Determination of low hydrogen concentrations in liquid sodium using a continuons analyzer

Determination of the hydrogen content in liquid sodium in dependence on the temperature of a cold trap and on injections of different hydrogen concentrations into the argon gas cushion is described. Measurements were carried out in a convection sodium loop by means of a monitor using the principle of hydrogen diffusion through a nickel membrane into a space evacuated by an ion pump. The results confirmed that the temperature of the cold trap controls the hydrogen concentration in the sodium loop, and proved that operating the cold trap decreased the hydrogen concentration in sodium in dependence on time, which could suitably be demonstrated by the monitor. The results showed that the sensitivity of the monitor was such that it reliably measured the 4% change in hydrogen activity in liquid sodium for the given system, at a concentration level of 0.1 ppm, and thus also its applicability for alarm signalling of water leaks into sodium for fast reactor steam generators. (author)