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Columbia Generating Station Information
RICHLAND, Wash. – Columbia Generating Station, the Northwest’s only nuclear power plant, is scheduled to begin a refueling outage at 12:01 a.m. Saturday morning. This is the 18th refueling outage since the plant began operations in 1984. It is the third refueling since the station owner, Energy Northwest, changed to a two-year operating cycle following the R-15 outage in 2001.
The outage is scheduled for approximately 38 days with restart tentatively planned for mid-June. However, refueling outages involve extensive maintenance work on the power plant, sometimes requiring schedule changes.
Energy Northwest officials said they are committed to keeping the outage as short as possible, but not at the expense of quality work or safety. “Our primary goal and first priority is a safe, efficient outage that leaves Columbia ready to operate reliably for the next two-year cycle. We will take as much time as needed to work safely, but want to have the plant generating power again as soon as possible,” said Dale Atkinson, Energy Northwest vice-president for nuclear generation. “We will be working 24-hours per day to make the absolute most of our time off-line.”
Approximately one-third of the 764 fuel assemblies in the reactor core will be replaced during the outage. The outgoing assemblies have been depleted of their useful energy and will be stored in plant’s spent fuel pool.
Outage Manager Ron Hogue said this outage will bring major improvements and updates to the plant that will directly improve the long-term reliability and value of Columbia. “One of our major work items will be the replacement of two, 90-ton heat exchanges. The units ensure water returning to the reactor core is at the appropriate temperature and pressure.”
“We will also be working on the High Pressure Core Spray system, one of multiple systems that allow operators to inject water directly into the core in emergency situations. A pump and motor within the HPCS system will be replaced during the outage. The system includes redundant pumps and motors to provide additional emergency capability,” Hogue said.
Hogue also highlighted a new Digital Electro-Hydraulic control system for the plant’s turbines. The DEH system regulates steam flow through the plant’s rotating turbines. The turbines are connected to the generator that produces Columbia’s electrical output.
“The current DEH system uses 1970’s analog technology and was responsible for an unplanned nine-day plant shutdown October 31, 2006 that ended the longest operating run in the plant’s 21-year history,” Hogue said. “While we were pleased to set a 486-day on-line record, we obviously would have preferred to stay running straight through to this refueling outage. The new DEH system uses modern digital technology to improve reliability and will remove a reliability challenge we have faced in recent years,” he said.
Refueling outage maintenance work will also include checks of the main condenser’s cooling water tubes. The condenser unit cools steam from the reactor back into water that is pumped back through the reactor in a closed-loop system. Condenser tube leaks can allow cooling water to enter the reactor water loop.
The outage also contributes to the local Tri-Cities economy bringing approximately 1,800 skilled temporary workers from across the nation to Columbia to assist with the refueling work.
Columbia provides enough electricity to serve a city the size of Seattle; and more than 10 percent of the power supplied by the Bonneville Power Administration.
Reliability of the 1,157 megawatt plant has improved dramatically since it began operations in December 1984. Energy Northwest officials attribute the plant’s improved operation to employee performance, equipment upgrades, and continuous process and procedure refinements.
Statistics show generation runs in the 1980s rarely exceeded 100 continuous days. By the 1990s the plant managed eight runs of 200 or more continuous days on-line. The first 300-plus day record came in 2003. The current 486-day record run is the third to exceed 365 days of continuous operation since February 2003.