ML20058K086

Technical Evaluation Rept on Response from Commonwealth Edison to Generic Ltr 88-01 Pertaining to LaSalle County Station,Unit 2

ML20058K086
Person / Time
Site:	LaSalle
Issue date:	07/31/1989
From:	Bates R VIKING SYSTEMS INTERNATIONAL
To:	NRC
Shared Package
ML20058K090	List: ML20058K086 ML20058K092 ML20058K136 ML20059N029 ML20059N030
References
CON-NRC-03-87-028, CON-NRC-3-87-28 GL-88-01, GL-88-1, NUDOCS 8908030127
Download: ML20058K086 (33)

Text

'

d

3. . 1 -m ' .

pq l L, .  :

(l

• j d

!.f, .l .!

.~ ->

i

'1VNId S' _,

L j. 3

! f' 1-TECHNICAL EVALUATION REPORT *W-RESPONSE FROM-COMMONWEAL'DI EDISON W GENERIC LETTER 38-01 i p PERTAINING W THE  ;

IASALLE COUNTY STATION, UNIT 2 I

. -j 4'

L.:. Published July, 1989 .,

r. .

i' O. ~

prepared by e ,

l Robert C. Bates p ,

q Armand Lakner= '

i l^

1; Viking Systems International-- ,

, 2070 Wm. Pitt Way j ll .Pittsburgh,'PA r

l > <

Prepared fort U.S. Nuclear Regulatory Commission 7, .Washington, D. C. 20555 under.

Contract No. NRC-03-87-028, Task Order 005 dEd30l2 l

- m.< Ah -

I '

-, w ,- -+y-*- -, ,-,e -w ,

• t

.i L* lt .

'l R

TI i ABSTRACT l 7

This report contains an evaluation of the licensee (Commonwealth Edison)

.; submittal for LaSalle County Station, Unit 2 which was submitta' in response to the NRC Generic Letter 88-01 in which Commonwealth Edison F

was requested to (1) Furnish their current plans relating to piping replacement and other measures to mitigate ICSCC, inspectiou,Lrepair, and leakage detection. (2) Indicate whether they plan to follow the NRC Staff positions, or propose alternative seasures. Commonwealth Edison's plans are evaluated in Section 2 of this report in terms of compliance to NRC Staff positions. Section J contains an evaluation of an alternative position concerning a change to the Technical Specification on ISI and concerning alternatives to portions of the l

l.

NRC Staff position on leakage detection.

t i b

n 1

h I.

l:

I i

U

- . - - - - + .m. ., . . . , _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __.,

1 i

• l SIM4ARY r l l

1 The Licensee,~ Commonwealth Edison, submitted a response to the NRC.

]

Generic Letter 88-01. Commonwealth Edison's response' pertaining to ~ -I the austenitic stainless steel piping in the LaSalle County-Station, .

j Unit 2 (a BWR nuclear power plant) was evaluated-in terms of: (1) Their R Y previous and planned actions to mitigate IGSCC to provide assurance; of continued long-term service. (2) Their Inservice Inspection (ISI) i

! Program.. (3) Their Technical Specifications pertaining to ISI and i their plans to ensure that leakage dete d on will be in conformance

[ vith the NRC Staff position. (4) Their plans to notify the NRC of' significant flaws identified (or changes in the condition of the welds q previously known to be cracked) during inspection.

f.8 i Commonwealth Edison enddraes 12 of the 13 NRC Staff positions which are outlined in Generic Letter 88-01, although a provision was applied i l( to one of those twelve (that on Crack Evaluation and Repair Criteria)..

They' proposed alternatives to portions of the NRC position on_ leakage.

't detection.1 g a Extensive mitigating actions have been performed at LaSalle 2 resulting in 50:IGSCC Category A welds, 137 IGSCC Category B welds, and 8 IGSCC- 9 Category C welds.. No IGSCC Category D, E, F. or G welds exist. Future t

plans include implementetion of Hydrogen Water Treatment and performance of. weld-repairs as needed.

p-l

[ An.-ISI program proposed for LaSalle 2 conforms with the NRC' Staff j positions on inspection schedule, methods and personnel, and-sample- I ll . expansion. Specific welds to be inspected during the next two refueling outages were identified.

Generic Letter 88-01 requested a change to the Technical Specification

] (TS) to include a statement that the ISI program will conform with

]! the NRC Staff position. Commonwealth Edison proposed including such ,

a statement in the ISI Program rather than in the TS.  !

l} '

lf ' I 11 .

4

L .j)o si e i 33's :o CONTENTS }

ABSTRACT. ......,....................... -

1 ,

SUMHARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 ,

li I

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

2. EVALUATION OF RESPONSE 'M GENERIC LETTER 88-01 ........ 2.

'i.

.t 2,1 Documents EEaluated ................... 2 i

E' 2.2 Review of Commonwealth Edison's Responses to Staff.

• 3 :, Positions and Implementation of-Those Positions . . . .. . . 3

-ll 2.3 Review of Classification of Welds. Previous Mitigating

j. Actions, and Previous Inspection Program ... . ... . . . . 5 1

-1 2.3.1 Current IGSCC Classifications ............ 5 Lp 2.3.2 ' Design and Construction Changes ........... 8'  :

.i

. 2.3.3 Stress Improvement '

. . . . . . . . . . . . . . ... . 10 2.3.4 Previous Inspection Programs ............. 10

-2.3.5 Evaluation or Previous Mitigating

) Actions and Inspections- ............... 12

.s:

2.'4 Current Plans for Mitigating Actions '

........... 13 2.4.1 Summary of Plans ................... 13

i; 2.4.2 Evaluation of Conformance to Staff

Positions and Recommendation ............ 13 '

T

- y 2.5 Plans for Future Inspections ............... 13 .

2.5.1 Summary of Inspection Schedule ........... 14 2.5.2 Methods and Personnel ................ 15 ji 2.5.3 Sample Expansion .................. 15 j 2.5.4 Evaluation and Recommendations ............ 15 e

t- 111

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

i-iii.E .

