Dossier Nuclear Energy
"KKB is in good condition"
Mike Dost, Beznau power plant Director on the ENSI decision
ENSI gives green light for Beznau 1 nuclear power plant
The most important answers
The safety case
The safety case presents the methods and results of all tests that Axpo performed in the course of nearly three years in order to provide proof of safety. The additional analyses that were carried out last year corroborate the proven safety of the plant, as already demonstrated in mid-November 2016. Axpo's extensive analyses unequivocally confirm the cause of the inclusions (aluminium oxide) detected in 2015. It was confirmed that these occurred during the manufacture of the RPV and not during plant operation. With the help of a replica of an RPV ring, Axpo was also able to clarify the impact of non-metallic inclusions on material properties, provide the integrity verification, and respond to the question of the available safety margin for continued operation of the plant.
The safety case proves that the reactor pressure vessel fulfils all national and international provisions and requirements for the continued safe operation of KKB Unit 1.
In the course of the root cause analysis, material tests verified and validated the source of the inclusions. Thanks to a RPV replica ring, it was possible to carry out extensive material tests demonstrating that the aluminium-oxide inclusions have no negative impacts on the RPV material properties and that its integrity is fulfilled for long-term operation of 60 years.
Lengthy testing process
The supervisory authority ENSI repeatedly stated that it would take the necessary time to perform an extensive, technical review of the documentation submitted by Axpo. The timeframe is understandable given the complexity of the safety case. The endorsement of our extensive safety case attests to the high safety standards of the plant.
Preventing deterioration during shutdown
Axpo took measures to prevent deterioration during shutdown. These were communicated to the authorities and presented on plant tours. Periodic inspections and maintenance were carried out in the same manner as if the plant had been in operation. Function tests were performed regularly and moving components were repeatedly rotated. In order to fulfil all the safety-technical requirements, the plant will undergo a detailed inspection before the restart. Axpo specialists will ensure the safe operation of the plant.
Is the Beznau nuclear power plant safe?
The Beznau nuclear power plant fulfils all safety requirements. With continuous retrofitting and renewal investments in the range of CHF 2.5 billion, Axpo has ensured that KKB complies with the required safety standards at all times. The Swiss supervisory authority ENSI has confirmed previous assessments with the endorsement of the latest safety case. Axpo plans to operate the plant as long as it is safe and economical. Decommissioning is not a topic at this time. With the continued operation of the plant, Axpo ultimately makes a valuable contribution to the implementation of the Swiss Federal Council’s energy strategy.
Further information about nuclear energy