Materials management strategies for VVER reactors - Materials' Ageing and Degradation in Light Water Reactors - page 304

Table 8.8 Examples for ageing monitoring programmes of structures and structural components

Building or part of the
building

Structure Aim of the

monitoring

Measurements Evaluation and criteria

Main building complex:
all buildings,
including reactor
and auxiliary
buildings, stacks,
diesel-building and
other structures

Reference points Building

movements;
settlement; control
of stability of
cracks caused by
movements

Fixed geodetical
measuring points;

3D evaluation of building movements;
correlation with groundwater table;
allowable declination of vertical axis
of reactor pressure vessel defi ned by
functioning of CRDM

Reactor building: fl oor
slabs and walls

Heavy reinforced
concrete

Interaction with
boric acid media

Investigation of
samples; inspection
of check-holes

Control of mechanical and chemical
properties and comparison with
reference values

Reactor building,
turbine building,
intermediate
building and
galleries: fl oor slabs
and walls

Reinforced
concrete

Control of possible
leakages and
consequent
leaching

Investigation of
samples; inspection
of check-holes

Control of mechanical and chemical
properties and comparison with
reference values

Reactor building: fl oor
slabs and walls

Carbon steel liner Control of

corrosion rate,
identifi cation
of possible
leakages

Ultrasonic control of
liner wall thickness
at the identifi ed
places

Control of corrosion rate and thickness;
focused investigation if the overall
leak tightness is less than the
reference value for the given unit
(comparison with allowable leak rate)

Reactor building and
auxiliary building:
fl oor slabs and
walls

Decontaminable
coating and
painting

Control of
condition of
coating and
painting

Walk-down and visual
control according to
checklist

Expert judgment

Main building complex:
all building parts

Hatches, gates,
penetrations,
fi re protection
doors;

Control of condition
of doors

Walk-down and visual
control according to
checklist, fl uorescent
test

Expert judgment