.t.:

} ,-

' t 2.6 Changes in the Technical Specification

t . Concerning ISI ... . . . ... . . . . ... . . . . . . . . .. 15 3

I

.i 2.7 Confirmation of Leakage Detection in the Technical Specification ............... 16 l'

2.8 Plans for Notificat -n of the NRC of Flaws .. ...... 16 s

'{

2.8.1 Summary of Position .................. 16 5

2.8.2 Evaluation and Recommendation ............ 17 -;

t

3. ALTERNATIVE POSITIONS . . . . . . . . . . . . . . . . . . . . . . 17

, 3.1 Alternative Position Concerning ISI in the i Lf Technical Specification .................. 17

,3.1.1 Commonwealth Edison's Position ............

17-l 3.1.2 Evaluation and Recommendation ............ 18 i j .3.2 CE's' Position Concerning Leakage Detection ......... 19 -

U Jr 3.2.1 Conformance with Regulatory Guide 1.45 ........ . .19 t L-3.2.2 CE's Position on Requirements for Unidentified Leakage. ................

21 q

3.2.3 CE's. Position on Frequency of Leakage Monitoring ... 21 i 3.2.4 CE's Position on Definition of Unidentified Leakage . 22 I y ,

3.2.5 Operability of Leakage Monitoring Instruments- . . . . 23 3.2.6 Evaluation-and Recommendation ............ 23

4. CONCLUSIONS AND RECOM4ERDATIONS ................. 24 l

5. REFERENCES

.......................... 28-  ;

I iv

.I p.

- +

, j

'Q .

1. INTRODUCTION  ;

Intergranular' stress corrosion cracking (IGSCC) naar weldsents in .i

. , Boiling Water Reactor (BWR) piping has been occurring for almost 20 years. Substantial efforts'in research and development have been j sponsored by the BWR Owners Grc.up for IGSCC Research, and the results ]

of this program, along with other related work by vendors, consulting i firms and confirmatory research sponsored by the NRC, have permitted I the development of NRC Staff positions regarding the IGSCC problems.

The technical basis.for NRC Staff positions is detailed in Reference j 1, and further background is provided in Reference 2.

c 1 L The results of these research and development programs prompted the  ;

NRC to irsue Generic Letter 88-01 (see Reference 3) requesting all  :)

licensees of BWR!s and holders of construction permits to:

l 4

(1) Furnish their current plans relating to-piping replacement, '

inspection, repair, and leakage detection.

(2). Indicate whether they:

(a) Plan'to follow the staff positions, or 21 (b) Propose alternative measures. l) l Specifically, Generic Letter 88-01 stated that an acceptable licensee  !

response would include the following items-1 (1) Current plans regarding pipe replacement and/or other measures

'1 taken or to be taken to mitigate IGSCC and provide assurance of continued long-term piping integrity and reliability.

(2) An inservice inspection (ISI) program to be implemented at i thu next refueling outage for austenitic stainless steel piping.

(3)-A change to the Technical Specifications to include a statement 1 '

,.l

}l ,o i tga 1

'T 1 ', .

.i 3

} (2) "LaSalle County Station Units 1 and 2, (Response to) Request- >

s for Mditional Information, Generic Letter 88-01," Docket Nos. ,

h 373/374, Commonwealth Edison, One First National Plaza, Chicago, Illinois 60609, June 30, 1989.

H,sreafter, in this report, these documents will be, referred to r,s Commonwealth Edison Submittals No. I and No. 2, respectively, i i and collectively, as the Commonwealth Edison Submittals.

., i I

!. .2.2 Zeview of Commonwealth Edison's Responses to Staff Positions and Implementation of Thoae Positions. I

$. -i Generic Letter 88-01 outlines 13 NRC Staff positions pertairiing to (1) materials, (2) processes, (3) water chemistry, (4) weld overlay, (5) partial replacement,.(6) stress improvement-of cracked.

weldments, (7) clamping devices, (8) crack evaluation and repair criteria, (9) inspection methods .and person'nel, (10)11nspectida -

schedules, (11) sample expansion, (12) leak detection, and (13)'

y reporting requirements. . Generic Letter 88-01 states that the i H ,

licensee should indicate in their submittal whether they endorse these NRC Staff positions or propose alternative positions. Table 1 of this report, which was constructed from a similar table in  ;

. Commonwealth Submittal No. 2 and some additional information from '

. Commonwealth Edison Submittal No. 1, shows Commonwealth Edison's positions on the 13 NRC Staff positions.

Note tha',-Commonwealth Edison indicated acceptance of twelve of ,

3  ;

e o

E i_._.m.m. ___'___'_i__________.____________ _ ,_ .-.. - =- -+ *

.j}l .en a.

t 3 ,

Tab 1'e1 '

Summary of CE's Responses to' Staff Positions -i CE Has/W113 CE Accepts NRC, Applied Conside for

,, Staff Position Staff Position- In Past Future Use L. Materials yes yes yes(*)

2. Processes yes yes yes(*)

3. Water Chemistry yes no yes  ;

4. Weld Overlay . yes- no(b) y,,(b)

5. Partial Replacement yes no_ yes(*)

6 , Stress Improvement of l Cracked Weldsents yes yes .yes(,) _

7. Clamping Devices yes no yes(*) i

8. Crack Evaluation and y,,(c)

Repair Criteria yes(c) ,,

9. Inspection Method and Personnel yes yes yes

~

10. Inspection Schedule yes no yes

11. Sample Expansion yes no' yes(*)

12. Leak Detection no(d) no yes i

13. Reporting Requirements yes- yes yes

-i: Notes:.

(a) Will-implement as necessary.

.(b) Weld overlay to be reviewed for application to welds with L

, flaws in excess of limits permitted by NUREG 0313, Revision

2. , To date; no veld with flaw indications has been found at LaSalle 2.

i (cs accept with provision. See text for discussion.

