ML20058K159

Final Revised Technical Evaluation Rept on Response from Niagra Mohawk Power Corp to Generic Ltr 88-01 Re Nine Mile Point,Unit 2

ML20058K159
Person / Time
Site:	Nine Mile Point
Issue date:	03/31/1990
From:	Bates R, Lakner A VIKING SYSTEMS INTERNATIONAL
To:	NRC
Shared Package
ML17056A933	List: ML20058K159
References
CON-NRC-03-87-028, CON-NRC-3-87-28 GL-88-01, GL-88-1, NUDOCS 9003230172
Download: ML20058K159 (32)

Text

... , . - .

., a ENCLOSURE 2

,1 .

1 i ,. ,

I- -

REYlSED l i FINAL -l l

l l 1 i

l' l TECHNICAL EVALUATION REPORT ON ,

RESPONSE FROM W E .

NIAGARA MOHAWK POWER CORPORATION W GENERIC LETTER 88-01

' PERTAINING W W E NINE MILE POINT, UNIT 2 f

.1 Published March, 1990 j

'l l

l

';l prepared by l

3 Robert C. Bates [

..l Armand Lakner l Viking Systees International j 2070 Wm. Pitt Way-Pittsburgh, PA

,r Prepared for:

, U.S. Nuclear Regulatory Commission

,. Washington, D. C.'20555 .

RZYLSED Contract No. NRC-03-87-028 Task Order 005

4 FINAL ,

fhh

,, . .e ,

ABSidACT This report contains an evaluation of the licensee (Niagara Mohawk Power Corporation) submittal for Nine Mile Point, Unit 2 which was submitted in response to the NRC Generic latter 88-01 in %ich Niagara Mohawk was requested to: (1) Furnish their current plans relating to piping replacement and other measures to sitigate IGSOC, inspection,  !

repair, and leakage detection. (2) Indicate whether they plan to follow .

the NRC Staff positions, or propose alternative measures. Niagara a Mohawk's plans are evaluated in Section 2 of this report in terms of compliance to NRC Staff positions. Section 3 contains en except hn that Niagara Mohawk presented concerning the requirement to limit the increase in unidentified leakage to 2 spa.

b P

4 i

4

+

l i

~

I

(

t i- ,

f 4

.s.'--'

. , . - -,4 ,, --.s---.- , ~,e .n. -. .,-,e *.e., ,w,w- ,< ~ ~ - , . - , . , . -mm,,, o-ew-.-,- - , - . -~ --

SlHRRY

' The Licensee Niagara Mohawk Power Corporation, submitted a response

' to the NRC Generic Letter 88-01. Niagare Mohawk's response pertaining to the mustenitic stainless steel piping in Nine Mile Point, it 2 (a BVR nuclear power plant) was evaluated in terms of: (1) Their previous and planned actions to mitigate IGSCC to provide assurance  ;

f of continued long-term service. (2) Their Inservice Inspection (ISI)  ;

Program. (3) Their Technical Specifications pertaining to ISI and

! their piens to ensure that leakage detection will be in conformance l with the NRC Staff position. (4) Their plans to notify the NRC of j

significant flaws identified (or changes in the condition of the welds \

l previously known to be cracked) during inspection and evaluation of

'; such flaws. l l

Niagara Mohawk endorsed 12 of the 13 NRC Staff positions which are 1 outlined in Generic Letter 88-01, although they applied provisions i to those concerning Materials, Inspection Method and Personnel, and l t

Inspection Schedules. They presented an exception to one (concerning leakage detection).

p Niagara Mohawk claims that all velds except one contain conforming, IGSCC-resistant materials, and they classified these welds as IGSCC Category A. htually, most of the welds contain non-resistant h materials. No future mitigating treatments are planned.

I I Niagara Mohawk agreed to submit the required change to the Technical >

Specification on ISI, implying that they will comply with the NRC Staff

- position on inspections, Theirplannedinspectionsch$dulescomply with the NRC Staff position for the welds as they have classified them, but they are inadequate for the weld classifications that should  ;

pertain.

11

+. -,- ~ . _ . , , ..w,_m._._.m . . ~ , - _ . , , ._,m.m ,, ,,,.mr ~ .. ._,,

.,l

-J c .

)

CONTENTS i  !

.- ABSTRACT li SUMhMRY ,

1  !

1. INTRODUCTION .

2

2. EVALUATION OF RESPONSE TO GENERIC LET7ER 8801 Documents Evaluated 2 2.1 l

Review of Niagara Mohawk's Responses to Staff Positions 3-2.2 and Implementation of Those Positions .

Review of Cassification of Welds, Previous Mitigating 4

'2.3

. Action, and Previous inspections 2.3.1 Summary IOSCC Classifications of Welds 6 2.3.2 Welds Between Non resistant Castings and 8 Resistant Piping '

2.3.3 Repair SVelds to Castings and Welds in Appurtenances 8 2.3.4 Field V' elds in the RCS with Carbon Between 0.035%- 9 and 0.040%

' 10 2.3.5 Solution Treated, Type 316L Welds in the WCS 10 f, 2.3.6 Table of Histories and IGSCC Classifications of Weids t

12 l l 2.3.7 Previous Inspection Programs 2.3.8 Evaluation of Previous Mitigating Actions 12 l

and Inspections 2.4 Current Plans for Mitigating Actions 13 l ,

13  !

2.4.1 Niagara Mohawk's Faition 2.1.2 Evaluation of Conformance to Staff Positions 13 l and Recommendation .

. 2.5 Plans for Future Inspections 14 Niagara Mohawk's Position on Inspection SchMules 14 2.5.1_

2.5.2 In ccessible Welds 15 l 1ii l -

i . - _. ... . - . . . _ , . . . - . -_ ~. ._ _ _ . _ _ . _ _ ~ . _ . . . ., _ _ . _ . _ . . .-

i . .

2.5.3 Methods and Personnel 15 2.5A Sample ExparA.a 18 2.5.5 Evaluation six! Recomeendations 18 2.6 Changes in the Technical Specificailen Concerning ISI 19 2.6.1 Niapra Mohawk's Position 19.

