ML20151K521

Requests Relief from 1989 Edition of ASME Boiler & Pressure Vessel Code,Section XI for Catawba Unit 2.Attached Relief Request 97-03,provides Detailed Description & Justification for Request.Calculation,Encl

ML20151K521
Person / Time
Site:	Catawba
Issue date:	07/29/1997
From:	Gordon Peterson DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20151K525	List: ML20151K521 ML20151K554
References
NUDOCS 9708060102
Download: ML20151K521 (11)

Text

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l g Duke Power Company A Dear Ewy Cc.ap.9 1

Casawba Nuclear Station 4800 Concord Road l York, SC 29745 l

l Cary R. Peterson (803) 831-4251 omCE i Vice 1%sident (803) 831-3426Mx l

r July 29, 1997 ,

U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001

Subject:

Catawba Nuclear Station, Unit 2 Docket No. 50-414 Request for Relief from 1989 edition of the ASME Boiler and Pressure Vessel Code,Section XI Serial No. 97-03 Pursuant to 10 CFR 50.55a (g) (6) (i), Catawba Nuclear Station l

requests relief from the 1989 edition of ASME Boiler and '

Pressure Vessel Code,Section XI for Catawba Unit 2.

Complete coverage of two welds was not obtained during Unit 2 end-of-cycle 8 refueling outage. The welds involved are one of the Reactor Vessel Closure Head Meridonal welds and a Containment Spray Heat Exchanger shell to flange circumferential weld. Complete coverage has been determined to be impractical for both of these welds.

Attached is Relief Request 97-03, which provides a detailed description and justification for this request.

Should phere be any questions concerning this request, please call D. Tower at (803) 831-3419.

Very truly yours,

- A ///

Gar R. Peterson 9700060102 970729 PDR P

ADOCK 05000414 PDR f f ll lf f nrv, a ..,:,

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i Document Control Desk Page 2 {

l I July 29, 1997 i

Attachment l- xc

L.A. Reyes, Regional Administrator Region II Senior Resident Inspector Catawba Nuclear Station i

P.S. Tam, Senior Project Manager ONRR l

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ATTACHMENT RELIEF REQUEST 97-03 l

Request for Relief  !

.. Serial No. 97-03 Page 1 of 4 DUKE ENERGY CORPORATION 1

STATION: CATAWBA NUCLEAR STATION UNIT 2 10-YEAR INTERVAL REQUEST FOR RELIEF NO. 97-03

1. System / Component (s) for Which Relief is Requested:

ASME Section XI Code Class 1 Examination Category: B-A Pressure Retaining Welds in Reactor Vessel, and ASME Section XI Code Class 2 Examination Category: C-A Pressure Retaining Welds in Pressure Vessels.

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Weld Number item Number i 2RPV-101-104G B01.022.003 1 2BNSHX-3-5 C01.010.008 I

Code Requirement:

II. I l

ASME Section XI 1989 Edition, Examination Category: B-A Pressure l Retaining Welds in Reactor Vessel , Table IWB-2500-1, item Number i B01.022 and Examination Category: C-A Pressure Retaining Welds in l Pressure Vessels, Table IWC-2500-1, Item Number C01.010 requires a

, volumetric examination of essentially 100% of the weld length. Duke Energy

Corporation, with NRC approval, has adopted Code Case N-460 which defines " essentiaily 100%" as greater than 90% coverage of the weld volume.

4 lil. Code Requirement from which Relief is Requested:

Relief is requested for the above identified Class 1 Reactor Vessel Closure Head Meridonal Weld, from meeting the coverage requirements as defined in ASME Section XI, Figure IWB-2500-3, Examination Volume E-F-G-H, and Class 2 Containment Spray Heat Exchanger Shell to Flange Weld, from meeting the coverage requirements as defined in ASME Section XI, Figure IWC-2500-1, Examination Volume A-B-C-D.

