NUREG-161 1

Aging Management of Nuclear

Power Plant Containments for

License Renewal

U. S. Nuclear Regulatory Commission

Office of Nuclear Reactor Regulation

W. C. Liu, P. T. Kuo, S. S. Lee
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NUREG-161 1

Aging Management of Nuclear

Power Plant Containments for

License Renewal

Manuscript Completed: September 1997

Date Published, September 1997

W. C. Liu, P. T. Kuo, S. S. Lee

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

U.S. Nuclear Regulatory Commission

Washington, DC 20555-000 1

ABSTRACT

The Nuclear Regulatory Commission (NRC) published its license renewal rule,

Title 10 of the Code of Federal Regulations (10 CFR) Part 54, on May 8, 1995,

providing the requirements for renewal of operating licenses for nuclear power

plants. 10 CFR 54.21(a)(1)(i) requires an aging management review of

containment structures to ensure that the effects of aging will be managed so

that their intended functions will be maintained for the period of extended

operation. In 1990,*the Nuclear Management and Resources Council (NUMARC), now

the Nuclear Energy Institute (NEI), submitted for NRC review, the industry

reports (IRs), NUMARC Report 90-01 and NUMARC Report 90-10, addressing aging

management issues associated with PWR containments and BWR containments for

license renewal, respectively.

Recently, the Commission amended 10 CFR 50.55a to promulgate requirements for

inservice inspection of containment structures. The final rule on §50.55a,

"Codes and Standards for Nuclear Power Plants; Subsection IWE and Subsection

IWL," was published in August 1996. This rule incorporates by reference the

1992 Edition with the 1992 Addenda of Subsections IWE and IWL of Section XI,

Division 1, of the American Society of Mechanical Engineers (ASME) Boiler and

Pressure Vessel Code addressing the inservice inspection of metal

containments/liners and concrete containments, respectively.

The purpose of this report is to reconcile the technical information and

agreements resulting from the NUMARC IR reviews and the inservice inspection

requirements of Subsections IWE and IWL as promulgated'in §50.55a for license

renewal consideration. This report concludes that Subsections IWE and IWL of

Section XI, Division 1, of the ASME Code as endorsed in §50.55a are generally

consistent with the technical information and agreements reached during the IR

reviews. Specific exceptions are identified and additional evaluations and

augmented inspection activities for renewal are recommended.

iii iii NUREG- 161 1

CONTENTS

Page

ABSTRACT............................................................ ii

ABBREVIATIONS ........................................................ vii

LIST OF TABLES .... I...................... ............................. ix

1. INTRODUCTION.......................................................1I

2. LICENSE RENEWAL EVALUATION OF AGING MANAGEMENT OF CONTAINMENT

STRUCTURES ........................................................ 1.

3. CONCLUSIONS ...................................................... 2

REFERENCES .................................................. ......... 4

TABLES

1. AGING MANAGEMENT OF PWR CONTAINMENTS FOR LICENSE RENEWAL ............. 7

2. AGING MANAGEMENT OF BWR CONTAINMENTS FOR LICENSE RENEWAL ............. 27.

APPENDICES

A IMPLEMENTATION HIGHLIGHTS OF SUBSECTIONS IWE. AND IWL THROUGH

10 CFR 50.55a.............................. I......................4

B LIST OF PWR CONTAINMENT COMPONENTS ................................. 49

C LIST OF BWR CONTAINMENT COMPONENTS ................................. 50

V NUREG-1611

ABBREVIATIONS

ACI American Concrete Institute

AISC American Institute of Steel Construction

ARDM Age-Rel ated Degradation Mechanism

ASME American Society of Mechanical Engineers

ASTM American Society for Testing and Materials

BWR Boiling Water Reactor

CS Carbon Steel

CFR Code of Federal Regulations

CR0 Control Rod Drive

ECCS Emergency Core Cooling System

GSI Generic Safety Issues

IR Industry Report

ISI Inservice Inspection

IWE Subsection of ASME Code, Section XI, "Rules for Inservice Inspection

of Nuclear Power Plant Components," containing "Requirements for

Class MC and Metallic Liners of Class CC Components of Light-Water

Cooled Plants"

IWF Subsection of ASME Code, Section XI, "Rules for Inservice Inspection

of Nuclear Power Plant Components," containing "Requirements for

Class 1, 2, 3, and MC Component Supports of Light-Water Cooled

Plants"

IWL Subsection of ASME Code, Section XI, "Rules for Inservice Inspection

of Nuclear Power Plant Components," containing "Requirements for

Class CC Concrete Components of Light-Water Cooled Plants"

NEI Nuclear Energy Institute

NRC Nuclear Regulatory Commission

NUMARC Nuclear Management and Resources Council

ppm Parts per million

PWR Pressurized Water Reactor

RG Regulatory Guide

SS Stainless Steel

SCC Stress Corrosion Cracking

vii vii NUREG-1611

LIST OF TABLES

ix ix NUREG- 1611

TABLE 1. AGING MANAGEMENT OF PWR CONTAINMENTS FOR LICENSE RENEWAL

Page

Concrete & Steel Containment One-time Inspection................... 7

Concrete Structure - Aging Mechanisms

Freeze-Thaw ................................................ 8

Leaching of Calcium Hydroxide................................ 9

Aggressive Chemical Attack .................................. 10

Reaction with Aggregates .................................... 11

Elevated Temperature ........................................ 12

Irradiation of Concrete..................................... 12

Concrete Interaction with Aluminum........................... 13

Structural Steel & Liner - Aging Mechanisms

Corrosion.................................................. 14

Elevated Temperature........................................ 15

Irradiation of Steel........................................ 15

Stress Corrosion Cracking ................................... 16

Reinforcing Steel - Aging Mechanism

Corrosion of Embedded Steel .................................. 17

Reinforcing Steel & Prestressing Tendons - Aging Mechanisms

Elevated Temperature ........................................ 18

Irradiation of Steel........................................ 19

Containment Structures & Components - Aging Mechanism

Fatigue ................................................... 20

Containment Structure & Its Concrete Basemat - Aging Mechanisms

Settlement................................................. 21

Erosion of Cement .......................................... 22

Containment Structure & Its Components - Aging Mechanism

Strain Aging of Carbon Steel ................................ 23

Concrete Containment Prestressing Tendons - Aging Mechanisms

Stress Relaxation of Prestressing Wire, Shrinkage Creep,

Anchorage Seating Losses, and Tendon Friction................. 24

Corrosion of Tendons........................................ 25

Containment Pressure Retai~ning Components - Aging Mechanism

Mechanical Wear ............................................ 26

xi xi NUREG-1611

Table 2. AGING MANAGEMENT OF BWR CONTAINMENTS FOR LICENSE RENEWAL

Page

Concrete & Steel Containment One-time Inspection .................

Concrete Structure - Aging Mechanisms

Freeze-Thaw.........................

Leaching of Calcium Hydroxide ......... Aggressive Chemical Attack.......

Reaction with Aggregates ............. Elevated Temperature ................. Irradiation of Concrete..............

..............

..............

..............

..............

..............

..............

27

28

29

30

31

32

32

Structural Steel & Liner - Aging Mechanisms

Atmospheric Corrosion ...................... Local Corrosion............................

Elevated Temperature ....................... .Irradiation of Steel .......................

Stress Corrosion Cracking...................

.................

.................

.................

.................

.................

Reinforcing Steel (Rebar) - Aging'Mechanism

Corrosion of Embedded Steel.................................

-Reinforcing Steel & Prestressing Tendons - Aging Mechanisms

Elevated Temperature.......................................

Irradiation of Steel.......................................

Containment Structures & Components - Aging Mechanism

Fatigue ..................................................

Containment Structure & Its Concrete Basemat - Aging Mechanisms

Settlement.................................................

Erosion of Cement .........................................

Containment Structure & Its Components - Aging Mechanism

Strain Aging of Carbon Steel ...............................

Concrete Containment Prestressing Tendons - Aging Mechanisms

Stress Relaxation of Prestressing Wire, Shrinkage Creep,

Anchorage Seating Losses, and Tendon Friction................

Corrosion of Tendons.......................................

Containment Pressure Retaining Components - Aging Mechanism

Mechanical Wear.................... :............... I........

33

34

35

35

36

.37

38

39

40

41

42

43

44

45

46

xiii xiii NUREG- 1611

1.0 INTRODUCTION

Part 54 of 10 CFR, the license renewal rule, was published on May 8, 1995,

providing requirements for renewal of operating licenses for nuclear power

plants. 10 CFR 54.21(a)(1)(i) requires an aging management review of

structures and components within the scope of license renewal to ensure that

the effects of aging will be managed so that their intended functions will be

maintained for the period of extended operation. Containment structures are

subject to this requirement.

Recently, the Commission amended 10 CFR 50.55a to promulgate requirements for

inservice inspection of containment structures. The final rule on §50.55a,

"Codes and Standards for Nuclear Power Plants; Subsection IWE and Subsection

IWI," was published on August 8, 1996 (61 FR 41303). This rule incorporates

by reference the 1992 Edition with the 1992 Addenda of Subsections IWE and IWL

of Section XI, Division 1, of the American Society of Mechanical Engineers

(ASME) Boiler and Pressure Vessel Code addressing the inservice inspection of

metal containments/liners and concrete containments, respectively [References

1 and 2]. Guidance for implementation of the containment inspection

requirements is described in Appendix A of this report.

In 1990, the Nuclear Management and Resources Council (NUMARC), now the

Nuclear Energy Institute (NEI), submitted for NRC review, ten industry reports

(IRs) addressing aging issues associated with specific structures and.,

components of nuclear power plants for license renewal. Of the 10 IRs, one

addresses PWR containments, and another addresses BWR containments [References

3 and 4]. No safety evaluations were developed for the review of these IRs.

However, NUREG-1557 provides a brief summary of the technical information and

NUMARC/NRC agreements resulting from the review of nine of the 10 IRs. The

NUMARC Report 90-08, "Low-Voltage, In-Containment', Environmentally-qualified

Cable License Renewal Industry Report,"[Reference-5] is not addressed in this

NUREG since the subject is being addressed under*GSI-,168.

On August 26, 1996, the Commission issued Draft Regulatory Guide DG-1047,

"Standard Format and Content for Applications to Renew Nuclear Power Plant

Operating. Licenses." for public comment as part of the implementation of

10 CFR Part 54, the license renewal rule. A comment was received concerning

whether the NRC staff had any plans to limit the scope of license renewal

review for containments since the final rule on 10 CFR 50.55a, which endorses

the 1992 Edition with the 1992 Addenda of Subsections IWE and IWL, was

published on August 8, 1996. The purpose of this NUREG is to reconcile the

technical information and agreements resulting from the NUMARC IR reviews and

the inservice inspection requirements of Subsections IWE and IWL as

promulgated in §50.55a for license renewal consideration.

2.0 LICENSE RENEWAL EVALUATION OF AGING MANAGEMENT OF CONTAINMENT STRUCTURES

The NRC staff reviewed Tables 83 and B4 of NUREG-1557 [Reference 5] for the

PWR and BWR containments, respectively, to determine if Subsections IWE and

IWL inspection requirements are consistent with the technical agreements from

the IR reviews. Where NUREG-1557 indicates that an aging effect on specific

I 1 NUREG-1611
structures is non-significant, the NRC staff recommends no aging management

program. Where NUREG-1557 indicates that'an aging effect is non-significant

if certain conditions are met, the NRC staff reviewed Subsections IWE/IWL and

§50.55a to determine if the containment inspection requirements would be

adequate to manage that aging effect regardless of whether those conditions

are met. Where NUREG-1557 indicates that an aging effect should be managed

with specified programs, the NRC staff reviewed Subsections IWE/IWL and

§50.55a requirements to determine if they are adequate to manage that aging

effect for the renewal term. If the NRC staff determined that Subsections

IWE/IWL and §50.55a requirements should be augmented to manage a certain aging

effect for the renewal term, additional inspections or evaluations are

recommended. The results of the NRC staff evaluation are provided in Tables 1

and 2 of this report for the PWR and BWR containments, respectively. The PWR

and BWR containment structural components evaluated in NUREG-1557 are listed

in Appendix B and Appendix C of this report, respectively.

