I will "assume" you are referring to a ½" check valve coming from the foot well suction fitting to pump 1, first confirm it is ½", or is it 2". Check valves should be available from any spa store, plumbing supply etc. When the spa was emptied, the check valve continued to hold water and subsequently froze causing the fracture.
Secondly, I would suggest keeping the insulation you dug out, putting it into plastic grocery "Tee Shirt bags", and stuff them back into the cavity created minimizing the need and cost for a large amounts of "new sprayed in foam".