Materials management strategies for VVER reactors - Materials' Ageing and Degradation in Light Water Reactors - page 296

Table 8.5 Identifi cation of the ageing mechanisms for civil structures and structural
components.

Component Degradation

location

Degradation process/ageing effect

Reinforced
concrete in
the hermetic
compartments

Reinforced concrete Corrosion/boric acid corrosion/

material loss
Change of material properties due
to heat/decrease of strength,
modulus of elasticity
Change of material properties due
to irradiation
Fatigue/crack initiation and
propagation
Settlement/increasing stress levels
breaking, cracking

Insertion elements Corrosion/boric acid corrosion/

material loss

Liner Fatigue/crack initiation and

propagation
Local corrosion/material loss/crack
initiation and propagation

Biological protection Change of material properties due

to heat/decrease of strength,
modulus of elasticity
Change of material properties due
to irradiation
Fatigue/crack initiation and
propagation
Corrosion/material loss
Settlement/increasing stress levels,
breaking, cracking

￿ ￿ ￿ ￿ ￿ ￿

Decontaminable
coatings

Change of material properties due
to heat and/or irradiation

Other reinforced
concrete
structures

Reinforced concrete Corrosion/boric acid corrosion/

material loss
Change of material properties due
to heat/decrease of strength,
modulus of elasticity
Change of material properties due
to irradiation
Fatigue/crack initiation and
propagation

Insertions Corrosion/boric acid corrosion/

chemical corrosion/material loss
( Continued )