MARVIKEN-CFT, Marviken Full Scale Critical Flow Tests

1 - Description of test facility: The major components of the facility are: - The pressure vessel with a net volume = 425 m3, a maximum design pressure = 5.75 MPa and a maximum design temperature = 545 K. - The discharge pipe attached to the pressure vessel bottom. The discharge pipe consists of a ball valve and pipe spools which house the instrumentation upstream of the test nozzle. - The test nozzles and rupture disc assemblies. A set of test nozzles of specified lengths and diameters (tubular section lengths from 0.166 to 1.809 m and tubular section diameters from 0.2 to 0.509 m) were used to which the rupture disc assemblies were attached. - The containment and exhaust pipes, consisting of the drywell, the wet-well, fuel element transport hall, the ground level exhaust pipe, and the upper exhaust pipe. 2 - Description of the tests: Before each test the vessel was filled with degassed water up to a certain level which varied between the tests (from about 16.5 to 20 m above vessel bottom). The pressure was around 5 MPa (one test around 4 MPa). A pre-test warm-up period produced a temperature profile along the vessel height. After a stabilizing period of several hours, the test was initiated by failing the discs contained in the rupture disc assembly. Measurements recorded in the vessel, the discharge pipe, and the test nozzle, provided the data, while the vessel fluid was discharged through the test nozzle into the containment and further through the exhaust pipes to the ambient atmosphere. The test was terminated when the ball valve begun to close or when pure steam was entered the discharge pipe. 3 - Experimental limitations or shortcomings: Initial maximum pressure was limited to about 5 MPa