“Glass” is a generic term for a wide variety of materials. So is “metal”. Metal can be brittle, sometimes that’s even desirable. That’s what tempering and hardening are about.

A molten salt reactor is a material science problem. Conventional “metal” doesn’t work because of the corrosion. If glass has some desirable property then we can overcome the “bumping in to it” problem. Maybe with a hand rail. Or staying away from the operational nuclear reactor.

I’m not suggesting glass actually be used. I’m saying if it was I wouldn’t be surprised.