I just ran into the same issue trying to load up my save today. The error says "Corrupt map: unknown decorative prototype ID 1170." on the latest experimental version (2.0.19) and "Corrupt map. Unknown decorative ID: 1170." on the latest stable version (2.0.15).

The 3 previous autosaves are also ...

Really awesome addition to the reactor!
I just finished building one in my .17 playthrough, so it's cool to think about.
One thing that could be improved:
In the real world hotter things not only glow brighter, but a different colour. It goes from black to deep red to cherry to orange (look up ...