ML20058D645

Forwards Comments on NUMARC Rept 90-10, BWR Containment License Renewal Industry Rept & Requests Addl Info

ML20058D645
Person / Time
Issue date:	10/24/1990
From:	Jocelyn Craig Office of Nuclear Reactor Regulation
To:	Griffing E NUCLEAR ENERGY INSTITUTE (FORMERLY NUCLEAR MGMT &
References
NUDOCS 9011060192
Download: ML20058D645 (29)

Text

.

t October 24, 1990 Mr. Edward P. Griffing Manager, Technical-Division 7

Nuclear Hr.nagement and Resourses Council

/

1776 Eye Street, N.W.-

Suite 300 Washin9 ton, D.C. 20006-2496

SUBJECT:

BOILING WATER REACTOR CONTAINMENT LICENSE RENEWAL INDUETRY REPORT

' Boiling Water Reactor the topical report (NUMAFC Report Nuniber 9010) was By letter of July 25, 1990, Containinent License Renewal Industry Report,"

forwarded to the NRC for review and approval. The technical review of the report is continuing, and the staff determined that additional information is needed. The request for additional information is provided as en enclosure to this letter. As conveyed to you during earlier meetings, this report also lacks both sufficient justification for the conclusions reached and guidance for the licensees.

The reporting and/or recordkeeping requirements contained in this letter affect fewer than ten responcents; therefore, OMB clearance is not required under P.L.96-511.

If you have any questions concerning this request please contact me or P.T..Kuo at 492-3147.

Sincerely, NnN.8Nif,'Dhre'cNr License Renewal Project Directorate Division of Reactor Projects. III, IV, Y and Special Projects Office of Nuclear Reactor Regulation

Enclosure:

'As stated DISTRIBUTION hfintral'Filef D. Crutchfield, w/o enc 1.

G. Bagchi C. McCracken J. Partlow w/o encl. F. Gillespie, w/o enc 1.

R. Bosnak R. Jones

-.W. Minners w/o enc 1. A. Thadani J. Vora

'J. Durr, RI C. Cheng J. Richardson W. Travers w/o encl.

l LRPD r/f.

L. Marsh PDR R. Borchardt-i R. Kirkwood

' O P~

L. Shao w/o encl.

j L

DTC~~I~EEFD:PH

-LRPD:SC

tRPD:D n.

%ig NAME :Nacksong*/f: PKuo.

JCraig/

.....:.........g:.......p....:.........

q...........:. g g.p,y,. hg agig Q:gM.....

,,q g W

m 10/2f/90 l

DATE-:10/y//90 A

10/y'/90 -

~ ~ ~~~DfiICIAL PfCdif EDPY DocuEeiit'Eante: GRIFFT W EETTIE 9011060192 901024 SN h~

b

??

9.3

'\\n

^M## % }

1 i.

hg

• [,

s-UNITED STATES g

NUCLE AR REGULATORY COMMISSION g

a

-l WASHINGTON. D. C. 20655 001 2 4 1930 Mr. Edward P. Griffirig L

Manager, Technical Divistor, i:

Nuclear Managerxnt and Resourses Council 1776 Eye Street, N.W.

Euite 300 Washington, D.C. 20006-2496

SUBJECT:

B0!Lil:0 WATER PEACTOR CONTAll' MENT LICEt:SE RENEWAL, IMOUSTRY REFCP.T ByletterofJuly 25, 1990, the topical report, " Boiling Water Reactor Contairwient License Renewal Industry Report." (EUHARC Report Number 90-10) was forwarded to the NRC for review and approval.

The technical review of the report is continuing, and the staff determined that additional information is needed.

The request for additional information is provided as an enclosure to this letter.

As conveyed to you during earlier seetings, this report also lacks both sufficient justification for-the conclusions reached and guidance for the licensees.

The reporting and/or recordkeeping requirements contained in this letter i

affect fewer than ten respondents; therefore, OMB clearance is not required under P.L.96-011.

If you have any questions concerning this request please contact me or-P.T. Kuo at 492-3147, 1

Sincerely, U

I

.4<si ohn W. Craig, Director License Renewal Project trectorate Division of Reactor Project? - III.

IV, V and Special Prajects 1

Office of Nuclear 'aeactor Regulation L

Enclosure:

i As stated

,1

)

N l,

1 1;

~..

t.;

8 e

Mr. Edward P. Griffing Manager, Technical Division huclear Nanagement and Resourses Council 1776 Eye Street, N.W.-

Suite 300 Washington, D.C. 20006 2496

SUBJECT:

BOILING WATER REACTOR CONTAINMENT LICENSE RENEWAL INDUSTRY REPORT Sy letter of July 25, 1990, the topic 61 report (NUMAFC Report Nuster 9010) w

" Boiling Water Reactor Containment Licen:;e Renewal Industry Report,"

' forwarded % the NRC for review and approval. The technical review of the report 1 continuing, and the staff determined that additional information is neeted.

?he request for additional-information is provided as an enclosure to this le u r.

As conveyed to you during earlier meetings, this report also lacks both sufficient justification for the conclusions reached and guidance for the licensees.

The reporting and/or recordkeeping requirements contained in this letter

' affect fewer than ten responcents; therefore, OMB clearance is not required under P.L. 96 511.

If you have any questions concerning this request please contact me or P.T. Kuo at 492 3147.-

l:

Sincerely, L

John W. Craig,l Project Directorate Director License Renewa Division of Reactor Projects. III, IV, V and Special Projects a

L Office of Nuclear Reactor Regulation

Enclosure:

As stated

,)1STRIBUTION Gentral File D. Crutchfield, w/o enc 1.

6. Bagchi C. McCracken J. Partlow w/o enc 1. F. Gillespie, w/o enc 1.

R. Bosnak R. Jones W. Minners w/o enc 1. A. Thadani J. Vora J.-Durr, RI C. Cheng J. Richardson W. Travers w/o enc 1.

LRPD r/f L. Marsh PDR R. Borchardt R. Kirkwood L. Shao w/o enc 1.

l-0FC : LRPD:PM

LRPC:SC LF:PD:D

..... 2 NAME-:DJacksongf: PKuo

..... :.......... f :.......r.... :......g

/

s

JCrai

'10/d90'...:............:............:............:.......

DATE-:10/g///90

10/y>/90 0FFICIAL PECORD C0FY Locument haaie: GRIFFING LETTER

Document I ane:

LICENSE ret:IWAL 1R Fequestor's 10:

Bell-Author's Nate:

C. Jackson Document Connents:

l

~s

w l.

L COMMENTS ON FLEARC INDUSTRY REPORT (IF.)

j

• BWP CONTAINMEhTS L ICENSE PEi:EWAL 1R" l

[

1.

CEl!EP.AL CO WENTS I

i I.

As indicated in the IP, the life extension licensing decision is based in l

part on the existence of acceptable maintenance, inspection, test and analytical evaluation procedures. However, existence of these procedures does not necessarily provide adequate grounds for life extension. Absent 1

is the criteria / guidance to be used by a licensee seeking license renewal when preparing a plant-specific document identifying the current structural state of the containment components and including the results of appropriate past maintenance / inspection / test procedures. This-docunent will be reviewed by Ge NRC Staff and ultimately used, in part, as a basis for license renewal. This report should provide clear l

,, guidance to a licensee on what. plant specific actions required if the IP is referenced.

2.