{

(d) Commonwealth Edison applied exceptions to.the NRC Staff position.on'this item. See text for discussion. '

i 4

.j{^:,

- b,

=..

the thirteen NRC Staff positions and applied' exceptions (as ,

, discussed later) to the NRC Staff positions pertaining to leakage g detection. Concerning Item 8 on Crack Evaluation and Repair - ,

,[ Criteria, Commonwealth Edison applied a provision that a favorable stress distribution arising from stress improvement would be taken into account in their calculations, j i

i i

l-2.3 Review of Classification of Welds. Previous Mitigatina i Actions, and Previous Inspections l

2.3.1 Current IGSCC Classifications and Sumary of Materials and Mitigating Treatments Weld-by-weld descriptions were not provided in Commonwealth-Edison Submittal No. 1; however it does contain a summary of the IGSCC classifications of the welds which is shown l

in-Table 2a of this report. Weld-by-weld descriptions'are j

~

contained in Commonwealth Edison Submittal No. 2. Included are the IGSCC classification, weld identification, and mitigating treatment (s) of each weld in'each of the varioua 3

piping systeu at LaSalle 2. Since Refueling Outage No. 2 l occurred-between the time that Commonwealth Edison Submittals .

e No.' I and No. 2 were prepared (at which time, stress  !

improvement was applied to six welds),the numbers of welds I in certain IGSCC classifications changed. -Table 2b, developed  ;

from the veld-by-weld descriptions _ contained in Commonwealth Edison Submittal No. 2, summarizes-the number of welds in ~!

each of the various IGSCC classifications on a system-by- l

$ i system basis after Refueling Outage No. 2. Note that, o according to the Commonwealth Edison Submittal No. 2, LaSalle j 2 contains a total of 195 welds that are within the scope of Generic Letter 88-01 divided as follows: 50 IGSCC Category A welds, 137 ICSCC Category B welds, and 8 IGSCC Category 5

~ i

m.. 't

]p c,-

h l 1 l:-

'l

.Ij ! '

' ' ~

Table 2a.

Summary of IGSCC Classification of Welds (Prior to Refueling Outage No. 2)

Number of Welds Classified in Diameter- Indicated IGSCC Catenory System Inches A B C D- E- F -- G Total i-Recirculation Outlets '24 4 40' O 1 0 0 0 45 Noz-SE 24 0 2 0 0 0 0 0- 2 Header 16 8 8 0 0 !O 0- 0 16 Risers 12 30 20 0 0 0 0 0 -50 Noz-SE 12 0: 10 0 -0 0- 0 0 10 Decon 4 6 4 0 0 0 0 2 12 Shutdown Cooling 20 0 10 0 0 0 '0 1< 11 SDC, LPCI, LPCS, 12 2 23 0 0 0 O -1~

26 HPCS, W -

o RCIC, Spare Noz. 4&6 0 20 0 1 0- -0 2 23

'Rx Clean Up', JPI Head Vent, CRD Cap.

Totals 50 137 0 2 0 0- 6 '195 6

w.s

'et  :

1

.m 1:-

n2 q[

t 1; lI

~

Table 2b l q

lf i o

-[ ~ Summary of IGSCC Classification'of Welds (After Refueling Outage No. 2) .

-l . \

.t Number of Welds Classified in Diameter Indicated IGSOC Catenory System Inches A B C D E F G Total Recirculation-Outlets'- '

'24 4 40 1 0 0- 0 0 45

Noz-SE 24 0 2 0 0 0 0 0 2 Header' 16 8 8 0 0 0 0 0 16 lr 1 q; Risers 12 30 20 0 0 ,0 0 0 50 Noz-SE 12 0 10 .0 0- 0 0 0 10 "

6 -4, Decon 6 4 2' ' 0: 0 0 0 12 q

1-_ Shutdown Cooling 20 0 10 1 0 -0 0 0 11

[ SDC, LPCI, LPCS, 12 2 23 1- 0 0. 0 0 26 q p HPCS FW i i'

RCIC, Spare Noz. 4&6 0 20 3 0 0 0 0 23 Rx Clean Up, JPI Head Vent, CRD Cap.

Totals 50 137. 8 0 0 0 0 195

} ;.

I li

lt -

p 7

ji ,

lr-I:'> 1 o

-..Lx..--_--L__-_.l-_?---_-_-_-_.--------._-- . - - - - , ,- , . , ,- -- - -- ~

sj'

.i 3 t

?

+

'C welds. No IGSCC Category D, E, F or G ' welds currently exist at LaSalle 2.

The mitigating treatments leading to these classifications are summarized in Table 3, and additional details concerning- J "o .

the mitigating treatments are discussed below. "

c 2.3.2 Desian and Construction Channes Commonwealth Edison Submittal No. I states that-1'1tial- j t

L a i

i' Table 3 ,

Materials and Mitigating Treatments as LaSalle 2

l. -

No. of No.' of Weld 'I Welds with with Indicated j IGSCC Materials Indicated -Treatment Caten 1st Comp. 2nd Comp. Weld Materials SHT THSI MSIP-A Conforming Conforming Conforming 18' 18 0 0 304 SS 304 SS- 308 SS .

A Conforming Conforming Conforming 32 0 0- 0 316L SS 316L SS' 316L SS B .Non- Non-- Non- 137 0 92 t45

-Conforming Conforming Conforming C Non- Non- Non- 8~ 0 0 8' Conforming ' Conforming Conforming j i

8-e jp, i ,

t I.t ,

N

7. .~M _

h,/ ' x, .

p;,-_

n

[

JJ '  ?

.' designs were revised to reduce the amount of IGSOC susceptible. I b stainless steel piping. Construction practices were'also x

1 changed to make the material less sensitive to IGSCC. '!he l specific changes were not disclosed, but'it' is presumed that' r it included the use of corrosion' resistant material-(per j NUREG 0313, Revision 2) and/or solution heat treating the  ;

._ .. 50 IGSCC Category A welds.

e 3 3".

