It is mostly Harpers decision.  Although it is true that it is passed by the commons, the conservatives will vote how Harper tells them to.  

The outcome of most votes is largely known beforehand, since political parties normally instruct members on how to vote. A party normally entrusts some Members of Parliament, known as whips, with the task of ensuring that all party members vote as desired. Members of Parliament do not tend to vote against such instructions, since those who do so are unlikely to reach higher political ranks in their parties.

This is a rather rare situation in Canada as we currently have a minority government - so at least one other party agreed with Harper on this, I'm not really sure which one.

It's true that the medical community was a bit upset - it seems to me though that Harper was more worried about the longterm effects of the medical community finding another source than they he was about providing the medical isotopes.  

The problem I have with pebble bed reactors is that they contain the fuel too well, essentially making it unreprocessable. If we only burn the U-235 component, our uranium reserves really aren't all that large. To say that current reactors can use burned fuel is not in general true, since there are very few breeder reactors operating.

Have you compared fuel prices lately? The days of cheap uranium are over. Natural uranium is only about 0.7% U-235. A pound of U3O8 after enriching losses only gives you about 0.004 pounds U-235 at an enrichment of around 4%. Fission energy gives about 2x10^9 kWh(thermal) per ton. At the price peak this summer of $135/pound, this gives a cost of $135*2000/0.004/2e9= 3.4 cents/kWh(thermal). Compare this to coal at $62/ton and 6150 kWh/ton = 1 cent/kWh(thermal) or natural gas at $8/MMBTU = 2.7cents/kWh(thermal). Where's your cheap nuclear fuel now?

Even at the current price of $90/ton, this still leaves uranium prices at 2.25 cents/kWh(thermal). Modern reactors generally get about 1.3 - 3 times as much energy out as there is U-235 in their fuel, since they burn some U-238 as well, but this still leaves them paying comparable fuel prices to coal plants. With all the extra capital costs, just how do you expect them to make money?

As far as nuclear safety goes, why is it that we are so concerned about radiation from nuclear plants, when coal plants release many, many times as much radiation?

I'm not as concerned about the plant being turned back on, as I was about the Nuclear Safety Commission being overruled by a politician.  If I can't trust the nuclear safety commission to declare a plant safe, then who can I trust - the politicians?