ASME B&PV Code for
In-Service Inspection of
Nuclear Containment
Buildings
Steven G. Brown, PE
Introduction
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Why is this of interest outside the nuclear industry?
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Acknowledgements
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Professional Development Hour
More than that – sharing information across various industries for
improvement of the profession
K. R. Rao – Campion Guide to ASME Boiler and Pressure
Vessel Code
Working Group Containment
Entergy
Disclaimer – The views presented are my own
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If it’s right, it’s because my mentors got it right,
If it’s messed up, it’s probably my original idea.
Terminal Objective
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At the conclusion of the class the engineer
will have a basic understanding of the
current rules requiring inservice inspection
of nuclear containment vessels.
Enabling Objectives
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State the purpose of containment vessel as
used at commercial nuclear power plants in
the US
Describe the general types of containment
vessels currently used in the US commercial
nuclear power industry.
State the difference between Class MC and
Class CC components.
State the regulations requiring inservice
inspection of nuclear containment buildings.
Enabling Objectives (cont)
Be able to state the section of ASME Code
providing requirements for inservice
inspection of Class CC components of
nuclear containment vessels.
 Discuss the type and frequency of inservice
examinations for nuclear power plant
containment vessels.

Purpose of Containment

10 CFR 50 - GDC 16 Containment
Designs - Key design requirement for all
U.S. commercial nuclear plants.
Establish an essentially leak tight barrier
against the uncontrolled release of
radioactivity into the environment
 Ensure that the containment design
conditions important to safety are cont
exceeded for as long as required for postaccident conditions.
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Typical Steel Containment Vessels
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Steel Pressure Vessel –
Class MC
Typically Carbon Steel
Approx. 40 to 60 psi
> 100 Feet Diameter
> 200 Feet Tall
Shell thickness 1.5” or
more
Concrete Shield Building
Containment Design Diagrams on this and
subsequent slides are from EPRI TM-102C
Typical Steel Containment Vessels
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BWR Mark I –
Class MC (typical)
Nominal 62 psi
Removable Head
Torus suppression
pool
Typical Steel Containment Vessels
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BWR Mark II (Shown) –
Clas MC Typical
Nominal 45 psi
Removable Head
Suppression pool below
BWR Mark III (Not
Shown) – May be MC or
CC
Large vessel with internal
drywell
Suppression pool internal
around drywell
Typical Concrete Containment
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Concrete Structure
with steel liner
Concrete provides
structural element –
Class CC
Steel liner provides
leak tightness – Class
MC
Typical Concrete Containment
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Post-Tensioned Concrete
Containment
Concrete is kept under
compression by a system
of steel tendons
Tendon system and rebar
are Class CC.
Provisions for Containment
Inspections and Testing