There is some' confusion concerning the materials in 18 of the welds that are classified as IGSCC Category A. For each

. of these welds, Commonwealth Edison Submittal No. 2 contains l the following statements under the heading " Materials", in  ;

the weld-by-weld listing of materials:

U

.e L FirstComponent: Conforming 304 S/S.'

4 h-c ' Second Component: Conforming 304 S/S;

.l

{ Weld: Conforming 308 S/S.

}'

.o

i; The meaning of.these statements is not clear. Types 304-stainless steel and 308 stainless steel,.according to NUREG 0313, Revision 2, are not conforming materials. Commonwealth u Edison may, however, used the word " conforming" in. conjunction j with the material type, perhaps implying-that the-'m aterials j used~were:actually Types 304L stainless steel and 308L. q g stainlese steel. . In any. event, the IGSCC Category A welds. '

are correctly' classified-since they were solution heat r

L l

treated.

L The remaining 32 IGSCC Category A welds contain Type 316L a L

stainless steel which is conforming material per NUREG 0313, j ir .

Revision 2.

1'

!s I k i.

i 9 1 14 A

'9.

( , &

T t *- *- y -.r - .x--

ji T.cf

]

-: r.

R 2.3.3 Stress Improvement

.)

~

Note that'all of the IGSCC Category B and IGSCC Category = .]

~ .C welds (a total of 145 welds) contain non-conformin:

materials. Stress Improvement.(SI) treatments, including both Induction Heating Stress Improvement (IHSI) and the-Mechanical Stress Improvement Process (MSIP), were applied-to all of those welds, and'all SI treatments were followed-with inspections performed by personnel from the Electric'-

(Power Research Institute (EPRI). .The majority of the welds

,, treated with SI (137 of a total of 145) were treated'within'

. two. years of commercial operation so those welds are

( classified as IGSCC Category B. The other eight SI-treated I

welds are classified as IGSCC Category C since the SI q treatments were applied after more than.two years of commercial operation.. It'may be noted by' comparison of Tables'

< 2a and 2b that six of the IGSCC Category C welds were stress it improved during Refueling Outage No. 2.

2.3.4 Previous Inspection Programs

.LaSalle.2 has had two refueling outages with the following.

starting dates: ,

Refueling Outage' Startina'Date No. 1 01/87 f No. 2- 10/88 Commonwealth Edison Submittal No.'2 contains a weld-by-weld i

, p listing ofLinspection schedules and-inspection results h ,

p performed during those refueling outages. These schedules-p are summarized:in Table 4. 'No IGSCC Category A welds were.

inspected during those outages,;but about 75 % of the IGSCC Category B welds and all of the IGSCC Category C welds were T

10 i

y -#

I tm

-t

.]  ;

e 'l

-Table 4

! Summary of Inspection Schedules for LaSalle 2 d.

i; No. Inspected /Schduled ,

Durinn Indicated R.O.

,i-IGSCC No. in Past Future Required by  ;

L. Caten. Caten. 01 02 03 04 Generic Letter 88 ,ji 1 'A 50- .0 0 4 7 25% every 10 years (at least-(8%) (14%) 12% in 6 years) b

' B-' 137 648- 19 b

16 0 50% every 10 years (at least i j (47%) (14%) (12%) 25% in 6 years) '

C- 8- 2 7 3 8 All within the next 2 refueling i I

(25%) (88%) (38%) (100%) cycles, then all every 10 years

, (at 50 % in 6 years) i

, 'D. 0 - - - - All every 2 refueling cycles  ;

l: E 'O - - - -

50% next refueling cycle, then all every 2 refueling cycles q F 0' - - - -

All every refueling outage 0 All next refueling cycle G - - - -

Note: .

6 y a 'One of these inspections was conducted only.on the  ;;

I.'D. surface.

b Eight of the IGSCC Category B welds.were inspected during both RF#1 and RF#2. Two of the welds scheduled for.

inspection during RF#3 were inspected during RF#1 and/or, '

RF#2.

v Dates for Refueling Outages are: {

. =- !

R .O. No .- Beginning Date- R.O. No. Beginnint y ce 01 01'/87 03 03/90 02 10/88 04 01/92 11

~

f' 4 inapected during either Refueling Outage No. 1 or Refueling l

Outage No. 2_or both. Some of the inspections listed in Table.4 may have been the post-SI inspections-(recall from

'ti the preceding section that.all'SI-treated welds received post-treatment-inspections), but that was not disclosed in '!

I the Commonwealth Edison Submittals.

,. No IGSCC has been found during inspections, although base-metal spot indications were found in two of.the welds (No.

RR-2002-01A, classified as IGSCC Category B and No. RT p 2003-24, classified as IGSCC Category C). Both are considered L acceptable for service, l'

2.3.5 Evaluation of Previous Mitigatina Actions i and Inspection's ,

.f Extensive' actions (following guidelines provided in Generic  !

i Letter 88-01.and NUREG 0313 Revision 2) have been taken ,

at.LaSalle 2 to mitigate IGSCC including design and h construction changes and stress improvement. The result 7 is that all welds at LaSalle 2 that are within the scope-  !

of Generic Letter 88-01 contain corrosion resistant materials-  ;

and/or.have been treated with either solution heat treating or stress improvement, and all welds at LaSalle 2 have been '

li arrectly classified as'either IGSCC Category A, B, or C..

l. Although some confusion exists concerning whether some of n

. the IGSCC Category A welds contain resistant material (per l

NUREG 0313, Revision 2),-these' welds are properly classified since they were solution beat treated. Post-SI inspections

! vere performed on all SI-treated welds'by EPRI personnel,-  !

so NRC Staff requirements that post-SI inspections must be performed in order to qualify the welds for classifications of IGSCC Category B or C have been satisfied.

?

12 gs 9

-m .- - _

a ,

' 1 3, .

