Materials management strategies for VVER reactors - Materials' Ageing and Degradation in Light Water Reactors - page 292

Table 8.3 Concept for ensuring long-term operation

Goals Ensuring

Safety functions/
performance

Production/
economy

Functioning of
the operating
organization

How Review, assessment and amendment of the plant programmes

Reconstitution of the TLAAs

Principles

− All systems, structures and components (SSCs) have to
be covered by certain plant programme(s), for example
preventive/corrective maintenance, ageing management,
scheduled replacement
− All ageing mechanisms have to be considered
− All plant activities have to be considered, that is the
routine activities should be integrated with those specifi c
to LTO
− Synergies have to be utilized

Results PLiM Programme for LTO

should also be considered when identifying the scope of AMPs. In some
VVER operating countries, the SSCs which are important for production
are also within the scope of AMP (e.g. turbine, cooling water system).

Identifi cation of ageing mechanisms

The identifi cation of ageing mechanisms and their effect on the safety is
based on the following information:

￿ Analysis of the operational experience

◦ Experience at the individual plant: events-related ageing, for example

￿ ￿ ￿ ￿ ￿ ￿

load cycles.
Experience at plants of the same design. ◦ Generic industrial experience.

￿

￿ Research results.

￿ Analysis of results of destructive and non-destructive tests.

￿ Review of the design assumptions regarding ageing.

After analysing these sources of information, the dominating ageing mecha-
nisms, critical locations and measures for ensuring the required status of
SCs can be identifi ed. A list of important mechanical systems and compo-
nents and the relevant ageing mechanisms are given in Table 8.4.
Examples for the identifi cation of the ageing mechanisms of cables are
given in Table 8.2 and more fully listed below in the table.