Materials management strategies for VVER reactors - Materials' Ageing and Degradation in Light Water Reactors - page 300

structures, etc., at the plant are within the scope. Most of these building
structures are complex, and heterogeneous from the point of view of struc-
tural design, layout, manufacturing and construction of members, material
composition and contact with environment (Katona et al ., 2009a).
In the case of the Paks NPP, it would be diffi cult to adopt the AMPs
described in the GALL Report (US NRC, 2010), where nine groups of
building structures and seven groups of structural components are defi ned,
and ten ageing management programmes cover the whole scope. At the
Paks NPP the large number and variety of building structures and struc-
tural components requires establishment of a hierarchical structure of age-
ing management programmes.
Type A programmes have been developed for foundations, reactor sup-
port structures, building movement, reinforced concrete structural members,
high temperature concrete, equipment foundations, steel and reinforced con-
crete water structures, liners (Carbon-steel), prefabricated panels, masonry
walls, earth structures, doors and hatches, steel-structures, cable and pipe
supports, paintings and coatings, SS-liners, cable and pipe penetrations, fi re
protection structures, main building settlement, support structures of cabi-
nets, seals and isolation and corrosion in a boric acid environment. These
programmes are related to specifi c structures, that is structural commodities
or specifi c ageing mechanisms (e.g. building settlement due to soft soil con-
ditions). An exceptional A-type programme is the control of leak tightness
of the containment, which is related to the containment only.
The buildings having identifi ed safety functions are composed from struc-
tural commodities. Using these type A programmes for specifi c structures
(commodities), 30 type B programmes have been developed which cover all
plant building structures. These AMPs contain the identifi cation of ageing
effects and mechanisms to be managed, the lists and details of the proper
application of type A AMPs to be applied, while managing the ageing of the
given building. The type B AMP also contains logistical type information
since the accessibility of certain buildings is limited.

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8.4.2 Steps for the development of AMP

The AMP can be developed in the following sequence:

1 Identifi cation of degradation mechanisms and locations susceptible to

ageing

2 Identifi cation of the mitigation and preventive measures

3 Identifi cation of the parameters to be controlled

4 D e fi nition of the method for the detection of ageing effects

5 D e fi nition of the monitoring, trending, condition evaluation