Internally coated zirconium nuclear fuel element can - with first rough surfaced zirconium oxide layer and second copper layer

摘要

A zirconium (alloy) fuel can has a two-layer internal coating, the first layer being of zirconium oxide having a thickness of 0.5-2.0 microns and a mean surface roughness of 0.5-3.5 microns and the second layer being of copper. The coating is pref. formed by treating the chemically roughened internal surface of the can with steam at 250-400 deg.C for 3-80 hrs. in an autoclave and then electrolessly plating with copper. A pref. alloy comprises 1-2% Sn, 0.05-0.2% Fe, 0.05-0.15% Cr, 0.03-0.1% Ni and balance Zr. The zirconium oxide layer provides firm anchoring of the copper layer and prevents diffusion between the copper and the zirconium can and permeation of hydrogen to the can.