Request for Relief

.. Serial No. 97-03

., Page 2 of 4 IV. Basis for Relief:

Reactor Vessel Weld During the ultrasonic examination of the Reactor Vessel Closure Head Meridonal Weld 2RPV-101-104G (Item No. B01.022.003) shown in Attachment 1, :: overage of the required examination volume could not be obtained. Causes of these limitations are due to the proximity of the lifting lug to the meridonal weld, which limits the ultrasonic coverage to 30.23% of the required volume. In order to achieve greater than 90% coverage of the required volume from the outside surface of the head, the lifting lug would have to be removed. Ultrasonic examination from the inside surface of the head is not feasible because of the high radiation exposure that would be incurred. Radiography would not provide any additional coverage because of the lifting lug location.

Heat Exchanaer Weld During the ultrasonic examination of the NS Heat Exchanger Weld 2BNSHX-3-5 (l tem No. C01.010.008) shown in Attachment 1, coverage of the required examination volume could not be obtained. Single sided weld configuration due to flange geometry reduced the coverage to 53.85%. In order to achieve greater than 90% coverage of the required volume, the weld configuration would have to be redesigned to allow for access from both sides of the weld.

Previous examination of a similar weld in Catawba Unit 1 showed that radiography would increase the coverage to only 59.67%.

V. Alternate Examinations or Testing:

No additional examinations are planned during the current interval for Weld ID Numbers 2RPV-101-104G (Item No. B01.022.003) and 2BNSHX-3-5 (item No. C01.010.008).

VI. Justification for the Granting of Relief:

Reactor Vessel Weld l Although the examination volume requirements as defined in ASME Section XI 1989 Edition, Figure No. IWB-2500-3, Examination Volume E-F-G-H for Weld ID Number 2RPV-101-104G (Item Number B01.022.003) could not be met, the amount of coverage obtained for these examinations provides an acceptable level of quality and integrity. For results of the examinations, '

reference Attachment 2, Pages 1,2,3,4,5,6,7 of 7. i The Reactor Vessel (RV) closure head meridonal weld is by definition not in the beltline area of the RV; therefore, it is not subject to fluence levels equal 2 '

to or greater than 1E17 n/cm . RV materials not in the highly irradiated

Request for Relief

.. Serial No. 97-03 Page 3 of 4 beltline region are not prone to negative material property changes (i.e.,

embrittlement) associated with fuel reactivity neutron bombardment. Based on 10 CFR 50.55a, the ASME Section XI 1975 and 1989 editions, require examination of essentially 100% of the length of beltline welds during every inspection interval. The RV closure head meridonal weld does not meet the requirements of a beltline weld due to a significantly lower fluence exposure, thus resulting in far less potential degradation of ductility. The Catawba Nuclear Station Unit 2 (CNS-2) RV was assembled by Combustion Engineering (CE) and is free from unacceptable fabrication defects. CE performed rigorous state-of-the-art RV inspections following fabrication to ensure no significant flaws existed.

The location of the RV lifting lug over a majority of the RV closure head meridonal weld prevents obtaining 100% volumetric examination coverage; therefore, the 100% volumetric examinations are impractical. Removal of the lifting lug is not a viable altemative and would create an undue burden on Duke Energy Corporation.

Heat Exchanaer Weld Although the examination volume requirements as defined in ASME Section XI, Figure No. lWC-2500-1, Examination Volume A-B-C-D for Weld ID Number 2BNSHX-3-5 (Item Number C01.010.008) could not be met, the amount of coverage obtained for these examinations provides an acceptable level of quality and integrity. For results of the examinations, reference Attachment 3, Pages 1,2,3,4,5 of 5.

. If a leak were to occur at the weld in question which is the NS Heat l Exchanger channel barrel circumferential weld to the manway cover flange I bolting ring, there are several periodic tests and visual inspections that are performed by established procedures that will identify the leakage for prompt Engineering evaluation. The following periodic tests and inspections assure a timely identification and resolution is made to maintain overall Heat  !

Exchanger operability and reliability:

Once per year prior to a Unit scheduled refueling outage, an NS system pressurized leak test is performed per PT/(1/2)/A/4203/03 to walk down the NS system and visually inspect system components for leakage to assure any identified leakage is evaluated for correction. Additionally, Operations performs a monthly walk down of NS and other primary systems to identify leaks, but the system may or may not be pressurized.

