Creep affects the performance of engineering components. The data on t
he creep rate of materials during the actual service condition is requ
ired to predict the performance of the components during their service
time. During the life of a nuclear reactor, its main structural compo
nents are affected by thermal and irradiation creep. Availability of d
ata on the irradiation creep behaviour of materials is restricted due
to the availability of limited irradiation space for testing in the re
actors, and due to the complexity of irradiation rigs for creep testin
g. Small size pressurised capsules which are simple in construction an
d occupy less volume are widely used for generation of data on irradia
tion creep behavior of materials. This paper discusses the details of
pressurised capsules developed at IGCAR for determination of irradiati
on creep behaviour of stainless steel and zirconium alloys.