jaro wrote:
darryl siemer wrote:
Download Fiorina's... topic - it's interesting that decades of neutron absorption by natural Zirconium in CANDU pressure tubes, does not significantly shift the isotopic composition to less absorbing Zr isotopes.
For similar reasons (having to do with Avogadro's Number), I would expect a HfN coating to last some years as well.
Coating failure is generally caused by its peeling off, cracking etc., not by its being totally dissolved off or "transmuted" to something else. In this case, it's realistic to assume that the fraction of Hf transmuted per year will be on the order of 3% (barns * 10^24cm^2* flux/cm^2/s * #seconds/year). If the resulting composition changes cause cracking, etc., then the coating will fail to protect whatever it's covering.
Per Peterson pointed this out to me when I'd suggested nickel plating the stainless steel guts of a fluoride salt-based MSR. In any case, it's something that only real-world experimentation will prove one way or the other.
The latter (...only real-world...) was the gist of my "question" to DOE's head NE R&D honcho after his talk last night.