What is the value of a 1972 double struck nickel which was struck twice in the exact same place if the date is clear and the head is clear?

If it is certified by one of the recognized authorities on error coins, it could be worth up to $385. That's what the latest copy of the Numismatic News Coin Market lists for the 1972 doubled die variety in Uncirculated condition. Even the slightest amount of wear will reduce that value dramatically. But it is possible that you have a much more common (and basically worthless) example of "die bounce". The doubled die error occurs only when the doubling is actually on the striking surface of the die and all coins struck by that die will show identical features.