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IAEA CRP on Aging Management of
Concrete Containment Buildings
Dan J. Naus
First Consultancy on Assessment &
Management of Concrete Containment
Buildings and Other Structures
Vienna, Austria
29 May 2012
1
Olkiluoto NPP
In 1989 IAEA Initiated a Program to
Assist Member States in Understanding
and Managing Aging of NPP SSCs
“Safety Aspects of Nuclear Power Plant Ageing (IAEA-TECDOC-540),” January 1990
Increase awareness and understanding of aging and its relation to safety
Identify approach and actions needed to effectively manage NPP aging
“Methodology for Management of Ageing Of Nuclear Power Plant Components Important to Safety (IAEA Report 338),” 1992
Technical issues (e.g., safety impacts of aging, effectiveness of monitoring and mitigation techniques, and procedures to estimate future performance)
Methodologies for selection of key plant components important to safety and performing aging management studies
Representative components for pilot studies based on safety significance and aging susceptibility
Primary nozzle of reactor pressure vessel
Motor operated isolation valve
Concrete containment building
Instrumentation and control cables within containment building
2
Doel NPP
Pilot Studies Conducted on Management of
Aging of NPP Components
“Pilot Studies on Management of Ageing of Nuclear
Power Plant Components (IAEA-TECDOC-670),” October 1992
Phase I results provided for each of four components
Pilot study on concrete containment building
Design functions
Service conditions during normal/abnormal operating conditions
Potential degradation factors and aging mechanisms
Methods for mitigation of degradation
Phase II activities addressed aging of concrete containment buildings through a Co-ordinated Research Program
“Summary Results of the Survey on CCB Ageing (IAEA/NENS),” 1995
“Assessment and Management of Ageing of Major Nuclear Power Plant Components Important to Safety - Concrete Containment Buildings, (IAEA-TECDOC-1025),” June 1998
3
Thange NPP
Pilot Studies on Aging of NPP Components
Identified Several initial Objectives
Produce a summary of current
aging management practices and
experiences
Compile a state-of-the-art report
on repair techniques and materials
Develop crack mapping and
acceptance/repair guidelines
Develop a set of condition
indicators and associated
guidelines for monitoring aging
4
Worldwide Survey of Owners/Operators Conducted in
Support of CRP Objectives Provided Responses From
Over 150 Units in 15 Countries
Part 1: General Plant Information
Part 2: Inspection, Investigation, and Preventative Maintenance Programs
Part 3: Age-Related Degradation Experience
5
Concrete Containment Ageing Questionnaire
Part 2: Inspection, Investigation, and
Preventative Maintenance Programmes
8
Concrete Containment Ageing Questionnaire
Part 2: Inspection, Investigation, and
Preventative Maintenance Programmes (Cont.)
9
Instrument No. Installed Frequency of Routine
Recording
Times Used in Repair
Investigation
Identify Formal
Procedures Used
Strain Gauges
Thermocouples
Stress Cell
Humidity Gauge
Length Change
Others
Instrumentation/Monitoring:
A.1 Concrete - Instrumentation
Please complete the following table by identifying the instrumentation installed and details of recording:
Is data logging computerized? No _______ Yes _______
Is data compared to original design specification? No _______ Yes _______
Are operating limits defined? No _______ Yes _______
If yes, please provide details.
Concrete Containment Ageing Questionnaire
Part 2: Inspection, Investigation, and
Preventative Maintenance Programmes (Cont.)
10
Method
Frequency of
Routine
Inspection
Times Used in Repair
Investigation Procedure Used
Acceptance
Criteria
Pulse Velocity
Impact Hammer
Permeability
Leakage
Probe Penetration
Pullout
Others
Instrumentation/Monitoring (cont.):
A.1 Concrete - NDE/NDT
Concrete Containment Ageing Questionnaire
Part 2: Inspection, Investigation, and
Preventative Maintenance Programmes (Cont.)
11
Other Techniques Frequency Times Used in Repair
Investigation
Formal Procedure
Used
Acceptance
Criteria
Frequency of core drills for routine inspection _______ years
Number of core drills as part of repair investigation _______
Are formal procedures used? No _______ Yes _______ (identify)
Is concrete core obtained used to obtain material properties? No _______ Yes _______
Which of the following properties obtained? (Record yes or no)
Strength _______ Modulus _______ Chemical _______ Porosity _______ Others _______
A.1 Concrete - Others:
Are any other procedures used aspart of the inspection/monitoring of concrete? No ____ Yes ____
If yes, please fill in the following table:
Instrumentation/Monitoring (cont.):
A.1 Concrete - Cores
Concrete Containment Ageing Questionnaire
Part 2: Inspection, Investigation, and
Preventative Maintenance Programmes (Cont.)