P W* 2.4 Current Plans for Mitinatina Actions y

'# , 2.4.1 Summary of Plans' f{>

1 Commonwealth Edison's plans for future mitigating antions for LaSalle 2' consist of (1) evaluation of Hydrogen Water

-l-y: Treatment as a long term mitigation scheme to provide additional protection for IGSCC susceptible welds, and (2)

' application of weld overlay repairs as needed. Concerning the latter, Commonwealth Edison Submittal No. I states:

" Weld Over.'.ay has been reviewed for application to welds; that have flaw indications in excess of the limits

.- permitted by NUREG 0313, Revision 2. To date, no flaw-indications of a magnitude requiring an overlay reinforcement have been found at LaSalle Unit 2.

2.4.2 Evaluation of Conformance to Staff Positionst and Recommendation

+

g Since: (1) extensive mitigating actions have already been applied so that all welds at LaSalle 2 are either IGSCC Category-A, B, and C welds; (2) Hydrogen-Water Chemistry,

, if it is implemented, will-further reduce the possibility of IGSCC at LaSalle 2; and (3) welds will be overlay repaired as needed, Commonwealth Edison's previous actions and current ~

plans concerning mitigating treatments follow the guidelines:

O of Generic Letter 88-01 and NUREG 0313 Revision 2.

,; Therefore, acceptance of those plans is recommended.

v  ?

, 2.5 Plans for Future Inspections Commonwealth Edison Submittal No. I states-that an augmented ISI 13 J

(

f. '

fl,.: ' ,

1 f t:

1

' ~

program will be con' ducted at'LaSalleL2 beginnin's in 1988 (Refueling.

[t -

Outage No. 2) as outlined below.

.I 2.5.1 Summary of Inspection Schedule -l l

1 l

.., Commonwea'Ith Edison Submittal No. 1' states the following i a;

.a concerning inspection' schedules:' l

. "Beginning with the next refueling outage for LaSalle Unit 2 (December 1989), ASME Code class 1, 2 and-3 piping made of stainless steel that is four (04) inches or largar-in-nominal diameter and contains reactor coolant at a temperature above 200'F during power operation will be subjected to an augmented inspection program. This '

y augmented inspection program will conform to the NRC

!. staff positions on schedules, methods and personnel,.

I and sample expansion delineated in Generic Letter 88-01."

3' .

' Commonwealth Edison Submittal No I also states-that the 4 number of welds to be inspected is not evenly distributed) to each' outage.

Commonwealth Edison Submittal No.'2 contains inspection plans for LaSalle 2 on a weld-by-weld basis for the next two  ;

refueling outages (Refueling Outages No.-3 and No. 4 scheduled'

[I m to begin in 3/90 and 1/92, respectively). A summary of these- ,

schedules, showing'the number of welds in each of the various IGSCC Category scheduled for inspection during each-of the next two refueling outages, is shown in Table 4 of this report U along with the requirements for inspection-schedules as #

ll - - delineated in Generic Letter 88-01 and NUREG 0313, Revision 4

- 2. . Recall =(from Section 2.3.4)'that-this table also contains  :

similar inspection schedules-for the two previous refueling outages including inspection during Refueling Outage No.

14 4

j ,

s -- .,

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

y .,; .

. a . - -

b.

J'

i ,1 V

g <

g .2 which was the outage referred to in Commonwealth Eatson '

. Submittal No. I as the initial inspection of their augmented ISI program.-

-Note that Commonwealth Edison's plans for inspection schedules for all welds at LaSalle 2 that are within the scope of:

. ,l. Generic Letter 88-01 comply with the NRC Staff guidelines

• /

provided in Generic Let*er 88-01, 1 I

w,

' c 2.5.2 Methods and Personnel  !

~-j l' f

[ '

4 As indicated in the previous section the augmented' inspection

.- program will be conducted using methods and persannel~in

}i[ conformance with the NRC Staff positions as delineated in Letter 88-01..

g 2.5.3'Sampie Expansion j :.-

, Commonwealth Edison Submittal No. I states that the Sample  !

!L Expansion in the-augmented' inspection program will conform .

to the.NRC Staff position as delineated in Letter 88-01.

2.5.4 Evaluation'and Recommendations

! ' L

'- l

,1 l

.o Commonwealth Edison's position and plans concerning inspection I

-o ^ '

schedules, methods and personnel, and sample expansion comply

[ 'with the NRC positions on those items as delineated in NUREG

?- 0313, Revision 2 and Generic Letter 88-01~ Thus, acceptance of Commonwealth Edison's plans is recom.nended.

l

h. I w

{ d.6 Changes in the Technical Specification Concerninn ISI j ' Commonwealth Edison proposed an alternative position to the NRC 15 ocm <

. I'

• [' '

t

,,.. ( 4 t

-l ,

- Staff position concerning a change to the Technical Specification. I

'!- This alternativeLposition is discussed in Section 3 of this report.

p

-2.7 Confirmati. _; .

• Leakane Detection

~

g in the Technical Specification  ;

't j

i Portions of Commonwealth Edison's position on leakage detection conform with the NRC Staff position, but Commonwealth Edison offered ~ j alternative positions co;._.cning other portions. Thuri, discussion of leakage detection is deferred to Section 3. "Alterr.stives Positions and Exceptions."

C f

2.8 Plans for Notificatibn of the NRC of Flaws t 2.8.1 Summary of' Position

l. +

l r.:

Commonwealth Edison Submittal No. I states that the NRC will L

L, be notified-(in accordance with Ge'neric Letter 88-01) of- 3 o the following conditions:

l 1

4

" Flaw' indications exceeding the acceptance: criteria of.

applicable Section XI, Subsection IWB-3500."

