23.04.2019 | Half a century of climate-friendly power production

Beznau 50-year anniversary

The Beznau nuclear power plant (KKB) is celebrating its 50-year anniversary. Thanks to extensive upgrades and investments in maintenance and modernisation amounting to over CHF 2.5 billion the plant fulfils all the specified regulatory and legal safety requirements. 

Axpo plans to operate the plant as long as it is safe and economical. With the continued operation of KKB, Axpo is making a valuable contribution to Swiss power supply and to a stable power grid. Further operation of the plant is an important pillar in implementing the Energy Strategy 2050 (more here).

The plant comprises two units. The commercial commissioning of the first (KKB 1) unit took place in December 1969 after four years of construction. KKB 2 followed in April 1972. As of commissioning up to 2018, KKB 1 produced approx. 121 273 and KKB 2 approx. 128 153 gigawatt hours of electricity. As compared to generation with a brown coal power station, a total of about 300 million tonnes of CO2 emissions were prevented.


1964: The former NOK makes the decision to build a nuclear power plant on Beznau Island

1965: Ground-breaking for the first nuclear power plant in Switzerland

1967: The NOK Board of Directors decides to build a second, nearly identical unit on Beznau Island

1969: KKB 1 goes on grid after a construction period of only 48 months. KKB 2 follows on 3 April 1972 after a 4-year construction period

Summary of the most important upgrades and modernisation investments over the last decades

1991/2015: Installation of the ANIS plant information system in 1991 and its modernization in 2015. State-of-the-art hardware and software solutions process thousands of signals per unit in order to ensure seamless monitoring and recording of the operating history

1993: Realisation of the NANO emergency system. NANO returns the plant to stable, safe operation after a failure in the control centre or primary safety systems

1993/99: Replacement of the steam generators in both units: With the preventative replacement of the steam generators, the risk of an unscheduled outage is reduced

1993: Construction of ZWIBEZ: The interim repository on the KKB grounds safely stores radioactive waste and fuel elements until they are removed to the deep geological repository

1995: Replacement of the high-pressure turbines: The replacement results in a performance increase

2001: Realisation of a digital reactor protection system. The system ensures digital monitoring of the reactor and launches a fast shutdown before design limits are exceeded

2007: Construction of a simulator. The simulator enables employees to train under realistic conditions and to simulate the impacts of technical changes in the plant

2015: Preventive replacement of the reactor pressure vessel heads based on experience from abroad

2015: Upgrade of a new, redundant, autarkic emergency power supply system: With its commis-sioning, an additional, earthquake- and flood-proof emergency power supply system is created. Four high-performance diesel generators ensure reliable power supply to the plant for an autarkic period of seven days

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