Subject: Maintaining Constant Temperature, Isolated Energy Container

Is there a way to have a container maintain a constant temperature/amount of 
energy with no energy leaving or coming in? For example if I were to place an 
iron ball that was heated to 200 degrees in a box could I have it maintain 
that temperature with no outside energy source to maintain it (the iron ball 
not trying to equalize with ambient environment)? I was wondering for heat if 
the ball was placed in vacuum box and was magnetically (permanent magnet) 
levitated that would eliminate conduction heating. I was wondering if there 
was a way to retain or block the Electromagnetic waves from going out or 
coming in (photon of light and heat wave characteristics). The box structure I 
believe would be able to eliminate kinetic energy. I read the tokomak uses 
electromagnetic system to shield the walls. However, if there is another way 
that does not require energy. Thanks for the consideration.

Re: Maintaining Constant Temperature, Isolated Energy Container