A connon sentence appears at the end of discussions in various Sections:

l

• No further evaluation of (a degradation sechanism) is required for the l'

components listet below, beyond assurances by license renewal applicant that no plant-unique design or operating features exist wh.ich would j

preclude the applicant frosiverifying this conclusion."

('

It is not clear from thes.e statenients what the IR requires the applicant to do. How can one verify a conclusion without perfonning an t

evaluation? On the other hand, the applicant can verify the assumptions thct led to the' stated conclusion.

1 7

While this may be read to mean that a licensee should complete an l

i undefined review without more detailed guidance, it is likely to be misinterpreted by the users as to its applicability. Examples of plant-unique features which could be-potential contributors to a specific degradation mechanism.should be provided, as applicable.

!3.

No discussion has.been made in the report on synergetic or combined effects of various degradation mechanisms such as the effects of strain aging, irradiation and temperature.

4..

Guidance-should be provided for the steps a utility say take if plant specific design or operating features exist that would preclude the licensee from verifying the conclusions of the IR (See cessent 2). Also,_

guidance should be provided-to the licensee, for "what to do," whose plants are not designed to ASME Section III fatigue requirements.

9

.t-5.

Periodic testing of containnents, in accordar.cc with Appendix J of 10 CFE Part 50, does provide assurance of leak tightness of the containmer.ts under the designated test pressure which is generally low compared to the contairir.ent desigr. pressure and containment capacity. However, the visual inspections required to be performed prior tc the integrated leak rate testing are focused towcrds leak tight integrity and not towards detecting any aging mechanisn.. Thus, these inspections, as currently perforted, cannot be relied u absence of aging mechanisms. pon to provide confidence in assuribg the 6.

The discussion on " fatigue" should address all types of fatigue resulting from different sources of thers.tl' fatigue, mechanical fatigue, and the subject of environment-accelerated fatigue in areas where periodic steam and cor.densate may be present.

l 7.

Containment qualified coating must be addressed from the standpoint of coating degradation leading to corrosion of the drywell and suppression pool liner surface. Coating degradation should be included as an age-related degradation mechanism addressed for metal containments and i

steel liners. Protective coating flaws can lead to corrosion of the substrate.

B.

When addressing Mark I Steel Containment Components, the suppression torus ir.terior surface should be added. Suppression pool interior surface should be added when addressing Mark II Steel Containment Components.

g.

In Mark I units, large capacity snubbers are used as torus seismic restraints. These hydraulic devices also function during operational SRV discharges into the torus, and are intended to allow free thermal l.

expansior, of the torus. However, internal corrosion due to separation of fluids may cause the large capacity hydraulic snubbers to malfunctior.

As part of the license renewal for Mark I BWRs, these large capacity snubbers should be inspected for internal corrosion, the fluids should be drained and replaced and the snubbers should be stroked to determine l

if they can deliver the intended behavior.

10. The current inspection, maintenance and replacement programs at a plant are largely based on the expected need and degradation during the current-license-period.

It is quite conceiveble that as the plant ages further, acre stringent inspection and more frequent maintenance and replacessent will be required to manage age-related degradation. -The IR does not acknowledge the need for potenticily revising the current inspection, maintenance and replacement program.

1.

o 4 The IR should address assessment and potential a.odification of the existing-inspection, maintenance and replacement programs, and cemonstrate how such programs or modifications will eliminate the need for consideration of certain degradation mechanisms. Otherwise, the IR should not discord any cosibination of aging mechanisms and components from further plant-specific consideration.

11. The IR, as written, does not clearly specify the assumptions that were made in performing the degradction analyses presented in this IR. Since the IR is expected to be widely used for license renewal purposes, the report should include a complete listing of all assused parameters and, preferably, a user-oriented checklist such that the user can verify the applicability of the assumptions that were made in performing the degradation analyses.

12. Corrosion of steel containmer.ts especicily on inaccessible surfaces, is a significant potential degradation mechanism for BWR contcinments. The IR correctly identifies this degradation mechanism and recossends aging management to address localized corrosion. However, the IR asserts that i-aging sianagement is not required to address the general corrosion L

problesis, and that good " housekeeping" procedures (e.g. clean up spills, inspection of seal and monitoring for corrosion products) are adequate to manage localized corrosion. Based on experience (e.g. Oyster Creek),_the corrosion problems with BWR containments may be a mechanism which is difficult to manage even within the current licensing period. There are large uncertainties in the state-of-the-art knowledge in assessing corrosion. The accuracy of ultrasonic devices in measuring material thickness in inaccessible areas is questionable. The rate of corrosion-and the influence of the environmental parameters are not adequately known for these surfaces. Several issues need to be' defined including: an acceptable thinning of a carbon steel liner and the related criteria.

It is recognized that.the severity of the corrosion problem is plant-specific and.the IR may not be able to address the issue i

generically. However, a methodology to evaluate current programs and activities and. criteria and/or methodology to assess the current plant condition could be included.

13. The discussions'of stress corrosion cracking (SCC) are limited in the IP to components made of stainless steel. Ferriticmaterials(i.e., carbon i

and low alloy steels) are also susceptible to SCC *nf hydrogen-induced cracking (caused by hydrogen buildup from local cor..esion processes) under sosie conditions, especially at a high pH' level-(caustic cracking).

The IR should address the degradation of ferritic materia.ls, especially the attachments (e.g., bolts and welds).

14. Hydrogen cracking is also a potential local degradation phenomenon. For example, the failure of the contairment post-tension tendon anchors at Farley in 1985 was attributed to this mechanissi. Hydrogen cracking as a i

separate degradation mechanism should be addressed in the IR.

-t

(

4, IE. The IR tends to exclude bellows from degradation by fatigue due to the low number of anticipated cycles. I,amage of bellows by low cyc'e fatigue is credible, especially when it is environmentally assisted, ano should be discussed in the IR in the context of the aging management programs.

16. The discussions of the age-related degradation mechanisms, their effects on the plant components and the recormended mitigating programs are all L

based on experience in operating the plants in the last 20-30 years.

It is reasonable to expect that the components will exhibit more severe age-related degradation as they age further, especially beyond their p

current license period. However, the IP did not demonstrate how the limited observations made during the early years of the pla,nts can be l'

extrapolated to address the potential problems of later years. The IP L

should discuss the potential for additional modifications to manage plant

, aging and the need to carefully-review experience to identify degradation due to aging and implement corrective actions.

17. 8WR plants have undergone a great deal of evolution since their first l

cospercial use. The IR has attempted to address the containment details at each stage of this evolution. The IR should demonstrate how it has evaluated all such plant specific details; otherwise, the aging related cegradation should be addressed on a plant specific basis.

18. Several combinations of degradttion mechanisms and containment components were eliminated in the IR (Section 4.0) from further consideration for license renewal based on the argument that certain construction materials and methods can ensure soundness of the structures against these l

degradation mechanisms. However, the questions are whether these j-materials and methods were used at the plants seeking license renewal and

- whether these plans will indicate any aging related damage at the end of the current licensing period. Therefore, the IP should_ keep these-degradation mechanisms and the components open in Section 4.0 for plant-specific evaluation.

- 19. Several combinations of-degradation mechanisms and containments componentswereeliminatedintheIR(Section5.0)fromfurther consideration for license renewal based on the argument that certain inspection, maintenance and replacement programs can-manage the age-related damage. However, the question remains -as-to the extent cf the damage a-plant will suffer through the end of the current licensing Period and verification of the effectiveness of the plant-specific current programs to manage the degradation effect.

