ML20129B875

Safety Evaluation Accepting First 10-year Interval ISI Program Plan Addl Request for Relief

ML20129B875
Person / Time
Site:	Grand Gulf
Issue date:	10/18/1996
From:	NRC (Affiliation Not Assigned)
To:
Shared Package
ML20129B644	List: ML20129B639 ML20129B875
References
NUDOCS 9610230139
Download: ML20129B875 (18)

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UNITED STATES s* NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. SegeH001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION OF THE FIRST 10-YEAR INTERVAL INSERVICE INSPECTION PROGRAM PLAN ADDITIONAL P.EDUESTS FOR RELIEF l ENTERGY OPERATIONS. INC.

l GRAND GULF NUCLEAR STATION. UNIT 1 DOCKET N0. 50-416 i

1.0 INTRODUCTION

Sy letters dated May 21 and July 31, 1996, you requested relief from the j requirements of Section XI, " Rules for Inservice Inspection of Nuclear Power Plant Components," of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) for the first 10-year inservice inspection 4 (ISI) interval in accordance with Paragraphs 50.55a(g)(5)(iv) and (g)(6)(1) of

?- 10 CFR Part 50. ,

S The Technical Specifications (TSs) for Grand Gulf Nuclear Station (GGNS), ,

i Unit I states that the inservice inspection of the ASME Code Class 1, 2, and 3 components shall be performed in accordance with Section XI of the ASME Code 1 and applicable addenda as required by 10 CFR 50.55a(g), except where specific 1 written relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(i). The 10 CFR 50.55a(a)(3) states that alternatives to the 4 requirements of paragraph (g) may be used, when authorized by the Commission, a if (i) the proposed alternatives would provide an acceptable level of quality i and safety or (ii) compliance with the specified requirements would result in

hardship or unusual difficulty without a compensating increase in the level of quality and safety.

Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1,.2, and 3 components (including supports) shall meet the requirements, except the design and access provisions and the pre-service examination requirements, set forth in the ASME Code,Section XI to the extent practical within the limitations of design, geometry, and materials of construction of the components. The regulations require that inservice examination of components and system pressure tests conducted during the first 10-year interval and subsequent intervals comply with the requirements in the latest edition and addenda of Section XI of the ASME Code incorporated by reference in 10 CFR 50.55a(b) 12 months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. The applicable edition of Section XI of the ASME Code for the GGNS first 10-year ISI interval is the 1977 adition through the summer 1979 addenda. The GGNS first 10-year interval commenced on July 1,1985.

ENCLOSURE I l

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Pursuant to 10 CFR 50.55a(g)(5), if the licensee determines that conformance l with an examination requirement of Section XI of the ASME Code is not

practical for its facility, information shall be submitted to the Commission  ;

l in support of that determination and a request made for relief from the ASME l

' Code requirement. After evaluation of the determination, pursuant to 10 CFR 50.55a(g)(6)(1), the Commission may grant relief and may impose l alternative requirements that are determined to be authorized by law, will not

endanger life, property, or the common defense and security, and are otherwise

in the public interest, giving due consideration to the burden upon the j licensee that could result if the requirements were imposed.

l In a letter dated May 21, 1996, Entergy Operations, Inc. (licensee), submitted i a new first 10-year ISI interval request for relief and 14 revised requests

! for relief from the ASME Code,Section XI, requirements for GGNS, Unit 1. The l licensee provided additional information by its letter dated July 31, 1996. ,

! 2.0 EVALUATION AND CONCLUSIONS i The staff, with techni:a1 assistance from its contractor, the Idaho National

! Engineering Laboratory (INEL), has evaluated the information provided by the i licensee in support of its first 10-year inservice inspection interval new and 14 revised requests for relief from ASME Code,Section XI, requirements for GGNS, Unit 1. Bued on the information submitted, the staff adopts the contractor's conclusions and recommendations presented in the Technical ,

Evaluation Report (TER) attached. i The staff has reviewed the licensee's requests for relief from the first 10-year interval Code examination requirements for GGNS and cor.1Indes that the Code examination requirements are impractical for the wolds co. .ained in Request for Relief I-00019. Compliance with the code would require redesign or replacement of the affected component, therefore, relief is granted pursuant to 10 CFR 50.55a(g)(6)(i).