3.0 CONCLUSIONS

The NRC staff has reconciled the technical information and agreements from the

NUMARC IR reviews and the inspection requirements of Subsections IWE/IWL as

promulgated in §50.55a for managing the effects of aging for PWR and BWR

containments for the period of extended operation. The staff found that the

requirements of Subsections IWE/IWL and §50.55a will be an effective aging

management program for managing the aging effects of containment structures

for-the period of extended operation, provided that the following additional

evaluations and inspections specifically for license renewal are also

performed:

a. Specific requirements contained in Part 54, the license renewal rule, such

as Part 54. 4 for scoping and intended function, and Part 54.21 for

evaluating time-limited aging analyses.

b. ASME Section XI, Appendix VII and Appendix VIII [References 6 and 7] to be

implemented-when ultrasonic examinations are utilized for inspection of

contai nments.

c. The following issues, in addition to implementing Subsections IWE/IWL

through §50.55a, should be addressed in a license renewal application:-

(1) Management of potential aging effects of structures in inaccessible

areas when conditions in accessible areas may not indicate the

presence of or result in degradation to such inaccessible areas.

This is discussed in Items 1, 3, 4, 9, and 13 of Table 1 for PWR

containments, and in Items 1, 3, 4, 9,*and 13 of Table 2 for BWR

containments of this report.

(2) Fatigue associated with containment penetration bellows and

penetration sleeves. This is discussed in Item 16 of Table 1 for

PWR containments, and in Item 16 of Table 2 for BWR containments of

this report.

NUREG-16112 2
(3) Settlement associated with containment concrete basemat bearing on

soil or piles, or experiencing significant changes in ground water

conditions. This is discussed in Item 17 of Table 1 for .PWR

containments, and in Item 17 of Table 2 for BWR containments of this

report.

(4) Erosion of cement for porous concrete if subfoundation layers of

porous concrete are used in the construction of containment concrete

basemat with the presence of underground water. This is discussed

in Item 18 of Table 1 for PWR containments, and in Item 18 of Table

2 for 8WR containments of this report.

(5) Performance of examinations specified in Examination Category E-B

for pressure retaining welds, and Examination Category E-F for

pressure retaining dissimilar metal welds of Subsection IWE for

license renewal. This is discussed in Item 12 of Table 1 for PWR

containments, and Item 12 of Table 2 for BWR containments of this

.report.

(6) Cracking of penetration bellows.

Table 1 for PWR containments, and

containments of this report.

This is discussed in Item 12 of

Item 12 of Table 2 for BWR

(7) Elevated temperature of prestressing tendons for (prestressed)

concrete containments. This is discussed in Item 14 of Table

PWR containments, and Item 14 of Table 2 for BWR containments

this report.

1I

of

for

The NRC staff recommends that the requirements

through §50.55a, and those items identified in

above be incorporated into the Standard Review

(SRP-LR).

of Subsections IWE and IWL

sections 3.a. through 3.c.

Plan for License Renewal

3 3 ~NUREG-161 1
REFERENCES

1. Subsection IWE, "Requirements for Class MC and Metallic Liners of Class CC

components of Light-Water Cooled Power Plants," Section XI, Division 1,

Boiler and Pressure Vessel Code, American Society of Mechanical Engineers,

New York, N.Y., 1992 Edition and 1992 Addenda.

2. Subsection IWL, "Requirements for Class CC Concrete Components of LightWater Cooled Power Plants," Section XI, Division 1, Boiler and Pressure

Vessel Code, American Society of Mechanical Engineers, New York, N.Y.,

1992 Edition and 1992 Addenda.

3. "Pressurized Water Reactor Containment Structures, License Renewal

Industry Report," NUMARC Report Number 90-01, Revision 1, Nuclear

Management and Resource Council, September 1991.

4. "BWR Containments, License Renewal Industry Report," NUMARC Report Number

90-10, Revision 1, Nuclear Management and Resource Council, December 1991.

5. NUREG-1557, "Summary of Technical Information and Agreements from Nuclear

Management and Resources Council Industry Reports Addressing License

Renewal," U.S. Nuclear Regulatory Commission, October 1996.

6. Appendix VII, "Qualification of Nondestructive Examination Personnel for

Ultrasonic Examination," Section XI, Division 1, Boiler and Pressure

Vessel Code, American Society of Mechanical Engineers, New York, N.Y.,

1989 Edition.

7. Appendix.VIII, "Performance Demonstration fofr' Ultrasonic Examination

Systems," Section XI, Division 1, Boiler and- 0?ressure Vessel Code,

American Society of Mechanical Engineers, New'York, N.Y., 1989 Addenda.

8. NRC Information Notice 97-10, "Liner Plate Corrosion in Concrete

Containments," March 13, 1997.

9. NRC Information Notice 97-11, "Cement Erosion from Containment

Subfoundations at Nuclear Power Plants," March 21, 1997.

10. NRC Regulatory Guide 1.35, Revision 3, "Inservice Inspection of Ungrouted

Tendons in Prestressed Concrete Containments," July 1990.

.11. ACI 201.2R-77, "Guide to Durable Concrete," American Concrete Institute."*

12. ACI 215R-74, "Consideration for Design of Concrete Structures Subjected to

Fatigue Loading," American Concrete Institute."*

13. ACI 318, "Building Code Requirements for Reinforced Concrete," American

Concrete Institute.**

NUREG- 16114 4
REFERENCES (Continued)

14. ACI 359, "Code for Concrete Reactor Vessel and Containments," American

Concrete Insti~tute.**

15. NRC Information Notice 92-20, "Inadequate Local Leak Rate Testing," March

* 3, 1992.

16. Letter from T. F. Plunkett of the Florida Power and Light Company to

.Stewart D. Ebneter of NRC, dated January 25, 1993i.

*:denotes that the citation is used as a reference to provide only

background information.

5 5 ~NUREG- 1611

TABLE 1. AGING MANAGEMENT OF PWR CONTAINMENTS FOR LICENSE RENEWAL

Component,Aging I

Item Mechanism & Aging IIssue and Evaluation* ______Effects

01 Concrete & Steel

Containment

Aging mechanism:

Not applicable.

Aging effects:

General

Issue: A "one-time inspection for license

renewal." NUREG-1551 states that one time

inspection is an unresolved issue regarding

staff request for inspection of concrete

containment & steel containment to assess the

current condition of containment and to

provide a baseline information for any future

inspections (Page B-28 of NUREG-1557).

Recommendation: The issue is resolved with the

implementation of IWE/IWL through §50.55a.

However, specific-recommendations for

applicable aging effects are addressed

hereinafter in this table.

Discussion: Subsections IWE and IWL require

periodic inspection of the'containment in

accessible areas. These inspections would

periodically assess the condition of the

containment and each inspection would provide

a documented baseline for subsequent

inspections. Furthermore, §50.55a(b)(2)(ix)(E)

and (b)(2)(x)(A) require an evaluation of

inaccessible areas when conditions exist in

accessible areas that could indicate the

presence of or result in degradation to such

inaccessible areas.

However, the management of potential aging

effects of inaccessible areas, when conditions

in accessible areas may not indicate the

presence of or result in degradation to such

inaccessible areas, is addressed individually

for each applicable aging effect (i.e., Items

1, 3, 4, 9, and 13 of this table). Conditions

for such inaccessible areas should be

evaluated for license renewal. A program for a

one-time inspection may be proposed.

7 7 NUREG-1611
-I02 Concrete Structure

Aging mechanism

Freeze-thaw

Aging effects:

Scaling, cracking,

& spalling

Issue: NUREG-1557 states that freeze-thaw is

non-significant if the following conditions

are met: concrete containment structures

located in a geographic regions of negligible

weathering conditions (weathering index <100

day-inch/yr); and if located in severe

(weathering index >500 day-inch/yr) or

moderate (100-500 day-inch/yr) weathering

conditions with the concrete mix design meets

the air content & water-to-cement ratio

requirements of ASTM C260 or equivalently, the

ASME Sect. III, Division-2, paragraph CC

2231.7.1. The issue of whether freeze-thaw is

potentially significant for the concrete

containment dome, particularly in severe

weathering regions, is identified as

unresolved (Page B-29 of NUREG-1557).

Recommendation: The issue is resolved with the

implementation of IWL.

Discussion: Freeze-thaw results in scaling,

cracking, and spalling. Any freeze-thaw

degradation would initially appear in the

exposed concrete structure. Subsection IWI,

Examination Category L-A, requires periodic

visual examination of accessible concrete

surfaces and would detect any freeze-thaw

damage of the concrete containment, including

the dome, regardless of whether the above

weathering conditions are met.

NUREG-1611I 8
I. I.

03 ,Concrete Structure

Aging mechanism:

Leaching'of calcium

hydroxide

Aging effects:

Increase of

porosity &

permeability

Issue: NUREG-1557 states that leaching of

calcium hydroxide is non-significant for

containment concrete structures if the

foll 'owing conditions are met: concrete

structures not exposed to flowing water; and

for concrete 'structures that are exposed to

flowing water but are constructed using the,

guidance of ACI 201.2R-77 to ensure dense,

well-cured concrete with low permeability andcontrol cracking through proper arrangement

a Ind distribution of reinforcement (Page B-29

of NUREG-1557).

Recommendation: The issue would be managed

with the implementation of IWL through

§50.55a. .However, the management of potential

leaching of ca 'lcium hydroxide of inaccessible

areas of containment concrete structures when

conditions in accessible areas may not

indicate the presence of or result in

degradation to such inaccessible areas needs

to be justified on a plant-specific basis.

Discussion: IWL, Examination Category L-A,

requires periodic examination of accessible

concrete surfaces and §50.55a(b)(2)(ix)(E)

requires an evaluation of inaccessible areas

when conditions exist in accessible areas that

could indicate the presence ofor result in

degradation to such inaccessible areas.

Regardless of whether the above conditions are

met, potential leaching of calcium hydroxide

would be detected as water stains on

ac 'cessible surfaces by the IWL visual

examination. However, the management of

potential leaching of calcium hydroxide of

inaccessible areas (e.g., below grade portion

of concrete structures with presence of

flowing water) when conditions in accessible

areas may not indicate the presence of or

result in degradation to such inaccessible.

areas, needs to be evaluated on a plant

specific basis.

9 9 NUREG-1611
T V

04 Concrete Structure

Miing mec hanism:

Aggressive chemical

attack

Aging effects:

Increase of

porosity and

permeability,

cracking, and

spalling

Issue: NUREG-1557 states that aggressive

chemical attack is non-significant for above

grade concrete containment structures because

they are not exposed to ground water.

Aggressive chemical attack is non-significant

for below grade concrete containment

structures if the following conditions are

met: containment concrete is not exposed to

aggressive ground water (pH <5.5, chloride

>500 ppm, & sulfate >1500 ppm); or if exposed

to ground water that exceeds the pH, chloride,

sulfate limits, the exposure is for

intermittent periods only. NUREG-1557

indicates that inspection of concrete

containment structure should be in accordance

with IWL. NUREG-1557 states that evaluation

for management of inaccessible areas of below

grade concrete containment structures is to be

justified on a plant-specific basis (Page B-30

of NUREG-1557).