12
Techniques Used
for Anchorage
Element Inspection
Frequency
of Routine
Inspection
Times Used in
Repair
Investigation
Details of Procedures
or Methods Used
Acceptance Criteria/Details of
Procedures and Methods Used
Visual
Pullout
Others
Instrumentation/Monitoring (cont.):
A.2 Anchorage Elements
Techniques Used
for Reinforcing
Steel Inspection
Frequency
of Routine
Inspection
Times Used in
Repair
Investigation
Details of Procedures
or Methods Used
Acceptance Criteria/Details of
Procedures and Methods Used
Visual
Half Cell
Cover Meter
Others
A.3 Reinforcing Steel
Concrete Containment Ageing Questionnaire
Part 2: Inspection, Investigation, and
Preventative Maintenance Programmes (Cont.)
13
Instrumentation/Monitoring (cont.):
A.4 Prestressing Steel
Techniques Used
for Prestressing
Steel Inspection
Frequency of
Routine
Inspection
Times Used
in Repair
Investigation
Details of Procedures
or Methods Used
Acceptance Criteria/Details of
Procedures and Methods Used
Liftoff Test
Load Cell
Visual
Mechanical
Property Tests on
Wires
Grease Chemistry
Others
Concrete Containment Ageing Questionnaire
Part 2: Inspection, Investigation, and
Preventative Maintenance Programmes (Cont.)
14
Techniques Used for
Inspection
Frequency
of Routine
Inspection
Times Used
in Repair
Investigation
Details of Procedures
or Methods Used
Acceptance Criteria/Details of
Procedures and Methods Used
Visual
Leak Test
Penetration Assemblies:
NDT
1. Ultrasonic
2. Local Leak Test
3. Others:
Seals:
NDT
1. Ultrasonic
2. Local Leak Test
3. Others:
Instrumentation/Monitoring (cont.):
A.5 Liner and Penetration Assemblies
Concrete Containment Ageing Questionnaire
Part 2: Inspection, Investigation, and
Preventative Maintenance Programmes (Cont.)
15
Activity Frequency Location Details of
Methods Used
Applicable to Other
Plant Structures?
1. Protective Coating
2. Grouting Refurbishment
3. Sealant Removal or Replacement
4. Cathodic Protection
5. Others:
Preventative Maintenance
B. Preventative Maintenance Programmes
IAEA has Published Two Reports that Address
Assessment and Management of Aging of NPP
Containment Buildings
Containment descriptions and
design basis
Service conditions and aging
mechanisms
Inspection and assessment
methods
Operating experience
Aging management program
22
Survey Results and Knowledge of Practice in
CRP Member’s Countries Used to Prepare
Report on Aging Management
Introduction
Concrete Containment Buildings
Understanding Aging
Detecting Aging
Assessment and Repair of Aging Effects
Operating Experience
CCB Aging Management Program
Conclusions and Recommendations
Appendix I: Current Aging Management Practices and Operating Experience of Several Member States
Appendix II: Aging Experience of Non-Nuclear Concrete Structures
23
Point Lepreau NPP
Chapter One Provides General
Introductory Materials Related to
Ageing Management of CCBs
CCBs are designed to separate the reactor and other systems and equipment important to safety from outside environment
External and internal events considered
Although typically designed to a specified service life, economic pressures and decommissioning strategies mean that CCBs may have to perform safety functions for an extended period of time (100+ yrs)
Age-related degradation must be effectively controlled to assure adequate leak-tightness and structural integrity
Faulty design
Use of unsuitable or poor quality materials
Improper construction
Exposure to aggressive environments
Excessive structural loadings
Accident conditions
24
Angra 1/2 NPP
A Number of Existing NPP Programs, such as Periodic
Inspection and Testing, or Preventative and Corrective
Maintenance, Contribute to Aging Management of CCBs
Existing Programs should be Integrated and Modified
(As Appropriate) Within a Systematic AMP
25
Chapter Two Provides a General Description of
NPP CCBs that have been Developed to Address
Different Reactor Systems
Composed of several
constituents that, in concert,
perform multiple functions
Designed, constructed,
operated, and inspected in
accordance with national and
consensus codes and standards
Construction of PCC
26
Typical Design Parameters
for Selected PWR Plants
27
Type Material Ref. Plant Int. Diam
(m)
Free Vol.
