All five of Switzerland’s nuclear power reactors are set to receive upgrades mandated by the country’s nuclear regulator ENSI and intended to increase hydrogen control capabilities.

The nuclear power units will install new equipment to improve safety during severe accidents, ENSI says.

All Swiss reactors will have hydrogen control once the passive hydrogen re-combiners have been installed at the Gosgen and Leibstadt nuclear power station, ENSI added.

The Beznau reactor is required to submit plans by the end of 2015 to improve hydrogen control, and the Muhleberg station must develop a way to measure hydrogen as part of its management plan. The plan must be submitted to ENSI by the end of June.

These precautions and fixes are in large part because of the damage suffered by the Fukushima Daiichi nuclear power plant in March 2011. Without cooling water, the cores of units 1, 2 and 3 of the Japanese plant overheated and largely melted. Hydrogen generated by this high-temperature process caused explosions in the floors of reactor buildings at units 1 and 3. Unit 4 had not been operating, but was affected by a hydrogen explosion due to gas back-flow from unit 3.

Two months after the accident, the Swiss government announced its existing reactors would not be replaced once they reach the end of their operational life.

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