Thermal expansions of technetium-ruthenium alloys

Abstract

Technetium-99 is a long-lived fission product which contributes significantly to a beta radiotoxicity for a very long time in nuclear waste. The transmutation of 99Tc to stable 100Ru by neutron irradiation is an attractive option to reduce the long-term risk of the storage of high-level waste. In order to estimate the property and the behavior of technetium metal target for transmutation, rod-shaped samples of technetium-ruthenium alloys were prepared and characterized. The thermal expansions of Tc, Tc0.76Ru0.24, Tc0.51Ru0.49, Tc0.26Ru0.74 and Ru were measured by a push-rod dilatometer from room temperature to about 1300 K. The thermal expansion of Tc metal is larger than that of Ru metal. For Tc0.76Ru0.24, Tc0.51Ru0.49 and Tc0.26Ru0.74 alloys, the thermal expansion decreases with increasing ruthenium concentration. © 2002 Elsevier Science B.V. All rights reserved.