(The IP has rightly L

. acknowledged that the maintenance )rograms are plant-specific.)' Based on the plant-specific condition and tte maintenance programs; the applicant should evaluate whether these programs will manage degradation through the license renewal period. Therefore, the IR should keep these i

degradation mechanisms and components open in Section 5.0 for

' plant-specific resolution.

l

.s.

20.

For certain combinations of degradttion mechanisms and components, the IR in Section 6.0 proposes aging 6,enagement programs. The feasibility of these programs to manage aging depends on the extent of plant specific a

- wear and the effectinehess of similar programs used during the current ~

licensing period. Since such inforration is plant-specific, the IR should keep the degrad6tioa mechanisms and cos.ponents open in Section 6.0 fer plant-specific resolction.

21. The effect of life extension (i.e., the fact that a life extended plant will ba further degraded ther. its conditions at the end of the currently licensed life) on ar.y existing safety assessment study to the extent it affects the current licensing basis should be considered for license renewal. This should be addressed in the IR.

II.' SPECIFIC COMMENTS

~

1.

On page 1-2, at bottom of page under free standir.g steel containments should add, elevated temperature.

.2.

On page 1-3 to be consistent, post-tensioning systems should be changed to prestressed concrete containments and under this title, add the following:

(1 Creep and shrinkage cf concrete (O

Relaxation of prestressing tendons (3

Hydrogen embrittlement of anchor head steel 3.

Section 1.3.2: Nonsignificant Degradation Mechanism General Corrosion:

theadequacyofthecorrosionallowancemade(inthe design) for uncoated carbon-steel surfaces of BWR containments needs to be assessed-for the the license renewal term.

Differential Settlement: DifferentialSettlement(orsettlement)ofa BWF containment supported on piles can not be discarded without knowing the condition of piles after 30 or 40 years of exposure to variable substructure environment (e.g., fluctuating ground water, chloride content of ground water). The IR should be revised to address-this issue or this issue should be identified as an item to be included in plant-specific evaluation, as appropriate.

4.

On page 1-8, there is mixing of containment structural components and containment systes; components in the listings of BWR steel contairment and BWF concrete containment components. The listings as presented are not inclusive nor consistent. For instance, there are downcomers in Mark I containments (steel or concrete) but they are not listed. However, in Mark 11 containments they are listed.

In Mark 1 steel containments, the-ring girder is listed but its function and location are unknown. For a number of structures and components the interior surface and exterior surface are listed.

c

-6 5.

Pages 1-8,1-9,1-10:

Under Mark 1. II and 111 Steel Components,

' Embedded shell region" probably should be sioved to page 1-10 under Common Cosiponents P.

This is because the drywell near the embedment is a region of geometric 61 discontinuity and acts as a stress riser.

It is a,

likely site for fatigue damage. The fatigue usage factor (taking into consideration the pro of repeated loadings) posed life extension and expected levels and cycles should be calculated to ma te sure it is still below a factor of one.

6.

Page 1 10: General Corrosion - the staff does not agree that general corrosion is not a significant age-related degradation mechanism for 6WR freestanding steel components constructed ' lith austenitic stainless steel, coated on all exposed surfaces, or designed with a corrosion allowance.

Imperfections in coating coverage can actually aggravate corrosion effects. Cracks have been found in the stainless steel liners at one plant and corrosion is occurring in coated and uncoated surfaces at greeter that designed allowances in some cases. The ASME subsections thht cover l

inservice inspections are still under review and not endorsed and used.

UT and flew evaluations are only now being added to Subsection IWE. Since these inspections have never been donc, and the requirements never implemented, it would seem that some further evaluation will be required to detennine the significance of general corrosion and the need for aging management as appropriate.

7.

On page 1-10, under Mark 1 Steel Containment, add "3,' transition region form the cylindrical to the spherical portion of the drywell" because this is L

.a geometrical discontinuity.

8.

On page 1-10, for the highly stressed containment, why are only the vent header and downcomers and bracing in Mark I steel containments listed, i-L but not.these same components in Mark I concrete containments nor the D

downcomers with and without bracing in Mark !! containments? - All components subjected to SRV loading should be' considered for fatigue.

9.

On page 1-10, under. general corrosion it is stated that free-standing l

steel containment components are constructed with austenitic stainless steel, coated on all exposed surfaces or designed with a corrosion allowance.

TW the staff's knowledge there are no BWR free-standing steel containments constructed of sustenitic stainless steel.:If there is no such containment, revise the statement-.

' 10. On page 1-11, penetration sleeves and bellows should be deleted from this-list. Penetration sleeves-and bellows are seldom inspected. Most sleeves are uncoated.

11. On page 1-11 first line, change to *... corrosion of carbon steel surfaces without coatings, with deteriorated coetings, or a corrosion allowance require further evaluation."

~

After ".. verifying-these conclusiors.*

(at the end of the second paragra h} add " Care should be exercised to identify surfaces originally coated ut-the coating has since deteriorated. These surfaces need to be evaluated further for general corrosion."

7

12. On page 1 11, it is iniplied that components designed with a corrosion allowance need no further evaluation of general corrosion. From the experience with the Nine Mile Point I torus corrosion, the actual corrosion was greater that the corrosion allowance. Therefore, evaluation for corrosion for such a component is required.

Further, the inside surface of the Mark I steel drywell and that of the steel liner of the Mark I concrete drywell at the basemat top level as well as the inside surface of the torus should be evaluated for corrosion or coatint degradation.

13. Delete 'without coatings or a corrosion allowance" at the top of page 1-11 and ir, the fifth line of page 1-12. Oyster Creek has a general corrosion problem that may limit normal life of containment even though surfaces are coated end there was a corrosion allowance.

I

14. On page 1-12, the first paragraph - Ceneral corrosion is a potentia 11) significant age-related degradation mechanism for carbon or low alley steel surfaces without coatings... Add "with or" in front of without (seeSpecificComment6).

15. On page 1-12, add " Torus internal surface (uncoated)* as item 3 or. der Mark I.

Add " Suppression charter interior surface" as item 3 under Mark 11.

16. The statenant that."[C]orrosion is not a significant age-related degradation for BWR containment prestressin ducts contain corrosion-inhibiting grease" g tendons, because the tendon is not true because the tendons may not be contpletely covered by grease due to voids in grease or leakage of grease or ingress of water into the ducts and tendons have failed due to microbiological 1y influenced corrosion (NIC) when the grease decomposed-("A Study of Microbiological 1y Influenced Cortesion in Nuclear Power Plants.and a Practical Guide for Countermeasures" EPPI NP-45E2, May UBE).: Corrosion should be considered a significant age-related degradation mechanism for BWR containment-prestressing tendons.

17. Section 1.3.3: Adequate Current Program Except for monitcring of prestress forces and hardware components of the prestressing systam of prestressed concrete containments. there are no scheduled inspectica and seintenance programs for BWR containments.

Inspections and remedial actions are thought about only when a deficiency or a degradation mechenism is identified and reported for a specific class

-(e.g. 3WR MKI) of contoinment.

For prestressing losses, the current

=

surveillance prograsi on'y (i.e. R.G.1.35) ensures that the prestress forces are adequate for 40 year life of the plant. Additional steps need to be implemented to ensure that the prestressing forces will be adequate for the license renewal tenn. Thus, it is inappropriate to make a statement that the current monitoring programs are adequate to detect various degradation mechanisms in BWR containments.

