Environmental Engineering Reference
In-Depth Information
Examples of the licence renewal approach are the Russian and
Hungarian cases. For licence renewal, the regulations require the perfor-
mance of integrated plant assessment, focusing on the review of plant con-
dition, effectiveness of ageing management programmes and validation
of time-limited ageing analyses for the extended period of operation. In
Hungary, the national rules for licence renewal have been developed on the
basis of 10CFR54, the licence renewal rule of the U.S. Nuclear Regulatory
Commission. In Russia, the rules are defi ned within the context of national
regulation.
In this chapter - after an overview of the basic technical features of VVER
plants - the basic issues and methods for ensuring LTO of VVER plants will
be presented. The dominating degradation mechanisms of structures and
components limiting the operational lifetime of the plants will be identifi ed,
on the basis of operational experience and research results. The method for
evaluating the condition of the plant; review of existing plant activities for
ensuring the required performance and functionality of safety-related sys-
tems, structures and components; and development of ageing management
programmes and other related plant programmes are described. Integration
of particular plant programmes into a system that ensures safe LTO is shown
on the basis of particular examples. Trends and needs for future research are
also presented.
The presentation of the ageing issues will focus on the older VVER-
440/213 and VVER-1000 plants. The VVER-440/230 plants (Kozloduy
NPP, Bulgaria and Bochunice V1 NPP, Slovakia) are already on permanent
shutdown. In contrast to this, the Kola 1 and 2 and Novovoronesh 3 and 4
units in Russia have already received licences to operate for a further 15
years. This was after implementation of modernization and safety enhance-
ment programmes (Rosenergoatom, 2003) to cope with the safety issues
relevant to this design (IAEA, 1992). The LTO and plant lifetime manage-
ment of VVER-440/230 is not a generic practice and will be discussed below,
although only to a limited extent. The LTO of the VVER-440/213 plants
requires specifi c engineering effort and will be discussed in detail. From the
point of view of LTO, the newly designed and constructed VVER plants are
also of less interest. Obviously, they have been designed and manufactured
taking into account the ageing lessons learned from operational experience.
The question about the need and possibility of longer than designed opera-
tion of these plants is not on the agenda today.
8.2 Description of operating VVER reactors
In the sections below, the basic design characteristics of VVER plants are
presented. The design and manufacturing features which are relevant from
the point of view of LTO are discussed.
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