Experimental Studies of the Equilibrium Between Zircaloy and Tritium During Hot Isostsatic Pressing of Spent Fuel Hulls

Abstract

The purpose of the study is to establish the HIP conditions, that results in a complete densification of Zircaloy-2 hulls and also gives a minimum of tritium (T) contamination of the HIP gas.

At HIPing only 20-40 ppm of the added T was released to the HIP gas, which corresponds to specific tritium activity of 5-10Bq/L gas at 20°C, 1 atm. To gain a better understanding of the system Zr-H- experimental result have been compared with equilibrium calculations. Tritium containing Zircaloy hull and probably also reactor hulls can be HIP-ed at a temperature of 1000-1050 C for a time of 2 hours at a pressure of 100 MPa without much tritium contamination of the HIP gas and result in a fully dense Zircaloy block suitable for an efficient self containment of rad waste.