3

- 18. On page 1-15, under General Corrosion, it is stated that general corrosion of BWR f ree standing steel containment components constructed with carbon steel and without a corrosion allorence or coating on exposed surfaces is adequately addressed by current testing programs and procedures. The statement is misleading and not factual. The implication that components with a corrosion allowance and coating need no consideration for general corrosion is not proven by fccts, (see NRC information notices 0E-82, 8979).

Further, the statement gives the impression that there is an established effective program of monitoring and inspections, which is not valid.

In view of this fact, further evaluation of general corrosion is required for all free standing steel containments.

19. On page,1-19, Stress Corrosion Cracking - It is very poor practice to wait for the crackin detecting mechanism.g to get to the point that a leakage rate test is the Other measures should be established to detect the cracking cf liner plates,

20. On page 1-21, aging management options should include NDE measurements.

j Some plants have had to chip out-concrete inside the drywell to make Ntr measurements of sand pocket areas. The sand pocket areas should be noted-on figure 3.1-1 "BWR MARK I TYPE METAL C0t:TAINMENT".

l

21. On page 3-11, top line:.Regarding'the Firebar D or polyurethane sieterial place in the gap between the steel containment vessel and concrete shield wall, the IR states that "s,any plants removed this material after pouring the shield well concrete." The replacement materials and the possible remedies to prevent corrosion are not adequately discussed in the IR.

Since the IR is expected to be used as a generic report -it should

-envelop all possible scenarios of design, construction and maintenance or identify exceptions.

i I

L

22. On page 3-11, last paragraph: The IR describes structural modifications made for "most Mark I plants" and makes a case of how strong the L

structure became as a result of the modifications. However, the IR does not address the plants where these modifications were not performed. The IR should address the design and construction of all BWR containments including the modifications. Othemise, the ~IR should clearly identify

_the plants that are not under its scope.

(This comment applies to many statements made throughout the IR).

23. On.page 3-17, it is stated that the downcomers are provided with

. -structural bracing systems.

It is noted that not all the downcomers are provided with structural bracing systems. The downcomers in Nine Mile Point 2. for example, do not have the lateral bracing system. Add

"... typically downcomers..."

14. On page 3-19, under 3.1.3.2 the word 'pretensioning" on the fourth line should be changed to "prestressing".

g p-r-v-

v.

.9 9-25.

In both Mark 11 and Mark III concrete containments and Mark III steel containment, it is indicated that the basement is considered as a load carrying portion of the containment pressure boundary. However, there is no e,ention as to how the basemat of Mark I concrete drywell is considered.

26. On page 3-29 ANSI 5.12 should be ANSI N101.2.

27. On page 3-31, Table 3.2-1.

For ' Freestanding Steel Containments', the material of construction for suppression chamber shell should be changed to read " Carbon steel (1) or clad with stainless steel (Mark III?, since Mark III metal containment vessei is made of carbon steel clad wTth stainless steel up to about one foot above the normal suppression pool level.

28.' For Mark III steel containments' the concrete basemat has a steel liner.

Modify ' Material of construction' for basemat to read reinforced concrete with stainless steel liner or carbon steel liner clad with stainless steel.'

29. For ' Concrete Containment *, the material of construction for basemat shoul" read ' concrete with carbon steel or stainless steel liner', not i

' Carbon with...'

30. On page 3-39, it is stated that the leak chase channelt c..

arlugged or opened during leak-testing.

Is this actually done? If tL.

i. accurate,

.how are the leak chase channels embedded into the concrete treated?

e

31. On page 3-39, the first line of the second paragraph should read '[A]

l-special feature of the concrete containments (Mark I, II 6nd III) 1s..'

i since all three concrete containments have leak chase channels.

32. On page 3-41, this section needs expansion to provide assurance ti.at coating will continue to perform their needed function during life extension.

33. On page 3-43, in section 3.3.1 under historical performance, it thould be noted that the cathodic protection systems have not been found effective in minimizing corrosion and also in NRC Information Notice 88.82, the l

j degradation of coating of the torus inside surface was addressed. The latter is also reflected in the IR on page 3 46 under maintenance.

Adequate inservice inspection of the drywell shell at sest plants.(Mark I containment) have not been 'perforwed to verify corrosion rates.

34.- On page 3-44,- it is stated that corrosion of the exterior. surface of a Mark I drywell in the cylindrical shell region. is not' considered an L

age-related concern. However, up to 6 mils / year.of corrosion of the exterior surface of the Mark I spherical shell region has been detected.

Local and general corrosion has occurred. The corrosion appears to be due to leakage from the reactor cavity or equipment pool line-leaks. The extent of corrosion at other Mark I planto is unknown due to lack of inservice inspection measurements.

Licensee actions to identify and l

evaluate the extent of this mechanism should be included in the IR.

' 35.. On page 3-44, in the paragraph numbered 3.Is not an age-related concern?

if the origin of the moisture is not known, how does one know that this It also states that "...In either case, it is not considered an age-related concern." This conclusion is not adequately justified.

Based on operation experience, the corrosion of Mark I and II exterior J

surfaces is a potential concern from the life extension point of view.

Since the 2 to 3 inch gap is inaccessible, moisture could be trapped especially if. filling matnial has not been removed and is deteriorating.

36. Page 3-45, this section does not address the extent of drywell corrosion with respect to determination of corrosion rate, nor evaluation of the corrosion to determine when drywell well is less than minia'm code u

allowables.

37.' On page 3-45, first two paragraphs:

Reference is made in the IR to the

?

effect of. the leak tight integrity tests on age-related degradation.

There is a concern that the increase in leakage, caused by age-related degradstion, may be too rapid for the standard schedule of leak tight tests to be adequate. The IR should be revised to address this concern.

L

38. Page 3 ab, maintenance: The IR acknowledges that maintenance is

+

i plant-specific. The effect of age-related degradation mechanisms on the containment components depends, in part, on the extent of maintenance.

Therefore, it is not clear how the IR can generically address the plant-specificproblems(e.g.,protectivecoatingandcorrosion). The IR may have to leave these issues open pending resolution on a plant-specific basis.

39. On page 3-47, ANSI N45.2-1971 is referenced in Regulatory Guide 1.54, which addresses quality assurance requirements for protective coatings applied to nuclear power plants. Delete N101.1-1972 and N5.12-1967.

40. On page 3-47, last paragraph: Regarding concrete containments, the IR cites observations of ' voids / honeycombs in the concrete, cracking /spalling of concrete, and low compressive strengths." The IR concludes that "these were all related to construction and placement methods, and thus were not age-related."

a).

These observations do not support the claims made elsewhere in the

.IR regarding superior quality of the concrete, b)

Although the cited observations may not be age-related, the aging mechanisms can cause accelerated degradation of concrete of poor quality. The IR'should make the degradation analyses considering such concrete qualities.

41. On page.3-48, last paragraph: The IR states that " inspections of concrete containments are plant unique."

If this is so, the IR.should require that a comparison be made of' the inspections performed for a particular plant with some acceptable standard requirements.

, 3

(~ 42. /, General Connent on Section 3.

A table listing the typical important design and operating parameters (e.g., tesiperature, pressure) of the L

drywells and pressure suppression chambers for different types of BWR containments would be helpful to licensees in determining whether this IR is applicable to their plants.

In the text, thL internal design pressures for drywells are given for Mark 11 and !!! type components, but other parameters are not given.

L

43. On page 4-3: Significance to containments - austenitic stainless steel is corrosion resistant, but because of the operating environments, cracking has been found. Also, in the second paragraph, some utilities have experienced greater than design corrosion allowance degradation.