Material condition inspections within the Auxiliary Building and other plant areas are further performed monthly by designated building area owners per NSD 104 that will identify leakage points for eva.'uation.

System Engineers review work requests written on their systems on a frequent basis as part of their ' Engineering Support Program' for leakage '

potential that could adversely impact off site dose analysis from post accident

Request for Relief

,, Serial No. 97-03 Page 4 of 4 leakage into the Floor Drain System (WL), Tech Spec 3/4.4.6, 'Rescior j

Coolant System Leakage,' to evaluate priority for immediate corrective actions.

NS system pump runs, required by ASME Code Section XI, lWP testing requirements, are perforrned quarterly that will expose the subject welds to NS system pressure. If leakage occurs, the above periodic tests and

inspections will identify the leakage for corrective evaluations.

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) Based on these evaluations, it is Duke Energy Corporation's position that the limited coverage will not endanger the health and safety of the general public.

Duke Energy Corporation will perform UT examinations to the extent

practical using procedures and personnel qualified in accordance with .ASME i Section XI, Appendix i and Section V, Article 4, for the Reactor Vessel Closure Head and Appendix ill 1989 Edition for the NS Heat Exchanger, f Vll. Implementation Schedule

These examinations will continue to be scheduled in accordance with the requirements of ASME Section XI for future Inspection Intervals at Catawba j Nuclear Station, Unit 2.

Evaluated By: * '

/ Date '/

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NDE Level 111 Review By: 4/; u , . [ # Date 7-/9'-~/7

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7 Reviewed By: -

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'O Attachment 1 Description Table Attachment 2 UT Examination Data B01.022.003 Attachment 3 UT Examination Data C01.010.008 i

- ASME Class 1 & 2 Inservice Inspection Request For Relief No. 974)3L r For Catawba Unit 2 Ilased On ASME Section XI- 1989 Code Attachment 1 .

Page 1 of 1 - ,?

Licensee .I Reason For Request Proposed Attemate '*

item No. Exam Category System Or Area To Be ,

IFitne No. Component Examined Examination

~ B01.022.003 B-A Reactor Vessel Reactor Vessel Limited scan due to geometric configuration. Lifting None.  ;

IWB-2500-3 Meridonal Lug covers 15.0

• of Meridonal Weld. i Head Weld Actual coverage obtained = 3023% ,

(See Attachment 2)

Heat C01.010.008 C-A NS Heat Exchanger Exchanger Limited scan due to geometric configuration. None .i*

IWC-2500-1 Shell Actual coverage obtained = 53.85%

Circumferential One-sided examination due to shell-to-flange W eld configuration (See Attachment 3) l 1

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97-95 ATTA<_4 sear 2 <

DUKE POWER COMPANY exam Start: 14:26 Form NDE-UT-2A/RPV ULTRASONIC EXAMINATION DATA SHEET FOR PLANAR REFLECTORS (Reg. Guide 1.150) Exam Finish: 16:59 Revision 4 Station: Catawba Unit: 2 Component / Weld ID: 2RPV-101-104G Date: 4/2/97 Weld Length (in.): 21.5 Surface Condition: As Ground Lo: 9.2.1 Surface Temperature: 70

• F Pyrometer S/N: MCNDE 27017 Examiner. Winfred C. Leeperhp gel:_ 11 Scans:

1N8 al Due:

Examiner: David Zimmermang evel: 11 45 0 54.5 dB 70 0 dB Configuration: MERIDONAL Procedure: NDE-660 Rev.d FC: 45T O 54.5 dB 70T O dB N/A 60 O dB Calibration Sheet No: #" " #"

60T O dB 9702031,9702032 Other Y dB Scan Surface: OD Max Mp W L Beam Exam IND # g  %

DAC Max Max Max L1 L2 W1 Mp1 W2 Mp2 Dir. Surf. Scan Damps DO NOT WRITE 20%dac 20%dac 20%dac 20%dae 20%dac 20%dac D() NOT WRIT E

• *d* 8 *d* * *d* * *d* 8 "d* 6 *d*

IN T ilS SP 4CE 100%dac 100%dac 100%dac 100%dac 100%dac 100%dac IN THIS SPACF-NRI Remarks:

• 35' - 51.5 dB,35'T-51.5 dB Limitations: (see NDE-UT-4) G 90% or greater coverage obtained: yes O no O Sheet [ of 7 _

Reviewed By: p Level: Date: Aujity e Inspecto ', Date: Item No:

Larry Mauldin Af/,M/,

b ill 4/16/97 [ .

