The US did a similar thing at Camp Century [1] on Greenland. They installed a PM-2A nuclear reactor there, as far as I know they relayed very sparse information to the Danish goverment during the time, especially about the secret Project Iceworm [2].
There was a danish article about it with some good pictures of the camp including one which looks like a part of the reactor [3]
[1]: https://en.wikipedia.org/wiki/Camp_Century