Oil filled radiator upcycle

So I've got my hands on two big soviet era oil filled radiators here in Bulgaria.
Could I incorporate them with my wood stove as thermal mass? Could I put them on each side of my stove to heat up or would something bad happen?

I am not sure about those heaters, on a rare occasion I had a mate killed when one caught on fire somehow.
Rocks, solid masonry, bricks are excellent thermal mass and could be safer.

I think they ought to work well as a thermal store. According to heatingtrends.com they are filled with Diathermal oil. I'm not quite sure what that is, however they state:

Diathermal oil, unlike water, has excellent thermal stability. It never reaches the boiling point, does not evaporate, and therefore does not expand so much and does not create critical pressure inside the radiator housing.

As long as the radiators do not appear damaged, they ought to be reasonably safe. The oil has a boiling point of about 300 degrees Celsius, but a pretty low rate of thermal expansion so the radiator doesn't get stressed. You might want to check what sort of temperature you do see next to the stove just in case.....