44., On page 4-3, second paragraph:. Regarding the air gap between the drywell metal shell and the concrete shield, the IR states that " corrosion precursors in this area may be detected through the presence of moisture or corrosion products in drain output from these areas."

.a)

If this detection is to be the basis for eliminating the & gradation mechanistis, the approach should be more positive to prwide adequate j

confidence.

b)

Corrosion on' inaccessible surfaces is difficult to assess. Thus, i

the corrosion allowance on well thickness is difficult to verify and enforce.

in general, the rates of localized corrosion are much higherthangeneralcorrosion(duetopitting,etc.). Thus, if localized corrosion occurs and remains undetected, there is a strong-likelihood of leakage. This is a potentially serious concern with BWR containments and the IR should recossend more aggressive aging management programs to identify and evaluate this mechanism.

45. On page 4-4. the.end of the second paragraph indicated that a general corrosion rate of 3 mils per year can be expected for Mark I and 11 steel containment exterior surfaces. Therefore, after 40: years of regular licensed plant life, general corrosion of the amount of 0.12 inches can be expected. This already exceeds the typical corrosion i

allowance of 0.0625 inches. If this is the case the adequacy of the L

containment shells should be carefully assessed and documented when these i

L plants apply for license renewal.

l i

46.

In view of Comment 45, the statement (last paragraph of page 4-4) that

'[6]eneral corrosion is not a significant age-related degradation mechanism for components... have a corrosion allowance provided" is not justifiable.

47. On page 4-4 with respect to the compressible material in the gap, chlorides and sulfates can also be leached from Firebar D and polyurathene which can accelerate corrosion. The IR should address this additional concern.

i-l l

1 l

. ; 9

.1 48. On page 4-10, the IR asserts that "the carbon steel surfaces are coated" and, thus, eliminates corrosion as a potential degradation mechanism. To be acceptable, it should be confimed that carbon stet 1 surfaces for 8WR containments are coated and, if =so, that the coating are intact.

Since, elsewhere the IR st6tes that maintenance is plant-specific.

If coating repairs have been perforsed, the history of such repair will be required in order to make plant-specific degradation assessments.

49. On page 4-19, the IR states that " clevis pins, shear lugs and door mechanissis are accessible for visual confirmation of the absence of i

ongoing degradation, such as corrosion or freeting." The licensees should ccnfim that visual examination of these areas are part of existing programs and that corrosion or fretting is includcd.

50.' Section 4.1.3 provides a brief ' discussion of the different types of cyclic L

loedings releted to containment. On page 4-17, a table is presented l

which sununarizes the maxinom expected number of cycles for 80 years of operation for each load type. Provide the basis for the expected number l

of cycles for the following load types:

a.

Pipe reactions at penetrations b.

SM' discharge loads c.

Steam condensation loads t

51. The loadings provided in the table 4-17 do not appear to hcve considered the expected cycles resulting from LOCA loads.

Provide a quantified estimate of the LOCA cycles and revise the table on page 4-17 accordingly.

.52.

On_ page 4-16, it is stated that the allowable number of cycles for carbon steel corresponding to an alternating stress intensity of 30 ksi is 50,000. This allowable appears to be based on a carbon steel with an ultimate tensile strength (lfts) greater than 115 ksi. The material in question-appears to be a' carbon steel with UTS less than 80 ksi. From the ASHE Section 111 Appendices.1977 Edition, Figure 1.9-1, the allowable number of cycles for this r.aterial corresponding to an f

alternating stress intensity of 30 ksi= is 20,000. Provide a discussion of this apparent discrepancy including any significantximpact on fatigue cusslative usage factors. For example, if the total number of expected cycles for 80 years of operation increases significantly due to the addition of cycles resulting from LOCA loads the margin of safety on cuawlative usage factors could be significantly reduced.

In addition, the above. analyses should include an evaluation of environmental effects on fatigue crack initiation to the extent needed to show that the analyses are conservative.

yi 4

- 53. On page 4-17, at the top of the rage, the nunber of cycles for each event is listed.

For sore of the events the cycles can be reasonably estimeted.

For others such as seismic, SRY steam condensation loads, etc., the nur.ber of cycles are at best a guess.

It appears for seismic load during 60 years of operation the estimation of 20 cycles is low.

It is realized that for some sites there mey not be any earthquake during that period but for other sites the earthquakes may be more frequent.

Since this IP covers all EWR plants, details of how this nustier is estim6ted should be provided.

In addition, it is not known how the 1000 cycles are established for SV discharge and other loads. Further it is to be noted that for low cycle fatigue for some of the components, such as, the downcomers in Mark I and the unbraced downcomers in Nine Mile point 2 (Mark 11), a high level of stresses may become more significant.

54 There is no sention of propagat,1on of cracks in the base metal during

' transients and normal loads.

l

55. Page 4-20: Associated with the free thermal expansion of the torus is the problem of potential wetr of the lubrite pads which are provided to allow sliding of the Mark I torus with minisum friction. However, wear may increase friction with time such that incretsed thermal stresses result in the Mark I pressura suppression system. The re this problem without offering suastantial justification. port dismisses Adequate I

documentation that wear will not be excessive to the point where increased sliding frictions will result should be developed.

r 50., One principal source of stresses in the steel would be residual stresses L

from welting.

It should be confirwed that the residual stresses were relieved in fabricating the steel containment for all BWR plants.

If not, these stresses should be considered in the evaluation, 57.

On page 4-31 at the bottom of the page, the last listed age-related y

degradation mechanism, i.e., reactions with aggregate, is misleading and should be " reactive aggregates." The reaction may be between aggregate-materials and the constituents of cement, specifit. ally alkalies, which may result in expansion, cracking and deterioration of concrete.

SP..

Onpage4-33,astatementismadethatchlorideenhancescorrosionrites by lowering the pH of the solution. The statement is incomplete.

Chloride acts by destabilizing the passive layer on the steel and by increasing the' incidence of pitting and crevice corrosion. Chloride will lead to lower pH in localized corrosion cavities, but not in the bulk

solution, l'

Lowering of pH in the concrete over time can be caused by carbonation.

l The potential-for lowering of the pH in the concrete, with associated enhanced reinforcement corrosion is not considered in the document but should be. Carbonation occurs most rapidly in environments of around 50 60% relative humidity, which may be typical of many above ground

-o cs

. t environmen'.s. The paper listed

• gives c model for carbonation rates.

This sedel, or otter calculations should be applied to support are conclusion concu r.ir g carbonatior..

59. On page 4-25, regarding stress corrosion cracks of steinless steel cladding of suppression pools, the IR uses the fracture mechanics ar.alysis results for perry to conclude that.*the cracks would r.ct propagate through the base setti..."

The 1F should provide justification as to how the plar.t-specific analysis I

results for the current licensing period can be used for generically eliminating the SCC problems of all plar.ts, especielly during the license renewal period.

60. On page 4-34, last paragraph, the IR states, tSt the ' concrete used for containment construction is of high quality" and neludes specifications of various parameters.

It should be confimed that these specificatior.s eraelop the concrete qualities of all plants. Otherwlte, the IR should clearly state that the evaluation presented in it is based on these assumptions.

61. On page 4-37, "In-service surveillance to identify coating maintenance is needed to assure acceptable coating perfornnce" should be added at the end of the first paragraph.

