YC-backed [1] micro-reactor company Oklo won the RFP to supply an Alaskan air base with nuclear power to replace its current coal based energy system. Oklo has come a long way. They were part of the Summer 2014 batch according to their YC profile. Three years ago they suffered a hiccup when the Nuclear Regulatory Commission rejected their application to build and operate a reactor in Idaho:
https://news.ycombinator.com/item?id=29937836
They still need NRC approval, but replacing coal with nuclear power on a cold, remote air base is a great application for a micro-reactor.
[1] https://www.ycombinator.com/companies/oklo