Mochovce 3&4: Primary circuit pressure test completed

Mochovce 3&4: Primary circuit pressure test completed
Successful testing of Unit 3 primary circuit pressurisation is a milestone in the construction of the Mochovce nuclear power plant.

Slovenske elektrárne has successfully tested six steam generators and pipelines connected to Unit 3 reactor of the Mochovce Nuclear Power Plant, with the unit’s steam generators and pipelines withstanding 10 minutes of pressure of up to 19.12 MPa (megapascal), almost 190 times the normal atmospheric pressure.

We filled the primary circuit system with water and gradually pressurised it to the required level. The test included 208 valves, whose hermetic seal enabled us to reach such a high testing pressure,” explained John Clark, Mochovce 3&4 Project Director.

We demonstrated that the system and components can safely hold 1.5 times normal operating pressure, inspected all relevant equipment and successfully tested remote operations from the control room.”

Picture depicting pressure test of separable loops

Picture depicting pressure test of separable loops.

Following the pressure test, Slovenske Elektrarne will continue to prepare Unit 3 components and systems for another major milestone: Cold Hydrostatic Test (CHT), or Cold Hydro, a test aimed at verifying the integrity of weld points and interfaces associated with the equipment and pipes of all those pressure-containing components, such as pressure vessels, piping, pumps, and valves relating to the reactor coolant system.

The pressure test was operated from the main control room, the “brain” of the nuclear power plant that was energised a year ago.

The pressure test programme was approved by the Nuclear Regulatory Authority of the Slovak Republic and is one of the key preconditions for the commissioning of the power plant.

Unit 3 of the Mochovce Nuclear Power Plant is almost 94 percent complete, while Unit 4 is at 80%, with a total of 60 million man-hours worked on site.