The nuclear reactor at Chalk River, Ont. that once produced most of North America's supply of medical isotopes, will now not be back online until late April.
Atomic Energy of Canada Limited said Wednesday evening that a repair team continues to work around the clock, seven days a week, to get the NRU reactor, back online. But is said the earliest return-to-service date would now be the end of April.
The reactor has been down since May. Until then, it had supplied a third of the world's isotopes and 80 per cent of the isotopes for the Canadian medical market. As well, its products were used for other forms of nuclear science research.
When a tiny leak was found in the reactor last spring, it was hoped it would be shut down for only a month. But when the reactor was drained and more holes found, AECL announced there would be a long-term repair.
It had been hoped that the reactor would be back up by March. But with repairs going slowly, it now appears that won't happen until late April, and may even be later than that.
"Technical challenges with the repair sequence... continue to pose risk of schedule slippage. Further guidance on the return-to-service date will be provided when more information becomes available," the company said.
The repair is said to be highly complex. The team spent the first few months analyzing how to fix the reactor, and building mockups to practise on. Actual repair work didn't begin until Dec. 12.
After two months, the work is still only about 43 per cent complete. AECL said in a release Wednesday that preparations for the final repair sequence are underway. It says the repairs are complex and welders are practising on NRU mock-ups to qualify for the final repair sequence.
The NRU shutdown has left a huge hole in the world's supply of medical isotopes over the last year. Doctors have had to make do with an erratic supply or pricier foreign isotopes, as well as antiquated isotope alternatives. In many cases, doctors have simply used other, less precise, diagnostic tests.
Dr. Jean-Luc Urbain, president of the Canadian Nuclear Medicine Association, told a Commons committee last October that while most diagnostic tests haven't been cancelled, physicians have simply not been referring as many patients for nuclear tests as they once did.
He warned that without the early detection and assessment that nuclear medicine tests offer, many patients will see their cardiac diseases and cancers progress to a point where their death risk is higher, since they will be diagnosed later in disease progression.
The problem is only going to get worse in the coming weeks, as another reactor in the Netherlands that has taken up much of the slack in isotope production is now preparing to shut down for scheduled maintenance. The Dutch reactor is leaking tiny bubbles of gas into the primary cooling system.
It's also a tricky fix, with the cracked pipe encased in concrete, and the repair is expected to take six months.
