IRVINE (CBS) — Officials conducted emergency drills at Southern California Edison’s San Onofre nuclear power plant from 9 a.m. to 2 p.m. Tuesday.

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There has never been a radiation leak at the 42-year-old facility, but FEMA and the Nuclear Regulatory Commission require emergency testing every two years.

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More than 200 emergency management officials from across the state will be at the plant, as well as Southern California Edison’s Joint Information Center in Irvine.

Workers will respond to a fake radioactive gas leak by testing emergency shutdown procedures and securing fuel rods.

Residents should not be alarmed when emergency sirens are intermittently sounded between the hours of 8 a.m. and 12 p.m.

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Tuesday’s drills come as Japan increases the threat level of the disaster at the Fukushima power plant from a 5 to a 7 – the highest level on the International Atomic Energy Agency’s Scale. The Chernobyl disaster of 1986 was also a 7.