Recommendation: The issue would be managed

with the implementation of IWL through

§50.55a. However, the management of potential

aggressive chemical attack of inaccessible

areas of containment concrete structures when

conditions in accessible areas may not

indicate the presence of or result in

degradation to such inaccessible areas needs

to be justified on a plant-specific basis.

Discussion: Aggressive chemical attack results

in increase of porosity and permeability,

cracking and spalling. IWL, Examination

Category L-A, requires periodic examination of

accessible concrete surfaces and

§50.55a(b)(2)(ix)(E) requires an evaluation of

inaccessible areas when conditions exist in

accessible areas that could indicate the

presence of or result in degradation to such

inaccessible areas. Regardless of whether the

above conditions are met, potential aggressive

chemical attack would be detected by IWL and

*§50.55a(b)(2)(ix)(E).'However, the management

of potential aggressive chemical attack of

inaccessible areas when conditions in

accessible areas may not indicate the presence

of or result in degradation to suchý

inaccessible areas needs to be evaluated.

NUREG-1611 110
I r

05 Concrete Structure

Aging mechanism:

Reaction with

aggregates

Aging effects:

Expansion and

cracking

Issue: NUREG-1557 states that reaction with

aggregates is an unresolved issue. NUJREG-1557

indicates that the NRC staff believes that

alkaline-aggregate reactions can not be ruled

out. Tests involving aggregates alone are not

satisfactory in predicting aggregate

performance. Alkaline-aggregate reaction may

occur after 25 or more years (Page B-31 of

NUREG-1557).

Recommendation: The issue is resolved with the

implementation of IWL through §50.55a.

Discussion: If alkaline-aggregate reaction

occurs, it will manifest itself as spalling

and cracking of the surface of the concrete

due to expansion because of the chemical

reaction. Further, reaction with aggregates in

inaccessible areas would also occur in

accessible areas because aggregates were used

in construction of both accessible and

inaccessible areas. IWL, Examination Category

L-A, requires periodic examination of

accessible concrete surfaces and

§50.55a(b)(2)(ix)(E) requires an evaluation of

inaccessible areas when conditions exist in

accessible areas that could indicate the

presence of or result in degradation to such

inaccessible areas. IWL and

§50.55a(b)(2)(ix)(E) will detect such

degradation.

11 Ii NUREG- 1611
06 Concrete Structure

Aging mechanism:

El evated

temperature

Agilng effects:

Loss of strength &

modul us

Issue: NUREG-1557 states that elevated

temperature is non-significant for concrete

structures if it meets the following

conditions: concrete containment structures be

maintained at operating temperatures <660C

(1500F) and local area temperatures <930C

(2000F); or for concrete structures that

experience temperatures greater than the above

specified limits, a plant specific

justification should be provided (Page B-32 of

NUREG-1557).

Recommendation: For concrete containment

structures that experience temperatures

greater than the above specified limits,

plant specific evaluation is needed.

a

Discussion: Elevated temperature results in

loss of concrete strength and modulus which

may not be detected by the implementation of

IWL and §50.55a modification until the aging

effects are so severe as to result in cracking

and spalling. Thus, for concrete structures

that experience temperatures greater than the

above specified limits, a plant specific

justification should be provided.

-I. 9

07 Concrete Structure

Aging mechanism:

Irradiation of

concrete

Agiingi effects:

Loss of strength &

modul us

Issue: NUREG-1557 states that irradiation of

concrete is non-significant for containment

concrete structures (Page B-34 of NUREG-1557).

Recommendation: The issue is non-significant.

Discussion: The neutron fluence levels and

maximum integrated gamma doses experienced by

containment concrete during the license

renewal term is not expected to exceed the

level at which measurable degradation of /M

concrete strength properties occurs (1019ncm

& 10.10 rads, respectively). Thus the issue is

non-s igni ficant.

_____ J. a

NUREG- 1611 112
08 Concrete Structure

Aging mechanism:

Concrete

interaction with

aluminum

A ging effects:

Loss of strength

Issue: NUREG- 1557 states that concrete

interaction with aluminum is non-significant

for concrete containment structures if

aluminum piping was not used for concrete

placement, otherwise any adverse effects of

concrete interactions with aluminum would have

been identified during the initial acceptance

test prior to initial operation (Page B-42 of

NUREG-1557).

Recommendation: Concrete interaction-with

aluminum is not an issue for license renewal.

Discussion': Adverse effects of concrete

interactions with aluminum would have occurred

during the placement of concrete and would

have been identified during initial structural

acceptance test pr *ior to plant initial

operation. Identified concerns would have been

evaluated during plant construction for

appropriate corrective action. Any containment

having concrete placed through aluminum

pipelines which successfully completed its

acceptance tests was not adversely affected by

this placing condition. Thus it is not an

issue for license renewal.

13 13 NUREG-1611
09 Struct. Steel &

Liner

Agiingi mechanism:

Corrosion

Agiingi effects:

Loss of material

Issue: NUREG-1557 indicates that corrosion is

non-significant for above grade steel liner,

steel containment shells (except at the

proximity of the ice-condenser), and common

steel components. NUREG-1557 indicates that

galvanic corrosion is non-significant for

penetration bellows if they are protected by

shields from corrosive environment. NUREG-1557

indicates that inspection of structural steel

and liner should be in accordance with IWE.

NUREG-1557 also indicates that evaluation for

management of inaccessible areas of below

grade structural steel and liner is to be

justified on a plant-specific basis (Pages

B-37 and B-38 of NUREG-1557).

Recommendation: The issue would be managed

with the implementation of IWE through

§50.55a. However, the management of potential

corrosion of inaccessible areas of structural

steel liner, steel containment shells, and

common steel components when conditions in

accessible areas may not indicate the presence

of or result in degradation to such

inaccessible areas needs to be justified on a

plant-specific basis.

Discussion: IWE, Examination Categories E-A,

E-C, E-D, & E-G, provides periodic examination

of accessible areas-,4"o uncover evidence of

structural degradation and should detect

corrosion of structural steel and liner; IWE,

Examination Category E-P (Appendix J to

10 CFR 50, Type A test), requires a general

inspection and an integrated leakage test '; and

§50.55a(b)(2)(x)(A) requires an evaluation of

acceptability of inaccessible areas when

conditions exist in accessible areas that

could indicate the presence of or result in

degradation to such inaccessible areas.

However, the management of potential corrosion

of inaccessible areas of structural steel

liner, steel containment shells, and common

steel components when conditions in accessible

areas may not indicate the presence of or

result in degradation to such inaccessible

areas needs to be evaluated.

NUREG-1611 114
10 Struct. Steel &

Liner

Aging mechanism:

El evated

temperature

Aging effects:

Loss of strength &

modul us -

Issue: NUREG-1557 states that elevated

temperature is non-significant for containment

structural steel liner, steel containment

shells, and common steel components such as

penetration bellows/sleeves, personnel

airlock, equipment hatches (Page B733 of

NIJREG-1557).

Recommendation: The issue is non-significant.

Discussion: Operating temperatures within PWR

containment structures are 49-660C. 4120-1500F

which are well below the 3160C (600 F) level

at which the structural integrity of

rebar/concrete combination begins to be

significantly affected. Thus the issue is nonsignificant.

I

-4

11 Struct. Steel &

Liner

Aging mechanism:

Irradiation of

steel

Aging effects:

Loss of fracture

toughness

Issue: NUREG-1557 states that irradiation of

steel is non-significant for containment,

structural steel liner, containment shells,.

and common steel components (Page B-35 of

NUREG-1557).

Recomme ndation: The issue is non-significant.

Discussion: The cumulative radiation exposure

experienced by concrete containment liners or

free-standing steel containment shells

throughout the license renewal term is

expected to be far below the level of

2x 1017n /cm2(>1 MeV) which could cause a change

in mechanical or physical properties. Thus the

issue is non-significant.

15 15 NUREG-1611I
12 Struct. Steel &

Liner

Agiingi mechanism:

Stress corrosion

cracking (SCC)

Aging effects:

Crack initiation &

growth

Issue: NUREG-1557 indicates that SCC is nonsignificant for concrete containment steel

liner, free-standing steel containment shells,

and common steel components in the containment

environment unless dissimilar metal is used,

and in the case of SS bellows assemblies for

CS vent lines or pipe sleeves if the materials

are protected by shields from corrosive

environment-(Page B-37 of NUREG-1557).

Recommendation: This issue would be managed by

Examination Categories E-B & E-F of Subsection

IWE and Appendix J to 10 CFR 50. In addition,

an augmenited VT-i visual examination of

bellows bodies should be performed using

enhanced techniques qualified for detecting

stress corrosion cracking in bellows bodies.

Discussion: IWE, Examination Category E-F,

provides periodic surface examination of

pressure retaining dissimilar metal welds for

dissimilar metals and could detect SCC. IWE,

Examination Category E-B, provides periodic

visual examination of pressure ret 'aining welds

for containment penetrations. Also, any

leakage associated with the containment shell

or steel liner due to through-wall cracks

resulting fromSCC would be detected by

periodic Appendix J leak rate test & remains

within the limits of-plant specifications or

Subs 'ection IWE. Although §50.55a indicates

that Examination Categories E-B & E-F are

optional during the current term of operation,

these examinations should be performed for

license renewal to demonstrate that no SCC has

been initiated. In addition, since occurrences

of transgranular stress corrosion cracking

have been identified in operating plants on

stainless steel bellows [Reference 15], an

augmented examination on the surface areas of

bellows bodies should be performed so that

cracking would be detected.

a J.

NUREG- 1611 116
I 'I'

13 Reinforcingi Steel

(Rebar)

Aging mechanism:

Corrosion of

embedded steel

Aging effects:

Loss of bond & loss

of material

Issue: NUREG-1557 states that corrosion of

embedded steel is non-significan't for concrete

structures above grade if not exposed to

aggressive environment, pH<11.5 or chlorides

>500 ppm; or if exposed to aggressive

environment, concrete has relatively high

strength [27.6 MPa (4 ksi)], low water-tocement ratio (0.35-0.45), adequate air

entrainment (3-6%), low permeability, and

designed in accordance with ACI 318 or ASME

Section 111, Division 2. NUREG-1557 also

indicates corrosion of embedded steel for

concrete structures below grade exposed to

aggressive ground water (pH <5.5, chloride

>500 ppm, & sulfate >1500 ppm) should be

examined in accordance with IWL and management

of inaccessible areas should be justified on a

case by case basis. Also the NRC staff

considers that potential degradation due to

chloride corrosion (e.g., ground water

chemical attack).of PWR containments should be

addressed.(Page B-36 of NUREG-1557).

Recommendation: T he issue would be managed

with the implementation of IWL through

§50.55a. However, the management of potential

corrosion of inaccessible areas of embedded

steel when conditions in accessible areas may

not indicate the presence of or result in

degradation to such inaccessible areas needs

to be justified on a plant-specific basis.

Discussion: IWL, Examination Category L-A,

requires periodic examination of accessible

concrete surfaces and §50.55a(b)(2)(ix)(E)

requires an evaluation of inaccessible areas

when conditions exist in accessible areas that

could indicate the presence of or result in

degradation to such inaccessible areas.

Corrosion of embedded steel results in

cracking and spalling of concrete and would be

detected by inspections, regardless of whether

the above conditions are met. However, the

management of potential corrosion of

inaccessible areas of embedded steel, when

conditions in accessible areas may not

indicate the presence of or result in

degradation to such inaccessible areas needs

to be evaluated. This would also address the

staff.'s concern on chloride corrosion.

