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Decommissioning of the Trojan Nuclear Plant

Background

The Trojan Nuclear Plant was Oregon’s only nuclear power plant. It operated for almost 17 years, from March 1976 to January 1993. Trojan was co-owned by Portland General Electric, Eugene Water & Electric Board and PacifiCorp. Those three entities were responsible for Trojan's decommissioning.
 
The Trojan Nuclear Plant was located on U.S. Highway 30, approximately 12 miles north of St. Helens, in Columbia County.

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What is decommissioning?

Decommissioning is the process of removing the radioactive material from the site and restoring the site for other uses. Trojan was built on what was already an industrial site before PGE bought it. Now that decommissioning is complete, the site is safe for any type of use, including industrial, commercial or even residential.

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How long did decommissioning take?

The process took about nine years, from the spring of 1996 through December 2004.

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How safe is the site after decommissioning?

The site meets federal standards for residual radioactivity. Those standards are published in the Code of Federal Regulations, Title 10, Part 20 (10 CFR 20).
 
The regulations require that a person living or working on the site will receive no more than 25 millirem of radiation per year in excess of normal background. The regulations further require PGE to clean the site so that the level of residual radiation is "as low as reasonably achievable" (the "ALARA" standard).
 
A millirem is a unit of radiation. For reference, an average person in the U.S. receives between 200 and 300 millirem per year from a combination of cosmic radiation, natural background, and medical or industrial sources.
 
PGE showed that the site meets the standard. Between 2001 and 2005, it measured the entire plant site for residual contamination in a process called a "final survey." Regulators from the U.S. Nuclear Regulatory Commission and the Oregon Department of Energy inspected and reviewed the final survey. The NRC has also done some confirmatory surveys. Before PGE could release the site for unrestricted use, the final survey needed the approval from the NRC and the Oregon Energy Facility Siting Council. The Council aproved the site's unrestricted release in April 2005.

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Major milestones

PGE planned the decommissioning process in stages. The major stages included:
 
1995 Removing large components (4 steam generators and the pressurizer)
1996 Siting Council and NRC approval of the Decommissioning Plan
1999 Approval of planned "independent spent fuel storage installation" (ISFSI)
1999 One piece removal of the reactor vessel and its internal components (a first in the nation)
2000 ODOE and NRC review of the final survey plan
2001 Start of final survey
2003 All spent fuel transferred from the spent fuel pool to dry cask storage
2004 PGE completed the final survey and submitted all results to ODOE and NRC for review
2005 NRC and Siting Council approval for releasing the site

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Who oversees the decommissioning?

The Nuclear Regulatory Commission oversees decommissioning at the federal level. At the state level, the Siting Council and ODOE oversee decommissioning through a program of reviews and approvals. Documents that provide details of this review and oversight since 1994 include:
In December 2004, PGE submitted its complete report on the final survey. The Council approved the final survey in April 2005.

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What about spent fuel?

Trojan had about 790 spent fuel assemblies stored in the Trojan Spent Fuel Pool. Each assembly is 12 feet long and about 10 inches square. The decommissioning plan called for PGE to transfer the spent fuel from the pool to dry casks. This was completed in 2003. The dry casks are stored on a concrete pad located in the northeast corner of the Trojan site. Even after the rest of the site was decommissioned, the spent fuel storage area remains under Council jurisdiction until the federal government can establish a national spent fuel respository. At this point, we do not know when that will happen. See the staff report on spent fuel storage for more details.

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