Story Photos
 Photo by Roger Werth Mark Loizeaux demonstrates Wednesday how placing explosives on the southeast side of the Trojan cooling tower will help the tower tilt and then collapse upon itself. The drawing in red shows the three sequences of the tower's collapse. |
2,000 pounds of explosives will take down Trojan tower
Thursday, March 9, 2006 6:57 AM PST
By Barbara LaBoe and Janine Manny
Printable version
E-mail this articleRAINIER --- Like an incredibly high-tech version of notching a tree, demolition experts plan to weaken one side of the Trojan cooling tower to ensure it collapses in place.
Explosives will be placed on the south and southeast side of the cooling tower to soften or weaken that wall and make it crumble, said Mark Loizeaux, president of Controlled Demolition Inc., which will implode the tower. The crumbling on just one side will cause the tower to tilt slightly -- 100 feet maximum -- and rotate as gravity pulls the tower down.
"This tower wants to sit down based on gravity," said Loizeaux, speaking at a media conference Wednesday about the scheduled May 21 implosion. "And we're going to cajole it do what it wants to do anyway." The tower, located just outside of Rainier, is owned Portland General Electric.
The kinetic energy created when the tower tilts and rotates "will literally tear the structure up in mid-air," Loizeaux said.
CDI will use less than 2,000 pounds of nitroglycerine based explosives packed into 2,500 holes drilled within the tower.
While the system is complicated, the device that detonates the tower couldn't be simpler, Loizeaux said. The detonator is a couple of blasting caps connected to detonating cord and powered by a "9 volt battery like the one in your garage door opener," he said.
It's taken more than a year of planning and coordinating, but the implosion itself will be fast -- less than eight seconds. Areas of the tower will be detonated sequentially within split seconds of each other, Loizeaux said.
The areas to be detonated will be wrapped in chain link fence and special geo-textile fabric, so there won't be a visible blast or flash of light when the detonation begins.
The Kingdome was 100,000 tons of material compared to Trojan's 41,000 and about 70 million cubic feet in volume compared to 35 million cubic feet at Trojan. The Seattle site also had man-made soil underneath, a low water table and 100-year-old buildings across the street. Plus, there was the sentimental attachment of many fans and residents
"The Kingdome was an event, this is almost an afterthought, a quiet sigh," Loizeaux said.
The exact time of the implosion has not been set but needs to be later than first light, which is about 5:30 a.m., and early enough to deter spectators, according to Jon Vingerud, PGE Trojan Decommissioning Manager.
PGE officials stressed that the best place to watch the implosion is at home.
"We need to get the word out that we want people to watch this on TV," PGE spokesman Scott Simms said. "We need to reduce the burden on the public service folks out on the road."
The implosion project is a "go" Vingerud said, unless there is a lightning storm or heavy fog on the scheduled day. Wind and rain are not concerns.
The Trojan nuclear plant operated from May of 1976 to January of 1993. At its peak production, the plant produced 1,130 megawatts of power to the grid, enough to power 400,000 homes, plus the 42 megawatts needed to run the plant. Trojan employed about 1,200 people.
The plant was closed in 1993 when officials determined it was too expensive to replace the 1970s Westinghouse steam generators, Vingerud said.
In 1999, the nuclear reactor vessel was shipped to the Hanford Nuclear Reservation in southeastern Washington. By 2003, the final spent fuel was moved to on-site dried storage casks, and all asbestos was removed from the cooling tower.
The entire decommission price tag is $429 million.
"To date, from 1996 to the end of 2005, we've spent $300 million," Vingerud said. "The demolition is part of the remaining $129 million."
PGE will not release the breakdown of costs of specific phases of the project.
After the cooling tower comes down, PGE has another phase of demolitions planned. The power block, consisting of the turbine building, the control building, the auxiliary building and the fuel building will be demolished by the end of 2007. The containment building will be taken down in 2008.
The spent fuel containment casks will remain on site until 2024 and then moved to a federal depository in Nevada.
Plans for the site after 2008 have not been announced.
"There are no set plans," Simms said. "But development could coexist with the spent fuel storage."
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