For Requests for Relief I-00002, I-00007, I-00008,1-00009,1-00010, I-00012, I-00015, and I-00018, the staff concludes that the technical content did not change and that relief remains granted pursuant to 10 CFR 50.55a(g)(6)(1), as l determined in the previous Safety Evaluations (SEs) dated July 22, 1986, August 5,1986, July 22,1986, April 15,1992, May 25,1993, July 22,1986, September 29, 1986, and August 15, 1986, respectively. The details of the relief requests are given in the attached TER.

For Request for Relief I-00024, the licensee request to perform the pump / valve internal examination in accordance with the requirements of Table IWB-2500-1, Examination Categories B-L-2 and B-M-2 contained in the 1989 Edition of the ASME Code in lieu of the 1977 edition through the summer 1979 addenda. The  !

staff concludes that the licensee's proposed use of later editions of ASME Section XI provide an acceptable level of quality and safety for the Code requirements contained in Request for Relief I-00024. Therefore, pursuant to 10 CFR 50.55a(g)(4)(iv) the use of the 1989 Edition ASME Code,Section XI is approved for Request for Relief I-00024 provided that all associated requirements of the 1989 Code are met. ,

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The licensee has deleted Requests for Relief I-00004,1-00005, and I-00006,

,l from the GGNS, Unit 1, first 10-year inservice inspection program plan,

because the reliefs addresses Category B-A, Item Bl.10 welds and are revoked pursuant 10 CFR 50.55a(g)(6)(ii)(A)(1). The licensee stated ? Mat the augmented requirements of 10 CFR 50.55a(g)(6)(ii)(A)(2) Augee ted Reactor 1

] Vessel Examination have not been met, and will be addressed v future l

, correspondence. Requests for Relief I-00011 and I-00017 are to longer l required and the licensee's revisions of the reliefs removed them from the GGNS, Unit 1, first 10-year inservice inspection program plan.

1 With respect to the reliefs granted pursuant to 10 CFR 50.55a(g)(6)(1), the -

staff has determined that the requirements of the code are impractical and the I

relief granted and alternatives imposed are authorized by law, will not endanger life, property or the common defense and security, and are otherwise

in the public interest, giving due consideration to the burden upon the i

license that could result if the requirements were imposed.

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! Principal Contributor: Tom MO.ellan l j Dated: October 18, 1996 4

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TECHNICAL EVALUATION LETTER REPORT ON THE FIRST TEN-YEAR INTERVAL INSERVICE INSPECTION ADDITIONAL RE00ESTS FOR RELIEF EM i ENTER 6Y OPERATION INC..

GRAND GULF NUCLEAR STATION. UNIT 1.

D0CKET NUMBER: 50-416

1.0 INTRODUCTION

The licensee, Entergy Operations Inc., submitted one new and fourteen revised ,

requests for relief from American Society of Mechanical Engineers (ASME)

Boiler and Pressure Vessel Code,Section XI, requirements in a letter dated May 21, 1996. On July 25, 1996, a conference call with the licensee was held requesting additional information. The licensee submitted the required information in a letter dated July 31, 1996. The Idaho National Engineering i Laboratory (INEL) staff has evaluated the subject requests for relief in the following sections.

2.0 EVALUATION The Code of record for Grand Gulf Nuclear Station, Unit 1, first 10-year inservice inspection (ISI) interval, which commenced on July 1, 1985, is the 1977 Edition through Summer 1979 Addenda of ASME Section XI. The information provided by the licensee in support of the requests for relief has been evaluated and the bases for disposition are documented below.

Reauest for Relief I-00002. Rev. 2. Examination Cateaory C-F. Item C5.21. I A.

Pressure Retainina Weld in Pioino >1/2". Nominal Wall Thickness Reque.st for Relief I-00002, was previously evaluated and granted in a Nuclear Regulatory Commission (NRC) SER dated July 22, 1986.  !