(103 m3)
Des. P
(kPa)
Des. Leak Rate
(% Vol./day)
Large Dry RC Hemi. Dome Indian Pt. 3 41 74 324 0.1
Large Dry St. Cyl. Hemi Dome Davis Besse 40 81 276 0.5
Large Dry PC Shallow Dome Zion 43 81 324 0.1
Large Dry PC Hemi. Dome Trojan 38 57 414 0.2
Ice Condenser St. Cy. Hemi. Dome Sequoyah 32 -- 74 0.5
Subatmospheric RC Hemi. Dome Surry 38 51 414 0.1
Lg. Dry
Prestressed
Ice Condenser
Subatmospheric
Typical Design Parameters
for Selected BWR Plants
28
Drywell Wetwell
Type Material
Ref. Plant Des.
Temp
(˚C)
Free Vol.
(103 m3)
Des.
Temp
(˚C)
Free Vol.
(103 m3)
Des.
Pressure
(kPa)
Des. Leak Rate
(% Vol/day)
Pre MK Steel Sphere Big Rock Pt. 113 33 --- --- 186 0.5
MKI Steel Peach Bottom 138 5 138 4 386 0.5
MKII Rein. Concrete Limerick 138 7 138 4 386 0.5
MKIII Rein. Concrete Grand Gulf 166 8 85 36 103 0.35
BWR MKI BWR MKII BWR MKIII
Primary Regulations, Codes, and Standards
Identified Relative to Design, Construction, and
Inspection of Concrete Containment Buildings
29
Chapter Four Summarizes Methods Most
Commonly Used as Well as Those that Represent
Good Practice for Detection of Degradation
32
Detection and Evaluation of Impact of Relevant
Aging Mechanisms is the Key to an Effective
Aging Management Program
33
Inspection Activities are Designed to Detect and
Characterize Degradation Before Fitness-for-
Service is Compromised
Aggressive Ions (P)
Coating Bond Performance (P)
Broken Wires (T)
Coating Thickness (P)
Weld Cracks (L)
Coating Distress (P)
Elongation (T)
Free Water Quantity (P)
Leakage (L)
pH Value (P)
Prestressing Force Loss (T)
Reinforcement Corrosion (R)
Structural Degradation (L, T)
Surface Cracks (L, P)
Ultimate Strength (T)
Wall Thickness (L)
Yield Strength (T)
Coa
tin
g M
easu
rem
ent
Cro
ss-C
ut
Tes
t
Fou
r-E
lect
rod
e M
eth
od
Gre
ase
Tes
ts
Ha
lf-C
ell
Po
ten
tial
Lif
t-O
ff T
est
Liq
uid
Pen
etra
nt
Loca
l L
eak
Tes
t
Ma
gn
etic
Pa
rtic
le T
est
Rate
of
Co
rro
sio
n P
rob
es
Ten
do
n M
ech
an
ica
l T
ests
Ult
raso
nic
Tes
ts
Vis
ua
l In
spec
tio
n
Evaluation Method
Property or Characteristic*
X
X
X
X
X
X
X
X
X
X
X
X X
X
XX
X
X
X
X
X
X
X
X
X
X
X
*L = liner, P = protective media, R = mild steel reinforcement, and T = tendon.