" Change found in the condition of the welds previously known to have flaw indications." '

ba

! '"The evaluation by the CECO Nuclear Department for the .,

above conditions for continued operation and/or the  ;

?, .necessary corrective action to be taken."

e 16 .;

1

a

s W', .;

. i

' q Ff i 1

1

.2.8.2 Evaluation and Recommendation a

q Commonwealth Edison plans to comply with the NRC Staff i

position,. so it is recommended.that the plans for reporting l

of flaws should be accepted. l In addition, as indicated in Section 2.2 of this report. l 4

' Commonwealth Edison applied a provision to its endorsement

.[*

of the NRC Staff position concerning Crack Characterization and Repair Criteria. The provision applied'is-that a-

} faverable stress distribution arising from stress improvement

'II would be taken into account in their calculations. 'this is an acceptable approach,-so acceptance of this provision is recommended.

. 1

.i :

3. ALTERNATIVE POSITIONS 3.1 Alternative' Position Concerning ISI in the I Technical-Specification -

3.1.1: Commonwealth Edison's Position' It is the position'of the Commonwealth Edison.that it is.

9 l

t not approyriate to change the Technical Specifications to 1 includo statements in the'section on ISI that inservice i inspection programs for piping will'be in conformance with k

^ i the' staff positions'on schedule, methods and personnel.-

Rather,- it is more appropriate to pursue. changes to the station's Inservice Inspection Program to include statements I t.

1 indicating'conformance to Generic Lette- 88-01. Their reasons. .. ;

are quoted below from the Commonwealth Idison Submittal.

i (1) "The amendment would unnecessarily clutter the 17 1

e- ,r w +m.-- n '

. V&

}t;f e .

j

}s ,

.?  ;

technical specifications with information not ~!

q~'

appropriate for immediate operator, reference."

94

'(2) "The. amendment does not meet the screening criteria v for determining which regulatory: requirements and a operating restrictions should be retained in the

.i standard technical' specifications'and ultimately j

, in the plant technical specifications, as given in  !

the' Interim Policy Statement on Technical =

Specification Improvements,;52FR3788, February 6, 4 1987." .,

j, (3) "As the industry and the_NRC gain more insight into 1' the causes of, and methods f . prevention of IGSCC,

. I the requirements in this area will:be.. changing.  !

it '

Therefore, addition of a reference to the generic i[.

, letter.in the technical specifications would' require 'h that the technical specifications be updated las the?

{ , requirements in this area evolve." '

i> q 3.1.2'Evalustion and Recommendstion e

( . Generic Letter 8b O1 discloses that the' Inservice Inspection

~

L and Testing Sections may be removed from:the Technical Q Specifications and included in the Inservice Inspection 1 o

l: Program in the future-(as proposed by Commonwealth Edison). l-

[ .

Despite this consideration, the NRC Staff, spe'ifically c P, included a requirement _in Generic Letter 8bO1=to change-the Technical Specification to include a statement that the 7; section on ISI will conform with the NRC Staff position e.

1'l -

l schedule, methods'and personnel, and sample expansion. Thus, l t

/ ,, rejection of the Commonwealth Edison position is recommended.

4 Commonwealth Edison should change the Technical Specification on ISI as required by Generic Letter 88-01.

~

[

18 L

l:

.c-r . .D.

3 1 .

3.2 CE's Position Concerninn Leakane Detection-Ll; Table 5, constructed from information provided in a similar table L , in Commonwealth Edison Submittal No'. 2, summarizes Commonwealth j Edison's position on' leakage requirements in the Technical i Specification. Note that they indicated acceptance of portions

9 of the requirement:; outlined in Generic Letter 88-01, stated that t t

, two requirements are not applicable, and proposed alternative positions to the remainder _of the requirements.- They stated in I Commonwealth Edison Submittal No. 1 that the alternative positions are needed to avoid unnecessary plant modifications or unnecessary  :

restrictive plant operating conditions. Additional discussion- )

u is provided below on each requirement.  ;

.' ,1 l

-3.2.1 Conformance with Regulatory Guide 1.45 1 li l-

Generic Letter 83-01 states that leakage detection systems should be in conformance with Position C of Regulatory Guide  !

H l 1.45 or as otherwise previously approved by the NRC.

I Commonwealth Edison Submittal No. 2 states the following:

i-

"Section 5.2.5 of the LaSalle County Station Safety _

. Evaluation Report (NUREG 0515) provides an outline of  ;

the leak detection system. The conclusion reached in' l the SER was-that the system provides reasonable assurance that small lecks across the reactor coolant pressure boundary, can be detected,'as required by Criterion 30. .l of the General Design Criteria and Regulatory Guide 1.45." l 4:. 1 k, Elsewhere in both Commonwealth Edison Submittals, statements E are.made that the Technical Specifications on leakage-

. detection conform with Regulatory Guide 1.45. See, for i l

erample, the statement quoted in Section 2.3.4 of this report I l

19 j

i ,

l

i a .c eg; - i p

[t t 7-f'

$ Table 5- l t, .

np j' Licensee Positions on Leekage Detection  !

l

~

m, Already TS wil1 be Alternate (*)

Contained Changed Position: ..;

Position in TS to Include' Proposed

1. Conforms with Position C of no - yes O- '

Regulatory Guide 1.45

2. Plant: shutdown should be

-initiated when:

(a) within any period of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> no - yes

.or.less, an increase is

[ indicated in-the rate of

[j- unidentified. leakage in excess of 2 spa, or r

(b) the total unidentified leakage yes - -

attains a rate of 5 sps.

3. Leakage monitored at.four hour Not applicable. See text

intervals or less. -for discussion. j l

4.' Unidentified leakage includes all  ;

except (a) leakage into closed systems, -- -

yes or (b) leakage into the containment yes atmosphere from sources that .

are located, do not interfere with monitoring. systems, or not from throughwall crack.

• l -.

1

5. Provisions:for shutdown within 24 Not applicable. See text-hours oue to inoperable. measurement -for discussion. i' (U instruments in plants with Category JL D, E, F, or G welds.

?

(a) See text for discussions concerning alternate proposals.

v--

d fi 20

=

u o e ,

(from Commonwealth Edison Submittal No.1), l 7y.. .