Revision 2 incorporates changes to the Grand Gulf Nuclear Station (GGNS), Unit 1, pressure testing program resulting ft ;m NRC approval for use of Code Case N-498-1.

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ENCLOSURE 2 l

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i l The hydrostatic test was used as part of the original basis for j approval. However, the use of Code Case N-498-1 in lieu of the l Code-required hydrostatic test requirements does not effect the

evaluation of Request for Relief I-00002. Therefore, it is recommended that relief remain as granted in the NRC's SER dated j Jciy 22, 1986, pursuant to 10 CFR 50.5Sa W)(6)(i).

B. Egouest for Relief I-00004. Rev. 3. Examination Cateaory B-A. Item Bl.10.

a Reactor Vessel Shell Welds

Request for Relief I-00004 was previously granted in an NRC SER dated l July 22, 1986. This relief addressed a Category B-A, Item Bl.10 weld and

{ therefore was revoked by 10 CFR 50.55a(g)(6)(ii)(A)(1). Revision 3 l

simply deletes Request for Relief I-00004 from the Grand Gulf Nuclear Station, Unit 1, first 10-year inservice inspection program plan. The licensee stated that the augmented requirements of 10 CFR 50.55a(g)(6)(ii)(A)(2) have not been met, and will be addressed in future correspondence C. Reauest for Relief I-00005. Rev. 2. Examination Cateaory B-A. Item Bl.10.

Reactor Vessel Shell Welds Request for Relief I-00005 was previously granted in an NRC SER dated July 22, 1986. This relief addressed a Category B-A, Item Bl.10 weld and therefore was revoked by 10 CFR 50.55a(g)(6)(ii)(A)(1). Revision 2 ,

simply deletes Request for Relief I-00005 from the Grand Gulf Nuclear Station, Unit 1, first 10-year inservice inspection program plan. The licensee stated that the augmented requirements of 10 CFR 50.55a(g)(6)(ii)(A)(2) have not been met, and will be addressed in future correspondence.

D. Reauest for Relief 1-00006. Rev. 2. Examination Cateaory B-A. Item Bl.11.

Reactor Vessel Circumferential Shell Welds Request for Relief I-00006 was previously granted in an NRC SER dated July 72, 1986. This relief addressed a Category B-A, Item 81.11 weld and

J therefore was revoked by 10 CFR 50.55a(g)(6)(ii)(A)(1). Revision 2 simply deletes Request for Relief I-00006 from the Grand Gulf Nuclear i Station, Unit 1, first 10-year inservice inspection program plan.

E. Reauest for Relief I-00007. Rev. 2. Examination Cateaory B-J. Pressure

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Retainina Welds in Pinina i

Request for Relief I-00007, was previously evaluated and granted in an NRC SER dated August 5, 1986. Revision 2 incorporates changes to the Grand Gulf Nuclear Station (GGNS) Unit 1, pressure testing program resulting from NRC approval for use of Code Case N-498-1. The hydrostatic test was used as part of the original basis for approval.

However, the use of Code Case N-498-1 in lieu of the Code-required hydrostatic test requirements, as allowed by the NRC, does not effect the evaluation of Request for Relief I-00007. Also, Weld W-12 is deleted from the request due to the licensee obtaining greater than 90% coverage.

An editorial change was made correcting a system identification number which has no effect on the disposition of the relief. Therefore, it is recommended that 'elief remain as granted in the NRC's SER dated August 5, 1986, pursuant to 10 CFR 50.552(g)(6)(1).

F. Reauest for Relief I-00008. Rev. 3. Examination Cateaories B-G-2 and B-0.

Itens B7.10 and B14.10. Pressure Retainina Boltina 2 In. and Smailer and Pressure Retainina Welds in Control Rod Drive Housinas Code Reouirement: Table IWB-2500-1, Examination Category B-G-2, Item B7.10 requires a VT-1 visual examination of reactor vessel control rod drive bolting.

Table IWB-2500-1, Examination Category B-0, Item B14.10 requires 100%

volumetric or surface examination of control rod drive housing welds in accordance with Figure IWB-2500-18.

