Absorption behavior of radiolytic hydrogen under -ray irradiation on zirconium in nitric acid solution

Ishijima, Yasuhiro ; Ueno, Fumiyoshi  ; Abe, Hitoshi ; Sakai, Junichi*; Nojima, Yasuo*; Hashikura, Yasuaki*

Besause of good corrosion resistance in boiling nitric acid solution, some equipment in the nuclear fuel reprocessing plant has been made of zirconium (Zr). However, it is well known that Zr has susceptibility of hydrogen embrittleent by hydride formation. To evaluate radiolitic hydrogen absorption behavior, radiolytic hydrogen absorption tests and constant load tensile tests under -ray irradiation were carried out. From test results, the maximum value of absorbed hydrogen was 250 wppm. On the other hand, Zr did not failure in constant load tensile test under -ray irradiation until 1000 hr. These results shows that, Zr can absorb radiolytic hydrogen but hydride generation rate into the metal is very slow. And it is considered that it is improtant to evaluate hydride generation behavior under plant operation environment.