ML20065C663

Final Technical Evaluation Rept on Response from WPPSS to Generic Ltr 88-01 Pertaining to Washington Nuclear Plant 2

ML20065C663
Person / Time
Site:	Columbia
Issue date:	09/30/1989
From:	Bates R VIKING SYSTEMS INTERNATIONAL
To:	NRC
Shared Package
ML17286A531	List: ML20065C663
References
CON-NRC-03-87-028, CON-NRC-3-87-28 GL-88-01, GL-88-1, NUDOCS 8910030083
Download: ML20065C663 (31)

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I TECHNICAL EVALUATION REPORT ON RESPONSE FROM WASHING MN PUBLIC POWER SUPPLY SYSTEN W GENERIC LETTER 88-01 PERTAINING W THE

! WASHINGMN NUCLEAR PLANT NO. 2 Published September, 1989 prepared by Robert C. Bates Armand Lakner Viking Systens International 2070 Wm. Pitt Way Pittsburgh, PA Prepared for:

U.S. Nuclear Regulatory Commission Washington, D. C. 20555 under Contract No. NRC-03-87-028 Task Order 005 FINAL f1\00) D O N gf }

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4 ABSTRACT This report contains an evaluation of the licensee (Washington Public Power Supply System) submittal for Washington Nuclear Plant No. 2 (WP-2) which was submitted in response to the NRC Generic Letter 88-01 in which WP-2 was requested to (1) Furnish their current plans relating to piping replacement and other maaeures to mitigate IGS00, inspection, repair, and leakage detection. (2) Indicate whether they plan to follow the NRC Staff positions, or propose alternative measures.

WP-2's plans are evaluated in Section 2 of this report in terms of compliance to NRC Stati positions. Section 3 contains an evaluation of an alternative position concerning a change to the Technical Specification on ISI.

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i l The Licensee, Washington Public Power Supply System (VPN-2), submitted a response to the KRC Generic Letter 88-01 pertaining to the austenitic stainless steel piping in the Vaahington Nuclear Plant No. 2 (a BVR i

nuclear power plant). WP-2's response was evaluated in terms of t l (1) Their previous and planned actions to mitigate IGSCC to provide assurance of continued long-term service. (2) Their Inservice Inspection (ISI) Program. (3) Their Technical Specifications pertaining to ISI and their plans to ensure that leakage detection vill be in conformance with the NRC Staff position. (4) Their plans to notify the NRC of significant flaws identified (or changes in the condition of the welds previously known to be cracked) during inspection and l evaluation of such flaws.

I VNP-2 endorses 12 of the 13 NRC Staff positions wh!ch are outlined

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in Generic Letter 88-01, although they applied two provisions. The first is that welds treated with IHSI prior to operation were not given pre-treatment or post-treatment inspections. The second la the requirement for plant shutdown when the increase in the rate of unidentified leakage exceeds 2 gpm over a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period (they apply a 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> period rather than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />). They do not endorse or presently use HVC.

An extensive program of piping replacement, piping removal, corrosion resistant cladding. solution heat treating, and stress improvement was applied so that all welds within the scope of Generic Letter 88-01 are IGSCC Categories A and B. No additional mitigating activities are planned except to repair any velds that develop IGSCC.

WP-2's ten year ISI program conforms with the NRC Staff position on schedules, methods and personnel, sample expansion, and reporting of flaws: however, VNP-2 provided an alternate proposal to the NRC Staff position requiring a change to the Technical Specifications on ISI.

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a CCXITXTS ABSTRACT ............................. i

SUMMARY

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1. INTRODUCTION ......................... 1

2. EVALUATION OP RESPONSE TO GENERIC IIITER 88-01 ........ 2 2.1 Documents Evaluated .........-.......... 3 2.2 Review of VNP-2's Responses to Staff Positions and Implementation of Those Positfons ........... 3 2.3 Review of Classification of Welds , Previous Kitigating Actions, and Previous Inspection Progras .... 5 2.3.1 Summary of IGSCC Classifications ........... 5 2.3.2 Summary of Mitigating Actions ............ 5 2.3.3 Previous Insoection Program ............. 8 2.3.4 Evaluation of Previous Mitigating Actions and Inspections ............... 11 2.4 Current Plans for Kitigating Actions ........... 12 2.4.1 Repairs or Replacements ............... 13 2.4.2 Water Chemistry ................... 13 2.4.3 Evaluation of Conformance to Staff Positions and Recommendation ............ 13 111 l I

