26 Jan (NucNet): Swiss nuclear regulator ENSI has issued new requirements for hydrogen management and nuclear power stations in the country will install new equipment to increase safety during severe accidents, ENSI said in a statement.
All five commercially operational Swiss units will be retrofitted to increase hydrogen control capabilities, ENSI said. Two units, Gösgen and Leibstadt, will add passive hydrogen recombiners, meaning all Swiss units will have passive hydrogen control, ENSI said.
The two-unit Beznau will have to submit plans by the end of the year to improve hydrogen control, ENSI said. Mühleberg, which operates with an oxygen-free containment that makes hydrogen explosions theoretically impossible, will have to develop a way to measure hydrogen as part of a management plan due to the regulator by the end of June, ENSI said.
Gösgen has already submitted an application for use of the recombiners, while Leibstadt has until March 2016 to do so, ENSI said.
After the Fukushima-Daiichi accident in Japan in 2011, ENSI ordered a new review of hydrogen generation, release and distribution in containments.
The Fukushima-Daiichi accident progression included explosions attributed to the generation of hydrogen during the overheating of reactor fuel and the escape of the gas from primary containment followed by its ignition. Three reactor buildings – Units 1, 3, and 4 – were damaged by hydrogen explosions.