17 17 NUREG-1611
14 Reinf. Steel-&

Prestr. Tendons

Aging mechanism:

Elevated

temperature

Aging effects:

Loss of strength &

modul us

issue: NUREG-1557 states that elevated

temperature is non-significant for concrete

containment reinforcing steel and for concrete

containment prestressing tendons (Page B-32 of

NUREG-1557).

Recommendation: The issue is non-:significant,

except for prestressed tendons. The tendon

surveillance program should be augmented to

include additional tendons based on their sun

exposure or proximity to hot penetrations.

Discussion: Operating temperatures within PWR

containment structures are 49-660C 4120-150'F)

which are well below the 3160C (600 F) level

at which the structural integrity of

rebar/concrete combination begins to be

significantly affected. Thus the issue is nonsignificant for reinforcing steel. However,

increase in temperature increases prestress

loss in prestressed tendons. Prestress losses

increased from 8% to 14% when the temperature

was increased from 200C (680F) to 320C (900F)

[Reference 16]. Thus, temperatures due to sun

exposure or proximity to hot penetrations may

increase the prestress loss in tendons. The

tendon surveillance program described in

Regulatory Guide 1.35 [Reference 10] is based

on a small sample size, that is, a 4 percent

random sample including a repeat tendon.

Tendons subject to warm temperatures may not

be tested because of this small sample size.

The tendon surveillance program should be

augmented to include additional tendons.

These additional tendons should be selected

based on their sun exposure or proximity to

hot penetrations.

NUREG- 1611 118
15 Reinf. Steel &

Prestr. Tendons

Agiingi mechanism:

Irradiation of

steel a

Agiingi effects:

Loss of fracture

toughness

Issue: NUREG-1557 states that irradiation of

steel is non-significant for concrete

structures reinforcing steel (including

basemat reinforcing steel) and concrete

containment prestressing tendons (Page B-34 of

NUREG-1557).

Recommendation: The issue is non-significant.

Discussion: The cumulative radiation exposure

experienced by reinforced concrete containment

structures during the license renewal term is

expected to be below the level of 101 9n /cm2 for ,degradation of reinforcing steel, and PWR

concrete containment prestressing tendons &

corrosion inhibitors will not receive enough

radiation exposure during the license renewal

tepto 2incur age related degradation (<4 x

10 n/cm2, & 101 rads, respectively). Thus the

issue is non-significant.

19 19 NUREG- 1611
16 Containment

Structures &

Components

Aging mechanism:

Fatigue

Aging effects:

Cumulative fatigue

damage

Issue: NUREG-1557 states that fatigue is nonsignificant for containment structures and its

components, except for the pe 'netration sleeves

and bellows. NUREG-1557 also indicates that

fatigue is an unresolved issue for concrete

containment penetration sleeves and steel

containment penetration bellows and fatigue

damage may not be detectable by a leak rate

test (Pages B-40 & B-41 of NUREG-1557).

Recommendation: Fatigue is non-significant for

containment structures and its components

except for the penetration sleeves and

bellows. Fatigue of containment penetration

sleeves and penetration bellows is a "timelimited aging analysis" and must be evaluated

in accordance with the license renewal rule,

10 CFR 54.21(c).

Discussion: Fatigue is non-significant for

containment concrete, reinforcing steel,

prestressing system components, steel liners,

and free-standing steel containments, because

they are designed to have good fatigue

strength properties (105 cycles) of below

yield load in accordance with ASME Section

III, Division 2, or ACI 318, and ACI 215R-74

codes.

Containment penetration sleeves and

penetration bellows are designed to Section

III of the ASME Code which requires a fatigue

analysis based on an assumed number of cycles.

This fatigue analysis is a "time-limited aging

analysis" and must be evaluated in accordance

with license renewal rule §54.21(c) to ensure

that the effects of aging on the intended

functions will be adequately managed for the

period of extended operation.

NUJREG-1611 220
17 Containment

Structure & its

Concrete basemat

Aging mechanism:

Settlement

Aging effects:

Crack s, distortion,

increase in

component stress

level

Issue: NUREG-1557 states that settlement is an

unresolved issue for containment concrete

basemat for sites with soil, or significant

changes in ground water conditions, and the

effect of settlement needs to be evaluated

(Page B-42 of NUREG-1557).

Recommendation: The issue is resolved by

establishing a settlement monitoring program

which would ensure that differential

settlement of containment basemat does not

exceed the design criteria for a containment

structure and its basemat which is resting on

soil or piles, or experiencing significant

changes in ground water conditions.

Discussion: Effects of differential settlement

are potentially significant for a containment

structure and its concrete basemat that is

resting on soil or piles, or experiencing

significant changes in ground water

conditions. Subsection IWL does not address

the effects of settlement. Because the effects

of settlement could cause cracks and

distortion of concrete basemat and could

result in increasing stress levels greater

than original design basis in the basemat *and

other parts of the containment structure. The

effects of settlement of PWR containments need

to be evaluated. However, a settlement

monitoring program could ensure that the

differential settlement does not exceed the

design criteria for the containment structures

throughout the license renewal term. A

settlement monitoring program should be

provided to manage settlement for containment

basemat bearing on soil or piles, or

experiencing significant changes in ground

water conditions for the period of extended

operation.

21 21 NUREG- 1611
18 Containment

Structure & its

Concrete basemat

Agiingi mechanism:

Erosion of cement

AgingJ effects:

Loss of strength

Issue: NRC Information Notice 97-11 indicates

that erosion of cement from porous concrete

could be potentially significant for porous

concrete subfoundations below concrete basemat

if subfoundation layers of porous concrete are

used in the construction of concrete basemat

with the presence of underground water.

Recommendation: For those applicable plants,

the management of potential erosion of cement

from porous concrete needs to be justified on

a plant-specific basis.

Discussion: §50.55a(b)(2)(ix)(E) requires an

evaluation of inaccessible areas when

conditions exist in accessible areas that

could indicate the presence of or result in

degradation to such inaccessible areas.

However, the management of potential erosion

of cement from porous concrete of inaccessible

areas of containment concrete basemat when

conditions in accessible areas may not

indicate the presence of or result in

degradation to such inaccessible areas needs

to be evaluated on a plant-specific basis.

NUREG- 1611 222
19 Contai nment

Structure & its

Component s

Aging mechanism:

Strain aging of

carbon steel

Aging effects:

Loss of fracture

toughness

Issue: NUREG-155 '7 indicates that strain aging

is non-significant for steel containment

structures (including common components, such

as penetration sleeves, penetration bellows,

personnel airlock, and equipment hatches) that

meet the following conditions: Dynamic strain

aging is non-significant for free standing

steel containment structures that do not allow

loads to exceed the elastic limit. Static

strain aging is non-significant for free

standing steel containment structures that

were not cold worked; or if cold worked during

the forming process, the plates were

normalized or stress relieved or both after

forming with minimal (<5%) subsequent cold

working (Page B-43 of NUREG-1557).

Recommendation: This issue is non-significant.

Discussion: Dynamic strain aging is not

expected in the carbon steel components of

steel containments during their service life,

since the strains associated with the design

service loads are below the elastic limit of

the material. The PWR containment is made from

low-carbon steel, and the steel is normalized

or stress relieved or both following plate

rolling. Further, strain aging requires

stressing of the material to above its yield

stress, and aging Zý-i temperatures above 930C

(2000F). Carbon-related strain aging at

temperatures below 930C (2000F) is normally

negligible due to the low solubility of carbon

in this temperature range. The PWR containment

has a maximum temperature during normal

operation of about 660C (1500F), and loading

conditions do not produce service stresses in

the range of the material yield strength. Thus

strain aging is non-significant for the steel

containment structures and its components.

23 23 NUREG- 1611
20 Conc. Containment

Prestr. Tendons

Aging mechanism:

Stress relaxation

of prestressing

wire, shrinkage

creep, anchorage

seating losses, and

tendon friction

Aging effects:

Loss of prestress

Issue: NUREG-1557 indicates that loss of

prestress due to stress relaxation, shrinkage

creep, etc., would be a reduction of design

margin and could be potentially significant

for prestressing tendons for license renewal

(Page B-41 of NUREG-1557).

Recommendation: Loss of prestress for

prestressing tendons would be managed with the

implementation of Subsection IWL through

§50.55a. In addition, the tendon, prestress

evaluation is a "time-limited aging analysis"

and must be evaluated in accordance with the

license renewal rule, 10 CFR 54.21(c)..

Discussion: Subsection IWL, Examination

Category L-B, and §50.55a inspections would be

able to detect potential loss of prestress for

prestressing tendons. For example: IWL-2522

provides examination method for tendon force

measurements; IWL-3221 provides acceptance

standard for measuring tendon force;

§50.55a(b)(2)(ix)(B) states that "when

evaluation of consecutive surveillances of

prestressing forces for the same tendon ...

indicates a trend of prestress loss .. ,an

evaluation shall be performed;" repair and

replacement are addressed in IWL-4000 and IWL7000, respectively. In addition, the

recommendations of Regulatory Guide 1.35

[Reference 10] were incorporated into the 1992

Edition with the 1992 Addenda of Subsection

IWL and §50.55a(b)(2)(ix)(A)-(D), the final

rule, dated August 8, 1996 (61 FR 41304). Thus

the "loss of prestress" for prestressing

tendons would be managed with the

implementation of IWL through §50.55a.

Further, the tendon prestress evaluation is a

"time-limited aging analysis" and must be

evaluated for renewal to demonstrate that the

prestressing force will meet the design

requirements at the end of 60 years in

accordance with license renewal rule

§54.21(c).

NUREG-1611 224
21 Conc. Containment

Prestr. Tendons

AMing mechanism:

Corrosion of

tendons

Aging effects:

Loss of material

Issue: NUREG-1557 states that corrosion of

tendons is an un resolved issue in that the NRC'

staff is concerned that a large amount of

grease leakage can degrade concrete strength.

IWL (1992 Edition with 1992 Addenda) lacks

certain criteria contained in RG 1.35. These

criteria are addressed in 10 CFR 50.55a final

rule, dated August 8, 1996, Section

50.55a(b)(2)(ix)(A)-(D) on issues such as

failed wires and tendon sheathing filler

grease conditions. Also, anchor heads have

failed in prestressed concrete containments.

NUREG-1557 also states that prestressing

tendons 'and tendon anchorage hardware should

be examined in accordance with the provisions

of RG 1.35 for prestressed concrete

containments (Page B-39 of NUREG-1557).

Recommendation: The issue is resolved with the

implementation of Subsection IWL through

§50.55a.

Discussion: Subsection IWL, Examination

Category L-B,.and §50.55a inspections would be

able to detect corrosion of prestressing

tendons. For example: IWL-2525 provides

methods for examination of corrosion

protection medium and free water; IWL-3221

provides acceptance standard for corrosion

protection medium; IWL-2524 provides visual

examination of tendon anchorage areas; IWL3221 provides acceptance standard for

inspection of tendon anchorage areas;

§50.55a(b)(2)(ix)(A) states that "grease caps,

that are accessible must be visually examined

to detect grease leakage or grease cap

deformations ....... that indicates.

deterioration of anchorage hardware." In

addition, the recommendations of Regulatory

Guide 1.35 [Reference 10] were incorporated

into the 1992 Edition with the 1992 Addenda of

Subsection IWL and §50.55a(b)(2)(ix)(A)-(D),

the final rule, dated August 8, 1996 (61 FR

41304). Thus the "Corrosion of prestressing

tendons" would be managed with the

implementation of IWL through §50.55a.