Licensee's Code l'.elief Reauest: Relief is requested from the Code-required VT-1 visual examination of the reactor vessel control rod drive

bolting and volumetric and surface examination of control rod drive housing welds.

Licensee's Basis for Reauestino Relief (as stated):

"If the welds and/or the bolts fail while in operation. The maximum leakage rate, by calculation, will occur at the peripheral control rod drive (CRD) housing tube-to-flange weld. The maximum calculated leak rate is to 681 gpm. By criteria established in Subarticle IWB-1200,

" exemptions by make up capacity," the normal make up capability for GGNS is 878 gpm, which exceeds the calculated maximum leakage.

"The CRD housing supports would prevent ejection of the housings in case of total failure of the welds or bolts.

" Removal of the CRD support structure would result in hardships with no compensatory increase in the level of quality safety."

In response to questions from the Nuclear Regulatory Commission, the licensee responded with the following:

"In refueling outages 4 and 5, GGNS has changed out 16 and 22 CRD drive mechanisms, respectively. Visual examinations for bolting associated with forty (40) CRD mechanisms have been performed (a total of 320 bolts). Twenty-eight mechanisms are scheduled to be changed out in our upcoming refueling outage. Our current plans are to examine all removed bolting and replace with new bolting."

Licensee's Proposed Alternative (as stated):

"The welds and bolted connections will be subject to pressure testing in accordance with the requirements of ASME Section XI, Table IWB-2500-1 and ASME Section Code Case N-498-1. Permission is requested to allow performance of pump / valve internal examination in accordance with the requirements of Table IWB-2500-1."

Evaluation: Request for Relief I-00008, was previously evaluated and granted in an NRC SER dated July 22, 1986. Revision 3 incorporates changes to the Grand Gulf Nuclear Station (GGNS), Unit 1, pressure testing program resulting from NRC approval of Code Case N-498-1 for use.

The conditions of the original relief were; "l) performance of the code-required pressure test, and; 2) the Code-required 'xaminations e are performed on the accessible areas if CRD support structure or CRDs are removed for other maintenance activities." Grand Gulf has implemented Code Case N-498-1 satisfying Code-required hydrostatic test requirements.

Also, the licensee has been visually examining the bolting as it has been

1 l removed. Therefore, it is recommended that relief remain as granted in

! the Nuclear Regulatory Commission's SER dated July 22, 1986, pursuant to j 10 CFR 50.55a(g)(6)(1).

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j G. Reauest for Relief I-00009. Rev. 3. Examination Cateaories C-C and C-G, Items C3.40 and C6.10 Class 2 Pumo Intearally Welded Attachments and l

] Pressure Retainina Welds Request for Relief 1-00009, was previously evaluated and granted in an l NRC SER dated April 15, 1992. Revision 3 incorporates changes to the

Grand Gulf Nuclear Station (GGNS), Unit 1, pressure testing program l resulting from NRC approval for use of Code Case 5-498-1. The l hydrostatic test was used as part of the original basis for approval.

l However, the use of Code Case N-498-1 in lieu of the Code-required I hydrostatic test requirements does not effect the evaluation of Request for Relief I-00009. Also, Weld SB-4 is deleted from the request due to the licensee obtaining greater than 90% coverage. An editorial change  :

was made correcting a component identification number with has no effect on the disposition of the relief. Therefore, it is recommended that relief remain as granted in the NRC's FER dated April 15, 1992, pursuant to 10 CFR 50.55a(g)(6)(1).

H. Reauest for Relief I-00010. Rev. 6. Examination Cateoories B-J. C-F-1.

and B-K-1. Items B9.11. C5.22 and B11.10. Pressure-Retainina Welds in Class 1 and 2 Pirina and Intearally Welded Attachments Request for Relief I-00010 was previously evaluated and granted in an NRC SER dated May 25, 1993. Revision 6 incorporates changes to the Grand Gulf Nuclear Station (GGNS), Unit 1, pressure testing program resulting

