The region's largest power plant on Humboldt Bay for 52 years was shut down and replaced by a modern facility meant to produce next-generation electricity.

The switch was thrown on Pacific Gas and Electric Co.'s new King Salmon power plant, which began generating power as its two aged fossil-fuel units went offline Wednesday and Thursday.

”We're powering the county,” said PG&E Plant Manager Paul Roller. “This is the first day they've actually done that.”

Eight of 10 Wartsila natural gas engines that are the guts of the plant roared inside insulated walls. When all the engines are running, the plant can produce up to 163 megawatts of electricity. It's also flexible enough to ramp up or down depending on demand and how much renewable energy like wind or solar is being pumped into the electrical grid.

PG&E officially broke ground on the project in December 2008, and gathered a work force that at its peak was about 280 workers. While operational, crews are still putting the finishing touches on the facility.

Sid Berg, chairman of the Humboldt-Del Norte Building and Construction Trades Council, said the project brought in some especially skilled tradesmen, including top welders who were able to train apprentices.

”Everybody worked together,” Berg said. “It was a good example of how business and labor can work together.”

The original plant was built in the 1950s, consisting of a nuclear facility  and two fossil-fuel turbines. The nuclear element was last operated in 1976, and was not restarted after concerns about seismic issues were raised. The nuclear accident at Three Mile Island in Pennsylvania occurred three years later, and in 1984, PG&E decided to cap the King Salmon nuclear unit in 1984.

Now, PG&E is dismantling the nuclear unit and the two conventional elements. It has moved the 390 rods of spent nuclear fuel from a holding pool in the plant into specially built casks, which are now stored in an underground bunker on the site that is designed to withstand a 9.3-magnitude earthquake and a terrorist attack.

But there is substantially more work to be done. The radioactive reactor and nuclear infrastructure must be removed under strict protocols and trucked out of state to a certified facility. The 300-ton reactor vessel is in a hole 66 feet below sea level, and must be removed with a massive crane. Other parts of the facility must be cut down and removed in steel drums.

PG&E's Dave Pierce is responsible for the job, and the utility is determined to set a standard for other nuclear decommissioning efforts in the country.

”It's something we've never done before,” Pierce said, “so it's something new.”

Because the property is a nuclear site, parts of the two old conventional generators will have to be removed and tested before being shipped out. To handle that task, PG&E built a $2 million lab to check for potential radioactivity in components and soil.

Dozens of PG&E workers and contractors are busy moving onto the next phases of the effort, a complex and intertwined process that will take several more years to complete. The fossil-fuel units are expected to be removed by early 2012, with the complete decommissioning of the nuclear facility anticipated to be done in 2015.


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