<a href=showthread.php?s=&postid=14892466#post14892466 target=_blank>Originally posted</a> by melev
It looks like an area that may be under quite a bit of stress, but I'm not seeing the entire reactor. PVC can be glued to PVC with the cement, so technically it should mend. However, the outer section of plumbing will probably need to be supported.
The other option is to carefully remove what is left in the reactor, and glue in some new PVC in that spot. Just use the PVC solvent, without the primer. Let it cure for 24 hours before getting it wet again.
EDIT: It looks like a threaded fitting. If that is the case, you should be able to screw in the new piece where the old one was. Just be very careful in removing the old, trying not to damage the reactor's acrylic.