Pickering Nuclear Generating Station

Pickering Nuclear Generating Station

A unit at the Pickering plant
Location of Pickering Nuclear Generating Station in Ontario
Country Canada
Location Pickering, Durham Region, Ontario
Coordinates 43°48′42″N 79°03′57″W / 43.81167°N 79.06583°W / 43.81167; -79.06583Coordinates: 43°48′42″N 79°03′57″W / 43.81167°N 79.06583°W / 43.81167; -79.06583
Status Operational
Construction began 1966
Commission date 1971-73 (A station)
1983-86 (B station)
Decommission date 1997 (Units A2 and A3) Permanently shutdown and defuelled, but NOT yet decommissioned.
Owner(s) Ontario Power Generation (OPG)
Nuclear power station
Reactor type CANDU
Thermal power station
Cooling source Lake Ontario
Power generation
Units operational 4× 516 MW
2× 515 MW
Units decommissioned 2× 515 MW
Nameplate capacity 3,252 MW
Website
OPG - Pickering Nuclear

Pickering Nuclear Generating Station is a Canadian nuclear power station located on the north shore of Lake Ontario in Pickering, Ontario. The facility derives its name from the City (originally Township) of Pickering in which it is located. It produces about 14% of Ontario's power and employs 3,000 workers.[1]

Co-located at the Pickering station is a single 1.8 MWe wind turbine named the OPG 7 commemorative turbine.

Reactor classification

The reactors can be classified as follows:

PICKERING A

PICKERING B

Construction

The facility was constructed in stages between 1966 and 1986 by the provincial Crown corporation, Ontario Hydro. In April 1999, Ontario Hydro was split into five component Crown corporations with Ontario Power Generation (OPG) taking over all electricity generating stations. OPG continues to operate the Pickering station.

The Pickering station is one of the largest nuclear facilities in the world, comprising six operating CANDU nuclear reactors with a total output of 3,100 MW when all units are on line, and two non-operating units currently shut down in safe storage. The facility is connected to the North American power grid via numerous 230,000 and 500,000-volt transmission lines.

The facility was operated as two distinct stations, Pickering A (Units 1 to 4) and Pickering B (Units 5 to 8) until 2011. While primarily administrative in nature, the division was not wholly artificial, as there are some distinct differences in design between the two groups of stations. (Example: The Pickering A units employ a moderator dump as a shutdown mechanism, a feature not found in Pickering B.) There are, however, a number of systems and structures in common between the two stations; the most notable of these is the shared vacuum building, a negative pressure containment system. The operation of Pickering A and B was unified in order to reduce costs now that Pickering Units 2 and 3 are shut down in safe storage.

Partial shutdown

On December 31, 1997 the four Pickering A reactors were shut down by Ontario Hydro and placed in lay up, suspending work on upgrades to the shutdown system. Ontario Hydro committed to restarting the units, but the project underwent long delays and large cost over-runs.

Premier Mike Harris asked former federal energy Minister Jake Epp to study and make recommendations on the problems with the Pickering restart. Mr. Epp acknowledged the large cost over-runs and delays attributing blame to bad management. The Epp Review estimated the cost of restarting the remaining reactors at $3 – 4 billion and supported the continuation of the project.

The election of the Ontario Liberal Party in 2003 delayed action on the Epp report. The government of Dalton McGuinty appointed Epp to the Ontario Power Generation Review headed by John Manley to examine the future role of Ontario Power Generation (OPG) in the province’s electricity market, examine its corporate and management structure, and decide whether the public utility should proceed with refurbishing three more nuclear reactors at the Pickering nuclear power plant. The report recommended proceeding with the restart Pickering “A” reactors 1, 2, and 3, sequentially. (Unit 4 was restarted in 2003.) The report argued that the restart of units 2 and 3 would be contingent on whether “OPG will be able to succeed at the Unit 1 project."[2]

The McGuinty government accepted the OPG Review Committee's recommendation and allowed the restart of reactor 1, which still underwent cost over-runs and delays. In August 2005, the OPG Board of Directors announced that Units 2 and 3 would not be refurbished due to specific technical and cost risks surrounding the material condition of these two units.