25 25 NUREG- 1611
22 Containment Issue: NUREG-1557 does not address mechanical

Pressure Retaining wear for PWR containments. However,

Components mechanical wear could be potentially,

significant for components that are subject to

relative sliding or rotating motion and that

Agcin mechanism: are susceptible to fretting and/or lockup.

Mechanical Wear Recommendation: Mechanical wear for PWR

containment pressure retaining components

would be managed with the implementation of

Aging effects: Subsection IWE (Examination Categories E-D, EG, and E.-P).

Fretting, Lockup

Discussion: NUREG-1557 addresses mechanical

wear issue only for BWR containments. However,

mechanical wear should also be addressed for

PWR containments. Inspection and mitigation of

mechanical wear conducted in accordance with

the provisions of Subsections IWE & IWF, as

applicable, would ensure that the integrity of

containment pressure retaining components and

their supports is maintained throughout the

license renewal term. IWE, Examination

Categories E-D & E-G, provides periodic

examinations for the pressure retaining

components (including airlocks, and equipment

hatches). IWE, Examination Category E-P

(Appendix J to Part 50, Type B test), would

detect local leaks.f-tfor those components. Thus

any potential mecha'1"cal wear degradation

would be detected by the implementation of IWE

for those pressure retaining components.

(There are no PWR containment pressure

retaining component supports listed in

Appendix B of this report and therefore,

Subsection IWF is not applicable.)

* Evaluation is based on:

(1) the 1992 Edition with the 1992 Addenda of Subsections IWE and IWI of

Section XI of the ASME Code;

(2) the 1989 Edition of Section XI of the ASME Code including Appendix

VII, "Qualification of Nondestructive Examination Personnel for

Ultrasonic Examination," and Appendix VIII (1989 Addenda),

"Performance Demonstration for Ultrasonic Examination Systems;"

(3) the final rule on 10 CFR 50.55a, Codes and Standards, dated August

8, 1996 (61 FR 41303); and

(4) NUREG-1557, "Summary of Technical Information and Agreements from

Nuclear Management.and Resources Council Industry Reports Addressing

License Renewal," dated October 1996.

NUREG- 1611 226
TABLE 2. AGING MANAGEMENT OF BWR CONTAINMENTS FOR LICENSE RENEWAL.

Component,Aging I*

Item IMechanism & Aging IIssue and Evaluation* ______Effectsj________________________________________

01 Concrete & Steel

Containment

Aging mechanism:

Not applicable.

Aging effects:

General

Issue: A "one-time inspection for license

renewal." NUREG-1557 states that one time

inspection is an unresolved issue regarding

staff request for inspection of concrete

containment & steel containment to assess the

current condition of containment and to

provide a baseline information for any future

inspections (Page B-28 of NUREG-1557).

Recommendation: The issue is resolved with the

implementation of IWE/IWL through §50.55a.

However, speci fic-recommendations for

applicable aging effects are addressed

hereinafter in this table.

Discussion: Subsections IWE and IWL require

periodic inspection of the containment in

accessible areas. These inspections would

periodically assess the condition of the

containment and each inspection would provide

a documented baseline for subsequent

inspections. Furthermore, §50.55a(b)(2)(ix)(E)

and (b)(2)(x)(A) require an evaluation of

inaccessible areas when conditions exist in

accessible areas that could indicate the

presence of or result in degradation to such

inaccessible areas.

However, the management of potential aging

effects of inaccessible areas, when conditions

in accessible areas may not indicate the

presence of 'or result in degradation to such

inaccessible areas, is addressed individually

for each applicable aging effect (i.e., Items

1, 3, 4, 9, and 13 of this table). Conditions

for such inaccessible areas should be

evaluated for license renewal. A program for a

one-time inspection may be proposed.

27 27 NUREG-1611
02 Concrete-Structure

Aging mechanism:

Freeze-thaw

Aging effects:

Scaling, cracking,

& spalling

Issue: NUREG-1557 states that freeze-thaw is

non-significant for Mark I & Mark II concrete

containments because they are protected from

freezing by the secondary containment. Freezethaw is non-significant for Mark III concrete

containment components if the following

conditions are met: Mark III concrete

containment components located in a geographic

regions of negligible weathering conditions

(weathering index <100 day-inch/yr); and if

located in severe (weathering index >500 dayinch/yr) or moderate (100-500 day-inch/yr)

weathering conditions with the concrete mix

design meets the air content & water-to-cement

ratio requirements of ASTM C260-77; or

equivalently, the ASME Sect. III, Division 2,

paragraph CC 2231.7.1; or the susceptible

surfaces are protected by shielding (Page B-46

of NUREG-1557).

Recommendation: The issue is resolved with the

implementation of IWL.

Discussion: Freeze-thaw results in scaling,

cracking, and spalling. Any freeze-thaw

degradation would initially appear in the

exposed concrete structure. Subsection IWL,

Examination Category 1-A, requires periodic

visual examination of accessible concrete

surfaces and would detect any freeze-thaw

damage of the concrete containment, including

the'dome, regardless of whether the above

weathering conditions are met.

NUREG- 1611 228
-'F 1

03 Concrete Structure

Agiingi mechanism:

Leaching of calcium

hydroxide

Agjingj effects:

Increase of

porosity &

permeability

Issue: NUREG-1557 states' that leaching of

calcium hydroxide is non-significant for

containment concrete structures if the

following conditions are met: concrete

structures not exposed to flowing water; and

for concrete structures that are exposed to

flowing water but are constructed using the

guidance of ACI 201.2R-77 to-ensure dense,

well-cured concrete with low permeability and

control cracking through proper arrangement

and distribution of reinforcement (Page B-47

of NUREG-1557).

Recommendation: The issue would be managed

with the implementation of IWL through

§50.55a. However, the management of potential

leaching of calcium hydroxide of inaccessible

areas of containment concrete structures when

conditions in accessible areas may not

indicate the presence of or result in

degradation to such inaccessible areas needs

to be justified on a plant-specific basis.

Discussion: IWL, Examination Category L-A,

requires periodic examination of accessible

concrete surfaces and §50.55a(b)(2)(ix)(E)

requires an evaluation of inaccessible areas,

when conditions exist in accessibl-e areas that

could indicate the presence of or result in

degradation to such inaccessible areas.

Regardless of whether the above conditions are

met, potential leaching of calcium hydroxide

would be detected as water stains on

accessible surfaces by the IWL visual

examination. However, the management'of

potential leaching of calcium hydroxide of

inaccessible areas (e.g., below grade portion

of concrete structures with presence of

flowing water) when conditions in accessible

areas may not indicate the presence of or

result in degradation to such inaccessible

areas, needs to be evaluated on a plantspecific basis.

29 29 NUREG-161.1
04 Concrete Structure

Aging mechanism:

Aggressive chemical

attack

Aging effects:

Increase of

porosity and

permeability,

cracking, and

spalling

Issue: NUREG-1557 states that aggressive

chemical attack is non-significant for above

grade containment concrete structures because

they are not exposed to ground water.

Aggressive chemical attack is non-significan~t

for below grade containment concrete

structures if the following conditions are

met: containment concrete is not exposed to

aggressive ground water (pH <5.5, chloride

>500 ppm, & sulfate >1500 ppm); or if expos%d

to ground water that exceeds the pH, chloride,

sulfate limits, the exposure is for

intermittent periods only. NUREG-1557

indicates that inspection of containment

concrete structure should be in accordance

with IWL. NUREG-1557 states that evaluation

for management of inaccessible areas of below

grade containment concrete structures is to be

justified on a plant-specific basis (Page B-48

of NUREG-1557).

Recommendation: The issue w 'ould be managed

with the implementation of IWL through

§50.55a. However, the management of potential

aggressive chemical attack of inaccessible

areas of containment concrete structures when

conditions in accessible areas may not

indicate the presence of or result in

degradation to such inaccessible areas needs

to be justified on a plant-specific basis.

Discussion: Aggressive chemical attack results

in increase of porosity and permeability,

cracking and spalling. IWL, Examination

Category L-A, requires periodic examination of

accessible concrete surfaces and

§50.55a(b)(2)(ix)(E) requires an evaluation of

inaccessible areas when conditions exist in

accessible areas that could indicate the

presence of or result in degradation to such

inaccessible areas. Regardless of whether the*

above conditions are met, potential aggressive

chemical attack would be detected by IWL and

§50.55a(b)(2)(ix)(E). However, the management

of potential aggressive chemical attack of

inaccessible areas when conditions in

accessible areas may not indicate the presence

of or result in degradation to such

inaccessible areas needs to be evaluated.

NUREG- 1611 330
05 Concrete Structure

Aging mechanism:

Reaction with

aggregates

Aging effects:

Expansion and

cracking

Issue: NUREG-1557 states that reaction with

aggregates is an unresolved issue. NUREG-1557

indicates that the NRC staff believes that

alkaline-aggregate reactions can not be ruled

out. Tests involving aggregates alone are not

satisfactory in predicting aggregate

performance. Alkaline-aggregate reaction may

occur after 25 or more years (Page B-49 of

NUREG-1557).

Recommendation: The issue is resolved with

implementation of IWL through §50.55a.

th~

Discussion: If alkaline-aggregate react~ion

occurs, it will manifest itself as spalling

and cracking of the surface of the concrete

,due to expansion because of the chemical

reaction. Further, reaction with aggregates ii

inaccessible areas would also occur in

accessible areas because aggregates were used

in construction of both accessible and

inaccessible areas. IWL, Examination Category

L-A, requires periodic examination of

accessible concrete surfaces and

§50.55a(b)(2)(ix)(E) requires an evaluation 0o

inaccessible areas when conditions exist in

accessible areas that could indicate the

presence of or result in degradation to such

inaccessible areas. IWL and

§50.55a(b)(2)(ix)(E) will detect such

degradation.

eI

n

1.

31 31 NUREG- 1611
06 Concrete Structure

Aging mechanism:

Elevated

temperature

Aging effects:

Loss of strength &

modulus

Issue: NUREG-1557 states that elevated

temperature is non-significant for concrete

ýstructures if it meets the following

conditions: concrete containment structures be

maintained at operating temperatures <660C

(1500F and local area temperatures <930C

(2000F); or for concrete structures that

experience temperatures greater than the above

specified limits, a plant specific

justification should be provided (Page B-56 of

NUREG-1557).

Recommendation: For concrete structures that

experience temperatures greater than the above

specified limits, a plant specific evaluation

should be performed.

Discussion: Elevated temperature results in

loss of concrete strength and modulus which

may not be detected by the implementation of

IWL and §50.55a modification until the aging

effects are so severe as to result in cracking

and spalling. Thus, for concrete structures

that experience temperatures greater than the

above specified limits, a plant specific

justification should be provided.

07 .Concrete Structure

Aging mechanism:

Irradiation of

concrete

Aging effects:

Loss of strength &

modul us

Issue: NUREG-1557 states that irradiation of

concrete is non-significant for containment

concrete structures (Page B-57 of NUREG-1551).

Recommendation: The issue is non-significant.

Discussion: The neutron fluence levels and

maximum integrated gamma doses experienced by

containment concrete during the license

renewal term is not expected to exceed the

level at which measurable degradation of

concrete strength properties occurs (10'9n/crn

neutron radiation & 1010 rads gamma radiation,

respectively for concrete). Thus the issue is

non-significant.