2.6.2 Evslusion and Recommendatku '19 - -

2.7 Cnanraatie of Irak Detection in the Techakal SpedGeation -19 22 Plans for NotiScation of tha NRC ct'F1sw 20 j

2A1 Nia6xa Mohawits Position 20 4

2,8.2 Evaluating and Reccmmenktions 20

3. ALTERNAT[VE POSITION 20 ii 3.1 Atternsthe Pealtian Omcerning leak Detection in _

20 '

the Techaka! 5}weiSention 3,2 Evaluation and Recommernistions 22 Pl A CONCLUSIONS AND RECOMMENDATIONS 23 i REFBRENCES 27

[

t.

4 I

- ,l.

?

I 1

,5

.h i

iv [

& _A ^$ W 5?T?fasSAWYMW !5

'l.

8' ', 1. INTRODUCTION Intergranua e a, tress corrosion cracking (IGSCC) near weldsents in 13 oiling Water Reactor (BWR) piping has been occurring for almost 20 l J

years. Substantial efforts in research and development have been

.J  !

sponsored by the BWR Owners Group for IGSOC Research, and the results 1 of this program, along with other related work by vendors, consulting l fir:ns and coafirmatory research soonsored by the FAC, have permitted  ;

the development of HRC Staff positions regarding the IGSCC problems.

The technical basis for NRC Staff positions is dotailed in Reference i

1, and further background is provided in Reference 2.

{ ,

The results of these research and development programs prompted the

, NRC to issue Generic Letter 88-01 (see Reference 3) requesting all licensees of BWR's and holders of construction permits to I

(1) Furnish their current plans relating te piping replacement,

' inspection, repair, and leakage detection.

,i I (2) Indicate wher'.er they

.. j

.n (a) Plan to follow the staff positions, or  ;

l, (b) Propose alternativi measures.

l .

l Specifically, Generic Letter BB-01 stated that an acceptable licensee i

i res;& se would include the folicwing itemst (1) Current plans regarding pipe replacement and/or'other measures taken or t*' be taken.to mitigate IGSCC and provide assurance of continued long-tr.rm piping integrity and reliability.

I (2) An inservice inspec. tivi (ISI) program to be implemented at

! the next refueling catage for austenitic stainless steel piping.

r .; (3) A change to the Technical Specifications to include a statement l t i t l 1 i-

?

I l

• ~

.[.

in the section on ISI that the inservice inspection progras for piping will be in conformance with the staff positions ]

j on schedule, methods and personnel.

l l

'j (4) Confirmation of plans to ensure that the Technical Specification

! related to leakage detection will be in conformance with'the f Staff position on leak detection. -l (5) Plans to notify the NRC, in accordance with 10CFR50.55a(o), i

'( of any flaws identified that do not meet IWB-3500 criteria,

• of Section XI of the ASME Code for continued operation without l evaluation, or a change found in the condition of the welda previously known to be cracked, and an evaluation of the flaws ]

'r, for continued operation and/or repair plans.

4 i  ;

'- ThJs report contains a technical evaluation of the response which Niagara 4

Mohawk Power Corporation (called either Niagara Mohawk or NM in this re p t) submitted in response to the NRC Generic Letter 88-01' pertaining to the Nine Mile Point, Unit 2 (hereafter called Nine Mile 2).

l 1-]

2. PlALUATION OF R20PONSE 'IO GENERIC LETTER 88-01 1 ,

This eveloation consisted of a review ef tihe response to NRC Generic Letter 88-01 of January 25, 1988 by Niassra Mohawk to determine if their  ;

performance and plans are in conformance with the NRC Staff positions or if. proposed alternatives are acceptable. Proposed inspection schedules and amendments to the Technical Specification were included in the  ;

~

l review. ,

t 2.1 Documents Evaluated

l Review was conducted on.the information pertaining to Nine Mile 4

• 2 '

+ 4 ,

4 h

~ . . - , _ . .-_.m..- . . - * , . . _ - _ . , _ , . - . - . . . - . . _ . . . . . . . _ _ _ . _ _ . - . _ . . _ , . - - . . , . . _ . .-_...a.-.

- . . . - - . - . - - . . - . . . =- . . -- . - -- . - .. _- _-- . ..-..

i I

' *

• 2 provided by the Licensee in the following documents.  :

. j (1) "Nine Mile Point, Unit 2 Docket No. 50-410, NPF-69 (Response l

to Generic latter 88-01, NRC Position on IGSOC in BWR Austenitic Stainless Steel Piping)," Niagara Mohawk Power l Corporation, 301 Plainfield Road, Syracuse , NY 13212, l l

Duly 28,1988.

(;) "Nine Mile Point, Unit 2. Docket No.30-410, NPF-69,' TAC l

No. 69148 (Response to Request for Additional Information Concerning Generic latter 88-01)." Niagara Mohawk Power.

I Corporation, 301 Plainfield Road, Syracuse , NY 13212, l j

November 1, 1989. ,

(3) "Nine Mile Point, Unit 2,. Docket No. 50-410, NPF-69. TAC No. 69148 (Additional Response to Request for Additional  ;

' Information Concerning Generic Letter 88-01) " Niagara Mohawk i Power Corporation, 301 Plainfield Road, Syracuse , NY 13212, December 14, 1989. .

1 liereaf ter, in this report, these documents will. be referred to as 3

the Niagara Mohawk Submittals No. 1, No. 2, and-No. 3, respectively, and collectively as the Niagara Mohawk Submittals.

3 2.2 Review of Nianara Mohawk's Responses to Staff Positions ,

and Implementation of Those Positions.

I Generic Letter 88-01 outlines 13.NRC Staff positions pertaining ,

-I to-(1) materials, (2) processes, (3) water chemistry, (4) weld i

overlay, (5) partial replacement, (6) stress improvement of cracked .

weldments, (7) clamping devices,,(8) crack evaluation and repair criteria, (9) inspection methods and personnel, (10) inspection schedules, (11) sample expansion, (12) leak detection, and (13) ,

3 i

.ew e-. - , , - , e-w.-- ..-s e- - . , - ~ - , , , - -- , ..,.,y,- -, ,,e, .. , ,. -. ,- -- u ..L..+-w,s.,,w.w, . - - - n san. ,

i

> . j l-1.*

• e reporting requirements. Generic htter 88-01 states that the [

! licensee should indicate in their submittal whether they endorse these NRC Staff positions or propose alternative positions. Table 1 of this report, which is patterned after a similar table in l i

l Niagara Mohawk Eubmittal 2, contains a summary of the Niagara Mohawk positions on these items. .

f Note that Niagara Mohawk indicated that they endorse 12 of the 13 ,

items, sithough they applied provisions to three of these items.

