Is it okay to apply RTV on radiator neck?

The up­per ra­di­a­tor hose was flared and al­lowed coolant to seep through caus­ing the ra­di­a­tor neck (plas­tic) to form cal­cium de­posit. I sanded the radiator neck using 120 grit sandpaper to remove the calcium deposit and ended up thinning the neck more than I should've. I replaced the upper radiator hose however pressure is leaking between the hose and the radiator neck. Can I use RTV on the radiator neck to seal the leak? If yes, then which RTV should I use (black, blue, gray, etc.)? And if no, then is there something else I can do (other than replacing the radiator)?