NUREG-1611 332
08 .Struct. Steel &

,Liner

Aging mechanism:

Atmospheric

corrosion

Aging effects:

Loss of material

Issue: NUREG-1557 states that atmospheric

corrosion is non-significant for containment

steel components if the following conditions

are met: (a) containment steel components

fabricated from stainless steel, or for

components having intact protective coating,

or for components' having a corrosion allowance

,>1/32 inch. Aust 'enitic SS is corrosion

resistant. The atmospheric corrosion for

carbon and low alloy steels without protective

coatings is less than 0.5 mils per year or

<1/32 inches for a 60-year period, and (b) the

examination categories E-A, E-P, & E-C of ASME

.Sect.. XI, Subsect. IWE are required to be

performed in conjunction with 10 CFR 50,

Appendix J,.Type A leak rate test (Pages B-50

& 51 of NUREG-1557).

Recommendation: This issue would be managed

with the implementation of IWE through

§50.55a.

Discussion: IWE, Examination Categories E-A &

E-C, requires periodic examination 'of

accessible surfaces for containment steel

structures & its components; Examination

.Category E-P (Appendix J to 10 CFR.50, Type A

test), requires a general inspection and an

integrated leakage test; and

§50.55a(b)(2)(x)(A) ý5quires an evaluation of

inaccessible areas when conditions exist in

accessible areas that could indicate the

presence of or result in degradation to such

inaccessible areas. Atmospheric corrosion may

exist when relevant conditions for coated

areas including evidence of flaking,

blistering, peeling, discoloration, etc., and

relevant conditions for uncoated areas

including evidence of cracking, discoloration,,

wear, pitting, excessive corrosion, etc.,,

occur. If the examination areas are found to

be defective, or to be suspectable, the

augmented examinations of IWE-1240 will apply

to ensure that minimum wall thickness is

properly evaluated and maintained in

accordance with IWE-3512.

33 33 ~NUREG- 16 11
09 Struct. Steel &

Liner

Aging mechanism:

Local corrosion

Aging effects:

Loss of material

Issue: (a) NUREG-1557 indicates that local

corrosion would be managed with the

implementation of IWE-1240 for steel

containment and its common components. NUREG1557 indicates that a plant-specific aging

program is required to manage the local

corrosion of steel containment inaccessible

areas and/or embedded carbon steel containment

components (Pages B-53 and B-55 of NUREG1557). (b) NUREG-1557 indicates that local

corrosion is non-significant for concrete

containment liners and anchors if the

following conditions are met: Corrosion of the

liner plate is mitigated by protective

coatings on the interior surface, and by' the

alkaline environment between the exterior

surface of the liner plate and the concrete

structure. Stainless steel is corrosion

resistant (Pages B-54 of NUREG-1557).

Recommendation: All accessible areas would be

managed with implementing IWE through §50.55a.

However, the management of potential local

corrosion of inaccessible areas of structural

steel and liner when conditions in accessible

areas may not indicate the presence of or

result in degradation to such inaccessible

areas needs to be justified on a plantspecific basis.

Discussion: IWE, Examination Categories E-A,

E-C, E-D, and E-G, provides periodic

examination of accessible areas to uncover

structural degradation. This inspection would

detect local corrosion regardless whether the

conditions in (b) are met. IWE-1240 specifies

augmented inspections for areas likely to

experience accelerated degradation and aging.

§50.55a(b)(2)(x)(A) requires an evaluation of

acceptability of inaccessible areas when

conditions exist in accessible areas that

could indicate the presence of or result in

degradation to such inaccessible areas.

However, the management of local corrosion of

inaccessible areas' when conditions in

accessible areas may not indicate the presence

of or result in degradation to such

inaccessible areas needs to be evaluated.

I J.

NUREG- 1611 384
10 Struct. Steel &

Liner

Aging mechanism:

Elevated

temperature

Aging effects:

Loss of strength &

modulus

Issue: NUREG-1557 states that elevated

temperature is non-significant for PWR

containment structural steel and liner (Page

B-33 of NUREG-1557). However, NUREG-1557 does

not address elevated temperature effects on

BWR containment steel liner (Page B-56 of

NUREG-1557).

Recommendation: The issue is non-significant.

Discussion: Op eratingstempertu~res within BWR

containment structures ar <:6~ (1500F) which

are well1 bel ow the 3160C (6000F) l evel at

which the structural integrity of

rebar/concrete combination begins to be

significantly affected. Thus the issue is nonsignificant. This conclusion is also

applicable to the BWR containment steel liner.

11 Struct. Steel &

Liner

Aging mechanism:

Irradiation of

steel

Aging effects:

Loss of fracture

toughness.

Issue: NUREG-1557 states that irradiation of

steel is non-significant for containment

structural steel & liner (Page B-57 of NUREG1557).

Recommendation: The issue is non-significan t.

Discussion: The neutron fluence levels &

maximum integrated gamma doses incurred by

containment components, including containment

steel & liners throughout the license renewal

period are not expected to exceed the level *at

which1pieastirable degradation occurs

(Wx1 n/cm for all components made of carbon

steel, stainless steel, and liner plate). Thus

the issue is non-significant.

35 35 NUREG- 1611
12 Struct. Steel 8&

Liner

Aging mechanism:

Stress corrosion

cracking (SCC)

Aging effects:

Crack initiation &

growth

Issue: (a) NUREG-1557 indicates that SCC is

non-significant for containment components,

including penetration sleeves, bellows, and

vent line bellows if the following conditions

are met: for austenitic SS containment

components that are only exposed to the

containment or reactor building environment or

their normal operational stress levels are

less than materials yield strength or fracture

mechanics analysis has established that cracks

do not propagate; and for high strength bolts

if material yield strength is <1034 MPa(<150

ksi). (b) SCC would be managed for suppression

chamber shell interior surface by implementing

10 CFR 50, Appendix J integrated leak rate

test to maintain liner integrity (Page B-63 of

NUREG-1557).

Recommendation: This issue would be managed by

Examination Categories E-B & E-F of Subsection

IWE a~nd Appendix J to 10 CFR 50. In addition,

an augmented VT-i visual examination of

bellows bodies should be performed using

enhanced techniques qualified for detecting

stress corrosion cracking in bellows bodies.

Discussion: IWE Examination Category E-F

provides periodic surface examination of

pressure retaining dissimilar metal welds for

dissimilar metals i,.id could detect SCC. IWE,

Examination Category' E-B, provides periodic

visual examination of pressure retaining welds

for containment penetrations. Also any leakage

associated with the steel liner, including

suppression pool liner, due to through-wall

cracks resulting from SCC would be detected by

periodic Appendix J leak rate test & remains

within the limits of plant specifications or

Subsection IWE. Although §50.55a indicates

that Examination Categories E-B & E-F are

optional during the current term of operation,

these examinations should be performed for

license renewal to demonstrate that no SCC has

been initiated. In addition, since occurrences

of transgranular stress corrosion cracking

have been identified in operating plants on SS

bellows [Reference 15], an augmented

examination on the surface areas of bellows

bodies should be performed so that cracking

would be detected.

NUREG- 1611 336
1-3 Reinforcing Steel

(Rebar)

Aging mechanism:

Corrosion of

embedded steel

Agsingj effects:

Loss of bond & loss

of material

Issue: NUREG-1557 states that corrosion of

embedded steel is non-significant for concrete

structures not exposed to aggressive

environment (pH<11.5 or chlorides >500 ppm);

or for concrete exposed to aggressive

environment but has relatively high strength

[27.6 MPa (4 ksi)] and low water-to-cement

ratio (0.35-0.45), adequate air entrainment

(3-6%), low permeability, and are designed in

accordance with ACI 318 or ASME Section III,

Division 2. NUREG-1557 indicates corrosion of

embedded steel for concrete structures below

grade exposed to aggressive-ground water (pH

<5.5, chloride >500 ppm, & sulfate >1500 ppm)

should be examined in accordance with IWL and

management of inaccessible areas should be

justified on A case by case basis. Also the

NRC staff considers that potential degradation

due to chloride corrosion (e.g., ground water

chemical attack) of containments should be

addressed (Page B-52 of NUREG-1557).

Recommendation: The issue would be managed

with the implementation of IWL through

§50.55a. However, the management of potential

corrosion of inaccessible areas of embedded

steel when conditions in accessible areas may

not indicate the presence of or result in

degradation to such inaccessible areas needs

to be justified on a plant-specific basis.

Discussion: IWL, Examination Category L-A,

requires periodic examination of accessible

areas and §50.55a(b)(2)(ix)(E) requires an'

evaluation of inaccessible areas when

conditions exist in accessible areas that

could indicate the presence of or result in

degradation to such inaccessible areas.

Corrosion of embedded steel results in

cracking and spalling of concrete and would be

detected by inspections, regardless of whether

the above conditions are met. However, the

management of potential corrosion of

inaccessible areas of embedded steel, when

conditions in accessible areas may not

indicate the presence of or result in

degradation to such inaccessible areas needs

to be evaluated. This would also address the

staff's concern on chloride corrosion.

37 37 NUREG- 1611
I I

14 Reinf. Steel &

Prestr. Tendons

Aging mechanism:

Elevated

temperature

Aging effects:

Loss of strength &

modul us

Issue: NUREG-1557'states that elevated

temperature is non-significant for concrete

containment reinforcing steel and for concrete

containment prestressing tendons (Page B-56 of

NUREG-1557).

.Recommendation: The issue is non'-significant,

except for prestressed tendons. The tendon

surveillance program should be augmented to

include additional tendons based on their sun

exposure or proximity to hot penetrations.

Discussion: Operating temperatures within BWR

containment structures are <660C(1500F) which

are well below the 3160C (6000F) level at

which the structural integrity of

rebar/concrete combination begins to be

significantly affected. Additionally, concrete

containment prestressing tendons are normally

subjected to temperatures <600C (1400F). Thus

the issue is non-significant for reinforcing

steel. However, increase in temperature

increases prestress loss in prestressed

tendons. Prestress losses increased from 8% to

14% when the temperature was increased from

200C (680F to 320C (900F [Reference 16].

Thus, temperatures due to sun exposure or

proximity to hot penetrations may increase the

prestress loss in tendons. The tendon

surveillance program described in Regulatory

Guide 1.35 [Reference 10] is based on a small

sample size, that is, a 4 percent random

sample including a repeat tendon. Tendons

subject to warm temperatures may not be tested

because of this small sample size. The tendon

surveillance program should be augmented to

include additional tendons. These additional

tendons should be selected based on their sun

exposure or proximity to hot penetrations.

NUREG- 1611 338
15 Reinf. Steel &

.Prestr Tendons

Agzing mechanism:

Irradiation of

steel

Aging effects:.

Loss of fracture

toughness

Issue: N'UREG-1557 states that irradiation of

steel is non-significant for concrete

structures reinforcing steel (including

basemat reinforcing steel) and concrete

containment prestressing tendons (Page B-57 of

NUREG-1557).

Recommendation: The issue is non-significant.

Discussion: The neutron fluence levels &

maximum integrated gamma doses incurred by

containment components, including rebars &

prestressed tendons for both the current and

license renewal period are not expected to

exceed the level at which measurable

degradation occurs. (4x 101 n /cm2 for concrete2

containment prestressing tendons; 2 x 101 n/m

for all components made of CS, SS including

rebar, and liner). Thus the issue is nonsignificant.

39 39 NUREG- 1611
.16 Containment

Structures &

Components

Aging mechanism

Fatigue

Aging effects:

Cumulative fatigue

damage.

Issue: NUREG-1557 states that fatigue is nonsignificant for containment structures and its

components, except for the penetration sleeves

and bellows. NUREG-1557 also indicates that

fatigue is an unresolved issue for containment

penetration sleeves and penetration bellows

and fatigue damage may not be detectable by a

leak rate test (Pages B-58 & B-59 of NUREG1557).

