How to Tear Down a Nuclear Reactor

He was a young engineer not long out of college and recently married. His new job: Help build a nuclear reactor.

Thirty-five years later, Jarlath Curran is nearing retirement age. But he’s got one more thing to do: Help tear down that reactor.

Curran, 61, is one of the reasons Southern California Edison Co. decided to start decommission now of Unit I of the San Onofre Nuclear Generating Station. The company wanted some of the engineers who built and ran it for years to help dismantle the 450-megawatt reactor before they retire. The reactor provided energy for up to 500,000 homes and businesses from 1968 to 1992, when it was shut down.

Curran isn’t exactly happy with the assignment. “I never envisioned decommissioning a nuclear reactor,” he said. “Because they can be maintained such that they could really operate indefinitely.”

Scientifically, this may be so; economically, it isn’t. The reactor needed more than $100 million in upgrades to continue operating.

“It’s disappointing,” the Mission Viejo resident said. “Any engineer associated with operating a reactor plant wants to see it continue to operate. But that’s the way it is.”

The massive decommissioning effort is expected to take eight years and $460 million, said plant spokesman Ray Golden. No rate increase is anticipated to pay for the decommissioning.

Workers have started preliminary work such as moving furniture, checking radioactivity of building components and removing asbestos. They will begin taking apart the emergency diesel generator building this week.

The reactor, along with three steam generators and a pressurizer, will be removed from the containment building between 2001 and 2003, and the building itself will be demolished between 2006 and 2008, Golden said.

The reactor vessel, which is contaminated and will weigh about 500 tons when filled with a concrete grout as a safety measure, will be taken by slow-moving rail at night to Oceanside, where it will be loaded onto a barge. The barge will pass through the Panama Canal before heading to a nuclear waste dump in Barnswell, S.C.--the only facility in the nation that will accept it.

Spent nuclear fuel--used uranium--is now stored at the plant underwater in hundreds of metal bundles. These 12-foot-tall bundles, which will be radioactive for tens of thousands of years, will be inserted into steel-reinforced concrete vaults between 2004 and 2005.

These vaults will be stored at the plant because no high-level radioactive waste repository yet exists, although the U.S. Department of Energy is required by federal law to remove the spent fuel and safely store it at such a facility for thousands of years.

The government has been studying a repository site that could open as early as 2010 at Yucca Mountain, Nev. The Energy Department would then begin removing spent fuel from nuclear plants across the country, and could remove assemblies from the former San Onofre Unit I by 2024.

Critics, such as the Sierra Club, doubt that the Yucca Mountain facility will be built by then and say leaving the uranium on site turns a stunning stretch of the coast into a nuclear waste dump.

But Golden counters that the law is clear: The government is obligated to find a permanent home for the used fuel. “It’s a matter of when, not if,” he said.

Plant officials say the method of storing the fuel on-site above ground is safer than the current method of keeping it submerged in so-called cooling pools. The on-site method, called “dry casking,” requires no maintenance that could leave room for human error or technical failure.

Critics’ fears of the stored fuel are needless, and driven by a lack of understanding of nuclear power, Golden said. “As a nation, the general population is scientifically challenged. Most people could not explain what electricity is or how it’s made.”

Fascination with such matters, coupled with a belief that nuclear power is a superior form of generating energy, are among the reasons that Curran has stayed with San Onofre for so long.

Curran has held a variety of roles during his tenure at San Onofre, including Unit I plant manager from 1977 to 1981. For nuclear plants across the nation, this was a busy time. He recalls the construction of Units II and III, which at 1,120 megawatts apiece make San Onofre the second largest nuclear plant in the nation.

He remembers the protests of the late 1970s, and the safety enhancements implemented after the 1979 partial meltdown at Three Mile Island.

Retirement age at the plant is generally 65, meaning Curran could retire in 2004. But Curran said he sees no reason to stop--even with demolition underway of the reactor that brought him to San Onofre in 1965.

“It’s a fun job, an interesting and challenging job,” he said.