The first indication that things had gone awry came early last August. At that time, a 20-foot-long
cracked pressure tube shut down reactor Unit 2 at the Pickering nuclear power station just outside Toronto. Less than a week later, after a gallon of radioactive tritium spilled into Lake Ontario, authorities also closed Pickering’s Unit 1 reactor. The situation grew progressively worse, and last week Ontario Hydro officials announced that five of the province’s 11 nuclear generators were out of operation.
The announcement only served to fuel the growing public and political controversy surrounding Ontario’s—and Canada’s—beleaguered nuclear program. In the Ontario legislature Premier William Davis did little to allay criticism by blandly observing that Ontario Hydro’s difficulties were “modest” in light of the 10 years the system has been in place and operating successfully. And there was little solace in Ontario Hydro’s announcement that a task force, headed by James Donnelly, president of Atomic Energy of Canada Ltd., and Patrick Campbell, Hydro executive vice-president of operations, will look into the soundness of pressure tubes in all 18 Candu reactors in Canada and the seven sold abroad. Hydro also declared that it would postpone a Nov. 13 start-up of another unit at its Douglas Point complex on Lake Huron. By week’s end, concern had spread to Ottawa where NDP MP James Fulton called for a royal commission into the issue. Although Energy Minister Jean Chrétien rejected the appeal and affirmed that nuclear energy in Canada is a viable source of power, his assurances did not allay mounting fears that the country’s entire atomic energy system was in jeopardy.
Ironically, the questions about the technical integrity of the Candu system came as Atomic Energy of Canada announced that final negotiations were under way with Turkey for the purchase of a 635-megawatt Candu reactor, which would be the first export sale for Canada’s nuclear system since 1981. Norman Rubin, a researcher for Energy Probe, an environmental group, said that the Pickering breakdown has “cut to the heart of the Canadian decision to build pressure tube reactors when the rest of the world has decided to build pressure vessel reactors”—controversial as those have been at sites such as Three Mile Island. The pressure tube reactors make inspection of the tubes virtually impossible while the reactor is operating. The reactors have to be shut
down for inspection. And the tubes must be made of zirconium, which it now seems becomes brittle and can break as the reactor is cooled. Rubin said that the incident ruins Hydro’s theory that the tubes would wear gradually and allow for ample warning and replacement.
Rising doubt over the Candu technology increased opposition to Ontario Hydro’s costly plans to replace the malfunctioning pressure tubes and to expand its nuclear energy network. Ontario NDP Leader Robert Rae told Maclean's that he is concerned about Hydro’s proposal for 70-per-cent nuclear electrical generation by the 1990s. Rae estimated that it could cost $700 million to replace the reactor tubing at Pickering alone—almost as much as the $750 million it cost to build the plant. Even without replacing the tubing, the cost of the five shutdowns has been astronomical. Hydro estimates that it is losing about $1.25 million a day. For his part, Ontario Liberal Leader David Peterson put the cost of failures and shutdowns over the past three months at $192 million. Rubin accused Hydro of “perpetrating a public relations hoax” and claimed the real costs of the shutdowns per day are $300,000 per unit more than Hydro’s estimates. Rubin also speculated that long-term costs of the reactor breakdown could be higher if Hydro cannot run the reactors at full capacity until tubes are replaced.
Hydro is still trying to determine the cause of the pressure tube rupture at Pickering and cannot predict when the unit will come back into service. Hydro Chairman Milan Nastich estimated that the cost of replacing all pressure tubes in four Pickering reactors would be $530 million. He said that the job, beginning in 1985, would take about 15 months per reactor and would cost an average consumer 60 cents a month for 10 years.
Hydro’s critics say that the pressure tube disaster is proof the utility should scrap its plans for further construction of nuclear plants. Rubin said that Hydro is being “stupid” in going ahead with the new Darlington plant, which is under construction east of Toronto, when most other utilities in North America have cancelled their nuclear building programs because of falling demand and high interest rates. “Hydro isn’t building Darlington to keep us from freezing in the dark. They are building it from habit,” he said.
Whatever the cause of the pressure tube rupture and subsequent assessment of the trustworthiness of reactor equipment, restoring the once-shining reputation of the Candu system is likely to take as long as replacing the 4,220 zirconium tubes in Ontario.
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