Klepfer, H. H.
Manager, General Electric Company, San José, Calif.
Kosanke, H. D.
Advanced Nuclear Applications, Nucleonics Laboratory, Vallecitos Nuclear Center, Pleasanton, Calif.
Esch, E. L.
Engineer, General Electric Company, San José, Calif.
Pages: 14 Published: Jan 1969
In the course of post-irradiation examinations of Zircaloy-2 clad fuel rods, it was recognized that it might be possible to detect hydriding of the cladding by using neutron radiography. Experiments were performed by applying indirect transfer methods for neutron radiography since direct exposure with a photographic film would not be appropriate with highly radioactive specimens. After neutron irradiation, dysprosium indirect transfer screens were put in contact with X-ray film for approximately 24 h. The X-ray film negatives were analyzed with a densitometer. Neutron radiography was shown to be effective for detection of hydrogen in thin-walled Zircaloy-2 tubing to a lower limit of 500 to 700 ppm. Using a densitometer of 1 percent precision, a sensitivity of about ±400 ppm through the center of the tube and ±200 ppm through the wall of the tube at the 1000-ppm level was obtained. The neutrographic technique was also used to detect local concentrations of zirconium hydride in irradiated Zircaloy-2 fuel cladding which were not identifiable by other non-destructive means. The method, though not sensitive below 500 ppm hydrogen is, nevertheless, useful. Using neutron radiography, it is possible to determine whether chemical analyses give values representative of the hydrogen concentration in an entire fuel rod; the complete distribution of hydrogen in the cladding can be determined.
neutron radiography, zirconium alloys, neutrographs, hydrogen determination, hydrogen content, hydriding
Paper ID: STP43840S