Thursday, January 22, 2009

The Disaster of the Niagara Tunnel - Part 1

Sometime soon, when the birdies start to sing, and the snow melts, we will hear the grand judgment of our finest political minds, as to what nuclear design Ontario will choose. It will be down to the perfidious French or the plague-struck AECL.
Now, as always, people will eventually be attuned to the tremendous cost overruns. But should we be? Shouldn't we just throw in those cost overruns a the beginning, as a normal event? For example, Pt. Lepreau had a chance to 'lock in' costs at $450 million over a standard nuclear estimate. They chose to go for the lower estimate and absorb any cost overruns. They will soon be up to the same value!

Now, for the wonderful cost overruns that we should expect for Ontario, we only have to look at the saga of the Niagara Tunnel, in all its glory. This is especially relevant, since all the people who started this, are now in charge of the new nuclear build.

It all started a long time ago, children. That was in the wild days of the end of the Victorian (gas lamps, Sherlock Holmes) and the beginning of the Edwardian (electric lights, machine guns). Niagara Falls was a gold rush! People started riddling it with tunnels and sucking away all the water. It was realized that soon there wouldn't be a drop of water to go over the falls (a waste of good energy!), and a political battle ensued, between US and Canadian power producers, and the namby-pamby tourist lovers. A treaty was formed that allocated exact amounts of water for each country, and the amount for the pretty falls, which could be cut back at night when nobody was looking.

Now, most of that allocation got used up pretty quickly over the next fifty years, especially once the twin tunnels came into play. With that system, they could totally suck up all the water, and they did so, on occasion, when they had to repair the falls.

In my beginning years I had many tales of the twin tunnels from those who actually put them through. They essentially used the last solid rock layer above the Queenston Shale, which was the Whirlpool Sandstone. Because of the roof, they started out as a horseshoe, but tended to go into a box.

This was very fortunate for our tunnelers, who also left the tunnels unlined for some time, allowing the rock to move.

That would normally be the end of all new development, and no new tunnel, except for the fact that the old power stations were falling apart! They were either being hammered by the relentless erosion of the Niagara River upon the shitty shale, or they had the dreadful 'Rock Squeeze Disease". Now, RSD is a horrible condition for a tunnel. As the Toronto Power wheelpit showed, it did not matter how much concrete was in the lining, everything got crunched up anyway.

Thus, the demolition of these plants allowed a water allocation gap. The Americans with their lawyers were clamoring for 'use it or lose it', and they wanted to steal it all. We Canadians had to do something for national pride. Thus, we have the delicious irony that the new tunnel was formed out of the very forces that now threaten to destroy it!

Now, while I was there, we looked at this for thirty years, and could never find a good use for this little scrap of water. Nothing seemed worthwhile! But we had a giant reorganization, all the smart geotechnical guys went to Hong Kong, I went to Nuclear, and we had the leftovers in Niagara. At some point, it came to a head: The Americans were about to seize our water! Without a speck of practical knowledge, the Canadians came back with a desperate plan!

It all depended on making an absolutely perfect fantasy tunnel directly between the upper river and the pumped storage. This dammed lake being a place to store the water stolen at night, and they had to extend the height. Thus, they could siphon that small amount of water, and feed it through the established plant.

Of course, to even conceive of the fantasy tunnel, they would have to get rid of all memory of the horrible rock conditions, and this was no problem for them; they got somebody from Europe! A fantasy tunnel would have to be a perfectly smooth bore, done by a tunnel boring machine, and requiring a minimal concrete erosion liner. This had been done somewhere in the world.

Fantasy Tunnel with Thin Liner

Now why was the layout of this fantasy tunnel so important? It's because it was a very long tunnel, and you can only get so big with a used tunneling machine (cheaper!). They had very little room to work with! As well, nasty old physics was working against them in the form of a cubed law for water flow down a tube. The teeniest increase in the liner thickness had a huge effect! In fact, they could notice the effect of summer scum on the flow of the twin tunnels!

So, the tunnel boring machine had to bore glass-smooth walls for this to work. And somewhere in the world somebody took pictures of this, so it had to work!

But, alas, the best laid plans of mice and managers oft go to the crapper.

-to be continued with suitable pennies thrown.

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