Thanks for the comments.
I have really lot of ideas in my head. I am targetting the most simple solution that will just work. Not endlessly, but at least for few days.
Obviously it is possible to get excess heat without any special material.
Important is, that it is easily replicable and it can be built with low budget.
As we can see in the latest Russian report, it can be made from a stainless steel tube and it can work probably well.
It was also used by Rossi. Of course it is not ideal, but we have to determine its limitations.
Hopefully tommorow I will find some time to do a tests.
My idea is to create reactor, that you can built really quickly and should last for at least few tests and especially can be easily opened and then quickly sealed if needed - without tinkering with a cements, epoxy, etc. Now we are moving to better part of research, because we know at least basics about this thing so we can satisfy always basic requirements - for example a proper sealing that will work always.
Also I want to improve fuel loading process so it is as safe as possible yet with the good results.