"Old Tartarian “fireplaces"
Those where Radium reactors. The rods are used as the control rods. They used to drink and smoke Radium back then
This video shows the advertisements they used to sell Radium products.
it doesn't show how to make a Radium Reactor. though it's easy if you have enough radium.
Simply place Radium in a lead container drop the control rods and you have yourself a little nuclear heater for your living room.
https://www.youtube.com/watch?v=7lMSBKN7ey0