One of the provisions is applied to materials. This provision is discussed in Section 2.3 of this report. The second provision is-1 applied to inspection methods and personnel of inaccessible welds, {

and the third provision is applied to inspection schedules of certain l RWCU welds. The latter two provisions are discussed in Section 2.5 of tt' report. Niagara Mohawk proposed an alternative position ,

lj to th: NRC Staff position concerning le,ak detection. This item is discus ed in Section 3 of this report.

Also note, that even though Niagara Mohawk indacated an alternative l

'j position concerning materials and applied proei nen9 to the NRC Staff position on inspection methods and insp icion schedules, they indicated that they have either applied or will co sider application of all of the 13 NRC Staff positions in the future.

2.3 Review of Classification of Welds. Previous Mitimatina L Actions, and Previous Inspections i

^

~

Niagara Mohawk took action in response to Generic Letter 88-01 as described in the following statements in Niagara Mohawk Submittal- l i

No. 1: -

"NRC Generic Letter 88-01 requires that all austenitic stainless steel piping, four inches or larger nominal diameter and 4 ,

I l

l '

,j-1.

I f i Table 1 Summary of Niagara Mohawk's Responses to' Staff Positions  ;

Pertaining to Nine Nile 2 i NM HasNill  ;

i i

NM secepts NRC Applied. Consider for  ;

Staff Position- In_ Pant Future Use Staff Position  !

' yes(*) yes

1. Materials yes l j

i yes'

2. Processes yes

3. Water Chemistry yes 'I yes

4. Weld Overlay yes

yes

5. Partial Replacement yes i i .

6. Stress Improvement m yes yes Crscked Weldmert l yes yes

7. Clamping Devices  !

8. Crack Evalus. tion ano yes yes Repair Criteria

9. Inspection Method yes(*) yes and Personnel 4; yesI ") yes

10. Inspection Schedule i yes . yes

11. Sample Expansion no( ) yes .,

12. Leak Detection yes yes

13. Reporting Requirements t

l Notes: ,

t 9

(a) Provision applied. See text for discussion.

(b) Alternative position presented. See text for discussion.

i i

5 I

t

,. 'i

'e

• Q

t -

• containing reactor coolant at a temperature abovu 200'F during i '

power operation, be reviewed for the augmented requirements

,, Systems / components which escoed 200'F of NUREG 0313 Rev. 2.

L for extremely short periods of ties (less than one percent of the total design lifetime) were not considered to aset this criteria." f

" Stainless steel systems at Unit 2 with a design temperature of 200*F or greater were initially coheidered for review. '

Niagara Mohawk's evaluation determined that two systems, Reactor

}

Coolant Recirculation (RCS). and Reactor Water Cleanup (WCS),  !

The two systems fell within the scope of Generic latter 88-01. i

, l" were reviewed and each weldsent assigned an ICSCC category -l as directed by the generic letter." l l

1 7

Niagara Mohswk Submittal No. mas the following statement t I pertaining to the interprecation of the scope of Generic latter '

88-01 and the provision attav ad to their endorsement of the NRC 1 Staff position on materialst 3 "Those systems that see greater than 200'F temperature for- e extremely short periods of time (less than it of the total

~ design life of the plant) were not considered as systems which are above 200'F during power operation and consequently not

• included in the scope of Generic Intter'88-01."

The assignment. of ICSCC categories to welds at Nine Mile 2 and theit- justific.ation for those assignments are discussed in the  ;

following sections.

t 2.3.1 Summary ICSCC Classifications of Welds I Niagara Mohawk Submittal No. 1'contains the following statements pertaining to IGSCC classifications of welds at-

.j' .

i 6

. - .. -,_ _ . . _ - . . -- ._ _.. . _ _ . . _ . ._._.-..___.u...._.. .. -...-_.

jl F. o +

i .

Nine Mile 2.

. l "All weldsents within the scope of this review were  ;

t designated as IGSOC Category A with the exception of f j

j field weld RCS FW 107. This circumferential weld between I resistant piping and a non-resistant cast pump casing was repaired four (4) times. We have designated this l

weld Category D."  ;

l l Some welds contain crevices. Normally, such welds are  :

i l

considered non-resistant to IGSOC and should be classified I

I as IGSCC Category G: however, Niagara Mohawk Submittal No.

2 contains the following justification from omitting them from the welds that they considered to be within the scope of Generic 1Atter 66-018 "The Commission requested in their June 16, 1989 letter that welds containing crevices Le classified as IGSCC Category G, included in the Inservice Inspection Plan and scheduled for inspection during the next refueling .

y

't outage. Those welds which are not included in the Inspection Plan are socket type welds and are excluded because they are less than 4 inches in diameter. It is Niagara Mohawk's understanding that these welds may be excluded from the scope of Generic letter 88-01 because they are less than 4 inches in nominal' diameter."

It is implied in Niagara Mohawk Submittal No. I that most i

of the welds in the RCS and WCS systems are low carbon

' austenitic stainless steels materials (i.e., less than 0.0355 l

carbon). Some welds, however, involve higher carbon contents ,

(in the filler metal or base metal). Their reasons for the classification of these welds as IGS00 Category A are

, presented below.

7 i

_ - . . . - , , , . , . , , +_,,,,,L,,,,, --, ,,-m..w.v.,--y ,.,n. ,.w . . , . , . . ~--,..-,,,..e,.... .- - , . ,s

.. . l ll -

l j

i

'~ '

2.3.2 Welds Between Non-resistant Castinas and Resistant Pinina It Niagara Mohawk Submittal No.1 contains the following l

statements "NUREG 0313 Rev. 2.provides that welds between '

non-resistant (i.e., greater than 0.0355 carbon) castings .,

and resistant pipe may be considered as Category A if' I they have not been subjected to extensive repairs that  ;

may have changed the residual stress pattern. While j ,

the generic letter does not define "estensive" as used ,

in this context, it does state that the basis for this ,

provision is the service experience of such welds,-which have proven to be relatively free of ICSCC. *ince this f experience is based.on actual production v s where

each " typical" production weld receiv- averal repairs

'l~l before meeting final acceptance criterfs, we consider that welds having three or fewer repairs ESould be .

classified as not extensively repaired,'and thus, Category A. Records of the number of repairs on these welds show ,

ty that only one weld to a non-resistant valve body casting  ;

was subjected to extensive repairs. Based on the criteria 1 in the generic letter, this was classified a Category .

