Containment pressure and leak-tightness tests completed successfully at Olkiluoto 3
The containment pressure and leak-tightness tests, which took about two weeks, have been completed at the Olkiluoto 3 nuclear power plant unit. – The tests went well. We are pleased with the results, concludes OL3 Team Manager Mika Hassinen.
High quality requirements apply to the strength of the containment in order to ensure that radioactivity will remain inside the containment in the possible, but highly unlikely case of an accident. Pressure and leak-tightness tests therefore play a significant role in ensuring nuclear safety. The purpose of the tests that have now been carried out was to demonstrate that the inner containment, which protects the reactor primary circuit, is leak-tight and pressure-resistant.
The test comprised a total of six measurement phases at different pressure levels. The maximum pressure was 6 bar (abs). The sequenced measurement procedure verified that the structural behaviour of the containment is consistent with the design, also at the 4.9 bar (abs) pressure, which simulates a loss of coolant accident. – We used almost 90 sensors to measure the results of the leak-tightness test; the sensors measured containment temperature, pressure and humidity, explains Mr Hassinen.
According to Mr Hassinen, it can be concluded on the basis of the preliminary measurement results that the containment fulfils the leak-tightness and pressure-resistance requirements specified for it. – We continue the analysis of the measurements results and the final test results will be available in the near future.
GuillaumeDouet, who is the Commissioning Engineer responsible for the pressure and leak-tightness test for the plant supplier AREVA, considers the tests that have now been completed to be important to the overall progress of the OL3 project. - This was the first pressure and leak-tightness test conducted on an EPRTM unit, and the first pre-operational test of a reactor containment conducted since 2001 in Europe. We are extremely pleased with the good results of the test, cooperation with TVO and STUK, and that this first Containment Tightness Test of an EPRTM happens on OL3, explains Mr Douet.
Large compressors were used to pressurize in the containment. The longest continuous period of pressurization was ca. 30 hours.
The test sequence was supervised by inspectors of the Radiation and Nuclear Safety Authority. Close coordination and cooperation was required between the plant supplier, TVO and the authority in preparing for and executing the test.
The leak-tightness test is to be repeated at the plant unit three times in every 15-year period.
For more information, please contact: Käthe Sarparanta, OL3 – Senior Adviser, tel. +358 2 8381 4210.
Share