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jt 2.5 Current Inservice Inspection Plan . . . . . . . . . . . . . 14 2.5.1 Summary of Inspection Schedule . . . . . . . . . . . . 14 2.5.2 Inaccessible Welds ................. 15 1

2.5.3 Mett.ods and Personnel . . . . . . . . . . . . . . . . 15 2.5.4 Sample Expansion .................. 16 2.5.5 Evaluation and Recommendations . . . . . . . . . . . . 16 2.6 Changes in the Technical Specification Concerning ISI ...................... 17 2.7 Confirmation of Leak Detection in the Technical Specification , . . . . . . . . . . . . . 17 2.7.1 WNP-2's Position .................. 17 2.7.2 Evaluation and Recommendation . . . . . . . . . . . 19 2.8 Plans for Notification of the NRC of Flaws 20 and Evaluation of Flavs ..................

.2.8.1 WNP-2's Position on Flaw Evaluation . . . . . . . . . 20 2.8.2 WNP-2's Position on Reporting of Flaws . . . . . . . . 20 2.8.3 Evaluation and Recommendation . . . . . . . . . . . . 21

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3. ALTERNATIVE POSITION 3.1 Alternative Position Concerning ISI in the .

Technical Specification .................. 21 3.1.1 WNP-2's Position ........ . . . . . . . . . 21 21 3.1.2 Evaluation and Recommendation . . . . . . . . . . . .

4. CONCLUSIONS AND RECOMMENDATIONS . . . . . . . . . . . . . . . . 22

5. REFERENCES .......................... 25 it i

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1. INTRODUCTION I Intergranular stress corrosion cracking (IGSOC) near weldsents in Boiling Water Reactor (BVR) piping has been occurring for almost 20 years.

Substantial efforts in research and development have been sponsored by the BVR Owners Group for IGSOC Research, and the results of this program, along with other related work by vendors, consulting firms and confirmatory research sponsored by the KRC, have permitted the development of KRC Staff positions regarding the IGSCC problass. The

' technical basis for KRC Staff positions is detailed in Reference 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 dVR's and holders of construction permits to t

(1) Furnish their current plans relating to piping replacement, inspection, repair, and leakage detection.

(2) Indicate whether they:

(a) Plan to follow the staff poattions, or (b) Propose alternative measures.

Specifically, Generic Letter 88-01 stated that an acceptable licensee response would include the follo'ving items:

(1) Current plans regarding pipe replacement and/or other measures taken or to be taken to mitigate IGSCC and provide assurance of continued long-tern piping integrity and reliability.

(2) An inservice inspection (ISI) program to be implemented at the

! next refueling outage for austenitic stainless steel piping.

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(3) A change to the Technical Specifications to include a statement in the section on ISI that the inservice inspection program l

for piping vill be in conforiaance with the staff positions on schedule, methods and personnel, and sample expansion.

(4) Confirmation of plans to ensure that the Technical Specification related to leakage detection will be in conformance with the Staff position on leak detection.

(5) Plans to notify the NRC, in accordance with 10CFR50.55a(o),

of any flaws identified that do not meet IVb3500 criteria of Section II of the ASME Code for continued operation without evaluation, or a change found in the condition of the welds previously known to be cracked, and an evaluation of the flaws for continued used operation and/or repair plans.

This report contains a technical evaluation of the response which Washington Public Power Supply System (called WKP-2 or the Supply System ,

in this report) submitted in response to the NRC Generic Letter 88-01 pertaining to the Washington Nuclear Plant No. 2 (hereafter called VNP-2).

2. EVALUATION OF RESPONSE TO GENERIC IEITER 88-01 This evaluation consisted of a review of the response to NRC Generic Letter 88-01 of January 25, 1988 by the Supply System pertaining to WNP-2 to determine if their performance and plans are in conformance with the NRC Staff positions or if proposed alternatives ace uptable.

Proposed inspection schedules and amendments to the Technical Specification were included in the review.

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2.1 Documents Evaluated-4 l

Review was conducted on the information pertaining to WNP-2 provided by the Licensee in the following documents.

(1) " Nuclear Power Plar.t No. 2,' Supply System's Response to NRC's Ge.eric Letter 88-01," Docket No. 50-397, Washington Public Power Supply Systes, P.O. Box 968, 3000 George Washington Way, Richland, Washington 99352, July ?.6, 1988.

(2) " Nuclear Power Plant No. 2, Supply Systen's Response to Generic Letter 8B-01 Request for Additional Information "

Docket No. 50-397, Washington Public Power Supply Systes, P.O. Box 968, 3000 George Washington Way, Richland, Washington 99352, July 20, 1989.