62. On page 4-36, at the bottom of the page under Mark III steel contairment, one should add basemat reinforcing steel, i

,E3, On page 4-3E, lt of coatings or through the use of stair.less steelLiner P that as a resu

, that all of the problems have been taken care of, and that no further evaluation is necessary. On page 4-39, among the components listed for further liner corrosion evaluation, the basement liners for t.11 types of containment are not included.

k' hat is the basis for not including the g

basemat liner in the list of components for further evaluation?

64 On page 4-38, the applied coating on interior surfaces has been used in the IR as a reason for eliminating general corrosion as a degradation L

mechanism for liner plates. However, the IR did not desenstrate that the applied coating on liner plates in plants will remain intact throughout

• Papadakis, Y.V., C.G. Vayenas, and M.N. Ferdis, "A Recction Engineerin Approach to the Problem of Concrete Carbonation. */.IChi Journal, 35(10)g 1639-1650,' 1989.

, p.

4 4

-1!-

the license renewal period. Guidance should be included to i

l evaluate the status of coatings or interior surfaces.

65. On page 4 43, in evaluating the thermal eff ective on ccr. crete as ar, eging l

related mechenism, the IR acknowledges the reduction in the s.odulus of I

elasticity.

It argues thtt 'the containsent integrity is more directly affected by strength than modulus of elasticity

• and consequently I

concludes that "the reduction in elasticity is not significant.' The reduction in elasticity chtnges the stiffness of the structural elements resulting in redistrthutton of the load paths. This may inyt11date the existing design calculations.

In order to make the above conclusion, the IR should justify how the existing design calculations are valid in spite of the reduction in elastic modulus.

66. On page 4 46 under Mtrk I conct.ete containments the concrete basetert is

' not listed nor is it listed anywhere.

Its status r,6eds to be clarified.

l

67. On page 4-40, the IR indicates thtt the concrete stresses are limited to l

711 of the f ailure stress. However, if the seistiic load is included in the load colabination, the allowatle stresses will be larger than 711 of the failure stress. Unless otherwise justified, the IR should be revisec i

to acknowledge the possibility of existence of high stresses and consider their effect cn the fatigue evaluation.

I

68. On page 4-49, the IR isiplies that the seximuni permissible stress in the reinforcing steel is 24,000 psi. When seismic loads are included in the load combir,ation, the reinforcestent stresses may be much higher (e.g.

36,000 - 54,000 psi). Unless otherwise justified the resised accordingly to evaluate the effect of fatigue IR should be

69. On page 4-50, under Mark I concrete contcirment, add the drywell head to the li'.t.

70. On page 4 51 at the top of the page after Mttk I concrete contaitsents, add Mark !! concrete contairrient and the unbraced downcomer pipes l

(existingathineMilePoint2).

71. On pages 51-56, the discussions in Section 4.2.5 implies that a concrete mix can be designed such that the degradation of certain components due to aggressive chemical attack can be avoided. The IR further states that plant controis ensure detection of exposure of concrete to aggressive chemiccis. The IR also makes a cash against sulf ate attack due to *th membranes cer.erally placed arouno below grade concrete

• In these discussions, the IR makes several assumptions which are loosely stated over several pagr in eve hating the effect of a degradation sechanism ar.d eliminatir; certain possibilities. However, the question is whether these conditions exist ir, the plants potentially seeking license renewal. Also, it is not clear exactly what the IR requires a user to verify in order to use the degradation assessment results A

, presented in it. For example, what is the right concrete mix? Does it envelop all containrent construction? What types of plant controls have been referenced for detection of aggressive chea.icals?

!$ the degradation evaluation applicable even though a plant does not i

have membrants place around below grade concrete? In order to make a case in evaluating a degradation rechanism, the 3R should assure parameters that envelcp or are applicable for all BWR plants.

Otherwise, it should clotrly list the assumptions or exceptions.

72.

On page 4-57, the ip states that *1rradiation effects will have no inipact on reinforcing and liner plate steel uritil this value is exceeded."

$1 rice welds and heat affected zones suffer more den.ege than the base setal, the IR should confirsi that such local elements hcVe been considered in making the case against irradiation dasiege.

73. On page 4 07, the IR refers to five ACI provisions that may have been used to a.itigate cherlical reactivit document (IB) is siuch more recent (y of aggregates. Since the reference 1980) than the construction of most concrete containment structures, it is not clear whether the cited

)

mitigatirg provisions here rec 11y implemented.

This should be verified and confirmed in the IR. Otherwise, the IP should clearly provide a list of assurptions that were medo in evaluating, and especially eliminating, the effects of the degradation mechaniss,.

)

74. On page 4-70, the IR states that 'containeents are constructed of a dense, well-cured concrete, with an amount of cement suitable for strength development, and achieverent of a water-to coment ratio which is a characteristic of concrete having low perne&bility."

a)

Since, the concrete construction of a plant follows its own s pecification, it is not clear whether the above statement envelops t1e characteristics of all containment constructions. The IR should confirm this.

b)

The stated specifications are so qualitative that no comparison can be sede with the concrete quality of a specific containment.

The IP should provide more quantitative figures for possible verification by a user. Since stress corrosion of carbon steels occur in caustic environments as well, this should be added to the list of conducive environments provided in the IF.

i

75. On page 4-77, the IR depends on corrosion inhibiting grease to discount I

L corrosion of tendons. Microorganisms and other sources can degrade the I

tendon grease and make the tendons susceptible to corrosion. This potential should be evaluated.

76. On page 4-81 in the discussion of causes of delsminations, one cause which contributes most is not mentioned.

It is the radial tension resulting from tensioning the tendons. The IR should provide a discussion on potential seasures to eliminate this cause.

m

.,-.vw-~.-

m

l 1 1

77. Differential settlement is eliminated in the IR as a degradation problera for structures founded on piles. This assumes that pile corrosion is not l

a significtnt degradation probles. which is cortrary to experience cited I

in LHTA reports (Corrosion Control Manual for Rail Papid Transit, l

LNTAl't0152-83,LUTA1983). The IR should keep the settlement for pile foundations open pending resolution on a plant-specific besis, i

l 78.

In Section 4.3 for prestressed concrete degradation mechanism, two items L

with respect to grease should be addressed, i.e., the aging effect of the grease, and the effect of grease leakage into contrate.

l 79.

In Section 0.0, the items listed for evaluation should be consistent with t

, those idtntified in respective. sections.

80.

In Section E.0, the IP references an analytical assessment procedure.

In dealing with an analytical assessment procedure, one should provide approved analytic eethods whereby one can estimate contaiteent strength J

and stability when subjected to a local corrosion with possible material pro?erty change and wall thirning.

Please provide a discussion on how buctling strength of a containment as a result of local change of e.aterial properties and wall thinning will be obtained.

21, in Section E.), it is ir.dicated that the acceptability of containment for license renewal will L.c determined by containmer t using A!ME Code criteria. performing an analysis of the l

The report does not specify which version of the Code will be used. A discussion of the code application for l

license renewal is necessary.

ET. On pages 5-7, the IR states that "...several licentaes have instituted periodic wall thickness measurements.* The IR should specify acceptable l

techniques, frequency of measurements, acceptance criteria and sisillar actions to adequately identify and manage this mechanism.

83. On pages 5-0, the IR states that *... coupon samples placed in an identical environment provide acceptable data for corrosion rates.* The intent of this statement in the IR is not clear. Does the IR required each plant to perfonn such coupon tests or is this an assumption? The IR should provide clarification in this regard and clearly list all assumptions.

84. On page 5 8, UT measurements should be identified for all Mark 1 and !!

steel contairments.