'I D weld. All other welds between the resistant pipe and 1 cast valves and pumps are considered Category A."  ;

i-i 2.3.3 Repair Welds to Castinas and Welds in Anourtenances -

Niagara Mohawk Submittal No. 1 contains the following

i statements:

l

" Weld filler material with carbon contents greater than ,

O.035% was used, for the most part, in the fabrication I of components ordered c non-low carbon grades such as j 8

ll. l 1'

l l

1

_ a

4 .

the RCS pumps and valves. Repair welds to the castings .

f l

' were subsequently solution annealed and, therefore, are Category A.

i "However, appurtenances to the componcats such as vents t f' and drains did not receive a subsequent solution heat l

l treatment (and may also contain crevices in the fora r.-

of partial penetration welds) and, therefore, would be I classified Category G in accordance d th the generic letter.

Such welds, however, do not require Inservice y

Inspection (ISI) under ASME II, except for a possible l

visual inspection of the component internal surfaces '

l or a systes pressure test and are not considered within the scope of Generic 1ptter 88 01. Therefore, no change to the ISI Program Plan is needed for these welds."

l  ;

Ii

2.3.4 Field Welds in the RCS wi'h Carbon Between 0.035% and0.040%

l Niagara Mohawk Submittel No. I contains the following _

1 statements

Some filler Metal with carbon contents between 0.035% '

l and 0.04% was also used in field welds in the RCS. There  ;

is a discrepancy between the generic letter which only permits up to 0.035% carbon, and ASME II Part CSFA' 5.4 L which permits the low carbon grades E308L'and E316L to contain up to 0.040% carbon. ~ NUREG 0313, Rev. 2 which forms the technical basis for the generic letter, in-some cases refers to E308L and similar grades (i.e.,

no additional' restriction on carbon content) as being  ;

adequately resistant to sensitization, and'in other cases j to E308L, E316L and similar grades with a maximum carbon content of 0.035% as being adequately resistant. NUREG 1061, which formulated recommendations 1cter incorporated l

l  :

. .- -- -= -. _ _._ -. _ ... = . . .- - - ..-

_ _ _ _ _ _ ~ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ - _ _ _ _ _ _

i into Rev. 2 of NUREG 0313, does not place say requirements ]

on the carbon content of weld filler material other than ]

to confira the acceptability of k308L (no addittomal l

l carbon content restrictions) for corrosion-resistant I

cladding of weld areas in non-resistant piping. Since  !

the duplex structure (austenite plus delta ferrite) ja the weld metal's major defense against IGS00, th' o 4 1 i

carbon limit of the SFA 5.4 material rpecificaur. s l

adequate, and Niagara Mohawk considers it as t a5q the intent of Generic Intter 88-01."

2.3.5 Solution Trested. Troe 316L Welds in the WCS

' Niagara Mohawk Submittal No. 1 contains the followins .

statement ,

t "The stainless portions of the WCS. where this system ties in with the RCS, are fabricated with 316L grades. .

These materials, basically 4-inch. schedule 80, were not subjected to a sensitization test. They were, however.

03 water quenched from the solution annealing temperature, which is a more positive mechanise than testing to ensure the absence of grain boundary carbide precipitation. f

- Water quenching has been very effective, especially in i low carbon grades, and water quenched material has not  !

{g had any probles meeting A262-A when tested. Therefore, ,

j, we consider that water quenched wrought low carbon grades >

of stainless steel meet the intent of Category A of l Generic 14 tier 88-01, with or without a sensitization test.

i l 2.3.6 Table of Histories and IGSOC Classifications of Welds Niagara Mohawk' Submittal No. 2 containe's partial list of

- 10 i

f f

I

~, , . . , _ -. , , _ . , _ . , _ . . . , . . . . . _ . . , . . - _ _ . . . . . , , , - . . . . . _ _ . _ _ . .'

l*. .. o l L l L. .

4 l the welds considered to be within the scope of Generic 1Atter 88-01, ti.eir'IGSCC classifications, and weld histories.

l A complete list of welds is contained in Niagara Mohawk l Submittal No. 3. .According to those lists, all.except one r

l

. weld'(Wald No. 64-00FWA07 which is classified as IGSOC

' Category D) are classified as IGSOC Category A. r j

I Although Niagara Mohawk claims that all materials used I

f throughout the piping that is within the scope of Generic ,

1Atter 88-01, the tables showing weld histories do not support- .

their clais. This any be seen in the following summaries j

8 of the materials used in the various piping systees.

i Reactor Recirculation Systes: This system contains 105  :

welds classified as fo11ovst 104 IGSCC Category A welds ,

and 1 IGSCC Category D.' All 105 of the welds in this .l l' systes contain low-carbon, IGS00-resistant weld metal; .I however, they all contain Type 316 stainless steel (which, per Generic latter 88-01 and NUREG 0313 Revision 2,  ;

o is considered non-resistant to IGSOC) in either the .,

i upstream component, the downstream component, or both. ,

Residual Heat Removal Systest his system contains six

^

welds, all of which are classified as IGSCC Category

! A. 'All of the welds in this system contain io.:-enrbon.

IGSCC-resistant veld metall however, they all contain -

Type 316 stainless steel (which, per Generic.latter 88-01 and NUREG 0313 Revision 2, is considered non-resistant r

to IGSCC) in either the ipotream component, the downstream component, or '.,oth.

Reactor Pressure Vessel his system contains a total  ;

l of 38 velds, classified as IGSOC Category A and divided as follows: -

{

1 l

r l-11

. . _ - . _. _ _ _ . . ~ . . _ . _ . _ . _ _ . . . . . - - - - . _ _ . _ _ _ . - - _._ _ _ - _ - _ - _ . . _ . - _ . _ , , _ _ _ . _ _ _ _ - -

_- . ,_ _. _ . . _ . . _ . _ _ _ _ _ _ _ . - ~ . _ _ _ _ - - _ _ _

C . .. . j j

Twenty five Nozzle / Safe End welds, all of which '

• contain Inconel 182 buttered layers. .Inconel 182 is described in Generic latter 88-01 and NUREG 0313,  !