M7 6- 7 9 ~) 801.022.003

DUKE POWER COMPANY Exam Start: 14:26 Form NDE-UT-2A/RPV ULTRASONIC EXAMINATION DATA SHEET FOR PLANAR REFLECTORS (Reg. Guide 1.150) Exam Finish: 16:59 Revision 4 Station: Catawba Unit 2 Component / Weld ID: 2RPV-101-104G Date: 4/2/97 Weld Length (in.): 21.5 Surface Condition: As Ground Lo: 9.2.1 Surface Temperature: 70

• F Pyrometer S/N: MCNDE 27017 Examiner Richard B. Childerfgf gypj Scans:

al ue 8 Examiner Level: 45 O dB 70 0 dB Configuration: MERIDONAL Procedure: NDE-660 Rev: 2 FC: 45T O dB 70T O dB -

N/A 60 O dB Calibration Sheet No: # * **#

60T O dB 9702033 Other 0*-28.5 dB Scan Surface: OD Max Mp W L Beam Exam IND# g  %

DAC Max Max Max L1 L2 W1 Mp1 W2 Mp2 Dir- Surf. Scan Damps DO I40T WRITE 20%dac 20%dac 20%dac 20%dac 20%dac 20%dac D() NOT WRITE 5 %dac 5 %dac 50%dac 50%dac 50%dac 50%dac IN T ilS SP 4CE 100%dac 100%dac 100%dac 100%dac 100%dac 100%dac IN THIS SPACI:

NRI Remarks:

Limitations: (see NDE-UT-4) G 90% or greater coverage obtained: yes Q no @ Sheet . d of 7_

Reviewed By: Level: Date: Auth'o ~ nspecto - Date: Item No:

Larry Mauldin f A 111 4/16/97 / "

//7 6'2-92 801.022.003 1

DUKE POWER COMPANY ISI LIMITATION REPORT Revision 1 Component / Weld ID: 2RPV-101-104G ltem No: B01.022.003 Remarks:

SURFACE BEAM DIRECTION Due to Lifting Lug welded on top.a G NO SCAN Meridional Weld. Lug extends 15" over O LIMITED SCAN @1 82 01S2 S cw @ ccw weld, only 6.5" not covered FROM L 0.0" toL 15.0" INCHES FROM WO CL to 4.25" ANGLE: OO Q 45 O 60 0 Other 35' FROM ._N_A__ DEG to _ _N_A __DEG SURFACE BEAM DIRECTION Omm O LIMITED SCAN O1 02 0102 O cw 0 ccw FROM L to L INCHES FROM WO to ANGLE: OO O 45 O 60 0 Other FROM ,_ _ _ DEG to , _ _ _DEG BN DIRECBON O NO SCAN O LIMITED SCAN O1 02 0102 O cw 0 ccw FROM L . --- _ _ . to L -____ INCHES FROM WO _ __ _ _ _ . to _ ._ __ _._ __ __

ANGLE- 00 0 45 O 60 0 Other FROM DEG to DEG '

DRECDON O NO SCAN O LIMITED SCAN ,

O1 02 0102 O cw 0 ccw FROM L to L INCHES FROM WO to ANGLE: OO O 45 O 60 0 Other FROM , _ _ _ DEG to , _ _ _

Prepared By: W.C. LeepergQ gfle, vel: 11 Date: 4/2/97 Sketch (s) attached O yes O no Sheet 3 of 7 Reviewed By: Larry Mauld g te: 4/16/97 Authorized Inspector- gf Date: g.p 7 g ,c -

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