Hereafter, in this report, these vocuments will be referred to as WP-2 Submittels No. I and No. 2, respectively, and collectively as the VNP-2 Submittals.

2.2 Review of WP's Responses to Staff Positions and Implementation of Those Positions.

Generic Letter 88-01 outlines 13 HRC Staff positions pertaining to (1) materials, (2) processes, (3) water chemistry, (4) weld overlay, (5) partial replacement (6) stress improvement of cracked weldsents, (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) reporting requirements. Generic Letter 88-01 states that the licensee should indicate in their submittal whether they endorse these NRO Staf* positions or propose alternative positions. Table 1, constructed from a similar table in WP-2 l

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Summary of WP-2's Responses to Staf f Positions WP-2 Has/Will WP-2 Accepts NRC Applied Consider for Staff Position Staff Position In Past Future Use

1. Materials yes yes yes

2. Processes yes yes yes

3. Water Chemistry no(*) no(") yes(")

4. Weld Overlay yes no yes

5. Partial Replacement yes no yes

6. Stress Improvement of Cracked Weldments yes yes(b) yes

7. Clamping Devices yes no yes

8. Crack Evaluation and Repair Criteria yes no yes

9. Inspection Method and Personnel yes yes yes

10. Inapection Schedrie yes(C) yes yes

11. Sample Expansion yes yes yes

12. Leak Detection yes(d) yes(d) y,,(d)

13. Reporting Requirements yes yes yes (a) Alternate position proposed. Water chemistry guidelines of F"TI NP-4949-SR have been adopted, and the potential use of hydrogen water chemistry continues to be reviewed. See text for additional discussion.

(b) The "yes" for this item is taken from corresponding table in WNP-2 Submittal No. 2, but that response must be in error because no cracked weldments have been reported for WP-2.

(c) Inspection schedules vill comply with tl.e NRC Staff positions, but WP-2 applied the provisions that welds treated with IHSI prior to operation were not UT examined because the velds were not subjected to conditions conducive to IGSCC. See text for additional discussion.

(d) Provisions applied. See text for discussion.

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Submittal No. 2, presents WP-2's responses concoming their positions on the 13 items.

l Note that WP-2 does not presently use Hydrogen Water Chemistry (see Section 2.4.2. of this report for additional discussion).

Also note that WP-2 indicated acceptance of other 12 XRC Staf f l positions, although they applied provisions to two items (i.e.,

inspection schedules and leakage detection). Additional discussion is provided on these items in Sections 2.3 and 2.7, l respectively.

2.3 Review of Classification of Welds. Previous Mitigating Actions, and Previous Inspections I

2.3.1 Suasary of ICSOC Classification WP-2 Submittal No. I contains a sussary of the IGSCC classifications that are assigned to the velds that are within the scope of Generic Letter 88-01. According to that submittal, WP-2 contains 54 IGSCC Category A welds and 148 IGSCC category B welds for a total of 202 within the scope of Generic Letter 88-01. No IGSCC Category C, D, E, F, or G welds exist at WP-2. This results from extensive programs conducted at WP-2 to avoid IGSCC. Part of these were conducted prior to operation in 1983, and part were conducted during the first refueling outage in 1986. These are described in the following section of this report.

2.3.2 Suasary of Mitigatina Actions The large number of IGSCC Category A and B welds (and no welds of other classifications) is the result of extensive acasures taken to mitigste IGSCC at WP-2 as shown in Table 5

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2. his table was constructed, in part, from information provided in WP-2 Supaittel No.1 and, in part from a table in WP-2 Submittal No. 2 which provides a weld-by-weld list of welds, their IGSCC classifications, their materialt, and mitigating treatments.

Note that those seasures include the use of low carbon asterial (from piping replacement), corrosion resistant cladding (CRC), solution heat treating (SHT), and induction heating stress improvement (IRSI) treatments. Many of these measures were taken prior to operation of WP-2. Others were taken after the beginning of operation, but prior to two years of commercial operation. More detailed descriptions are quoted below from WP-2 Submittal No.1:

Pre-Operational Msasures "The core spray piping material outside the reactor pressure vessel (RPV) was changed from stainless steel to carbon steel. The piping inside the RPV is 304L."

"The ten reactor recirculation (RRC) inlet nozzle safe-ends were replaced with 316L material."

" Piping welds associated with the RRC safe-end c.hange out were solution annealed and/or corrosion resistant clad (CRC)."

" Controls were placed on welding to reduce sensitization."