10 CFR 50 - GDC 53 – Containments shall
be designed to permit
Appropriate periodic inspection of all
important areas, such as penetrations
 An appropriate surveillance program
 Periodic testing at containment design
pressure of the leak tightness of penetrations
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Philosophy of Containment
Examination
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ASME IWE and IWL define requirements for
containment examination
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Preservice
Inservice
Requirements based on Industry Experience and
Environmental Conditions
Visual Examination of Containment
Testing for Tendons
Pressure / Leakage Testing per 10 CFR App J
History of Code Requirements
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IWE 1st published 1981 (Class MC Components)
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Weld Based Examinations
Very similar to rules for Class 1 and 2 nuclear
components.
Subsequently addressed general degradation of
surface areas
Incorporated by rulemaking (10 CFR 50.55a) in
1996
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Required all containments to be treated as MC or CC
Included conditions for use
History of Code Requirements
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IWL 1st published 1988 (Class CC Components)
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Provided rules for examination of concrete surfaces
Similar to regulatory requirements already in
Regulatory Guides 1.35 and 1.35.1
Regulatory Guides only required for post tensioned
containments
Incorporated by rulemaking (10 CFR 50.55a) in
1996
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IWL replaced use of the Regulatory Guides
Transition period was allowed for plants using
regulatory guides
Applicable to ALL concrete containments
Current Regulatory Requirements
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10 CFR 50.55a
Incorporates ASME B&PV Code Section XI by
reference with conditions
 References ASME Section XI Sub-Section
IWE for Class MC containments and Liners of
Class CC containments
 References ASME Section XI Sub-Section
IWL for Class CC containments
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Containment Leak Testing
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10 CFR 50 – Appendix J
Periodic testing of containment vessel and
penetrations
 Type A tests – Integrated Leak Rate Test
 Type B and C tests – Local Leak Rate Tests
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IWE Examinations
IWE-1100 SCOPE
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This Subsection provides requirements for
inservice inspection of Class MC pressure
retaining components and their integral
attachments, and of metallic shell and
penetration liners of Class CC pressure
retaining components and their integral
attachments in light-water cooled plants.
IWE Examinations
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Exempted Components
Components outside the boundaries of the
containment system
 Embedded or inaccessible portions of
containment (with limitations on what
modifications to plant can embed)
 Piping, pumps, and valves (examined per
either IWB or IWC)
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IWE Examinations
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General Schedule for Inservice
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10 year inspection interval
Divided into 3 inspection periods (3 or 4 years)
Provisions for shifting interval (and one of the periods)
by one year
Preservice (in general)
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Exam conducted prior to placing component inservice
Includes repair or replacement
Same exam as required for periodic inservice exam
IWE Examination Tables
IWE Examination Tables
IWE Details
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Category E-A Containment Surfaces
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E1.11 – Accessible Surfaces
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E1.12 – Wetted Surfaces of Submerged Areas
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General Visual Each Interval
VT-3 per 10 CFR 50.55a
E1.20 – BWR Vent System (Mark I)
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General Visual Each Period.
Includes Bolted Connections – VT-3 per 10 CFR 50.55a
General Visual Each Interval
VT-3 per 10 CFR 50.55a
E1.30 – Moisture Barriers
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General Visual Each Period
IWE Details – Moisture Barriers
IWE Details
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Category E-C Augmented Examination
Applicable to areas subject to accelerated
degradation or with previously noted
degradation
 E4.11 – Visible Surfaces
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 Detailed
Visual Each Period.
 VT-1 per 10 CFR 50.55a
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E4.12 – Surface Area Grid
 Ultrasonic
Period
Thickness Measurement (UT) Each
IWL Examinations
IWL-1100 SCOPE
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This Subsection provides requirements for
preservice examination, inservice inspection,
and repair/replacement activities of reinforced
concrete and the post-tensioning systems of
Class CC components, herein referred to as
concrete containments as defined in CC-1000
{Section III Design Code}.
IWL Examinations
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Exempted Components
Steel portions not backed by concrete
 Shell metallic liners
 Penetration liners
 Inaccessible tendon end anchorages (with
limitations)
 Concrete surfaces covered by the liner,
foundation material, or backfill or otherwise
obstructed. (Aging concerns for buried
concrete addressed in later editions of code.)
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IWL Examinations
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General Schedule for Inservice Examination
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1, 3, and 5 years following Structural Integrity Test
(SIT)
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10 years after SIT and every 5 years thereafter
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Within 1 year on either side of anniversary
Total inspection window of 2 years
1 year plus or minus 3 months for concrete repairs
Preservice
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Within 6 months on either side of anniversary
Total inspection window of 1 year
Similar to IWE
Unique role of RPE
IWL Examinations
Two Major Divisions
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Category L-A – Concrete Surfaces
 All
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concrete containments
Category L-B – Unbonded Post-Tensioning
System
 Post
tension design only
 Tendons divided by type
 Separate population for tendons impacted by
repairs
 Provisions for sites with multiple plants / units
IWL Examination Tables
IWL Details
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Category L-A Concrete Surfaces
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L1.11 – All Accessible Areas
 General
Visual Each Inspection to identify suspect
areas
 Resolution per RPE
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L1.12 – Suspect Areas
 Detailed
Visual
 Up close exam to determine if the area is a problem
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Performed by or under the direction of a
Registered Professional Engineer
IWL Details
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Category L-B Unbonded Post-Tensioning
Systems
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Sample Size
 Sample
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of Tendons
4 % of Each Type
Minimum of 4 and Maximum of 10
 Reduced
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sample for good inspection history
2 % of Each Type
Minimum of 3 and Maximum of 5
 Separate
population with reduced sample size for
tendons affected by repair
Overview of Post-Tension
Containment
Parts of a Tendon Anchorage
Exposed Tendon Anchorage
Uninstalled Tendon
Parts of a Tendon Anchorage
IWL Details
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L2.10 – Tendon
 Tendon
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Force / Elongation Test
Hydraulic Ram connected to end of tendon
Load cell measures force needed to lift tendon off of the
shims
 Common
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Tendon
One tendon is measured in each inspection
 Results
trended to ensure tendon stress remains
above the minimum needed by design for life of the
plant
IWL Details
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L2.20 – Wire or Strand
 Destructive
sample of one wire (typical tendon up to
186 wires) from one tendon of each type – NOT the
common tendon
 Visual exam for entire length
 Sample from each end, the middle and area of most
severe degradation tested for
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Yield Strength,
Ultimate Strength, and
Elongation
IWL Details
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L2.30 – Anchorage Hardware and Surrounding
Concrete
Visual – Entire Sample Population
 Includes:
 Detailed
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bearing plates,
anchor heads,
wedges,
buttonheads,
shims, and
concrete extending 2 feet from edge of the bearing plate.
IWL Details
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L2.40 – Corrosion Protection Medium
 Sample
from each end of each examined tendon
 Chemical analysis for:
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Water content,
Water soluble chlorides, nitrates, and sulfides
Reserve Alkalinity (expressed as milligrams of Potassium
Hydroxide)
L2.50 – Free Water
 The
amount of any free water (if any) contained in
the tendon cap is documented and analyzed to
determine pH.
IWL Examinations
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Additional 10 CFR 50.55a exam:
Grease caps that are accessible must be
visually examined to detect grease leakage or
grease cap deformations.
 Grease caps must be removed for this
examination when there is evidence of grease
cap deformation that indicates deterioration of
anchorage hardware
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Additional 10 CFR 50.55a
Requirements
The licensee shall evaluate the
acceptability of inaccessible areas when
conditions exist in accessible areas that
could indicate the presence of or result in
degradation to such inaccessible areas.
 Reporting Requirements
 Other provisions
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Objectives
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

State the purpose of containment vessel as
used at commercial nuclear power plants in
the US
Describe the general types of containment
vessels currently used in the US commercial
nuclear power industry.
State the difference between Class MC and
Class CC components.
State the regulations requiring inservice
inspection of nuclear containment buildings.
Enabling Objectives (cont)
Be able to state the section of ASME Code
providing requirements for inservice
inspection of Class CC components of
nuclear containment vessels.
 Discuss the type and frequency of inservice
examinations for nuclear power plant
containment vessels.

References
10 CFR 50.55a
 ASME B&PV Code Section XI,
Subsections IWE and IWL, 2004 Edition
 Rao, K. R. (editor), Companion Guide to
the ASME Boiler and Pressure Vessel
Code, 3rd Edition
 EPRI TM-102C
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Questions ?