERENA boiling water reactor containment, with integrated pressure suppression system. The complete chain of passive safety components is available. The passive components - the Emergency Condenser, the Containment Cooling Condenser, the Passive Core Flooding System and the Passive Pressure Pulse Transmitter as well as the levels are represented in full scale. The volume scaling of the containment compartments is approximately 1:24. The reactor pressure vessel (RPV) is simulated via the steam accumulator of the Karlstein Large Valve Test Facility. This vessel provides an energy storage capacity of approximately 1/6 of the KERENA RPV and is supplied by a Benson boiler with a thermal power of 22 MW. With respect to the available power supply, the containment-and system-sizing of the facility is one of the largest ones worldwide. The Emergency Condenser system transfers heat from the reactor pressure vessel to the core flooding pools of the containment. The heat introduced into the containment (e. g. during accidents) will be transferred to the main heat sink (Shielding/Storage Pool) via the passive Containment Cooling Condensers. Therefore both systems are part of the passive cooling chain connecting the heat source RPV (Reactor Pressure Vessel) with the heat sink. At the INKA test facility both condensers are tested in order to determine the heat transfer capacity as Junction of the main input parameters. For the EC these are the RPV pressure and water level, the containment pressure and the water temperature of the flooding pools. For the Containment Cooling Condenser the heat transfer capacity is a function of the containment pressure, the water temperature of the Shielding/Storage Pool and the fraction of non-condensable gases in the containment. The containment cooling condenser was initially tested in full scale and the results were already presented at the ICAPP 2010. Further improvements have been made to this low pressure passive cooling system based on the first test results. The component was first tested individually and later in a so-called large scale integral test, simulating a LOCA, as part of the passive cooling chain.