35
Instrumentation is Aimed at Providing Verification of Design
Assumptions, Monitoring Short-Term Performance, and/or
Monitoring Long-Term Performance
Vibrating-Wire Strain Gages
Thermocouples
Pendulums
Extensometers
Load Cells
Humidity Gages
Precise Level Surveying
36
Examples of
Concrete Embedded Sensors
Chapter Five Addresses Condition Assessment
and Remediation of Aging Effects
Reinforced concrete structures almost from time of construction can start to deteriorate in one form or another due to exposure to the environment
Condition assessment programs monitor progress of deterioration and provide input to develop and implement remedial actions
No active intervention
More frequent inspections
Carry out repairs to maintain or restore
Demolish and rebuild
Repair can restore a structure to its former condition and (hopefully) a lower deterioration rate and repair frequency
37
A Remedial Measures Program Includes
Diagnosis, Prognosis, Scheduling, Method
Selection, Preparation, and Application
38
Repair of Corrosion-Damaged Concrete Involves
Halting One of the Three Process Necessary for
Corrosion Occurrence: Anodic, Cathodic, and
Electrolytic
39
Although Overall Performance of Concrete
Containment Buildings has been Good,
Degradation Requiring Repair has Occurred
40
Chapter Six Provides a Summary of Operating
Experience Related to CCB Degradation,
Inspection, and Repair Actions
Information on Several Member States
Aging Management Practices was also Assembled
41
Responses Representing Over 150 Nuclear
Power Units were Received From
Owners/Operators in 15 Countries
42
Res
po
nd
ing
Co
un
try
Un
it T
yp
e
Most Frequently Reported Manifestation of
Concrete Degradation was Cracking
Freeze/thaw
Elevated temperature
Thermal gradient
Sulfate attack
Seawater exposure
Chemical attack
Leaching
Abrasion
Impact
Shrinkage
Sealant failure
Creep
Leakage test
Irradiation
Chloride penetration
Carbonation
Alkali/aggregate reaction
Fatigue/vibration
Stray electrical currents
Construction defects
Design defects
Other
Subtotal of events
Cra
ckin
g
Sca
lin
g
Del
amin
atio
n
Sta
inin
g
Spal
lin
g
Eff
lore
scen
ce
Pop
ou
t
Du
stin
g
Vo
ids/
ho
ney
com
b
Incr
ease
d p
erm
eabil
ity
Oth
er
Sub
tota
l o
f ev
ents
Manifestation and Numberof Incidences Reported
Degradation FactorReported
10
7
12
--
6
--
--
--
--
54
1
10
7
--
--
--
--
10
--
23
1
4
145
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
2
--
2
1
--
1
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
3
2
--
7
--
--
--
--
--
4
--
--
--
--
--
--
--
--
--
--
--
--
1
--
--
--
5
--
--
--
--
--
--
--
--
--
--
--
--
3
--
--
--
--
--
--
10
--
2
15
2
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
9
--
--
11
--
--
--
--
--
4
--
--
--
--
--
--
--
--
--
--
--
--
--
--
1
--
5
--
--
--
--
--
--
11
--
--
--
1
--
--
--
--
--
--
--
--
--
--
--
12
7
--
2
--
--
--
--
--
--
2
--
--
--
--
2
--
--
--
--
7
2
2
24
--
--
--
--
--
--
3
--
--
--
--
--
--
--
--
1
--
--
--
--
7
3
14
--
--
--
--
--
--
--
--
--
--
--
--
--
--
1
--
--
--
--
2
1
4
20
7
15
--
6
8
14
--
--
56
2
10
10
--
3
1
--
10
1
54
16
11
244
44
Age at Which Cracks were First Reported could
not be Determined and about Forty-Five Percent of
Incidences Reported Required No Action
46
The Most Frequently Reported Manifestation of
Metallic Material Degradation was Corrosion
Freeze/thaw
Elevated temperature
Sulfate attack
Seawater exposure
Chemical attack
Shrinkage
Sealant failure
Creep
Leakage test
Irradiation
Chloride penetration
Carbonation
Fatigue/vibration
Stray electrical currents
Construction defects
Design defects
Other
Subtotal of events
Rei
nfo
rcin
g s
teel
corr
osi
on
Pre
stre
ssin
g t
end
on c
orr
osi
on
Co
nta
inm
ent
pen
etra
tio
n
Pre
stre
ss l
oss
Su
bto
tal
of
even
ts
Manifestation and Numberof Incidences Reported
Degradation FactorReported
--
--
--
--
--
--
--
--
--
--
4
--
--
--
6
--
2
12
--
--
--
2
--
--
--
--
--
--
--
2
--
--
--
1
--
5
--
4
--
--
--
--
2
--
--
--
--
--
--
--
-
1
--
7
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
2
--
2
--
4
--
2
--
--
2
--
--
--
4
2
--
--
6
4
2
26
47
Most Commonly Used Methods of Inspection
were Prescribed by Codes and Regulations
Visual Inspection
Instruments
NDE/NDT
Coring
Pullout Tests
Half-Cell Potential
Cover Meter
Lift-Off Tests
Load Cell
Mechanical Tests
Grease Inspection
Leakage-Rate Test
Other Tests
Percentage of Unitswith this Element, %
Concrete Anchorage Reinforcing Prestressing Liner/ E lements Steel Steel Penetrations
Percentage of Units Utilizing, %
84
52
28
<1
--
--
--
--
--
--
--
--
5
99
73
--
--
--
1
--
--
--
--
--
--
--
5
65
26
--
--
--