. from NRC approval for use of Code Case N-498-1. The hydrostatic test was used as part of the original basis for approval. However, the use of Code Case N-498-1 in lieu of the Code-required hydrostatic test requirements does not effect the evaluation of Request for Relief I-00010. Revision 6 added Welds G119W32 and G00lW39, and Lugs G3-Al-F, G, H, I and G4-B1-H, J, K, L to the request. However, the addition of these items does not affect the technical content of the request since the-

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coverage and nature of the limitations are the same. Also, Weld l G33G002W179 is deleted from the request due to the licensee obtaining greater than 90% coverage and Weld G001-W40 examination coverage was 4

changed to reflect the actual volume examined. Editorial changes were made with no effect on the disposition of the relief. Therefore, the I

conclusions of the previous evaluation have not changed and relief should 1

remain as granted in the NRC's SER dhted Nay 25, 1993, pursuant to 10 CFR  ;

} 50.55a(g)(6)(1).

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I. Rea> Jest for Relief I-00011. Rev. 6. Examination Cateaory C-F. Item C5.21.

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Class 2 Pressure Retainina Welds  !

i Request for Relief I-00011, was previously evaluated and granted in an l NRC SER dated July 22, 1986. Revision 2 deletes this request since the j actual examination coverage obtained is essentially 100% (> 90%). I J. Reauest for Relief I-00012. Rev. 2. Examination Catecory B-J. Pressure Retainina Welds in Pinina >4" Nominal Pine Size Request for Relief I-00012, was previously evaluated and granted in an NRC SER dated July 22, 1986. Revision 2 incorporates changes to the Grand Gulf Nuclear Station (GGNS), Unit 1, pressure testing program resulting from NRC approval of Code Case N-498-1 for use. The hydrostatic test was used as part of the original basis for approval.

However, the use of Code Case N-498-1 in lieu of the Code-required hydrostatic test requirements does not effect the evaluation of Request for Relief I-00012. Therefore, it is recommended that relief remain as  !

granted in the NRC's SER dated July 22, 1986, pursuant ti 10 CFR 50.55a(g)(6)(1).

K. Reauest for Relief I-00015. Rev. 2. Examination Cateaories B-A. B-D. and B-F. Items Bl.22. Bl.30. B3.90. B3.100. and B5.10 Pressure Retainina Weld in the Reactor Vessel. Reactor Vessel Nozzles. and Dissimilar Metal Welds u

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Request for Relief I-00015, was previously evaluated and granted in an I

NRC SER dated September 29, 1986. Revision 2 incorporates changes to the Grand Gulf Nuclear Station (GGNS), Unit 1, pressure testing program resulting from NRC approval of Code Case N-498-1 for use. The hydrostatic test was used as part of the original basis for approval.

However, the use of Code Case N-498-1 in lieu of the Code-required hydrostatic test requirements does not effect the evaluation of Request i for Relief I-00015. In addition, all Examination Category B-A, Item Bl.10 welds were removed from this request for relief due to the licensee obtaining greater than 90% coverage. Therefore, it is recommended that relief remain as granted in the NRC's SER dated September 29, 1986, pursuant to 10 CFR 50.55a(g)(6)(i).

L. Reauest for Relief I-00017. Rev. 1. Examination Cateaory C-H. Class 2 ,

Pressure Retainino Components 4 i

Request for Relief I-00017, was previously evaluated and granted in an NRC SER dated September 29, 1986. Revision I deletes this request since l authorization to use Code Case N-498-1 was approved in NRC SER dated April 11, 1995, pursuant to 10 CFR 50.55a(g)(6)(1).

M. Reauest for Relief I-00018. Rev. 2. Examination Cateaory B-P. Class 1 Pressure Retainina Components Request for Relief I-00018, was previously evaluated and granted in an NRC SER dated August 15, 1986. Revision 2 incorporates changes to the Grand Gulf Nuclear Station (GGNS), Unit 1, pressure testing program resulting from NRC approval of Code Case N-498-1 for use. The use of Code Case N-498-1 in lieu of the Code-required hydrostatic test requirements does not effect the evaluation of Request for Relief I-00018. Therefore, it is recommended that relief remain as granted in the NRC's SER dated August 15, 1986, pursuant to 10 CFR 50.55a(g)(6)(1).