85. Section 5.1, With respect to Section XI Inservice Inspection, it should l

be recognized that subsection !WE of ASME Section XI is not consistently used by all licensees. Also the deficiencies of the Subsection are being worked on by the code convaittees at the present time. Reliance on the potentially changing provisions of the code as a seans for detection of age related degradation is not appropriate. The IR should be revised to tiore adequt.tely address this issue.

I L

f

.y.

18

80. On page 5 9, the IR states that "a number of acceptable methods are available to detect and manage thtt 'no additional measures.. general corrosion...* ano then concludes

. is s.aintained and verified." This conclusion is not justified without confirming that these methods are, in ftet, used by til licensees. The conclusion should be revised or more information should be provided.

E7. Sections 5.2.1 and 5.2.2 briefly discuss methods which are available to detect and manage general and local corresion in the Mark I ECCS suction headers and the Mark I and 11 downcomers and bracing. However, the conclusions for both of these sections do not include enough specific requirements which are applicable to the license renewal tpplicant. To

,, provide the basis for the staff,to reach these same conclusions, the IF, should conttin either:

A more detailed description of each of the recoss. ended aging a.

management methods together with a specific requirement that each epp11 cant for license renewal comits to implementation of these methods, or b.

A requirement that each applicant for license renewal submits plant-specific prograars for managing general and local corrosion for sttff review prior to staff approvel of license renewal.

88. On pages 511 and 512, the arguments presented in the IR to eliminate local corrosion as a degradation mechanism for many components are inadequate. For example, how can corrosion be reliably detected on time

'from observation of water leaking, dripping or pooling...?' The IP should be revised to provide more definitive guidance and criteria.

89. Section 5.2.3 discusses two different methods to assure that degradation due to fatigue is properly managed for the penetration sleeves and vent header /downtomer intersection in Mark I containments. All of the staff's comments above relative to Section 4.1.3 in the Industry Peport are applicable to this section. Pending resolution of these comunents, the two aging managesent methods recommended in Section 5.2.3 will be acce: table to the staff. However, there should be a note that in this (eaci) Industry Report that each applicant for license renewal prepares l

and incorporates into the FSAR revision for renewal smittenance a susmary of its plant-specific analyses for the staff to review as part of its t

review of a license renewal application.

L 90.

In Section 5.2.3, page 5-13, several star.: lard methodologies in evaluatirg l

fatigue were discussed; design stress report, inservice inspection code l

and ASME code Section !!! for Class 1 vessels, etc. However, it is not clett if they address fatigue in an adverse condition such as presence of corrosion or large crack in base metal.

The IR should be revised to describe sethodology for perforsiing fatigue analysis once an adverse condition is identified.

e

i..

gl. On pages f4 4 ar.d 5 15, the IR proposed certain analysis methods to manage degradctiv.i due to fatigue.

Based on this proposal, the IP concludes that no furtntr evaluation due to fatigue is necessary for license renthal. The conclusion appears inappropriate since the applicant should first apply the proposed methods and evaluate the analysis results, ared then judge whether the fatigue dar. age for these components are uanageable through the license renewal period. Unless otherwise justified, the IR should be revised accordingly to provide the logical sequence for evaluation.

92.

On page 5-5 in discun ing Appendix J 1eakage rate testing, it is stated that the functional

'd structural integrity are periodically i

devonstrated b) perforriing Appendix J testing.

This is only partia11) true because types A, er,d 5 tests basically only indicate the leaktigtt i

it,tegrity.

Structural integrity can only be determined by structural integrity test. The 1R should be revised to reflect this point.

g3.

On page 5 22, the it eliminates differential settlement as a degradation rechanism since there are monitoring progrars.

The argument is inadequate since existence of the monitoring program alone does not ensure that settles,ent will be acceptable through the license reneh61 period. The actual settlemient should be evaluated and, based on the results, justific6 tion should be provided on a plant-specific basis to manage the settlerient issut.

94. Section 0: Aging Degradation Management A thorough focused baseltne inspections one of the basic ingredient of i

an effective aging / degradation management philosophy.

It should be i

performed prior to submitting an application for license renewal. The l

plant-specific aging / degradation management philosophy should include the consideration of (1) the actual codes and standards used in the construction. (E) construction related non-conformance reports (NCRs),

and (3) the performance experience during the operational life.

The enhanced inspection requirements for inaccessible areas, fluct potentially corrosion-prone areas and the areas subjected to groundwater as discussed in this Section,.should form part of the baseline inspection.

.95.

In section 6.1, page 6-3, it is stated that *!t should be noted that L

research and cevelopment for detectirig degradation in embedded region is under way.' Again, the emphasis is on how to find it and prevent it.

In the eeantime until the res,ults of ongoing research are finalized.a contingency guideline is nee

96. On page 6-3, the IR indicetes that the effects of local corrosion of an embedded contairment shell will be manifested in surface cracking and discoloration of the concrete.

This may not be true since the concrete surrounding the shell is riot thin enough for such annifestation. The IR should be revised accordingly, unless otherwise justified.

~ - ~ '

20

97. On page 0-4, the IR proposes t list of s.ariagement options. However, it is not clear how these good *housekeepins' options Sill a.anage the damage through the license renewal period. 01 the other har.c. the license renea l should be based on the actual dantage a contaitees.t has suffered and a e.anagesent program that considers the existing dmage and proposes the t.ew optioris. This should be reflected in the IR.

90.

In Section 6.3, page C 5, with respect to the s.cnagement of below grade reinforced concrete degradatior, emphasis is placed or prevention, ho direction is provided regarding now to detect degradation and what to do about it once detecttd.

If there is no reliable detectiot method, then a cor.tingency plan should be devised and evaluated to eeet the iemediate t.eed. This is an aree for potential future research.

99. The IR s.entions a refined analysis method in accordance with the 1.EllE Code to demonstrate adequacy of the corroded setcl.

However, it is not clear hw this method can be applicable for inaccessible surfaces. The IR should provide this clarification.

' 77. Differential settlement is eliminated in the IR as a degradation problein for structures founded on piles. This assuses that pile corrosion is not a significtnt degradation problen. which is contrary to experience cited in LETA reports (Corrosion Control Manual for Rail Rapid Transit, UMTA-tC-0152 83, LHTA 1983). The IR should keep the settlement for pile foundations open pending resolution on a plant-specific basis.

78.

In Section 4.3 for prestressed concrete degradation mechanism, two items with respect to grease should be addressed, i.e., the aging effect of the grease, and the effect of grense leakage into concrete.

79.

In Section 5.0, the items listed for evaluation should be consistent with those identified in respective, sections.

80.

In Section 0.0, the IR references an analytical assesssent procedure.

In dealing with an analytical assessment procedure, one should provide approved analytic eethods whereby one can estisate containment strength and stability wher. subjected to a local corrosion with possible eaterial property change and wall thitning. Please provide a discussion on how buckling strength of a containment as a result of local change of r.aterial properties and wall thinning will be obtained.

81.

In Section E.1, it is indicated that the acceptability of containment for license renewal-will be detennined by performing an analysis of the l

I containrent using A!ME Code criterie. The report does not specify which version of the Code will be used. A discu;sion of the code application for license renewal is necessary.

ET. On pages 5-7, the IR states that "...several licensees have instituted periodic wall thickness measurements.* The IR should specify acceptable techniques, frequency of measures,ents, acceptance criteria and staiilar actions to adequately identify and sanage this mechanism.

