This paper presents the results of study on radiation degradation occurring
in WWER-440 reactor pressure vessel (RPV) steel, using subsize impact spec
imens (5 x 5 x 27.5 mm(3)). The results of testing trepans and templates cu
t out from WWER-440 reactor pressure vessels are considered. Ductile-to-bri
ttle transition temperatures DBTT) obtained using standard Charpy and subsi
ze impact specimens are compared. The relation between these two values is
established. (C) 2000 Elsevier Science S.A. All rights reserved.