History of Science and Engineering Annotation << Back Modernization of VVER-1000 Surveillance Programs Erak D.Yu. Kochkin V.N. Zhurko D.A. Panferov P.P. Evaluation of the RPV material properties behavior during operation according to generally accepted world practice is carried out using tests of surveillance specimens. The main objective of the surveillance program of surveillance specimens irradiation conditions in VVER-1000 which have been put consists of insurance of safe reactor pressure vessel operation to the end of the design life time and possibility of life time extension. Preliminary calculated-experimental analysis into operation at last century, shows that specimens in one-level assemblies are irradiated with delay relative to the RPV and neutron flux gradient in the assemblies is very high, which doesn’t allow forming testing groups of specimens for testing. So, the surveillance program of VVER-1000, operated more than 15 years, should be upgraded. VVER-1000 surveillance program modernization should performed considering significant changing in surveillance specimens irradiation conditions caused by new type fuel assemblies installing in the core. This paper studies some features of VVER-1000 surveillance program, and opportunities of upgrading of surveillance sets for reactors’s lifetime extension up to 60 years or more. Keywords: VVER-1000; surveillance specimens program; lead factor; neutron flux. Contacts: E&#8209;mail: erak@mail.ru Pp. 142-153.