" Induction Heating Stress Improvement (IHSI) was performed on 113 welds made of non-conforming material. Dese welds were not UT examined after IHSI, because they had not been in service and not subject to IGSCC."

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t Table 2 Summary of IGSCC Classifications, Materials of Valds and Associted Components, and Mitigating Treatments Material for No. vith 1 Indicated Comp.___

IGSCC Dia., No. of Indicated Trest _._

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inch Velds _ ht2 Weld 2nd. CRD SHT IHSI A BL ' .. ids, 4 2 508' In 336 Jet Pump Noz 2 336 non non --

b A Butt velds, 24 2 508 In 336 -

RPV Noz/SE A Butt Velds, 12 20 non non non 20 Riser Elbows A Sweep-0-Lets 16 8 non non non 8 Riser / Header A Butt velds 12 10 508' In 316L -

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A Butt velds, 12 10 non non 316L 10 10 Riser /SE c c d B Butt velds various 113 non non non 13 S 333 B Sweep-O-Lets various 12 non non non 12' B Butt velds, 4 23 non non non 23' Cross connect to RWCU Notes and abbreviations:

a. Buttered with Inconel (type not given),

b. Buttered with Inconel (type not given). Post veld heat treated.

c. Treatment was on pipe side only. Five velds treated with CRC + S W.

d. Pre-service IRSI, no post-treatment W inspection.

e. IHSI vithin 2 years of operation. Pre- and Post-treatment UT.

Components: Nom - nozzle, SE - safe end, Sv - Sweep-O-Let Materials non - non-conforming material (either Type 304 or 316 S.S.).

336 - SA 336 F8 (contains 0.025% carbon).

508 - SA 508 C1 2.

In - Inconel (type not identified).

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i "The control rod drive recirculation line was deleted and the RPV nozzle capped with a carbon steel cap."

"The RRC bypass lines were espped with CRC stainless i steel caps."

Pogt-Operations 1 Messure_s "During the first refueling outage, the 35 remaining four-inch and greater non-conforming welds received IHSI.

This occurred .. 16 months after commercial operation.

The velds were UT examined by EPRI certified examiners before and after IHSI. _No cracking was detected."

"The two-inch RRC drain lines (15 welds) were replaced with 316L during the second refueling outage."

2.3.3 Previous Inspection Proarass WP-2 Submittal No. 2 contains a weld-by-weld listing of inspection histories and inspection plans which are summarized in Tables 3a and 3b in this report. These tables show the number of welds of various configurations and IGSCC classification that have been inspected during past inspections (Refueling Outage Nos. 1 through 4). They also contain similar summaries for future plans,- and these plans are discussed in Section 2.5 of this report.

Note that none of the IGSCC Category A welds have been l inspected. The 35 velds that were stress improved in 1986 were each inspected at that time. Aside from those inspections a total of 28 IGSCC Category B welds were inspected during Refueling Outage No. 2, 3, and 4. One of those velds was inspected twice, bringing the total number 8

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f "4 Table Sa Summary of Inspection Schedules for IGSCC Category A Welds at WP-2 .

t No. Inspected / Scheduled Durina Indicated Outane No of " Past Future Confira. Velds RF1 kF2 RF3 RF4 RF5 RF6 RF7 RF8 RF9 R10 R11 R12 R13 Butt welds, 4 4 Jet Pup Noz Butt velds, 2 2 RPV Noz/SE Butt welds, 20 2 3 Riser Elbows

-O-Lets 8 4 4 Sweep Riser / Header Butt velds 10 10 Nor/SE Butt welds, 10 2 Riser /SE Totals 54 6 6 15 4 Notes:

Requirements of Generic Letter 88-01 for IGSCC Category A welds:

25% every 10 years (at least 12% in 6 years).

Refueling Outages dates:

RF # Da e RF # Date RF ( Date RF # Date RF f Date 01 ~04 4/89 07 4/92 10 4/95 12 4/97 02 4/87 05 4/90 08 4/93 11 4/% 13 4/98 03 4/88 06 4/91 09 4/94 9

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I Summary of Inspection Schedules for IGSCC Category B Welds at WP-2 No. Inspected / Scheduled Durina Indicated Outane No. of Post Future Confirm. Velds RF1 RF2 RF3 RF4 kF5 M RF7 R[8 Rf9 R10 R11 Jt12 R13 Butt velds 113 14 8 11 2 18 4 13 8 SI in 1983 i Sweepolets 12 12 3 1 2 3 2 3*

SI in 1986 Butt welds, 23 23 1 3 2 1 6 1 3 Cross connect to RWCU l

Totals 148 35 14 1 14 11 3 22 8 8 13 1 14 l

Notes:

' a. These 3 inspections are repeat inspections of welds scheduled during Refueling Outage No. 4 Requirements of Generic Letter 8S-01 for 1GSCC Category B welds 50% every 10 years _(at least 25% in 6 years).

