New Record: Nuclear Power Plant Online for 940 Continuous Days

The Heysham 2 nuclear power station broke a nearly 22-year-old record for continuous operation when it shut down Unit 8 on September 16 after 940 days online.

The previous record—held by Pickering 7, a Canadian nuclear plant—was 894 days, set on October 7, 1994.

EDF Energy said that the Heysham reactor—a 615-MW unit located on the northwest coast of England near Lancaster—produced more than 14 TWh of electricity during its run. The unit was taken out of service for planned maintenance (Figure 1) and is expected to be offline for a little more than two months.



1. The Heysham 2 reactor in the UK set a new world record for continuous operation. Courtesy: EDF Energy

The Heysham unit is an advanced gas-cooled reactor, which can be refueled while online, making longer runs possible. The continuous operation record for a light water reactor—which requires shutdown for refueling—is 739 days, set by LaSalle Unit 2, an Exelon-owned plant located about 75 miles southwest of Chicago.

“EDF Energy’s expertise and investment has significantly improved the productivity of its nuclear power stations in Britain, providing more reliable, low carbon electricity for customers and industry. That strong performance underpins our credibility as a nuclear operator and developer,” said Vincent de Rivas, CEO of EDF Energy.

The Heysham shutdown came only a day after the UK government gave EDF Energy the green light to proceed with development of the Hinkley Point C project. That move had been heavily debated due to the $23.8 billion price tag and what some had felt was an egregious strike price guarantee for power generated by the station.

Heysham’s maintenance periods—or statutory outages—are scheduled every three years. Plans are made well in advance to ensure no impact on the nation’s electricity supply. The station will perform camera inspections inside the reactor and install some new plant equipment during the shutdown. The biggest project is said to be the replacement of two large gas circulators that help to cool the reactor.

Earlier this year, EDF Energy extended the scheduled closure dates for four of its nuclear power stations. Heysham 2 (Figure 2) is now expected to remain in operation an additional seven years until 2030.



2. Heysham 2 opened in 1988. It is expected to remain in service until 2030. Courtesy: EDF Energy

“The investment in the plant during the planned maintenance shutdown will support the plant’s lifetime extension—supported by 1,000 skilled people,” said John Munro, station director at Heysham 2.

The new continuous operating record is not expected to last long, however. Torness power station, another EDF Energy operated plant, is due to break Heysham 2’s record in February 2017 and will reach 996 days of continuous operation if all goes as intended. It is scheduled to shutdown for planned maintenance in April 2017.

Aaron Larson, associate editor (@AaronL_Power, @POWERmagazine)