N. Reauest for Relief I-00019. Rev.1. Examination Cateaories B-J and B-G-1. Items B9.11 and B6.30. Class 1 Pressure Retainina Welds and Reactor Vessel Boltina Code Raouirement: Item B9.11 of Examination Category B-J requires 100% volumetric and surface examinations of Class I circumferential piping welds NPS 4 or larger, as defined by Figure IWB-2500-8.

Table IWB-2500-1, Examination Category B-G-1, Item B6.30 requires 100%

volumetric examination of the reactor vessel stud hole threads and the ligaments between stud holes as defined by Figure IWB-2500-12.

Licensee's Code Relief Reauest: Relief is requested from the Code-required 100% volumetrie: exam N tion of N9 nozzle safe end-to-penetration welds and reactor pressure ves.el (RPV) closure stud holes.

Licensee's Basis for Reauestina Relief (as stated):

"The welds requiring relief attach the penetration seal to the safe end.

The penetration seal is a forged item allowing 14 socket-welded connections for each of the two N9 nozzles. The configuration of the )

penetration seal and the installing weld limits the access required for obtaining full coverage of the weld and associated base material. {

i "The weld is volumetrically examined from the safe end, obtaining 44.7%

coverage of the code volume. Examination from the weld and from the penetration seal side of the weld is prohibited due to component configuration and weld geometry (see figure 1) .

"The area of the RPV flange requiring relief is locatert between the stud hole and the RPV inside diameter (ligament area). The ligament area also contains the sealing surface that makes contact with the RPV head flange.

The seal surface is comprised of deposited weld material, and raised approximately 4" above the flange face creating a geometrical obstruction.

"A code volume of 96% is volumetrically examined without interference with the seal surface. The remaining 4% is contained within the restricted area associated with the seal surface (see Figure 2)*.

"The safe end material is SA 336-F8 (304) stainless steel, and the penetration seal is 304L stainless steel. Due to the geometric

• Figures are not included in this technical letter report

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i configuration of the weld joint, the examination can only be conducted from the safe end side of the joint, and therefore, does not obtain full coverage. The examination is able to obtain 44.7% of the code-required volume. The examineable area includes the inside surface of the safe end (304 stLinless steel material) including the heat-affected zone.

t "The primary degradation mechanism at the location is intergranular stress corrosion cracking (IGSCC). Fatigue is not a significant factor

, due to the limited fatigue loading at this location. Therefore, the potential for cracking at this location should consider IGSCC only. The occurrence of IGSCC is caused by the simultaneous presence of three factor:

"1) high stress, 2) aggressive environment, 3) susceptible material "The safe end and penetration seal side of the weld both see essentially the same stress and environmental conditions. However, there is a

. significant difference in material susceptibility between the 304 SS safe 2 end and the 304L penetration seal. Generic Letter (GL) 88-01, NUREG 0313 Revision 2, recognizes 304L type material as being IGSCC resistant. The 304 portion of the assembly including that side of the weld root is examined from one direction utilizing IGSCC techniques and qualified personnel. In addition, Generic Letter 88-01 excludes all piping smaller than 4" in nominal diameter. The N9 A&B safe ends are less than 4" in nominal diameter, therefore, under the rules of the generic letter, the safe ends are not susceptible to IGSCC."

In response to a request for additional information from the NRC, the following was submitted by letter dated July 31, 1996.

"Although these welds are size exempt from the augmented requirements of Generic Letter 88-01, NRC Position On IGSCC in boiling water reactor (BWR) Austenitic Stainless Steel Piping, GGNS conservatively classified these welds as Category D welds requiring augmented ultrasonic examinations using techniques best suited for the detection of IGSCC.

Since the initial evaluation and categorization, these welds have received stress improvement by the induction heating stress improvement ,

(IHSI) process and have been subsequently reclassified as Category C. As  !

part of the IHSI process, the welds received before-and-after ultrasonic j examinations and combined with other examinations have now been examined to the extent described in the relief request, four times each during the ,

first interval. Because of the small diameter, materials of construc- l tion, and the nozzle function, the area most susceptible to IGSCC is  :

examined. The examination technique utilizes the 45' shear wi.ve which is the preferred technique for detection of IG5CC.