Refueling Outages dates:

RF # Date RF f Date RF f Date RF # Date RF # Date 01 4/li6 04 4/89 07 4/92 10 ~4/95 12 4/97 02 4/87 05 4/90 08 4/93 11- 4/96 13 4/98 03 4/88 06 4/91 09 4/94 10

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• l of weld-inspections during those three refueling outages to 29.

2.3.4 Evaluation of Previous Mitigatinn Actions and_ Inspections Approval of IGSOC classification of welds at VNP-2 is recommended. This recommendation is based on reasons given '

in the following paragraphs.

Fif ty-four velds either contain resistant material or have been clad (with corrosion resistant cladding) or have been solution heat treated. These welds are correctly classified 4 as IGSCC Category A. Thirty-five welds were treated with IRSI and given pre-treatment and post-treatment UT inspections so that they qcalify for classification as IGSOC Category B welds. The remaining 113 welds, were given pre-operational IHSI treatments and also qualify as IGSOC Category B welds even though they were not UT inspected after the IHSI treatments. The justification for these classifications is discussed in the remainder of this section.

Concerning pre-IRSI and post-IRSI inspections of welds treated prior to operation Section 5.3.1.7 of NUREG 0313 Revision 2 states:

" Stress improved welds that were not inspected after the SI treatment are considered to be Category G weldsents urtil the post-SI inspection has been performed."

In addition, foot note # 1 in Table 1 of NUREG 0313. Revision 2 (the same table is included as Table 1 in Generic Letter 88-01) states:

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"All velds in nrn-resistant material should be inspected j after a stress improvement process as part of the process.

Schedules shown should be followed after this initial inspection."

WP-2 takes exception to these statements for velds that were treated prior to operation. Specifically, they stated:

"The Supply Systes takes exception to the requirement of note 1. Table 1 of Generic Letter for velds receiving stress improvement prior to operation. The purpose of the UT examination is to detect IGSOC. Prior to operation, the welds are not subjected to the conditions I conducive to IG5CC, Requiring a UT examination to detect IGSCC after a pre-service stress improvement (SI) would not increase the piping integrfty or reliaH 11ty."

i Clearly, WP-2 is justified in their position since the requirement for post-IHSI is intended to apply only to velds treated after commercial operation as indicated in the following statement, quoted from Section 5.3.1.2 of NUREG 0313, Revision 2:

"IGSCC Category B Weldsents are those not ande of resistant materials but have had an SI performed either before service or within two yearc of operation. If the SI is performed after plant operation, a ITT examination after SI to ensure that they are not cracked j is required."

2.4 Current Plans for Mitigation Actions l

The only plans presented by WP-2 for additional mitigating actions l-

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't ares (a) Perform repairs as needed. (b) Use controlled water chemistry (not HWC). These plans are discussed below, i

2.4.1 Repairs or Replacements WP-2 Submittal No.1 contains the following statement l "In the event it becomes necessary to repair or replace any additional stainless steel piping, the Supply System w111 incorporate appropriate state-of-the-art measures I delineated in the NRC staff positions listed on page 2 of the Generic Letter."

2.4.2 Water Chemistry WP-2 Submittal No.1 contains the following statements pertaining to water chemistry:

"The Supply System has reviewed the use of HWC at WP-2 and has concluded that this aethod of IGSCC mitigation vill not be implenented at WP-2 at this time.

The Supply System will continue to monitor industry experience with HWC as it has all IGSCC issues by continued participation in appropriate industry committees and workshops and by review of published literature."

"The Supply System has adopted the BWR Normal Water Chemistry Guidelines EPRI NP-4949-SR, for its chemistry control program at WP-2."

2.4.3 Evaluation of Conformance to Staff Position and Recommendation Since extensive mitigation actions have already been applied 13

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i at WP-2 with the result that all welds within the scope of Generic Letter 88-01 are IGSCC Categories A and B, acceptance of the WP-2 position on additional mitigation activities is recommended.

2.5 Current Inservice Inspection Plan 2.5.1 Summary of Inspection Schedule WP-2 Submittal No.1 contains the following statement:

"At least 25% of the 148 Category B welds and 12% of the 54 Category A welds will be examined within the next six years. Within ten years of the next refueling outage at least 50% of the Category B welds and at least 25%

of the Category A welds will be examined. 'lhis augmented ISI program will be implemented at the next scheduled refueling outage (Spring, 1989). This schedule complies with the staff position on inspection schedules, except for post SI UT as described ..."