--
6
3
--
--
--
--
--
--
99
26
--
--
--
--
--
--
18
45
16
16
--
3
65
53/--
--/--
--/10
--/--
--/--
--/--
--/--
--/--
--/--
--/--
--/--
53/30
--/8
68/100
InspectionTechnique
48
Visual Inspections of Concrete Structures were
Often Supplemented by Crack Mapping
Concrete visual inspection/crack mapping frequency
Summarized by percentage of units/owners responding
Crack mapping information summarized by
percentage of units/owners responding
49
Owners Supplementing Regulatory
Requirements Generally Used Longer
Inspection Intervals
Thermocouple
Strain Gauge
Stress Cell
Humidity Gauge
Invar Wire
Other
Percentage ofUnits Utilizing,
%
Percentage ofOwners Utilizing,
% Range Median
52
46
5
3
12
42
Number Used
20
17
10
5
5
10
27
103
8
1
4
--
8 to 1335
18 to 240
4 to 80
1 to 2
4
--
InstrumentationType
Leakage Rate
Impact Hammer
Pulse Velocity
Permeability
Others
Percentage ofUnits Utilizing,
%
Percentage ofOwners Utilizing,
%
26
17
17
5
5
24
7
10
5
12
Test Type
50
Chapter Seven Provides a Framework for an
Aging Management Program for CCBs
Objective is to Ensure Timely Detection and Mitigation of
Any Degradation that could Impact Safety Functions
51
Understanding Relevant Aging Mechanisms and
Their Potential Impact is the Key to an Effective,
Optimized AMP
Baseline, Construction and Commissioning, Operational History,
and Inspection and Surveillance Data, as well as Generic issues, Provide Data
52
Indicators of AMP Effectiveness Identified in
”Implementation and Review of NPP Ageing
Management Programme”
53
Details of the Containment’s Design/Construction and
Operational History are Required for Effective
Comparison or Correlation with External Experience
54
An Inspection/Monitoring Program must be
Defined as well as Criteria Against which Results
are to be Judged
To be Effective, an AMP should be Periodically Reviewed
and Updated to Reflect Plant Experience
55
Operate Plant Within Limits to Minimize Age-
Related Degradation, and, in Particular, Error-
Induced Degradation
It is Prudent to attempt to Control and Monitor the
Operating Environment of Inaccessible Parts of the CCB
Where Detection and Repair would be Difficult and Costly
56
Results help Provide Basis for Decisions
Regarding Type and Timing of Maintenance
Actions to Correct Detected Aging
57
Examples Illustrating Use of Performance Trending
as Part of an AMP and Use of Maintenance to
Reestablish Acceptable Performance
Example of how performance trending
can be used as part of
an aging management program
Example of how maintenance can be
used to reestablish acceptable
performance of a reactor building
58
Measu
red
Perf
orm
an
ce P
ara
mete
r
Re
ac
tor
Bu
ild
ing
Le
ak
ag
e R
ate
(% v
ol/
da
y a
t 1
24
kP
a)
Pa
inti
ng
Pro
gra
m (
% C
oa
ted
)
Chapter Eight Provides a Summary of CRP
Conclusions and Recommendations
Based on Input of Operators, Experience of CRP Participants,
and Information in Working Material Document
60
Coordinated Research Program on Concrete
Containment Buildings Derived Several
Conclusions
Performance of RC structures has been good, majority of identified defects initiated during construction and were repaired at that time
Techniques for detecting effects of concrete aging provide vital input for evaluating the structural condition of CCBs
Condition assessment methods for RC structures are well established and generally start with visual examination of the structure’s exposed surfaces
Concrete maintenance and repair techniques are well established and effective when properly selected and applied
Many utilities worldwide have responded to potential for CCB age-related degradation and implemented AMPs
Most effective AMPs had clearly defined and documented activities aimed at understanding, effectively monitoring, and mitigating aging
A framework for aging management of CCBs, consistent with existing IAEA guidelines, has been defined based on international experience and best practice
61
Confrentes NPP
Coordinated Research Program on
Concrete Containment Buildings Made Several
Recommendations
Utilities and Plant Owners that Do Not have an
AMP for CCBs should Build on Existing Aging
Management Activities to Develop a Systematic
AMP Based on Key Features of Understanding
Aging, Information Management, and Condition
Assessment
Information Exchange Initiated at the International
Level (IAEA, CSNI) should be Combined and
Expanded so that Individual Plant AMPs can be
Enhanced through a Wider Experience Database
Results Developed Under this CRP should be
Extended to Address Other Safety-Related
Concrete Structures
62
Construction of AECL NPPs