Unexpected Conversion of Stainless Steel to Lead

[Bituvo]

The technic manual says to use stainless steel blocks for one of the layers of a nuclear reactor. So I, not knowing it would all be converted into lead blocks, built it, and was surprised when it happened. The relevant code appears to be here. The reactor should work with either stainless steel or lead blocks if this is the case. I lost a lot of stainless steel this way.