Dukovany NPP – Solution for Deep Vacuum Load on the Containment (hermetic reactor enclosure)

In July, I&C Energo signed a contract with the Client, ČEZ, a.s., for the implementation of the public procurement project “Solution for Deep Vacuum Load on the Dukovany NPP Containment.” The purpose of the project is to eliminate the risks of failing to perform the basic safety function “Retention of Radioactive Substances” due to the loss of containment integrity caused by dangerously deep vacuum conditions.

The existing technical solution for the vacuum breaker assumes activation upon manual initiation by operators from the main control room or the emergency control room approximately 30 minutes after the initiating event. Based on a newly developed conservative safety analysis, it was decided to implement an automatic system for reducing vacuum in the containment (OPHO), which, in the event of a beyond-design-basis external event or a maximum design-basis accident, will ensure activation of the vacuum breaker system in approximately 6 minutes, thus preventing the limit value of 20 kPa vacuum from being exceeded.

The work will be carried out in controlled areas and in vital areas of the Dukovany NPP and will be implemented during outages of individual units until 2028.