Plant safety: AREVA qualifies a new hydrodynamic seal

AREVA JSPM, a wholly-owned AREVA subsidiary, has successfully qualified a new hydrodynamic shaft seal system (HD seal) that can withstand station black-out (SBO) conditions for an unrivalled period of 120 hours.

While new Safety Authority requirements recommend a minimum coping time of 72 hours, the extensive tests performed by AREVA JSPM under severe SBO conditions (high water temperature of 310°C and high pressure of 175 bar) certified that the new AREVA JSPM HD seal can maintain the integrity of the primary circuit for 120 hours, which considerably increases the current plant safety margins.

AREVA’s new HD seal thus helps utilities improve plant safety. Also more reliable and more stable in operation, notably thanks to its design that offers a triple redundancy, the new seal has an extended service life expected to reach a minimum of 10 years, spacing out the interval between inspections, and requires minimal maintenance, therefore optimizing plant availability.

Key element of the Reactor Coolant Pump (RCP), which circulates the primary coolant between the core and the steam generator, the shaft seal system ensures the leaktightness of the primary circuit. It is therefore essential to maintain the system’s performance even under extreme conditions such as extended SBO, in order to safeguard the reactor against core uncovering and thus preserve the plant’s safety and integrity.

"The SBO-qualification of our new HD seal for 120 hours represents a major industry step forward for enhanced plant safety", says Thierry Schietecatte, AREVA JSPM Chief Executive Officer. "It is the result of years of R&D combined with AREVA JSPM’s 40 years of maintenance experience on more than 400 RCPs worldwide, and close collaboration with utilities".

Part of AREVA’s Safety Alliance program, developed to help utilities demonstrate and upgrade the safety of their nuclear plant fleets, the new HD seal system has been designed to be installed in existing RCPs as a replacement for the current hydrostatic seals, as well as in third-generation RCPs for new nuclear power plants. It is suitable for both installed base and new-build markets.