They are completely replacing the innards of Darlington. This came much earlier than anybody thought mainly because of the Water Laser Effect, which shook the bejeeesus out of the place. They smoothed the water flow with more vanes on the pumps, but that just reduced the effect from Terrifying to Terrible.
It is a great example of cravenosity (sic) that the regulators allow this to go ahead without re-evaluating the seismic basis of the plant. After all, it's been like 40 years when we first started on defining it. Look what's happened since:
We have clearly defined megathrusts right under the plant. And I was the one who proved that the Pickering Fault Doesn't Exist. That bit of brilliance put me out of a job. :) But now we have bigger and nastier faults. I would say the main seismic hazard has gone up a factor of 10 from the old 5% of g. We are looking at an easy M6 right under the plant, and an M7 out in Lake Ontario. All at the very low probability of 10-4, and it goes up steeply at 10-5, a cliff which is not good.
Nobody at the pansy regulator can understand what I'm saying. All the experts have gone, and the gov't has ditched most of the geo-scientists, only ones left just want to say long enough to turn the lights out.
So they just throw in the same old junk so it lasts another 20 years. And all for the measly price of a zillion dollars.
Do you know they did so much for that plant that they actually anchored the whole thing into the rock (and have probably rusted out). There are mitigating factors that go against the factor of 10 worsening of seismic hazard, but I'm not telling.
Warning: Don't pursue this. They got everything tied up tighter than Putin. We can start from our head putin down to the Ontario lilli-putins. I just use that name instead of the famous German guy. I mean, everybody has them! They feed on apathy, and make it worse in a vicious circle. This destroys the economy.