The anti-nuclear group Sierra Club of Canada criticized the report for not attributing any blame to the problems of nuclear technology, noting that there were no energy or environmental experts appointed to the panel.[3]

Numerous changes in executive-level staff and project management strategy were made for the follow-on project to refurbish Unit 1. The experience of refurbishing Pickering A Unit 1 was significantly different from Unit 4, with a much tighter adherence to schedule and budget. Unit 1 was returned to service in November 2005, providing 542 MW of generating capacity for Ontario's electricity system.

In August 2005, the OPG Board of Directors announced that Units 2 and 3 would not be refurbished due to specific technical and cost risks surrounding the material condition of these two units.

The Pickering Nuclear Generating Station, viewed from the west. All eight reactors are visible, from 2.5km to 3.25km away.

Waste

The used nuclear fuel and some refurbishment waste generated by the plant sits on-site at the Pickering Waste Management Facility. All operational low and intermediate-level waste is transported to OPG's Western Waste Management Facility at the Bruce nuclear site near Kincardine, Ontario. OPG has proposed the construction and operation of a deep geologic repository for the long-term storage of low and intermediate level waste on lands adjacent to the Western Waste Management Facility.[4] The Nuclear Waste Management Organization is currently seeking a site for a potential repository for the used fuel from all Canadian nuclear reactors.

Future

In January 2016, the Province of Ontario approved plans to pursue continued operation of the Pickering Nuclear Generating Station to 2024.[5]

OPG will work with the Ministry of Energy, the Independent Electricity System Operator and the Ontario Energy Board to pursue continued operation of the Pickering Station to 2024. All six units would operate until 2022; two units would then shut down and four units would operate to 2024.[6] Extending Pickering’s operation will ensure a reliable, clean source of base load electricity during refurbishment of the Darlington Nuclear Generating Station and the initial Bruce Nuclear refurbishments.[7]

Any plan to extend Pickering’s life requires approval from the Canadian Nuclear Safety Commission (CNSC). OPG is currently working on a licence application to the CNSC for approval in 2018.

After operation of Pickering concludes, OPG will begin the longer term decommissioning process as refurbishment will not be pursued. The first step in the long term decommissioning process is to layup the reactors and place them into safe storage. Pickering staff will have future employment opportunities placing the Pickering units in a safe storage state, at the Darlington refurbishment and operations, or at the potential new build at Darlington.

OPG has begun planning for the station's end of commercial operations including the potential repurposing of the Pickering site location.[8]

OPG will proceed with a detailed planning phase for the mid-life refurbishment of the Darlington Nuclear Generating Station east of Toronto, with construction expected to start in 2016. The business decision to move forward with an investment in Darlington came after initial studies on the plant’s condition operating performance returned positive results.

In January 2016, the Province of Ontario announced its decision to proceed with refurbishment of Darlington.[5]

Incidents

A serious incident occurred on 1 August 1983. Pressure tube G16 in the Pickering A Unit 2 reactor developed a 2 metre long split. The reactor was safely shut down and the damage investigated. The cause was found to be the mislocation of annulus gas spacer springs which allowed the pressure tube to sag inside the calandria tube leading to hydrogen enrichment of the cooler areas. This made the tube more brittle so that it ruptured. There was some local fuel damage and the reactor was safely shut down by the operators with no increase in radioactive emissions. The eventual resolution was Large Scale Fuel Channel Replacement and all the pressure tubes were replaced in all Pickering A reactors. Since then, additional monitoring of the location of the annulus gas spacer rings has been a significant part of routine reactor inspections.[9]

On December 10, 1994 there was a loss of coolant accident. Said to be the most serious accident in Canadian history (June 2001) by The Standing Senate Committee on Energy, the Environment and Natural Resources. The Emergency Core Cooling System was used to prevent a meltdown.[10][11]

In 1994 Pickering Unit 7 set a world record for continuous operation (894 days) without a shutdown. [12] [13] This record remained standing for 22 years, before finally being broken in August 2016 by Heysham 2 Unit 8, an AGR type reactor in the United Kingdom.

On March 14, 2011, there was a leak of 73 cubic metres of demineralized water into Lake Ontario from a failed pump seal. There was negligible risk to the public according to the Canadian Nuclear Safety Commission.[14]

See also

References

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