As previously indicated. WP-2 Submittal No. 2 contains a list of inspections planned (on a weld-by-veld basis) for Refueling Outages Nos. 5 through 13(1990 through 1998), although they stated that this schedule may be modified by substituting welds or changing the outage in which'they are examined. Tables 3a and 3b of this report contain summaries of those inspection schedules along with summaries of previous inspection schedules j and the requirements for inspection of IGSCC Categories A and B welds as delineated in Generic Letter 88-01.

l As can be seen through an examination of Tables-3a apJ 3b, the statement quoted from WP-2 Submittal No.1 is confirmed 14

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, l by the actual inspection schedules. Note that 57% of the IGS00 Category A welds are scheduled for inspection during the nort four refueling outages. Note also that 61% of the IGSOC Category B welds are scheduled for inspection during the 10 year period covered by Refueling Outages Nos. 4 through 13 (1989 through 1998) with 39% echeduled for the first six years of that 10 year period. These percentages exceed the requirements of Generic Letter 88-01.

2.5.2 Inaccessible Welds VNP-2 Submittal No. 2 states:

"All welds within the Generic Letter scope are UT ins pectable."

2.5.3 Methods and Personnel Inspections vill be performed in accordance with requirements of Generic Letter 88-01 and KUREG 0313. Revision 2 as indicated in the following statement from VNP-2 Submittal No. 1:

"The examinations performed under the scope of the Generic Letter will comply with the requirements of ASME Section II he committed to by the WNP-2 Inservice Inspection Program Plan. The applicable Edition and Addenda is the 1900 Edition, Winter 1980 Addenda. This Code requirement has been augmented by the requirement to qualify the detailej procedure, equipment and examination personnel by the formal program conducted in accordance with the NRC/EPRI/BWROG Coordination Plan at the EPRI NDE Center in Charlotte, North Carolina. This complies with the staff position on methods and personnel."

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2.5.4 Sample Expansion -

WP-2 plans to comply with the NRC Staff position on semple expansion. Specifically, WP-2 Submittal No.1 states:

"If one or more cracked welds are found in Category A, i l B or C during a sample inspection, an additional sample of welds vill be examined during that outage. The sample vill contain the approxiaste same number of welds as the original sample."

l "Unless there exists a technical reason to select a l different distribution, the additional sample vill be similar in distribution (pipe sire, systes and location) to the original sample. If additional cracked welds l

! are found, all welds in that ICSCC category will be enained unless the sample was chosen on a technical

! 'sasis. In that case all the IGSCC category welds that meet that technical basis vill be examined. This complies with che stati position on sample expansion. Although WPN-2 does not have any Category E or F welds at this time, the Supply Systes will comply with the staff's position on increased saiple provisions if the situation becomes applicable."

2.5.5 Evaluation and Recommendation Since WP-2's positions on inspection schedules, methods and personnel, and sample expansion comply with the NRC Staff positions, acceptance of WP-2's positions is recoseended.

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1 I 2.6 Channes in the Technical Specification Concerninn ISI )

I VNP-2 proposed an alternative position to the NRC Staff position i concerning a change to the Technical Specification. This alternative position is discussed in Section 3 of this report.

2.7 Confirantion of Leak Detection in the Technical Specification 2.7.1 VNP-2's Position The VNP-2 Submittal states the following.

"The Supply Systes leaksge criteria per Technical Specification 3.4.3.2 is in agreement with the staff position on leak detection for Category A and B welds.

In the event Category D, E F, or G velds develop at WNP-2, the leak detection criteria vill be evaluated for compliance with the staff position."

Additional information concerning leakage detection la presented in Table 4 which was constructed from a similar table in WNP-2 Submittal No. 2 which contains the following explanatory notes:

Concernina the Technical Specification

'WP-2 is a NUREG-0123 Standard Technical Specification Plant."

Concernina Leakage Limits "The interval used to limit leakage to less than 17

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I' Table 4 Licensee Positions on Leakage Detection 58)

Already TS vill be Alternate (*)

Contained Changed Position D Position in TS to Include Proposed i

1. Conforms with Position C of yes - -

Regulatory Guide 1.45

2. Plant shutdown should be initiated whent (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 /> yes(*) - -

or less, an increase is indicated in the rate of unidentified leakage in excess of 2 gpm, or (b) the total unidentified leakage yes - -

attains a rate of $ gpm.

