Based on the explosions and pictures of the wrecked buildings, I’d guess a lot of equipment and plumbing was destroyed.
The Stortz emergency water connection I was familiar with, was nothing more than a 4” pipe from outside the facility directly to the pool through about 10’ of reinforced concrete. Can’t imagine a low velocity H2 explosion damaging anything that is designed to be last ditch, reliable and simple. As far a cracked steel pit liner....its still contained by surrounding reinforced concrete. This lack of water in a cooling pit is not believable to me. If its leaking, add make-up water. I’m sure it doesn’t have ‘a big hole’ in it.