" Recognizing that GGNS is conservative by including the subject welds into the classification of GL 88-01, has performed IHSI, has examined the area most susceptible to any known degradation mechanism four times during the interval, and has not experienced any known IGSCC in the reactor coolant pressure boundary, the completed examinations are

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believed to be adequate for ensuring integrity of the N-9 nozzle welds.

However, as GGNS prepares to advance into its second interval, these welds along with other items where relief has been obtained during the first interval will be evaluated to determine if improved coverage can be obtained. A revicu of available information indicates that the configuratial of the N-9 nozzle welds may permit the use of a 60* angle beam to supplement the 45* for obtaining an additional 30% coverage of the Code volume. This cannot be confirmed until the examinations are actually performed and beam plots developed.

"As evidenced by Revision 2 to Relief Request I-0006, Revision 6 to kelief Request I-00010, and the deletion of Relief Request I-0011 where welds have been eliminated from requests for relief because newer technology has permitted a successful examination of the Code volume, GGNS is conscious of our responsibility to evaluate previously identified limitation with newer technology and improve coverage where appropriate.

Because of this, relief for the upcoming interval will not be requested until each examination is evaluated based on the technology, experience, and equipment available at the time of the examination. At that time, the use of a 60* angle beam will be included into the examination technique for the N-9 nozzles to the extent possible, and if relief is still required, the confirmed additional coverage will be provided to the NRC during that submittal. One of the subject welds is currently scheduled for examination during Period I and the other during Period 2 of the second interval. The second interval is anticipated to begin June 1, 1997."

Licensee's Proposed Alternative:

The licensee proposed to perform the ultrasonic examination to obtain coverage of 44% of the Code-required volume using a 45' shear wave examination and 100% surface examination of the subject welds.

Evalt:ation: The RPV closure stud holes are receiving 96% of code-required volumetric examination. Grand Gulf Nuclear Station has adopted Code Case N-460 " Alternative Examination Coverage for Class 1 and Class 2 Welds",

which allows coverage to be reduced up to 10%, and therefore relief is not required.

The Code of record (77579) at Grand Gulf requires :100% volumetric and surface examination of the subject safe end welds. The licensee has examined 44% of the required volume due to the limited access from the penetration seal side and the safe end weld surface irregularity. This limited access prevents 100% coverage of the required volume making the Code-required examination impractical to complete.

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e The primary degradation mechanism at the weld is intergranular stress j corrosion cracking (IGSCC), therefore, the licensee utilized a 45* shear

! wave, which is the preferred technique for detection of IGSCC. These welds were conservatively included in the licensee's augmented program l

for the detection of IGSCC as Category 0 welds. Since the initial evaluation and categorization, these welds have received stress improvement by the induction heating stress improvement process (IHSI) and have been subsequently reclassified as Category C. As part of the IHSI process, the welds received before-and-after ultrasonic examinations and, combined with other examinations, have now been partially examined four times each during the first interval. Based on the small diameter, materials of construction, and the nozzle function, the area most susceptible to IGSCC was examined.

Due to the degradation mechanism expected, the volume examined, and the '

number of times examined during this interval, the examination performed should have detected degradation, if present. The limited volumetric

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examination in addition to the 100% surface examination performed should provide reasonable assurance of structural integrity. Therefore, based on the impracticality of the Code requirements and the examinations that ,

can be performed on these welds, it is recommended that relief be granted pursuant to 10 CFR 50.55a(g)(6)(1). However, it appears that using a combination of beam angles could increase coverage significantly.

.Therefore, the licensea should attempt to increase coverage using multiple beam angles during future examinations of these safe end welds.

O. Reauest for Relief I-00024. Examination Cateoories B-L-2 and B-M-2. Iteins B12.20 and B12.40. Class 1 Pumo Casino and Valve Internal Surface 1 Code Reauirement: Table IWB-2500-1, Examination Categories B-L-2 and B-M-2, Items B12.20 and 812.40 require a VT-1 visual examination of the internal s'urfaces of'one valve or pump of each group of valves or pumps I that are of the same constructional design, and manufacturing method, and that perform similar functions in the system, during each inspection interval.

