Looking at some articles I decided to calculate it.
An i7 3930K gives you about 60 MH/s the IBM Sequoia (6th most powerful computer in the world) is about 175,000 of those which equates to 10,500,000 MH/s or 10,500 GH/s. An ASIC does 14000 GH/s.
That running 24/7 gets you 0.351920 bitcoin in a year or ~$3,000 a year. Sequoia costs ~$25,000 in energy per day.
Not even close to worth it.
That would be if you just mined straight from the chain. Most miners use pool mining to increase the chance of hitting a block. This makes it difficult to calculate, plus built into the chain is the assessment of mining difficulty. You'd want to pulse the super computer so it didn't get calculated into the difficulty thus maxing profits. I believe most supercomputers also run on energy credits negotiated with the state in which they exist. All that said ASIC's mining is more efficient and specifically designed so I doubt anyone has tried it besides what I can only assume is an underpaid nuclear scientist.