Recommendation: Fatigue is non-significant for

containment structures and its components

except for the penetration sleeves and

bellows. Fatigue of containment penetration

sleeves and penetration bellows is a "timelimited aging analysis" and must be evaluated

in accordance with license renewal rule

§54.21(c).

Discussion: Fatigue is non-significant for

containment concrete, reinforcing steel,

prestressing system components, steel liners,

and free-standing steel containments, because

they are designed to have good fatigue

strength properties (10 5 cycles) of below

yield load in accordance with ASME Section

III, Division 2, or ACI-318, and ACI 215R-74

codes.

Containment penetration sleeves and

penetration bellows are designed to Section

III of the ASME Code which requires a fatigue

analysis based on an assumed number of cycles.

This fatigue analysis is a "time-limited aging

,analysis" and must be evaluated in accordance

with license renewal rule,§54.21(c) to ensure

that the effects of aging on the intended

functions will be adequately managed for the

period of extended operation.

NUJREG-1611 404
17 Containment

Structure & its

Concrete Basemat

Aging mechanism:

Settlement

Aging effects:

Cracks, distortion,

increase in

component stress

level

Issue: NUREG-1557 indicates that for BWR

containment concrete basemat bearing on soil

or piles, or experiencing significant changes

in ground water conditions, a settlement

monitoring program' is required to ensure that

the differential settlement does not exceed

the design criteria for the containment

throughout the license renewal term (Page B-62

of NUREG-1557).

Recommen dation: The issue would be managed by

establishing a settlement monitoring program

which would ensure that differential

settlement of containment basemat does not

exceed the design criteria for a containment

structure and its basemat bearing on soil or

piles, or experiencing significant changes in

ground water conditions.

Discussion: Effects of differential settlement

are potentially significant for a containment

structure and its concrete basemat that is

resting on soil or piles, or experiencing

significant changes in ground water

conditions. Subsection IWL does not address

the effects of settlement. Because the effects

of settlement could cause cracks and

distortion of concrete basemat and could

result in increasing stress levels greater

than the original design basis in the basemat

and other parts of the containment structure.

A settlement monitoring program could ensure

that the differential settlement does not

exceed the design criteria for the containment

structures throughout the license renewal

term. A settlement monitoring program should

be provided to manage settlement for

containment basemat bearing on soil or piles,

or experiencing significant changes in ground

water conditions for the period of extended

operation.

41 41 NUREG- 1611'
18 Contai nment

Structure & its

Concrete basemat

Aging mechanism:

Erosion of cement

Aging effects:

Loss of strength

Issue: NRC Information Notice 97-11 indicates

that erosion of cement from porous concrete

could be potentially significant for porous

concrete subfoundations below concrete basemat

if subfoundation layers of porous concrete are

used in the construction of concrete basemat

with the presence of underground water.

Recommendation: For those applicable plants,

the management of potential erosion of cement

from porous concrete needs to be justified on

a plant-specific basis.

Discussion: §50.55a(b)(2)(ix)(E) requires an

evaluation of inaccessible areas when

conditions exist in accessible areas that

could indicate the presence of or result in

degradation to such inaccessible areas.

However, the management of potential erosion

of cement from porous concrete of inaccessible

areas of containment concrete basemat, when

conditions in accessible areas may not

indicate the presence of or result in

degradation to such inaccessible areas, needs

to be evaluated on a plant-specific basis.

I 1.

NUREG- 1611 442
~*1*

19 Containment

Structure & its

Components

Aging mechanism:

Strain aging of

carbon steel

Aging effects:

Loss of fracture

toughness

Issue: NUREG-1557 indicates that strain aging

is non-significant for steel containment

structures (including common components, such

as penetration sleeves, penetration bellows,

personnel airlock, equipment hatches, and CRD

hatch), and concrete containment steel

components (including vent lines, vent line

bellows, and drywell head) that meet the

following conditions: Dynamic strain aging is

non-significant for containment steel

components that do not allow loads to exceed

ýthe elastic limit. Static strain aging is non-

.significant for containment steel components

that were not cold worked; or if cold worked

during the forming process, the plates were

normalized or stress relieved or both after

forming with minimal (<5%) subsequent cold

working (Page B-61 of NUREG-1557).

Recommendation: This issue is non-significant.

Discussion: Dynamic strain aging is not

expected in the carbon steel components of

containments during their service life, since

the strains associated with the design service

loads are below the elastic limit of the

material. The BWR containment is made from

low-carbon steel, and the steel is normalized

or stress relieved or both following plate

-rolling. Further,-strain aging requires

stressing of the material to above its yield

stress, and aging at temperatures above 9,30C

(2000F). Carbon-related strain aging at

temperatures below 930C (2000F) is normally

negligible due to the low solubility of carboný

in this temperature range. The BWR containment

has a maximum temperature during normal

operation of about 660C (1500F), and loading

conditions do not produce service stresses in

the range of the material yield strength. Thus

strain aging is non-significant for

containment steel structure and its steel

components.

43 43 NUREG-161 1
F I

20 Conc. Containment

Prestr. Tendons

Aging mechanism:

Stress relaxation

of prestressing

wire, shrinkage

creep, anchorage

seating losses, and

tendon friction

Aging effects:

Loss of prestress

Issue: NUREG-1557 indicates that loss of

prestress due to stress relaxation, shrinkage

creep, etc., would be a reduction of design

margin and could be potentially significant

for prestressing tendons for license renewal

(Page B-62 of NUREG-1557).

Recommendation: Loss of prestress for

prestressing tendons would be managed with the

implementation of Subsection IWL through

§50.55a. In addition, the tendon prestress

evaluation is a "time-limited aging analysis"

and must be evaluated in accordance with the

license renewal rule, 10 CFR §54.21(c).'

Discussion: Subsection IWL, Examination

Category L-B, and §50.55a inspections would be

able to detect potential loss-of prestress for

prestressing tendons. For example: IWL-2522

provides examination method for tendon force

measurements; IWL-3221 provides acceptance

standard for measuring tendon force;

§50.55a(b)(2)(ix)(B) states that "when

evaluation of consecutive surveillances of

prestressing forces for the same tendon ...

indicates a trend of prestress loss .. ,an

evaluation shall be performed;" repair and

replacement are addressed in IWL-4000 and IWL7000, respectively. In addition, the

recommendations of Regulatory Guide 1.35

[Reference 10] were incorporated into the 1992

Edition with the 1992 Addenda of Subsection

IWL'and §50.55a(b)(2)(ix)(A)-(D), the final

rule, dated August 8, 1996 (61 FR 41304). Thus

the "loss of prestress" for prestressing

tendons would be managed with the

implementation of IWL through §50.55a.

Further, the tendon prestress evaluation is a

"time-limited aging analysis" and must be

evaluated for renewal to demonstrate that the

prestressing force will meet the design

requirements at the end of 60 years in

accordance with license renewal rule

§54.21(c).

NUREG- 1611 444
21 Conc. Containment

Prestr. Tendons

Aging mechanism:

Corrosion of

tendons

Aging effects:

Loss of material

Issue: NUREG-1557 states that corrosion of

tendons is an unresolved issue in that the NRC

staff is concerned that a large amount of

grease leakage can degrade concrete strength.

IWL (1992 Edition with 1992 Addenda) lacks

certain criteria contained in RG 1.35. These

criteria are addressed in 10 CFR 50.55a final

rule, dated August 8, 1996, Section

50.55a(b)(2)(ix)(A)-(D) on issues such as

failed wires and tendon sheathing filler

grease conditions. Also, anchor heads have

failed in prestressed concrete containments.

NUREG-1557 states that prestressing tendons

and tendon anchorage hardware should be

examined in accordance with the provisions of

RG 1.35 for prestressed concrete containments

(Page B-55 of NUREG-1557).

Recommendation: The issue is resolved with the

implementation of Subsection IWL through

§50.55a.

Discussion: Subsection IWL, Examination

Category L-B, and §50.55a inspections would be

able to detect Corrosion of prestressing

tendons. For example: IWL-2525 provides

methods for examination of corrosion

protection medium and free water; IWL-3221

provides acceptance standard for corrosion

protection medium; IWL-2524 provides visual .examination of tendon anchorage areas; IWL3221 provides acceptance standard for

inspection of tendon anchorage areas;

§50.55a(b)(2)(ix)(A) states that "grease caps

that are accessible must. be visually examined

to detect grease leakage or grease cap

deformations ....... that indicates

deterioration of anchorage hardware." In

addition, the recommendations of Regulatory

Guide 1.35 [Reference 10] were incorporated

into the 1992 Edition with the 1992 Addenda of

Subsection IWL and §50.55a(b)(2)(ix)(A)-(D),

the final- rule, dated August 8, 1996 (61 FR

41304). Thus the "Corrosion of prestressing

tendons" would be managed with the

implementation of IWL through §50.55a.

45 45 ~NUREG- 1611
22 Containment

Pressure Retaining

Component s

Aging mechanism:

Mechanical wear

Aging effects:

Fretting, Lockup

Issue: Mechanical wear could be potentially

significant for components that are subject to

relative sliding or rotating motion and that

are susceptible to fretting and/or lockup.

(Page B-60 of NUREG-1557).

Recommendation: Mechanical wear for BWR

containment pressure retaining components &

their supports would be managed with the

implementation of Subsections IWE and IWF.

Discussion: Inspection and mitigation of

mechanical wear conducted in accordance with

the provisions of Subsections IWE & IWtF would

ensure that the integrity of containment

pressure retaining components and their

supports is maintained throughout the license

renewal term. IWE, Examination Categories E-D

& E-G, provides periodic examinations for the

pressure retaining components, (including

airlock, equipment hatch, CRD hatch & drywell

head). IWE, Examination Category E-P (Appendix

J t 'o Part 50, Type B test), would detect local

leaks for those components. The supporting

components such as downcomer bracing, column &

saddle supports, seismic restraints & vent

system supports are considered MC component

supports which are periodically examined by

Examination Category.F-A of Subsection IWF.

Thus any potential ýLechanical wear degradation

would be detected b~y the implementation of IWE

and IWF for those pressure retaining

components and their supports.

*Evaluation is based on:

(1) the 1992 Edition with the 1992 Addenda of Subsections IWE and IWL of

Section XI of the ASME Code;

(2) the 1989 Edition of Section XI of the ASME Code including Appendix

VII, "Qualification of Nondestructive Examination Personnel for

Ultrasonic Examination," and Appendix VIII (1989 Addenda),

"Performance Demonstration for Ultrasonic Examination Systems;"

(3) the final rule on 10 CFR 50.55a, Codes and Standards, dated August

8, 1996 (61 FR 41303); and

(4) NUREG-1557, "Summary of Technical Information and Agreements from

Nuclear Management and Resources Council Industry Reports Addressing

License Renewal," dated October 1996.

Note (1) "Concrete interaction with aluminum" is not addressed in NUREG-1557

for BWR containment. However, this item is evaluated and considered

not an issue for license renewal for PWR containment. Thus this

item is considered not an issue for BWR containment.

NUREG-1611 446
APPENDIX A -IMPLEMENTATION HIGHLIGHTS OF SUBSECTIONS IWE AND IWL THROUGH

10 CFR 50.55a,

Subsection IWE provides rules for inservice inspection, repair, and .replacement 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

power plants. Subsection IWL provides rules for inservice inspection and

repair of the reinforced concrete and the post-tensioning systems of Class CC

components. Licensees will be required to incorporate Subsection IWE and

Subsection IWL into their inservice inspection (151) program. Licensees will

be-required to implement the containment examinations in accordance with

Subsections IWE and IWL as endorsed by §50.55a by September 9, 2001.

