Beznau 1: Safety case submitted

16.11.2016 - Beznau nuclear power plant (KKB) has submitted the safety case for Unit 1 to the Federal Nuclear Safety Inspectorate (ENSI). Tests and analyses according to the roadmap accepted by ENSI were completed with positive results. Findings show that the irregularities detected in early summer of 2015 do not have a safety-relevant impact on the material properties of the reactor pressure vessel (RPV). The physical integrity tests confirm an adequate safety margin for a service life of 60 years.

The extensive tests carried out over the past months on the basis of a replica of the RPV ring in order to provide the safety case have now been completed. The safety case was submitted to ENSI on 14 November 2016 and includes all the results of tests performed on the RPV by Beznau over the last half-year. These are:

• Analyses of the source and formation of detected inclusions in the RPV base material
  
• Investigations regarding the impact of these inclusions on RPV material properties
  
• Strength tests and verification of the facture toughness of the steel
  
• Thermo-hydraulic analyses
  
• New tests on the already examined accelerated irradiation specimens
  
• Calculations of the available safety buffers for the future operation of the plant

With the safety case, Beznau provides the verifiable proof that the reliability and safety of Beznau 1 is ensured in keeping with the state of the art of science and technology, as well as national and international standards. Tests confirm the proof for long-term operation, which was produced in 2011/2012. As a result, Axpo has no safety-technical concerns regarding the continued operation of the plant up until about 2030. ENSI will review the safety case and take the decision on restarting the plant.