3. Leakage munitored at four hour yes(a) , _

intervals or less.

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.

5. Provisions for shutdown within 24 Not applicable - WP-2 does hours due to inoperable measurement not have any IGSCC Category D, E, F, or G welds, instruments in plants with Category

• D, E, F, or G welds.

(a) See text for notes.

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, i 2 spa is based on a 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> interval and part of NUREG-0123, ILO 3.4.3.2."

Concerninn Frequency of Leakane Measure.nants "WP-2 continuously records the led rate and performa a channel check on a 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> intertu."

2.7.2 Evaluation and Reconnendation o _ __

Although WP-2 Submittal No I states that the WP-2 Tec51 cal Specification on leakage detection is in compliance with the NRC Staff position, one deviation does exist. That deviation pertains to limiting the rate of increase in  !

unidentified leakage. The WP-2 Technical Specification i requires plant shutdown when, within a pulod of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> (rather than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or less, as required by Generic Letter 88-01), an increase in the rate of unidentified leakage in excess of 2 gpm is indicated. This is less restrictive than -

the NRC Staff requirement. so rejection of the WP-2 position '

on this item is recommended. It te further recommended that g WP-2 shonid amend their Technical Specification on leakage detection to comply with the NRC Staff position on limiting the rate of increase of unidentified leaxage in accordance with the requireaents delineated in Generic Le:ter 88-01.

Acceptance of the remaining portions of the WP-2 Technical Specification on leakage detection is recommended, six "

those positions comply with the NRC Staff position. However, in the event that any welde are reclassified to IGSCC Categories D, E, F, or G. WP-2 should (as they promised) change their Technical Specification to comply with the NRC Staff requirement for operability of leakage monitoring instruments.

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-______r -_ __

g 2.8 Plans for Notification of the NRC of F1sws l

and Evaluation of Flavs

. 2.8.1 WNP-2's Position on Fisw Evaluation

'lNF 'ubmittal No. I states the following "The Supply System will use ASME Section II Sectin..

IVB-3600 of the 1986 Edition of ASME Boiler and Pressure Vessel Code for methods and criteria for crack evaluation i and repair."

1 WNP-? Submittal No. 2 states:

"The Supply Systes has adopted the method suggested in the Generic Letter 88-01 for determining che crack growth rate."

2.8.2 WNP-2's Position on Reportina of F1sws_

WNP-2 Submittal No. I states that they comply with the staff

. position on reporting requirements. Specific. ally, that submittal states:

"The Commission will be notified if a flaw is found that does not meet Sectinn II, IWB-3500 criteria ~ . continued operation without evaluation. Prior to reseg operation, an evaluation.of the flaw justifying continued l operation and/or the repair plans will be submitted to the Commission for approval. Resumption of operation will not be ellowed until Commission approval has been granted. This coeplies with the staff position on p

l reporting requirements."

1.

20 L

l

• e , ,- - ,

...q 2.8.3 Evaluation and Recommendation l

. WP-2 positions on crack evaluation and reporting of flaws-are in conformance with the NRC Staff position, so acceptance of these positions is recommended.

3. ALTERNATIVE POSITION 4 3.1 Alternative Position Concernina ISI in the

-p Technical Specification 3.1.1 WP-2's Position '

WP-2 Submittal _ No. I contains the following statement:

"The Supply Systes does not- see a need to revise the WP.-2 Technical Specification cs recommended. The WP-2 ' Inservice Inspection Program Plan is a detailed,-

comprehensive document containing all inservice inspection requirements. Thia document contaia Section'II requirements, augmented NRC requirements and Supply System augmented-requirements. This document-has been submitted

for .NRC review and -approval has b'een received. The

- Inservice Inspection Program for Generic Letter _88-01 i has been revised to include all augonted requirements as committed to by. this esponse.1 The. revised program v111=be submitted to the NRC upon acceptance of this - i response to Generic Lett e 88-01."

j . 3.1.2 Evaluation and Recommendation WP-2's~ ISI program-inclu' ding the incorporation of the Jaugmented requirements is excellent, and-the continuance-L 21 L

'- > <s .- - - , . - -. .-

s yi of this program is recommended. However, this does not' adequately fulfill or substitute for the requirement specifically delineated in Generic Letter 88-01 to change the Technical Specification to include a statement that the section on ISI v111 conform with the NRC Staff position on schedule, methods and personnel, and sample expansion. Thus rejection of the WNP-2 position is recommended. 'WP-2 dould amend the Technical Specification to include a statearnt that their ISI program will conform with the NRC Staff positions on inspection schedules, methods and personnel, and sample expansion as delineated in Generic Letter 88-01.

