Jméno :Ing. Miroslav Švrček
Název :ASSESSMENT OF IRRADIATION SWELLING EFFECTS ON VVER-1000 CORE SHROUD
Autoři :ŠVRČEK M., PIŠTORA V., LAUEROVÁ D.
Abstrakt :Paper deals with calculation method used for assessment of influence of irradiation swelling on
VVER-1000 reactor internals, especially for assessment of core shroud durability and serviceability.
Swelling represents volume change of material under neutron irradiation. The associated material
degradation depends generally on neutron dose, exposure temperature and operational stresses. There
are two irradiation effects: First, gamma-radiation causes heat induction in the steel material, which
leads to local thermal gradients. Second, is the swelling itself. This leads to strain concentration in very
special locations (of high temperature and high neutron dose). In general, assessment of core shroud is
very complex and multitask problem. A lot of partial calculations have to be performed, such as
physical calculation to determine neutron dose and gamma fields, thermal-hydraulic one to obtain
ambient coolant temperatures and heat transfer coefficients, thermal (heat) calculation to determine
temperature distribution in core shroud, and stress-strain calculation to determine stress and strain
distributions necessary for subsequent fatigue assessment and determination of change of core shroud
shape.