Which of these is not a way, or a proposed way, to store nuclear fuel rods after they have been used in a nuclear reactor? a) putting them in a deep pool of water b) burying them in a deep underground storage facility c) sending them on the shuttle to be suspended in space d) putting them in concrete/lead casks and sitting at the reactor site

The answer is C.)sending them on the shuttle to be suspended in space. This is the answer because  after  the nuclear fuel rods come out of the reactor, they go into a deep pool to cool off. Then they are then stored in concrete and lead-lined casks for dry storage, until, ultimately, the US government builds a deep underground storage facility to house them permanently. They are never sent on the shuttle to be suspended in space. It would be too costly and too dangerous.