4. CONCLUSIONS AND REC 069ENDATIONS Concerning the thirteen NRC Staff positions as delineated in Generic Letter 88-01: WNP-2 endorsed twelve of the thirteen NRC Staff positirans-

.(i.e., those pertaining to materials, processes, weld overlay, partial replacement, streus improvement of cracked weldsents, clasping devices, crack evaluation and repair criteria, inspection method and peraonnel,

.l inspection a sedule, sample expansion, leakage detection, and reporting requirements), although they applied provisions to those on inspection

! . schedules and leakage' detection. They do not endorse or presently use (or intend to use) hydrogen water chemistry, although they do follow

-!! EPRI guidelines for water chemistry.

I WNP-2 supplied a list of welds that are covered in'the scope of Generic a

-Letter 88-01 which shows materials and mitigating treatments for

.} each weld. Their program for sitigating IGSCC has included piping I -replacement, solution heat treating, corrosion resistant cladding, and induction heating stress improvement (IBSI). Consequently, all b welds are classified as IGSCC Categories-A and B. No additional sitigating actions are pisoned except to repair welds (if the need i

arises) and to perform inspections. They will continue to use

. 22

[ .

?

controlled water chemistry, per industry standards.

l A ten year Inservice Inspection Program (ISI) has been developed for WP-2 which complies with the requirements of Generic Letter 88-01 l pertaining to schedule, methods and personnel, sample expansion, and plans for reporting flaws. Their provision to their endorsement of the NRC Staff position on inspection schedules is that 113 of the welds were treated with IHSI prior to operation, and these welds were not given pre-IHSI or post-IHSI inspections. This is an acceptable provision, and those welds still qualify for the IGSCC Category B classifications.

)

WP-2 declined to change the Technical Specification on ISI. Rather they proposed to rely on their Inservice Inspection Program. Such a position has already been considered and rejected by the NRC Staff position in the formulation of Generic Letter 88-01.

WP-2 stated that the Technical Specification pertaining to leakage detection is in compliance with NRC Staff positions v leakage.

However, there is actually one deviation. WP-2 requires pirat shutdown whenever any measuring instrument indicates an increase in the rate of unidentified leakage of 2 gpm in a four hour period (rather than in a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period, or less as required by Generic Letter 83-01).

The WP-2 position is less restrictive than that required by Generic Letter 88-01. Since WP-2 does not currently have any IGSCC Category D, E, F, or G welds, they are exempt from the requirements for operability of monitoring instruments that are detailed in Generic Lotter 88-01. However, WP-2 stated that if any welds are reclassified j as IGSCC Category D, E, F, or G in the future, they will sake required changes to the Technical Specification at that time.

As a result of this technical evaluation, the following recommendations l are made.

l l

, 23

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

[ .*

.l. .

..i (1) Acceptance of WP-2's classification of welds into IGSOC Categories A and B. Also, acceptance of WP-2's position on their program for mitigating IGSCC is recommended.

(2) Acceptance of WP-2's ten year ISI program, including their positions on inspection schedules, methods and personnel, and sample expansion.

(3) Rejection of WP-2's position concerning a change to the Technical Specification on ISI. WP-2 should amend their Technical Specification to include a statement that their ISI program will comply with the NRC Staff position on inspection schedules, methods and personnel, and sample expansion as delineated in Generic Letter 88-01.

(4) Acceptance of WP-2's position concerning leakage detection, except for that portion concerning the requirements for plant shutdown when an increisse in the rate of unidentifici leakage occurs. The WP-2 Technical Specification should be amended to require that plant shutdown should be initiated when, within any period of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or less (rather than 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> as currently required by WP-2), an increase is indicated in the rate of unidentified leakage in excess of 2 gpm.

I l

(5) Acceptance of the remaining portions of the WP-2 Submittal.

l.

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.. . .-- = . -- - . . . . . .

I a: 1 5

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5. REFERENCES

)

1 I

1. " Technical report on Material Selection and Processing Guidelines for BWR Coolant Pressure Boundary Piping " NUREG 0313 Revision 2 U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation, January, 1988.

2. " Investigation and Evaluation of Stress-Corrosion Cracking in Piping of Light Water Reactor Plants," NUREG 0531, U. S. Nuclear Regulatory C u a.:fon. February, 1979.

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

Generic 1,etter 88-01, U.S. Nuclear Regulatory Commission, January 25, 1988.

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