3.2.2 CE's Position on Requirements for Unidentified Isakane  !

.; I 11'

. Generic Letter 8&-01 requires that plant shutdown should j be initiated when, within say period of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or less,  !

any leakage detwetion system indicates an increase in the f I

rate of unidentified leakage in excess of 2 spa or its

} , equivalent, or when the total unidentified leakage attains i a rate of 5 spa or equivalent, whichever occurs first. The  :

Coenonwealth Edison Submittals state that the Technical '

Specifications are currently in conformance'with the 5 sps l requirement, but pertaining to the requirement concerning  ;

an increase in the rate of unidentified leakage in excess of 2 spa, Cosmonwealth Edison Submittal No.1 states: }

i "The sump fill-up rate is monitored continuously by chart I

recorder, and an alara sounds each time the sump pump l-starts. The sump pump discharge flowaeter totaliser j is recorded shiftly, and the leakage rate is determined.

• LaSalle Unit 2 has only two Category E welds which have been stable over the 2nd cycle. It is the station's opinion that addition of the 2 gpa requirement to their 3 technical specification would not provide a significant l increase in the level of plant safety." g 3.2.3 CE's Position on Frecuency of Leakane Monitorina Generic Letter 88-01 states that for sump level monitoring systems with fixed-messarement-iaterval methods, the level should be monitored at approxim.ately 4-hour intervals or y

less . Commonwealth Edison's position on this itan is that ,

it is not applicable because they do not use the

^

fixed-measurement-interval method.

I 21 a_ __

11 / -' .- !

i- i 3.2.4 CE's Position on Definition of Unidentified 14akane l Generic Letter !O-01, defines unidentified leakage est j (a) Imakage into closed systems, suc.h as pump seal or

3 valve packing leaks that are captured, flow metered, i i and conducted to a sump or collection tank, or i (b) leakage into the containment atmosphere from sources f

that are both specifically located and known either I not to interfere with the operations of unidentified  ;

~I-leakage monitoring systems or not to be iroc s I throughwall cr.-k in the piping within the reactor coolant pressure boundary.

l- As shown in Table 5, the LaSalle 2 Technical Specification currently conforms with Ites (b). The Commonwealth Edison Submittals both contain similar statements pertaining to- .

Iten (a). '!he 'one quoted below is from Commonwealth Edison

[ Submittal No. 1.

"The te<.tnical specification definition for identified /

i unidentifieJ 1eakase is in compliance with the definition suggested in the generic letter, except where in paragraph 2a of the staff position, it states that identified 1eakage which is captured to to be flow metered and conducted to a collection tari . The LaSalle techrdt i specifications do not require this leakage to be fi a i metered. Strict compliance with this provicion sight i l require plant modifications to allow meteing of a13 ,

i individual identified leakage paths. Total l ukage is  :

monitored via the drywell equipment drain susp pump ,

discharge flow totalizer meter. Readinge from this totalizer are taken shiftly and the total identified 22

.- T - -. -- -, . . - - . - . . _ . _ . _ - - _ _ _ _ _ _ - _ _ _ - _ _ _

~

's 6 o I

I; ,

' I l

l l

1eakage is determined from these readings. The sump j fill-up rate is monitored continuously on a control roam chart recorder. Since the LaSalle technical i specifications are currently in compliance with Rey Matory Guide 1.45, May, 1973, and the standard technical j specifications, the station does not intend to pursue an amendment in this area."

3.2.5 Operability of Leakene Monitorina Instruments For plants operating with any ICS00 Category D, E. F, )

or G welds, Generic Letter 88-01 requires that at least e

one of the leakage measurement instruments associated  ;

^' with each sump shall be operable. It further requires I

that the outage time for inoperable instruments shall be limited to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or that shutdown shall be immediately initiated.

i Commonwealth Edison stated that this requirement is not >

applicable since LaSalle 2 does not have any IGSOC ,

, Category D, E, F, or G velds. ,

s 3.2.6 Evaluation and Recommendation f-Some confusion exists concerning whether the Technical Specification on leakage detection conforms with t

{ Regulatory Guide 1.45, but in view of their statement (quoted in Section 2.3.4 of this report) tha hoy do l' conform and since the safety evaluation report states -

that leaks across the ' reactor coolant pressure boundary ,

I can be detected as required by Regulatory Guide 1.45,

( acceptance of Commonwealth Edison's position on this q item is recommended; g

y i: 23 i

b e p y Lg q- $ w s ~~e - 9v $ ,--- .- ,-wwe~ v--- -r---w.e---- .- -- ,, - , ,,,,,,,e - +-e,- --- - - - - - - - +

y. s :

o t<.. .

[ '

Although Commonwealth Edison's appoach to monitoring

' leakage (as described in Section 3.2.2 of this report) 8' is excellent, they should still add the requested r requirement pertaining to an increase in excess of 2 I spa requirement which was included in Generic Letter 88-01 after careful consideration by the NRC Staff j ,

concerning the added level of plant safety.

I Technical.y, requirements for frequency of leakage monitoring delineated in Generic Letter 88-01 are not i applicable to LaSalle 2 because that plant does not monitor with the fixed-measureneut-interval method.

Nevertheless it is recommended Ost leakage should be determined at LaSalle 2 at a compt able frequency (i.e.,

approximately every four hours or less) using flow l measurements.

Commonwealth Edison's position pertaining to thi definition of unidentified leakage is in compliance with l portion (b) of the definition provided in Generic k tter 88-01. Thus, acceptance of Commonwealth Edison's position

, on this item is recommended.

Commonwealth Edison's position pertaining to requirements for operability of monitoring instruments is in conformance with the NRC Staff position since they do not have any IGSCC Category 1), E F, or G welds. Thus, acceptance of their position is recommended.

f.