In endorsing Subsections IWE and IWL, 10 CFR 50.55a sets forth additional

requirements to assure that the critical areas of containments are

periodically inspected to detect and take corrective action for defects that

could compromise a containment's structural integrity. These additional

requi rements include:

(a) Four modifications specified in §50.55a(b)(2)(x) for examination of metal

containments and the liners of concrete containments. These are: (1) Section

50.55a(b)(2)(x)(A) states that the licensee shall evaluate the acceptability

of inaccessible areas of metal containments and the liners of concrete

containments (Class MC), when conditions exist in accessible area's that could

indicate the presence of or result in degradation to such inaccessible areas;

.(2) Section 50.55a(b)(2)(x)(B) permits alternative lighting and resolution

requirements for remote visual examination of the containment; (3) Section

50.55a(b)(2)(x)(C) makes the examination of pressure retaining welds and

pressure retaining dissimilar metal welds optional; and (4) Section

50.55a(b)(2)(x)(D) is added to provide an alternative sampling plan.

(b) Five modifications specified in §50.55a(b)(2)(ix) for examination of

concrete containments. These modifications must be implemented when using

Subsection-IW. Four of these issues are identified in Regulatory Guide 1.35,

Revision 3, but are not addressed in the referenced Subsection IWL. The five

modifications are: (1) Section 50.55a(b)(2)(ix)(A) requires that grease caps

which are accessible be visually examined to detect grease leakage or grease

cap deformation; (2) Section 50.55a(b)(2)(ix)(B) requires the preparation of

an engineering evaluation report when consecutive surveillances indicate a

trend of prestress loss to below the minimum prestress requirements; (3)

Section 50.55a(b)(2)(ix)(C) requires that an evaluation be performed for

instances of wire failure and slip of wires in anchorages; (4) Section

50.55a(b)(2)(ix)(D) addresses sampled sheathing filler grease and reportable

conditions.; and (5) Section 50.55a(b)(2)(ix)(E) requires that licensees

evaluate the acceptability of 'inaccessible areas of concrete containments when

conditions exist in accessible areas that could indicate the presence of or

result in degradation to such inaccessible areas.

(c) One limitation specified in §50.55a(b)(2)(vi) for effective edition and

addenda of Subsection IWE and Subsection IWL. It states that the 1992 Edition

with the 1992 Addenda of Subsection IWE and Subsection IWL shall be used when

47 NUREG-1611
performing containment examinations as modified and supplemented by the

requirements described in §50.55a(b)(2)(ix) and §50.55a(b)(2)(x),

respectively.

(d) One clarification specified in §50.55a(b)(2)(x)(E). It states that a

general visual examination as required by Subsection IWE shall be performed

once each period.

NUREG- 1611 448
APPENDIX*B - LIST OF PWR CONTAINMENT COMPONENTS

1. CONCRETE CONTAINMENTS (REINFORCED/PRESTRESSED)

* Concrete Dome

* Dome Reinforcing Steel

* Concrete Containment Wall Above Grade

* Containment Wall Reinforcing Steel Above Grade

" Concrete Containment Wall Below Grade

* Containment Wall Reinforcing Steel Below Grade

* Concrete Basemat

* Basemat Reinforcing Steel

" Containment Liner Interior Surface

" Containment Liner Above Grade Exterior Surface

* Containment Liner Below Grade Exterior Surface

" Basemat Liner Interior Surface

" Basemat Liner Exterior Surface

" Liner Anchors Above Grade

" Liner Anchors Below Grade

2. FREE-STANDING STEEL CONTAINMENT WITH FLAT BOTTOM & AN ICE CONDENSER

0 Dome Shell Interior Surface

0 Dome Shell Exterior Surface - Cylindrical Shell Interior Surface

* Cylindrical Shell Exterior Surface

*Embedded Shell Region

*Concrete Basemat

*Baseniat Reinforcing Steel

*Basemat Liner

*Liner Anchors

3. FREE-STANDING CYLINDRICAL & SPHERICAL STEEL CONTAINMENT WITH ELLIPTICAL

BOTTOM

*Containment Shell Interior Surface

*Containment Shell Exterior Surface

*Embedded Shell Region

*Sand Pocket Region

4. CONCRETE CONTAINMENTS PRESTRESSED ONLY

*Prestressing Tendons

5. COMMON COMPONENTS

" Penetration Sleeves

* Penetration Bellows

" Personnel Airlock

* Equipment Hatches

Reference:

Page B-45 of NUREG-1557, "Summary of Technical Information and Agreements from

Nuclear Management and Resources Council Industry Reports Addressing License

Renewal," dated October 1996.

49 49 NUREG- 1611
APPENDIX C - LIST OF BWR CONTAINMENT COMPONENTS

1. MARK I CONCRETE CONTAINMENTS

* Drywell Liner Interior Surface

* Drywell Liner Exterior Surface

STorus Liner Interior Surface

* Torus Liner Interior Surface at Wa

*Torus Liner Exterior Surface

* Liner Anchors

*Drywell Concrete

*Torus Concrete

* Drywell Concrete Reinforcing Steel

* Torus Concrete Reinforcing Steel

* Vent Lines

*Vent Line Bellows

* Vent Headers

*Downcomers and Bracing

*Vent System Supports

*Drywell Head

terl m e

2. MARK I STEEL CONTAINMENTS

*Drywell Interior Surface

*Drywell Exterior Surface

*Drywell Head

*Embedded Shell Region

*Drywell Support Skirt

*Sand Pocket Region

*Torus Interior Surface

*Torus Interior Surface at Waterline

*Torus Exterior Surface,

*Torus Ring Girder

*Vent Lines

*Vent Line Bellows

*Vent Header

*Downcomers and Bracing

*Drywell Exterior Shell with Compressible Material

*Vent System Supports

*Torus Seismic Restraints

*Torus Support Columns/Saddles

*ECCS Suction Header

*Ocean Plant with Uncoated CS Surfaces

*Uncoated Submerged CS Surfaces

3. MARK 11 CONCRETE CONTAINMENTS

*Drywell Liner Interior Surface

*Drywell Liner Exterior Surface

*Suppression Chamber Liner Interior Surface

'Suppression Chamber Liner Interior Surface at Waterline

*.Suppression Chamber Liner Exterior Surface

*Liner Anchors

*Liner Region Shielded by Diaphragm Floor

*Containment Concrete

NUREG- 1611 550
3. MARK II CONCRETE CONTAINMENTS (Continued)

" Concrete Containment Reinforcing Steel

" Drywell Head

" Downcomer Pipes and Bracing

* Concrete Basemat

" Basemat Liner

*Basemat Reinforcing Steel

*Prestressing Tendons and Ducts

4. MARK 11 STEEL CONTAINMENTS

*Drywell Interior Surface

.Drywell Exterior Surface

*Drywell Head

*Suppression Chamber Interior Surface

*Suppression Chamber Exterior Surface

*Suppression Chamber Interior Surface at Waterline

*Region Shielded by Diaphragm Floor

*Embedded Shell Region

" Sand Pocket Region

* Support Skirt

* Downcomer Pipes and Bracing

" Drywell Exterior Shell with Compressible Material

" Ocean Plant with Uncoated CS Surfaces

* Uncoated Submerged CS Surfaces

5. MARK III CONCRETE CONTAINMENTS

" Containment Liner Interior Surface

* Containment Liner Exterior Surface

" Suppression Chamber Liner or Cladding Interior Surface

* Suppression Chamber Liner Exterior Surface

* Concrete Containment Wall Above Grade,

* Concrete Containment Wall Below Grade

" Concrete Dome

* Basemat Liner

" Concrete Basemat

* Liner Anchors

* Containment Wall Reinforcing Steel

* Dome Reinforcing Steel

" Basemat Reinforcing Steel

6. MARK III STEEL CONTAINMENTS

" Containment Shell-Interior

" Containment Shell Exterior

" Suppression Chamber Shell

" Suppression Chamber ShellI

* Basemat Liner

" Liner Anchors

* Concrete Basemat

" Basemat Reinforcing Steel

" Concrete Fill-An Annulus

* Embedded Shell Region

Surface

Surface

Interior Surface

Exterior Surface

51 51 NUREG-1611
7. CONTAINMENT COMMON COMPONENTS

*Penetration Bellows

*Penetration Sleeves

*Dissimilar Metal Welds

*Personnel Airlock

*Equipment Hatches

*CRD Hatch

Reference:

Pages B-65, B-53, and B-52 of NUREG-1557, "Summary of Technical Information

and Agreements from Nuclear Management and Resources Council Industry Reports

Addressing License Renewal," dated October 1996.

NUREG-1611 552
NRC FORM 335 U.S. NUCLEAR REGULATORY COMMISSION 1. REPORT NUMBER

(2-8W (Assigned by NftC, Add Val.. SUPP., Rev. NRCM 1102, BILORPI AASETand Addendum Numbers, If any.)

3201,3202 BBIGAHCDT HE

(See instructions an Mhe reverse)

2 TITLE AND SUBTITLE NUREG-1611I

Aging Management of Nuclear Power Plant Contain ments 3 AERPR ULSE

for License Renewal 3. DTE YEOTPULSEDR

September 1997

4. FIN OR GRANT NUMBER

5 AUTHOR(S) 6. TYPE OF REPORT

W. C. Liu, P. T. Kuo, S S. Lee Regulatory

7. PERIOD COVERED (inclusive Dates)

8. PERFORMING ORGANIZATION - NAME AND ADDRESS (IffNRC, provide Division Office or Region, US Nuclear Regulatory Commission, and mailing address;, if confractor

provide name and mailing address)

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

U.S. Nuclear Regulatory Commission

Washington, DC 20555-0001

9. SPONSORING ORGANIZATION - NAME AND ADDRESS (If NRC, "a 'Sarue as abovet iffcontracor prvidee NRC Division, Office orRegion, U S Nuclear Regulatory Commission,

and mailing addres)

Same as 8. above.

10. SUPPLEMENTARY NOTES

11. ABSTRACT (g00 words or lAm,)

In 1990, the Nuclear Management and Resources Council (NUMARC), now the Nuclear Energy Institute

(NEI), submitted for NRC -review, the industry reports (IRs), NUMARC Report 90-01 and NUMARC Report

90-10, addressing aging management issues associated with PWR containments and BWR containments.

for license renewal, respectively. In 1996, the Commission amended 10 CFR 50.55a to promulgate

requirements for inservice inspection of containment structures. This rule amendment incorporates by

reference the 1992 Edition With the 1992 Addenda of Subsections IWE and IWL of the ASME Code

addressing the inservice inspection of metal containmentsfliners and concrete containments, respectively.

The purpose of this report is to reconcile the technical information and agreements resulting from the

NUMARC IR reviews which are generally described in NUREG-1 557 and the inservice inspection

requirements of subsections IWE and IWL as promulgated in §50.55a for license renewal consideration.

This report concludes that Subsections IWE and IWL as endorsed in §50.55a are generally consistent with

the technical agreements reached during the IR reviews. Specific exceptions are identified and additional

evaluations and augmented inspections for renewal are recommended.

12. KEY WORDSIDESCRIPTORS (List words or phrases that will assist researchers in locating fth report) 13 AVAILABILITY~ STATEMENT

aging management unlimited

license renewal 14 SECURITY CLASSIFICATION

containment structures (7his Pag)

Subsections IWE and IWL unclassified

10 CFR 50.55a (This Report)

10 CFR Part 54 ucasfe

15. NUMBER OF PAGES

16. PRICE

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