Revision 2 as non-resistant to IGSOC. ,

I j

Eleven Safe End Extension we16 , all of which contain ,

.i Inconel 182 in-the welde metal. Inconel 182 is '

described in Generic 1stter 88-01 and NUREG 0313,

'I >

Revision 2 as non-resistant to ICSOC.

Two Safe End Seal welds which contain conforming 1

(IGSOC-resistant) esterials.

l Residual Heat Removal Systes: This system contains 18 t

walds classified as ICSOC Category A. All of these welds i-contain conforming (IGSOC-resistant).

a 2.3.7 Previous Inspection Pronrass ,

P Niagara Mohawk Submittal No. 2 contains a list of welds that were inspected during the 1988 Refueling 0utage.

According to that list, a total of 10 of~the 106 welds in -l the Recirculation System were inspected. No flaws were l- reported, None of the welds in the other systems were reported to have been inspect'ed.

I 2.3.8 Evaluation of Previous Mitimatt'n'a Actions I

and Inspections i

Niagara Mohawk's reasoning pertaining to welds with crevices of diameters less than 4 inchi diameter (i.e., that those l  ;

welds are outside'of the scope'of Generic Letter 88-01) is-correct since Generic Letter 88-01 and NURBG 0313,. Revision 2 exclude components that are less than 4 inches in dia >.tr.

. 12

s .

.. a . .. ,

i. ..

s 7 ,

i Although Niagara Mohawk.clai m that 167'of the-168 weldsL at Nine Mine 2.are IGSCC Category A,;th6y are incorrect in

'that claim. 'IGSCC Category A classifications are justified

'only fcr the 18 welds in the Reactor Water Cleanup system;

. and.the two Safe End Seal welds.: The remaining welds'contain j

> materiala that-are not resistant to ICSCC, so these. welds-l should be reclassified into non-resistant classifications j 4 (either IGSCC Category D or IGSCC Category G, depending on, their= inspection histories).- In~accordance'with the

.:information Niagara Mohawk supplied pertaining to previous' inspections, only'10:of these welds have been previously' cj

.I,Lin inspected and classified as IGSCC Category D. The remaining: i I

non-conforming-welds should be reclassified as IGSCC. Category-G. -

3 2,4 jurrent Plans for Mitinatina Actions-2.4.1 Nianara Mohawk's Position lij  ;

l Niagara Mohawk Submittal No.-I containa the following

_ . statement concerning additional mitigation efforter l a; .

~

" Niagara Mohawk has en appropriate actions during:  ;

', construction of Nine Mile Point Unit.2 to mitigate ICSCC

^ -

and provide assurance oficontinued long-term piping ,

integrity and reliability..'Therefore,.we do not envision

~'

'any_ piping replacement or other mitigation measures."

r ,

2.4.2 Evaluation of Conformanca to Staff Positions and Recommendation  :;

.i Although Niagare ilohawk claims to have taken adequate measures. o i! -during conatruction to prevent.IGSCC; as previously discussed.:

n 1 <

13[ j 1

x X

[i '-

.. .- o

.= - . . . .

l Thus, . l most of the welds contain non-resistant materials-l

' Niagara Mohawk should either provide additional mitigating

.- )

mestacas in accordance with recommendations outlined.in j

Generic Letter 88-01, or they'should' provide ;an improved

[ l

- inspection program as outlined in the following section.

2.5 Flens for Future Inspections i

2.5.1 Niagara Mohawk's Position On Inspection Schedules .

q

?-

As indicated in' Table'1, Niagara Mohawk Submittel No. 2 -l I t a

endorses the NRC Staff postrion on inegectics schedules with 4 the following provisiont ,

"A111 welds are'IGSOC Category.A and are inspecte6 according to ASKE Section XI schedule with t.he exception of weld 64-00JW A07 in the RCS system which is Category D."

T '

Niagara Nbhawk Submittal No.1- contains the:following.

statement pertalaing to inspection of,the one' weld that-is 1

.. a classified as IGS00 Category D:-

l- "The' Inservice Inspection program wil1~be revised to-requi.re more frequent'examinatiosslof. field weld RCS. ,

FW A07."

H "It? vill'be schedeled for augmented examination during -

. the - first refueling' outage and every 'second refueling c outage thereafter."

p i l

Niagara Mohawk Subadttel No.t2 contains a list of the; welds that are scheduled for inspection during the next several' 1

x

• 14-

-)

+

J o z.

m u_ n _, a. L __ _ _ .. . . . , _ . . ' . m._. ,

. ~ _ __

y.. .- l J

l

g. . ...:. -

.I ,

• refueling outages. The number of inspections planned for f

i the welds classified.es IGS00 Category A are summarized in h ,:  ;

Table 2 of this report. )

[:,

. 2.5.2 Inaccessible Welds ,

Niagara Mohawk Submittal No. 3 lists a number of welds (all '

- currently classified.'ac IG500 Category A) that are partially

J

,-t inaccessible for inspection as:shown in Table' 3 of this :

n

- report. These include 12 welds in the Reactor Recirculation -

i

- System, one weld.in the~ Residual' Heat Removal System,.and-

. all 25 nozzle / safe'end welds'in the' Reactor Pressure Vessel.. f l

The' accessibility.cf welds-not scheduled for inspection has:

. not .beeri determined. ,

- Niagara Mohawk did not provide.any alternate' plans for t

ILIl inspection of welds that are partially inaccessible even though-the extent of examination for some,of those welds-I~ is 25% or less.

l-Lg 2.5.3-Methods and PersonneJ1, u As indicated in. table 1-of.this' report, Niagara Mohawk ,

l ] endorses the NRC Staff position on, inspection methods and l-I' personnel with a provici>>n. Tnne provision isistated in t

6 Niagara Mohawk Submittal =No. 2 en fallows:

" Reactor Pressure Vessel internal weld attachments are L visually inspected in accordance with ASME'Stoction XI."

L Niagare .% hat Sclaittal No.:1 states the following:

"The examinat. ion techniques eu.d personnel qualification L

h methods used for the volumetric examinations will be

" 15 L1 . .

t.

1 i 't. .

t e..~.+.r.,.. , ,. , ,4,, - - . . - ,,.c,.. . .,

..w.,%,4, 4._. ,,,,,. ..w_. , , , . ,,,,6 . .,w r a e.e.~,,,.,.,,..m%,. . . . #. -,. m.,....#...o. ..,,

.. o.