1

4. CONCLUSIONS AND RECOMMENDATIONS 5

Concerning the thirteen NRC Staff positions as delineated in Generic Letter 88-01: Commonwealth Edison endorses twelve of the thirteen NRC e

l 24 t

_ _ _ _ _ L _ _ _ ____ _ _ ___ _ - - -- - - - - - - - - - - -

7., . ,

4 Staff positions (i.e., those pertaining to esterials, processes, water  !

chemistry, weld overlay, partial replacement, stress improvement of cracked weldnents, cleaping devices, crack evaluation and repair I criteria, inspection methods and personnel, inspection schedule, sample  !

expansion, and reporting requirements), however, they applied the  !

provision that a favorable stress distribution would ba considered j I in applying the method for crack evaluation ar.d repair ariteria. They

~

l proposed alternative positions to portions of the NRC Staff position on leakage detection.

Commonwealth Edison has applied design and construction changes and <

l stress improvement treats,ents. As a result, no IGSOC Category D, E,  ;

F, or G welds exist at LaSalle 2. All welds within the scope of d

Generic Letter 88-01 .re either 10900 Category A, B, or C welds. A  !

weld-by-weld list of the'IGSCC classifications and mitigating treatments e i of specific welds was provided, which show that their IGSOC f classifications conform with guidelines provided by Generic Letter q; 88-01. Since all welds have either been replaced or received mitigating l~ treatments (or toth), no additional mitigating treatments are planned ,

except to apply repairs (by weld overlay or other approved method)  :

as needed. However, Hydrogen Water Treatment is currently under evaluation as a long term mitigation effort.

Inspection schedules, methods and personnel, and sample expansion will j conform with guidelines provided in NUREG 0313, Revision 2 and Generic ,

Letter 88-01, according to stecesents in the Commonwealth Edison Submittals. Weld-by-veld int,pection schedules from previous inspections ,

l and plans for the next two refueling outages (numbers 3 and 4) confirm that Commonwealth Edisor.'s planned ISI program conforms with the NRC L Staff position on schedulm.

Commonwealth Edis.on declined to change the Technical Specification an 101. Rather they proposed to include such a statement in the Inservice Inspection Program. Such action was specifically rejected

25 s

d k

~. .. # _. . _ _ . _ _ - _ __ --

.. _ _ n- i L* 1

,{ 4 I \

, in Generic latter 88-01.

l I

Commonwealth Edison stated that leakage detection systems at LaSalle j 2 are 'in conformance with Regulatory Guide 1.45 and that req:irements in the Technical Specifications for plant shut down in the event of )

unidentified leakage in excess of 5 gpa are in conformance with the l

NRC Staff position.

, i Commonwealth Edison also stated that they.do not use. fixed-measurement- l interval method for sump level monitoring, implying that they are exempt from the four hour monitoring requirement. They should, however. l determine leakage (at approximately four hour intervals or less) using f other approaches such as calculations from flow measurements.

Commonwealth Edison's pohition pertaining tc the definition of ,

unidentified leakage is in compliance with portion 2(b) of the  !

, definition provided in Generic Letter 88-01.  ;

I Requirements for operability of monitoring instruments, applicable to plants operating with IGSCC Category D E, F, or G welds, is not applicable because no such welds are present in LaSalle 2.

Commonwealth Edison applied an exception (and proposed an alternative position position) to the one of the leakage requirements outlined in Generic Letter 88-01. Specifically, they declined to change the Technical Specification to include a requirement for plant shut down when the increase in unidentified leakage exceeds 2 spe, claiming that such a requirement would not increase the level of safety. This clain pertaining to safety is in disagreement with considerations by the NRC Staff in the formulation of the Staff position.

1 As a result of this technical evaluation, the following recommendations are made:

l t

26 L

u I

p,. . . _ _ . ...~._ _ .,_ .. _. , _ . . _ _

es . 1

, f. ' . .

t (1) Acceptance of Commonwealth Edison's Classification of welds j U

into the various IGSOC categories since they comply with WRC l Staff guidelines. i t

(2) Acceptance of Commonwealth Edison's plan for mitigating IGSOC ,

since all welds have been replaced or treated (or both) in }

accordance with NRC Staff guidelines.

r (3) Acceptance of Commonwealth Edison's inspection plans for future }

inspections. ,

? .

(4) Rejection of Commonwealth Edison's position concerning changes to the Technical Specification on ISI. Commonwealth ~ Edison shov1d change the LaSalle 2 Technical Specification on ISI

to contain the statement required by Generic Letter 8&-01.

'i ,

(5) Rejection of the exception pertaining to plant shut when the  !

increase in unidentified leakage exceeds 2 spa. Commonwealth

.l-Edison should add the requirement to the Technical Specification ,

I

!I in accotdance with guidelines provided in Generic Letter 8801.

14 .

! (6) Rejection of Commonwealth Edison's position concerning frequency l of sump level monitoring. Commonwealth Edison should add the ,

requirement to the Technical Specification that leakage should .l be determined at approximately four hour intervals or less.

(7) Acceptance of the remaining portions of the Commonwealth Edison ,

Submittal.

I-i ,

l 1- -

t 1

t'

[ 27 i

10 l

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

( .. , , - . . - - - ..

j LF'*O I i

l

5. REFERENCES i I I i

'1

1. " Technical report on Material Selection and Processing Guidelines

,-[ for BWR Coolant Pressure Boundary Piping," NUREG 0313 Revisien i 2. U.S. Nuclear Reguistory Commission, Office of Nuclear Reactor

. Regulation, January, 1988.

i

2. " Investigation and Evaluation of Stress-Corrosion Cracking in Piping of Light Water Reactor Plants," NUREG 0531, U. S. Nuclear Regulatory Commission, February, 1979. i I

3. "NRC Position on IGSCC in BWR Austenitic Stainless Steel Piping," l l Generic Letter 88-01, U.S. Nuclear Regulatory Commission, January ',

! 25, 1988.  ;

I

?

l b

i t

t F

28 ,

s/

. _ . _ . . _ . . . . . . , , .