If you put in a bank account that is inactive, don't worry. When the refund gets sent to the bank, it should be denied due to the account being inactive. Once it is denied, the refund will be given back to the IRS and they will send a paper check to the address on file.
It does take a little longer to receive the check, but you can call the IRS for updates on where your check is at +1(800) 829-1040.