Fission gas behaviour during power transients in high burn-up LWR nuclear fuels studied by electron microscopy
A transmission electron microscope study was carried out on UO(2) nuclear fuel samples which had been subjected to short term in-reactor power transients, involving an increase of the fuel temperature of about 300 C. Under steady state operating conditions most of the fission gas (Xe, Kr) is retained in solution in the oxide fuel matrix, or is precipitated into a population of very small fission gas bubbles (less than 3nm diameter). This bubble population is subjected continuously to re-solution and re-nucleation, and large fission gas bubbles are not able to grow. In contrast, in fuels with about 4.5% FIMA burn-up, containing about 0.5 at% Xe and 0.6 at% Kr as fission gases, subjected to an increase in temperature through a power transient, a population of large fission gas bubbles grows, which is almost invariably associated with the dislocation networks. The implications of the growth of this fission gas bubble population are discussed.
Bibliographic Reference: Paper presented: NATO Advanced Research Workshop on Fundamental Properties of Inert Gases in Solids, Bonas (FR), Sept. 16-21, 1990
Availability: Available from (1) as Paper EN 35544 ORA
Record Number: 199110865 / Last updated on: 1994-12-02
Original language: en
Available languages: en