There are eight nuclear reactors at the Pickering site, all connected to a single vacuum building that serves as a common “containment structure” in the event of any major nuclear accident. The vacuum building is designed to suck up the radioactive steam and gases in the event of extensive core damage to one of the reactors. It was not designed to handle the simultaneous malfunctioning of two or more reactors, as occurred at Fukushima Dai-ichi in 2011, where there were three simultaneous core meltdowns.
The core of a CANDU reactor is a horizontal cylindrical vessel called a “calandria”, containing hundreds of coaxial “fuel channels”, running horizontally from one end of the calandria to the other. Each fuel channel consists of an inner “pressure tube” surrounded by an outer “calandria tube”. When the reactor has operated for 30 years at full power, the fuel channels are so weakened by heat, pressure, corrosion and radiation, that they need to be replaced along with the hundreds of “feeder pipes” connected to the hundreds of fuel channels at each end of the calandria.
If any of the pipes in the primary cooling system were to break, there would be a “loss-of-coolant accident” or LOCA. If the LOCA is a large one, there could be core damage and consequently radioactive releases. So the integrity of the pressure tubes, the calandria tubes, and the feeder pipes, as well as the thousands of tubes in the “steam generators” or boilers, is of great importance not only to the plant, but to the surrounding population.
The operation of “rebuilding” the primary heat transport system in a CANDU reactor by replacing all the pressure tubes, calandria tubes and feeder pipes, is called “refurbishment”. It is a very expensive and time consuming operation that has to be carried out in high radiation fields with airborne contamination a constant threat to the workers. In 2007, over 500 workers (mostly tradesmen) carrying out a refurbishment operation at the Bruce nuclear complex, right beside Lake Huron, inhaled plutonium-laden dust for a period of several weeks because they were told there was no need for them to wear respirators. No one was ever held to account for this inexcusable safety lapse.
At one point around 2000, four of the Pickering reactors (the “A” units) were supposed to be refurbished at a total cost of $1.3 billion. Only two were actually refurbished — units 1 and 4 — at a unit cost four times greater than the original estimate, and in a time frame more than three times longer than planned. The other two “A” reactors — units 2 and 3 — have been permanently shut down, and it was decided NOT to refurbish the other four reactors (the “B” units).
Now Ontario Power Generation (OPG) — the crown corporation that owns all the operating Ontario reactors — is “pushing the envelope” by operating the “B” units beyond their design lifetime, WITHOUT having replaced the deteriorating pipes. Here is what the CEO of Hydro Quebec said about this questionable practice, testifying to a Legislative Committee in Quebec City in January of 2013:
“I can tell you that Hydro-Québec’s management in no way would have considered to go beyond [the prescribed lifetime limit]. I would no more operate Gentilly-2 beyond [the prescribed lifetime limit] than I would climb onto an airplane that does not have its permits and that does not meet the standards. So, it is out of question to put anyone, i.e. us, the workers, the public, and the company, in a situation of risk in the nuclear realm.”
Indeed, Quebec actually shut down its only operating CANDU reactor, Gentilly-2, in December of 2012, having decided not to spend the enormous sum of money needed to refurbish it. OPG, on the other hand, has decided to run the four Pickering B reactors beyond the prescribed lifetime limit without the benefit of refurbishment.
In Quebec, the government had to step in and order the Gentilly-2 reactor shut down. In Ontario, the government could step in and order the Pickering reactors shut down, but apparently they are in a gambling mood. Unfortunately, they are gambling not only with rate payers’ money, but with their lives — as well as the fate of the entire Ontario economy. One (or more) catastrophic reactor accident at Pickering could make large parts of Toronto uninhabitable for many decades, and contaminate Lake Ontario and the St. Lawrence River with radioactive poisons.
Homeowners and private businesses cannot buy insurance against such a catastrophe. Every private insurance policy has a “nuclear exclusion” clause that voids all coverage in the event of radioactive contamination from a nuclear accident. The Government of Canada has a law on the books to provide for a tribunal that will adjudicate any insurance claims, without the benefit of any individual insurance policies. It’s a heck of a way to run an industry.
Gordon Edwards.
