Earthquake protection of the Beznau nuclear power plant

19.02.2021 - Axpo's response to today's media release from the Swiss Energy Foundation (SES) "Beznau nuclear power plant without earthquake protection for decades".

In today's communication, the authors of the communication claim that the Beznau nuclear power plant was operated "for decades without earthquake protection" with regard to the communicated assembly deviations in the two emergency diesels commissioned in the 1990s. This statement has no basis whatsoever. Axpo has invested around CHF 2.5 billion in the reliability and safety of the plant in recent decades, including in earthquake protection and ensuring the emergency power supply.

The following is correct:

• The two bunkered emergency diesel generators were retrofitted in 1992 and 1993. Before the emergency diesels were commissioned, the emergency power supply was ensured from the Beznau hydroelectric power plant and with existing emergency diesels at the plant.
• The safety of the plant was and is guaranteed at all times by redundant emergency power supply systems for cooling. A diesel generator is sufficient to cool the plant. Due to its large capacity, one diesel can even supply both units simultaneously. It should be emphasised that the diesel generators at the Beznau site are periodically and systematically checked for proper functioning.
• In addition to the six safety-classified emergency diesel generators at the Beznau site, two further operational diesel generators are available for beyond-design-basis accidents. In the event of an emergency, it is also possible to fall back on aggregates at the Reitnau storage facility. Until these units arrive at KKB, the plant can also be cooled with mobile units available at the site.

More information can be found here.