Carbon dioxide prompts alert at Diablo Canyon

For the first time in its history, Diablo Canyon nuclear power plant declared an alert Wednesday when unhealthy levels of carbon dioxide flooded into a room where lubrication oil is stored.

Workers had finished performing maintenance on a valve on the room’s fire-suppression system and were in the process of testing it when the accident occurred, said Jim Becker, plant manager.

The test called for a puff of carbon dioxide to be released; however, enough of the gas was released to make it unsafe for people to be in the room without a breathing apparatus.

The alert was declared at 10:56 a.m. An “alert” is one step up from an “unusual event,” which is the lowest incident notification level required by federal law. In this case, the alert was called because the incident posed an “immediate danger to life and health,” Becker said.

“This is the first time this has happened at the plant,” Becker said. “I can state that categorically.”

No one was injured in the accident, and the room was isolated. The plant continued to operate at full power, and no radiation was released.

With the help of Cal Fire, plant workers began ventilating the room about 4 p.m. to clear the carbon dioxide so it would once again be safe for people to enter. The ventilating was successful, and the alert was called off at 5:15 p.m.

As a precaution, emergency services officials decided to close but not evacuate Montaña de Oro State Park to the north of the plant. The closure remained in effect Wednesday afternoon, said Ron Alsop, county emergency services coordinator.

Alsop said his office was kept busy Wednesday responding to rumors that there had been a radiological release and Los Osos and other communities had been evacuated.

Rumors were spread via text message and word of mouth.

About 60 people broke into a panic and fled a local business group’s meeting in Pismo Beach after someone received a text message saying a radioactive cloud had formed. A person at the meeting said people ran from their tables and scurried for their cell phones to call loved ones as they crowded out the doors. Later in the day, others said they heard Diablo was under a malicious attack.

Rooms that store flammable liquids are equipped with fire-suppression systems that use gases such as carbon dioxide, which displace oxygen in the room when released and put the fire out.

Operators will investigate the accident to determine what went wrong with the system to cause too much carbon dioxide to be released, Becker said.

Reach David Sneed at 781-7930.