83. On pages 5 0, the IR states that "... coupon samples placed in an identical environment provide acceptable data for corrosion rates." The intent of this statement in the IR is not clear. Does the IR required each plant to perform such coupon tests or is this an assumption? The IR should provide clarification in this regard and clearly list all assumptions.

84 On page 5-8, UT measurements should be identified for all Mark 1 and Il steel containments.

85. Section 5.1, With res)ect to Section XI Inservice Inspection, it should be recognized that Su>section IWE of I.SME Section XI is not consistently used by all licensees. Also the deficiencies of the Subsection are being worked on by the code cossnittees at the present tise.

Reliance on the potentially changing provisions of the code as a seans for detection of age-related degradation is not appropriate. The IR should be revised to more adequately address this issue.

. a.

-18

80. On page 5-9, the IR states that "a number of acceptable methods are availetle to detect and manage general corrosion..." sno then concludes thtt "no additionei.c.:=sures... is maintained ar.d verified.' This conclusiot, is not justified without confirming that these methods are, 1

in fect, used by all licensees. The cor;clusion should be revised or more information should be provided.

E7. Sectier 5.2.1 and 5.2.2 briefly discuss methods which are available to detect eM manage general and local corrosion in the Mark I ECCS suction headers anc the Mark I and 11 dovncomers and bracing. However, the conclusior.s for both of these sections do not include enough specific requirements which are applicable to the license renewal applicant. To

' provide the basis for the staff to reach these same conclusions, the IF, should conttir, either:

~

A more detailed description of each of the recoss. ended aging a.

managenent methods together with a specific requirer.4nt that each applicant for license renewal comits to implemertation of these methods, or b.

A requirement that each applicant for license renewal submits plant-specific progrants for managing general ar.d local corrosion for sitif review prior to staff approval of license renewal.

~

(

t 88. On pages 5-11 and 5-12, the arguments presented in the IR to eliminate local corrosion as a degradation mechanism for many components are inadequate. For exac1ple, how can corrosion be reliab1) detected on time "from observation of water leaking, dripping or pooling...?' The IP should be revised to provide more definitive guidance and criteria.

89. Section 5.2.3 discusses two different eethods to assure that degradation due to fatigue is properly managed for the penetration sleeves and ver.t header /downcomer intersection in Mark I containments. All of the staff's connents above relative to Section 4.1.3 in the Industry Peport are applicable to this section. Pending resolution of these casments, the two aging managesent methods recessended in Section 5.2.3 will be acce: table to the staff. However, there should be a note that in this (eaci) Industry Report that each applicant for license renewal prepares and incorporates into the FSAR revision for renewal maintenance a susmary of its plant-specific analyses for the staff to review as part of its review of a license renewal application.

90.

In Section 5.2.3, page 5-13, several standard methodologies in evaluatirg fatigue were discussed; design stress report, inservice inspection code and ASME code Section 111 for Class 1 vessels, etc. However, it is not clett if they address fatigue in an adverse condition such as presence of corrosion or large crack in base met 61. The IR should be revised to describe sethodology for performing fatigue analysis once an adverse cor.dition is identified.

j

~~~

. o.

4 91. On pages 5-14 and E-15, the IR proposed certain analysis rethods to manage degradction due to fatigue. Based on this proposal, tha IP concludes that no further evaluation due to fatigue is necessary for license renewal. The conclusion appears inappropriate sirice the applicant should first apply the proposed sethods and evaluate the analysis results, and then judge whether the fatigue dar. age for these cor.ponents are sianageable through the license renewal period. Unless otherwise justified, the IR should be reviscd accordingly to provide the logical sequence for evaluation.

92. On page 5 5 in discussing Appendix 0 leakage rate testing, it is stated that the functional and structural integrity are periodically deronstrated by perforning Appendix 0 testing. This is only partia11) true because types A, and B tests basically only indicate the leaktigtt integrity.

Structural integrity can only be determined by structural integrity test. The IR should be revised to reflect this point.

93. On pge 5 21, the 1R eliminates differential settlesient as a degradation eechanist, since there are monitoring progras.t. The argument is inadequate since existence of the e,onitoring program alone does not ensure that settlen.ent will be acceptable through the license reneh61 period. The actual settlen,ent should be evaluated and, based on the results, justification should be provided on a plant-specific basis to manage the settlement issue.

/

- (l ~ - g4. Section 0: Aging Degradation Managesent A thorough focused baseline inspections one of the basic ingredient of an effective aging / degradation mcnagement philosophy.

It should be performed prior to subt.itting an application for license renewal. The plant-specific ag(ing/ degradation management philosophy should include the consideration of 1) the actual codes and standards used in the construction, (2) construction related non-confonnance reports (NCRs),

and (3) the performance experience during the operational life.

The enhanced inspection requirements for inaccessible areas, potentially corrosion-prone areas and the areas subjected to groundwater fluctuations, as discussed in this section, should form part of the baseline inspection, g5.

In Section 6.1, page 6 3,for detecting degradation in embedded region is it is stated that "It should be noted that research and development under way." Again, the emphasis is on how to find it and prevent it.

In the reantime, a contingency guideline is needed for detecting degradation until the results of ongoing research are finalized, g'.

On page 6-3, the IR indicates that the effects of local corrosion of an embedded containment shell will be manifested in surface cracking and discoloration of the concrete. This may not be true since the concrete surrounding the shell is not thin enough for such aianifestation. The IR should be revised accordingly, unless otherwisc justified.

20-

97. On page 6 4, the IR proposes t list of sar.6gement options. However, it is not clear how these good "housekeepiris' options kill a.anage the damage through the license renewal period. 01, the other her.c the licarise renewal should be based on the actual dat. age a contairmet.t has suffered and a e.aragesent program that considers the existirig dtsage and proposes the rtes options. This should be reflected in the IR.

90.

In Sectiot 6.3, page ( 5, with respect to the s.cnagement of below grade reinforced concrete degradatiori, esphasis is placed on prevention. ho direction is provided regarding now te detect degradation and what to do about it once detected. If there is no reliable detectier, eethod, thers a cot.tingency plan should be devised and evaluated to seet the iemediate need. This is an area for potential future research.

99.' The 10 sentions a refined ana13 sis sethod in accordarice with the t.!!!E Code to demonstrate adequacy of the corroded metal. However, it is not clear hw this method can be applicable for inaccessible surfaces. The 10 should provide this clarification.

o **

• 21-COWENTS OF AP EDITORIAL NATURE:

Page 1-P: Under the heading _' Mark I steel Contairment', 10, is this really ' ring girder of surpression chamberP If so, make it clear.

Page 3-40: The caption should be ' Mark III cortainment concrete backup detail,' not ' Mark 11...'

Page 3-42: The caption should be ' Mark !!! containment base liner code boundary,' not ' Mark 11...'

Pate 3-46: Change *...Ty>e E and C leak rate requirements as discussed previously.' to... Type 3 and C laak rate requirements as discussed Yn Appendix 0 of 10 CFR 50.*

~

' Page 4-9:. Thirteenth line froeitop, '(c) At the top... Merk !! concrete containments...." Mark 11 should be changed to Mark !!! there.

Stateenthlinefromtop,'(Figure 3.2-8)*mustbeamisprint,thereisto figure 3.2-8 in this report.

PaDe 410: Tenth line from bottom of page.

'Lubron' probably should be lubrite.

Page 5-20:

(, Rev. 3 July 1990, of Regulatory Guide 1.35 has been issued.

"l

,