Testing of the AP600 automatic depressurization system

The Automatic Depressurization System (ADS) of the Westinghouse AP600 reactor will be used to provide controlled depressurization of the reactor coolant system (RCS). This will, in turn allow the initiation and long term operation of gravity driven cooling flow in the RCS. ADS tests were conducted at the VAPORE test facility in Casaccia, Italy through a Technical Cooperation Agreement between Westinghouse, ENEA, SOPREN/ANSALDO, and ENEL to produce data for the development and verification of computer codes to simulate the system. The test program also provided insights about the operation of valves supplied from various vendors that could be used in the AP600 ADS. The data gathered from the tests showed the ability of the ADS design to fulfill its function over the range of conditions expected in the AP600. The tests also demonstrated the abilities of gate and globe valves from several vendors to initiate and terminate an ADS blowdown as could be required in the AP600.