.n.. ._.

i-l'

\

Table 2  ;

i L Summary _of Inspections Planned: for Welds Classified -

I .,

as IGSCC Category'A at Nine Mile 2

]

(

'No. of. No. of Welds Scheduled for Inspection Categ .* Du-ina Ind:.cated Refue:.ina Outanc '

, 19^0 RO 1992 RO :.994 R0 = J,cN R0 1998 R0 M l.

System' . Welds '

3 3- 24-RCS 1051 '6 5' 7 4

t 0 1l 1 0. 4 .

-RHS 6' 2

.f 11 , 38 4-38 14 2 11 0 RPV 1 1- 1 0 4- .

WSc 18 11 i

-23 '

8 5 '14 70

! Tota *. 167 10 i L -;

Abbreviations:

l

', RCS - Reactor Recirculation System- .i RHS - Residual Heat Removal System

"' RPV - Reactor Pressure Vessel .

WCS - Reactor Water Cleanup System Required by Generic Letter 88-01:-

' Inspect 25% overy 10 years-(at least 12%.in 6. years)..

's 3

a i

-1

'i

' 1'6 .

1 .

l-1 . .

. p.  ;

- ' ' .~ - ,.:.: , . . . , . - . - . , , , ;. . ,, , , __

.y

'e ,' . .. :.1

\; ~

Table 3' ,

.)

'i'

Inaccessible Relief Requests et Nine Mile'2(a)

,i..

Ins meted / Scheduled. 'Reliefi ,

Weld.No. 1983 R.O. Future -Reauest Extent Examined X RR-IWB-6' Elbow side only i 64-00-WA05 X .RR-IWB-6 100% with overlay.

64-00-WA06 -

f I limitations-

'l IL RR-IWB-10. ~25%j 64-00-WA17 X ~RR-IWB-10 ' 25% ,

j- 64-00-WA21 -

64-00-WA24 Y. X RR-IWB Pi- only I 4 00-WB01 X :X RR-IWB-6: Pipe s e'only- f G bow' side only= l 64-00-WB08 X RR-IWB-6 64-00-WB12

.X' ,

RR-I S 6- Pipe side only 64-00-SWO3' X RR-I W 6' Pipe side only '

-Pipe side only.

6 64-00-SW12 .

t 64-00-SW17 X '- X RR-I 4 6 Pipe side only L- 64-00-SW51 X X :R";I S 6 792 U

66-55-W001 X RR-IW6 : Pipe side only >

I

(see note bl All 25 X RR-IWB-9 -

Nozzle /

3

i. Safe End ,

L i Welds in RPV-l Lt Notes:

i (a) Accessibility has-not been determined for welds which were selected for inspection..,  ;

I (b) Extent for two nozzle / safe end welds is.100% with overlay

' interference. ' Extent for L other' nozzle / safe ~ end welds- ranges : [

from about 22% to nearly 100%.

17 -

• T l -l

.. . . - ... . . . . . . ~ . _ . . . . . . _ . . . . .-

.. : ._...~., ..:.-....

... -. - a

• I

3. 1 i

' _ qualified in accordance with the NDE Coordination Plan through the EPRI NDE Center in Charlotte,. North Carolina. Niagara Mohawk does not intend to use any alternate plans, such as-le 1 ASME C6de Case N-409,Lst'this time."'

L .

l 2.5.4 ,Samele Expansion O NiagaraMohawkSubmittalNE.1statesthefollowing:  ;

, I, - ~

'"If one or more cracked ~ welds in IGSCC categories are- .l f ' detected, we'will. expand the sample examined in accordance .

' with the staff position stated in the generic letter."' -

l 2.5.5 Evaluation and Recommen %tions Niagara Mohawk'c ..ipection pisas for the one weld that uey-

' classified as IGSCC Category D comply with.the NRC Staff position for inspections-of IGSCC. Category'D. Furthermore,

[

as can be noted'from Table 2,' Niagara Mohawk's planned q inspection schedules for welds that they have classified as-

.- q IGSCC Category A comply with the requirements of Generic Letter 88-01'for IGSCC Category A welds. However, as previously<

discussed, most of the welds that have been classified as IGSCC Category A contain materials that.are not resistant ~

to IGSCC so they should be reclassified <to either IGSCC ]

Category-D or IGSCC Category G,-depending upon their inspection.

histories. Furthermorer the inspection ,,lans should be revised i  ;

to reflect the requirements of Generic. Letter 88-01 for welds

]ll of those.1GSCC classiff. cations.

y-

'Concerning accessibility for ultrasonic examination, Niagara l Mohawk should rate accessibility of all welds-that are recommended for reclassification to IGSCC: Category D or IGSCC.'

Category G. ~ In addition,t they should plan ~ additional inspe.. Hon .

$ l

~18 1

1

~ x -

- . , J .- =. .-.a . - .

.: y . ,: + .

l , '.. :.

l r.. .

methods such as. visual'. inspection for those welds with limited -

1. accessibility (less than about'505). ,

1

~

Acceptance of Niagara Mohawk's positions concerning: a() 5' inspection schedule for weld' RCS W A07, (b) methods and -

personnel. and (c) sample expansion is recommended since. {

Niag' ara Mohawk's positions.on these items comply.with the' ,

~

NRC Staff position. '

.l r

2.0 Channes in the Technical' Specification Concernina ISI' f 1  ;

2.6.1 Nianera Mohawk's-Position-Niagara Mohawk Submittal No.'l'e .;ains the following ,

statement:

"Under separate cover, we ara submitting-an application l l ' to amend the-technical specifications to incorporate-

. g the r~equirements of.the generic letter."

i.

j e

. - - 2.6.2 Evaluation and RecommendationJ ,

J

, Since Niagara Mohawk committed to submitting'a change.to i

the Technical Specification on ISI in accordance with the

.I NRC Staff position, tentative acceptance of their position-is' recommended, pending actual' receipt of that submittal.

4.

2.7 Confirmation of Leak Detection in the' Technical Specification Discussion concerning le@ . p detection is'. deferred to Section-3 " Exceptions.to NRC N aff Pe.itions" of this report since Niagara -i j

Il?

19 5

n

!)..

m . ,

c.

l . ...;a.. ~ . - ...,e.-....  :

- . _... a .. ..:.

9

.. , . , t,.

,o ,,

I

~ Hohawk presented an exception to a pcrtion of the requirements

!' concerning leakage detection.