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l l Licensee's Code Relief Reauest: Relief is requested from the Code-required VT-1 visual examination of the internal surfaces of Class I pump i and valve internals during the first 10-year inspection interval.

Licensee's Basis for Reauestina Relief (as stated): l "Affected components have shown good reliability in service. Significant l man-hours ara required to perform disassembly of pumps / valves.  ;

, Additionally the expenditure of man-Rem is high. Disassembly of pumps and valves solely for the purpose of visual examinations inconsistent with as low as is reasonably achievable (ALARA), occupational exposure, i concerns and poses an excessive burden with no compensating increase in l quality or safety. Later editions of ASME Section XI incorporate  ;

, provisions requiring examination only if components are disassembled for maintenance, repair, or volumetric examination. These Code requirements are contained in Code Year and addenda that have been endorsed for use in 10 CFR 50.

"All components are designed, fabricated, installed, and tested in l accordance with the requirements of ASME Section III, Class 1.

"The alternate examination requirements eliminate unnecessary man-Rem exposure and man-hours expenditure that provide no compensating increase in quality or safety.

"The alternate examination requirements eliminate unnecessary component disassembly that would contribute to degrading component life and 1 increase risks associated with potential reassembly errors." l l

Licensee's Prooosed Alternative:

Permission is requested to allow performance of pump / valve internal examination in accordance with the requirements of Table IWB-2500-1, Examination Categories B-L-2 and B-M-2 contained in the 1989 Edition of the ASME Code. Note 2 to this table states: " Examination is required

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only when a pump or valve is disassembled for maintenance, repair, or volumetric examination. Examination of the internal pressure boundary shall be performed to the extent practicable. Examination is required only once during the inspection interval."

Evaluation: The Code of record (77S79) at Grand Gulf requires a VT-1 visual examination of valve body internal surfaces. Disassembly of a valve to gain access for examination requires a significant amount of l manpower, time, and radiation exposure. As a result, later editions of j 1

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, the Code were modified to eliminate the impracticality of disassembling a valve for the sole purpose of performing the visual examination. In the 1989 Edition of Section XI, a VT-3 visual examination is required only l when a valve is disassembled for maintenance, repair, or other

) inspection. The licensee's proposed alternative is equivalent to the

requirements of Examination Categories B-L-2 and B-M-2, Item B12.20 and B12.50, of the 1989 Edition of the Code. Since this Code edition has been approved for general use by incorporation into the regulations, it is considered an acceptable alternative to the requirements of the Code of record. Therefore, the INEL staff recommends that use of the require-ments of Examination Categories B-L-2 and B-M-2, Items B12.20 and B12.50, of the 1989 Code be approved, pursuant to 10 CFR 50.55a(g)(4)(iv),-

provided that all associated requirements of the 1989 Code are also met.

3.0 CONCLUSION

The INEL staff has reviewed the information provided by the licensee and concludes that the Code examination requirements are impractical for the welds contained in Request for Relief I-00019 and, therefore, recommends that relief be granted pursuant to 10 CFR 50.55a(g)(6)(i).

For Requests for Relief I-00002, I-00007, I-00008, I-00009, I-00010, I-00012, I-00015, and I-00018, it was determined that the technical content had not changed and that relief should remain granted pursuant to 10 CFR 50.55a(g)(6)(1), as determined in the previous evalu'ations.

Pursuant to 10 CFR 50.55a(g)(4)(iv), i,t is concluded that the licensee's proposed use of later editions of ASME Section XI provide an acceptable level of quality and safety in lieu of the Code-required examination for Request for Relief I-00024. Therefore, it is recommended that the use of later editions of ASME Section XI be approved for Request for Relief I-03024.

Requests for Relief I-00004, I-00005, I-00006, were revoked by 10 CFR 50.55a(g)(6)(ii)(A)(1). The subject revisions remove them from the program plan.

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! Requests for Relief I-00011 and I-00017 are no longer needed and the subject l revisions removed them from the program plan, i

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