CERENKOV LIGHT IMAGES OF LWR NON-FUEL ASSEMBLIES

Year
1989
Author(s)
G.J. Young - Atomic Energy of Canada Limited
A. Nilsson - Swedish Nuclear Power Inspectorate
N. Danielsson - Swedish Nuclear Power Inspectorate
J. D. Chen - Atomic Energy of Canada Ltd.
P. Vodraska - International Atomic Energy Agency
A. Nakaoka - Central Research Institute of Electric Power Industry
Abstract
A series of tests was performed at a pressurized- water reactor (PWR) and a boiling-water reactor (BWR) in Sweden to study the \"near-neighbour effect\" on non-fuel assemblies that were constructed to simulate irradiated assemblies. Two types of non-fuel assemblies of PWR and BWR design were constructed. One type had the fuel rods f i l l e d with helium and the second was a skeleton whose fuel rods had been removed. To assess the near-neighbour effect, the non-fuel assembly was placed in the centre of a 3 x 3 irradiated fuel assembly matrix. The cooling time of the neighbouring assemblies ranged from 0.5 to 4 years and the burnups ranged from 19 000 to 40 000 MUd/t U. Three types of Cerenkov Viewing Devices were used in the tests, and the results were documented with the help of photographs. The observations and interpretation of the Cerenkov images from the non-fuel assemblies are discussed.