When the Point Lepreau generating station in New Brunswick was shut down in March 2008, NB Power officials said the refurbishment would span 18 months and cost $1.4 billion.
More than four years and another billion dollars later, the provincial Crown utility company is hoping the repairs will extend the plant's life by 27 years, supplying about one-third of New Brunswick's power needs.
"Point Lepreau will be a valuable asset and a great investment for $2.4 billion," NB Power president Gaetan Thomas said in an interview.
"We are still going to be able to produce clean energy from Point Lepreau — over 700 megawatts — for less than nine cents per kilowatt hour and that makes it a very competitive option."
But Norm Rubin of Energy Probe, a Toronto-based energy watchdog group, said the refurbishment and the lapses along the way underscore the risks associated with nuclear technology.
"Because it's nuclear it is inherently hazardous and everything has to go right," Rubin said.
"Because of that, every kind of small boo-boo turns into a megaproject boo-boo, so it is an unforgiving technology.
"Some of the problems that turned this thing into a laughing stock were really weird ... like dropping a turbine into the ocean."
On Oct. 15, 2008, two turbine rotors plunged into the Saint John harbour as they were being loaded onto a barge for delivery to Point Lepreau. They had to be recovered and sent back to the manufacturer for repair in the United Kingdom.
There were also two spills of radioactive heavy water within the past year, one of which prompted an evacuation. In each case no one was hurt and the heavy water was retrieved.
The setbacks were noticed by Hydro-Quebec, which announced last month that it would not proceed with a $4.3-billion refurbishment of its Gentilly-2 reactor — the only nuclear power plant in Quebec. The Crown-owned utility company's president cited the problems at Point Lepreau as a factor in the decision.
Critics of the work at Point Lepreau constantly warned of what happened in Ontario. In 1997, four nuclear reactors in Pickering, Ont., were shut down to perform upgrades to the emergency shutdown system, and the effort to restart them resulted in long delays and major cost overruns.
A review committee appointed by the Ontario government attributed the cost hikes to bad management.
"We actually applied all the lessons from Ontario, but because it was the first time to do a Candu-6 reactor there were other lessons to be learned," Thomas said.
One of the biggest lessons to be learned was how to properly replace the plant's 380 calandria tubes, which house fuel channels and uranium fuel bundles that power the reactor.
The first effort by Atomic Energy of Canada Ltd. to install the tubes failed when tiny scratches caused by wire brushes raised concerns that joints might not be reliable for 25 years. The tubes had to be removed and reinstalled.
AECL, a federal Crown corporation, benefited from that lesson when they began a similar refurbishment of the Wolsong-1 reactor in South Korea, NB Power says.
The refurbishment of the Candu-6 at Wolsong began in April 2009 — a year after the start of the Lepreau project — and ended in July 2011.
"The lessons that they've learned from our jobs were applied at Wolsong," Thomas said. "That is why we believe they have a responsibility for some of these delays."
New Brunswick governments of both Liberal and Progressive Conservative stripes have tried in vain to convince Ottawa to shoulder the extra costs of the Point Lepreau refurbishment, arguing the province should not be on the hook for AECL's delays climbing the learning curve of fixing a Candu-6 reactor.
But Prime Minister Stephen Harper has not budged, saying only that his government will abide by the terms of the contract, which have not been made public.
The cost overruns have stoked fears that customers in the province could face steep rate hikes in the future. But Thomas said NB Power will be able to restrict rate increases to an average of two per cent per year over the next decade while also paying down $1 billion of its $4.6 billion debt, even if the federal government doesn't pony up.
In recent weeks, NB Power has resumed generating electricity at Point Lepreau, raising and lowering reactor power and connecting and disconnecting it from the grid. The company declined to say exactly when it will resume full operations.
Point Lepreau was commissioned in 1983 and was the world's first Candu-6 reactor to begin commercial production of electricity.