Development of a Monitoring Technique for the Permeation Behavior of Tritium in Pure Nickel to Pure Water

A technique to monitor the permeation behavior of tritium in metals to pure water was successfully developed. A metal membrane separated two containers: one is for tritium loading as an upstream side, and the other is for tritium permeation release as a downstream side. Tritium was loaded by gas absorption at controlled temperatures of 303 K, 323 K, and 373 K and pressures of 4 and 8 kPa at the upstream side. Pure water in the downstream side was automatically and continuously circulated to a solid scintillation counting apparatus by which the tritium concentration in the pure water was directly measured for more than 100 h. When the present technique was applied, almost diffusional permeation behavior of tritium at the nickel-water interface was demonstrated.