2.8 Plans for Notification of the NRC~of Fisws 2.8.1 Nianara Mohawk's Position ,

l Niagara Mohawk Submittal Ko. 1 contains the'following .

statement:

"Nitgara Mohawk will notify the Commission of any flaws .!

identified that exceed the acceptance criteria of'ASME i l

Section XI, subsection I O-3500. This ~ r J.fication will -

include our justification for.continr operation-and/or. t our repair plans."

2.8.2 Evaluation and Recommendations -

q Niagara Mohawk plans to comply with the.NRC Staff position

~

concerning reporting of flaws.,so acceptance of their plans I

for reporting of flaws is recommended. -Furthermore, Niagara Mohewk indicated (as shown in Table 1:of this report) that they endorse and_ plan to utilize the NRC Stsff position concerning Crack Evaluation and Repair Criteria, so acceptance of their position on:this item is' recommended.3 4

Jr.' i3. ALTERNATIVE POSITION ~ 1 1

3.1-Alternative Position Conterninn Leak Detection i u

in the Technical Specification NkagaraMohawkSubmittalNo.-1conta' ins'thefollowingstatement 20 x .

w >

o t

,-.-4 m.._.--.. ...._...._.] - ......__..._.,.._......L_~_...

.. . -._ __ _ ._. . _ _ _ _ . . _ _ , _ - .~.. __.. _ - _ . _- -__. _ -_.

, -. . ,_ , l

7_,.

.

f N: ,

- concerning theirequirement that the Technical Specification on 4 1eakage detection should be in conformance with-the NRC Staff '

+ l position.- '

" Plant Technical Specifications Section f.3.2 reisted' to 1

leak-detection: conforms to the staff position statedlin the-generic letter to the extent. practical'. The-2 spa increase in unidentified leakage was not included in the initial: ,!

.I Technical Specifications wtrn they.were issued, and there is; no need to revise the Plant 'hchnical Specifications since -

there is only one service sesreitive sustenitic stainless steel

. piping-weld inside the' primary containment."

Niagara Hohawk Submittal No. 2 adds the following statements concerning Niagara Mohawk's alternative. position on leakage

^l i detection. -

lli

" The Staff position on leak detection identifies a--regirement l r

l I

that plant shutdown should be initiated for inspection and '

corrective action in the' event of an increase of 2 gallons (g

per minute in unidentified drywell: leakage within a'24; hour period. The Unit 2 Technical-Specifications do not contain '

j this requirement, but this was. determined to be acceptable ,

under the Generic Letter 88-01 clause 'or'as previously approved

.by.iheNRC.'" 'the statement ' practical in our' response was4 1

meant to point out the difference from the Staff' position on #

1eak detection."

" Unit 2 has corrosion resistant material throughout the

.l.

susceptible systems. Consequently .its Technical. Specification,- y although not'in full conformance with Regulatory Guide.l.45 as stated in' Generic Letter.-88 0 1, was reviewed and-' approved

.as acceptable by the Commission."

l' [

21 h,  !

+

,v--- r---- & - , ,,e , - , , . ,e -e,3e , , - + . - , -._,...e .-. . - , ,-.-- - - - - . - - - . . - . - . .- , . - - - ee b.-4 .---,=~ sew.---

.I~, 7. . I.

y e.- ..- ,

l'}~

f.

i 4

3.2 Evaluation and Recommendations

, i Niagara Mohawk's position concerning conformance with Position C of Regulatory Guide 1.45 is unacceptable. Niagara Mohawk did not provide a detailed comparison of their Technical Specification concerning leakage detection and Position.C of Regulatory Guide j 1.45. Niagara Mohawk will need to provide such a comparison-for-evaluation by the NRC Staff.  :

q-In addition,Eas previously mentioned.1 Nine Mile 2, contrary to l l Niagara Mihawk's claim does not contain corrosion resistant materialsutn nearly all of the welds. TheNRC3taff,informulating-

[ the requiraients that should be included in the Technical-

--. Specificatio1s concerning leakage detection, recogaized that some-BWR nuclear. power plants would contain all (or nearly all) IGSCC:

l Category A welds. Furthermore, prior approval-of the Technical 'I Specifications does not constitute exemption from this requirement.

Thus, rejection of Niagara Mohawk's position of not incorporating a leakage requirement concerning the-limiting rate of increase of unidentified leakage (as stated in Generic 14tter 63-01)-in l

'{

'" the Nine Mile 2 Technical Spec.ifications is recommended.

In. addition, Niagara Mohawk did not supply a response when requested

- i in a Request for Additional Information (RAI)'to state whether or not they comply with other portions of the NRC: Staff positions  :

on the follcwing itras:

(1) The limit of'the total unidentified leakage of!5' spa.-

(2) The definition'(or description)'of unidentified leakage.

(3) The frequency of leakage monitoring. q

'(4) The operability.of-leakage monitoring devices.

j 22 1

,. 4.

. s . n . .

However, based on a review of the Technical Specifications of Nine p Mile 2, the.following items were found'to be unacceptable l

. (1) The primary containment'drywell' floor drain tank'and l

i. equipment drain tank fill rate is monitored at-least once-per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> rather than every four hours or less as. ,

i required in Generic Letter 88-01. j

.q F (2) The requirements for operability of leakage-monitoring instruments do not meet the requirements' delineated in j Generic Letter 88-01 for plan'ts operating with welds. j classified as Category D, Category E, Category F, or Category G.

It is recommended that Niagara Mohawk amend the~Nine Mile 2 j Technical Specification on ?eakage detection to include the Generic--

-l Letter 88-01 leakage detection requirements:as discussed above.

-i y 4. CONCLUSIONS AND RECOMMENDATIONS i

.1 Niagara Mohawk endorses 9 of the 13 NRC Staff positions without  !

i provisions-(i.e., those pertaining to Processes Water Chemistry, Weld -

Overlay, Partial Replacement, Stress Improvement of Crack'ed Weldsents, Clamping Devices, Crack Evaluation and Repair.Criceria;= Sample.

