Reduction of deuterium loss by immersing Zr deuteride in liquid Na

Zr-deuteride pellets were encapsulated with and without Na. Deuterium released from the capsule was measured by quadrupole mass spectroscopy. The results show that Na significantly reduced the permeation flux of deuterium. The models were developed to analyze the experimental results. It was assumed that the rate limiting step is a dissolution process of deuterium from Zr deuteride to liquid Na. Hydrogen release from the hydride pin during operation was evaluated. Na increases the thermal conductivity between the pellet and the cladding, which lowers the temperature of the hydride pellet. It is concluded that Na-bonded pins have a great effect on reducing deuterium loss.