Expansion, and. Reporting Requirements)'. . They also endorse those

. pertaining to Materials, Inspection Method and Personnel' and Inspection 7

Schedules. although'they applied provisions to these. items. The 3 provisions applied to these items are acceptable- except that they have-incorrectly classified most-welds as IGSCC Category A. Niagara Mohawk presented an alternative position to that of the NRC Staff concerning the item on-leakage detection.

i A list of welds that are within the scope of Generic laitter 88-01 is i

d, n 1 j

l

I

m. ._ j

contained in Niagara Mohawk Submittals No. 2 and No. 3 which give IGSCC  ;

classifications assigned to welds, weld histories (including materiali, lI ~

used for components and welds in the piping systems), and inspection-i schedules. All except one of.the welds at Nine Mile 2 are classified L

as IGSCC Category A welds, in part, because Niapira Mohawk claims that IGSCC-resistant materialsLwere.ussd during const uction. _The one j{ exception is a weld classified as IGSOC Category D. However. the list l

of materials shows that most of the welds in the austenitic piping system actually contain materials such as Type 316 stainless steel h

' or Inconel 182 that are not resistant to corrosion. These welds,.

therefore, are mistakenly classified as'IGSOC Category A and should

] be reclassified into nou-conforming categories.

a 1

l Inspection plans for one IGSCC Ca'tegory D weld conform with the NRC

. Staff position on inspection'of such welds. In addition, their inspection plans for welds classified as IGSOC Cate,ory A wuld' be acceptable if those welds were correctly' classified. However, since j

those welds are incorrectly classified, their inspection plans are I- not acceptable per requirements of Generic' Letter.88-01..

rii;

- Niagara Mohawk stated that they would comply with the NRC Staff position requiring a' change in the Technical Specification:on'ISI including inspection schedules, methods and personnel and sample expansion.'

They stated that an amendment to the Technical Specification on ISI l would'be submitted under separate cover.

7 Niagara Mohawk's position concerning conformance with Position C of Regulatory Guide 1.45 was found unacceptable, and they will need to >

provide-the NRC Staff.with a detailed. comparison between Regulatory

-r Guide 1.45 and the Nine Mile 2 leakage detection system for evaluation.

1- Niagara Mohawk did not provide detailed'information in their RAI response concerning some of NRC Staif positions'on leakage detection requirements.. -However, Kiegara Holawk claims.that the Technical i l

1 24

, ,, , , . - - - - . ~ , . . . . .-.-..a , -, - . , , . ~ , . . - _ . , - - . . . -

,,-.c.

I . . .: . -  :

lji ,

-Specification for itine Mile 2 is already.in compliance with'the NRC.

f. Staff position on leakage detection as delineated in Generic Letter  ;

88-0; to the extent that it is practical. In addition, Niagara Mohawk stated that they do not need to comply with the Generic Letter 88-01 requirement concerning limiting the increase in unidentified leakage 1 to-2 spo because their Nine Mile 2 Technical Specificati ns have received prior approval from the NRC Staff and that it la not necessary since they only have one susceptible weld. The staff reviewed the

} dine Mile 2 Technical Specifications and found that Niagara Mohawk

.will need to amend the Nine Mile 2 Technical Specifications to include the following Generic Letter 88-01 requirements:~(1) That plant shutdown.

shKG1d be initiated when the rate of increase of unidentified leakage during any 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period or less reaches 2 8Pa. (2) Frequency of

! leakage monitoring. (3) Operability of leakage monitoring devices.:

As a result of this technical evaluation, the following recommendations

~ '

are made.

(1) Rejection of Niagara Mohawk's classification of~ welds in the

] Reactor' Recirculation-System, the. Residual Heat Removal System, and the Reactor Pressure Vessel which have-been' classified as IGSCC Category A System even though they contain ,

non-resistaat materials such as Type 316Lstainless steel and Inconel 182. Niagara Mohawk should reclassify those welds as IGSCC Category D or IGSCC Category G, depending on their inspection histories (2) Rejection of Niagara Mohawk'c inspection plans for the welds-

~

[ that have been incarrectly classified. Niagara Mohawk should  ;

revised'its inspection plans in accordance with the requirements for inspection of Generic Lette 88-01 for IGSCC Category D

, and IGSCC Category G welds. ,

(3) Acceptance of Niagara Mohawk's IGSCC inspection plans for the-  !

1

> 25

)

'l-

- . .. . . , , - . . , . . _ _ _ _ . . _ _ . . . . . _ _ , , . ..-, . . . . . - _ . . . , _ . - ~ _ , . . - .

L .s',

L.:.. o s e ,s #1 $1

. welds that 'contain resis: ' rr'attais (as discussed in Section- '

' 2.3.6 of this report).

(4) Acceptance of Niagara Mohawk's position on planned inspections of- weld RCS W A07 (classified as 1GSOC Category D) 'and their positions on inspection methodai and personnel, sample expansion, and reporting. requirements. ,

i I (5) Tentative ecceptanca of Niagara Mohawk's' position on changing- lx the Technical Specification concerning--ISI. pending receipt h I

and evaluation of the promised supplemental submittal..

-;l

• (6) Rejection of Niagara Mohawk's position concerning' limiting

.the rate of increase--of unicentified leakage to 2 spa. Niagara l Mohawk also needs to address frequency of leakage monitoring l and operability of leakage monitoring devices os discussed l

previously. In addition, they need to" amend the Nine Mile' 2 Technical Specifications to incivde the Generic Letter,88- 9 01 leakage detection requirements, y

- (7) Rejection of' Niagara Mohawk's position.concerning4conformance-~

with Position C of Regulatory Guide 1.45. :They need to provide:

a comparison between Regulatory Guide-1.45 and the Nine Mile 2 leakage detection requiremei.cs.

(8) Accepthnce of the remaining portions of-the' Niagara Mohawk-Submittals.

1 f~ j 1

i 26-i

.i

,',l, , ; < -

W

(- i n - , - o.

c - . . ' c, - -5. REFERENCES

" Technical report on Material Selection and Processir. Guidelinee

~

1.

for BWR Coolant Pressure Boundary Pipins," NUREG 0313, Revision 2,- U.S. Nuclear Ryulatory Commission Office of Nucliest Reactor -

Regulation, January, 1988.

2. " Investigation-and Evaluation of Stress-Corrosion Cracking;in Piping -

of Light Water Reactor Plants,":NUREG 0531, U. S. Nuclear Regulttory Commission February, 1979. c

3. "NRC Position on'IGSCC in BWR Austenitic Stainless Steel Piping,-

Generic Letter 88-01, U.S. Nuclear Regulatory Commission, January--

25, 1988.

(

t F

i

\

2 27 l;

?

yy a m :n _ r - ar - -