ONS-2017-079, Supplemental Information to Support NRC Review of Relief Request No. 17-0N-001; Alternative to Extend the Code Case N-770, Inspection Item B Examination Frequency

Supplemental Information to Support NRC Review of Relief Request No. 17-0N-001; Alternative to Extend the Code Case N-770, Inspection Item B Examination Frequency

ML17321A086
Person / Time
Site:	Oconee
Issue date:	11/13/2017
From:	Grant H Duke Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
17-ON-001, ONS-2017-079
Download: ML17321A086 (12)

Text

ENCLOSWRE 1 TO THIS LETTER CONTAINS PROPRIETARY l1NFORMATION TO BE WITHHELD FROM PUBLIC DISCLOSURE UNDER 10 CFR 2.390 H. Todd Grant

(_~ DUKE General Manager, Nuclear Engineering ENERGY Oconee Nuclear Station Duke Energy ON01 VP I 7800 Rochester Hwy Seneca, SC 29672 ONS-2017-079 0 . 864.873.6767 f: 864.873.5791 Todd. Grant@duke-energy.com November 13, 2017 10 CFR 50.55a ATTN : Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Duke Energy Carolinas, LLC (Duke Energy)

Oconee Nuclear Station, Units 1 and 2.

Docket Numbers 50-269 and 50-270 Renewed License Numbers DPR-38 and DPR-47

Subject:

Supplemental information to support NRC review of Relief Request No. 17-0N-001 ;

Alternative to extend the Code Case N-770, Inspection Item B Examination Frequency

References:

1. Duke Energy Letter; "Fifth Ten Year lnservice Inspection Interval, Relief Request No. 17-0N-001; Alternative to extend the Code Case N-770, Inspection Item B Examination Frequency" dated October 3, 2017.

2. NRC Letter; "Oconee Nuclear Station, Units 1 and 2 - Supplemental Information Needed for Acceptance of Relief Request No. 17-0N-001 " (Accession No. ML17292A142)

Ladies and Gentlemen, Duke Energy is submitting the attached supplemental information for Relief Request No. 17-0N-001 for Oconee Units 1 and 2. Duke Energy submitted the Relief Request (Reference 1) on October 3, 2017. However, the NRC has determined that an independent flaw analysis by the NRC staff is needed to support their technical evaluation of the Relief Request and accordingly submitted a request for the specific supplemental information needed (Reference 2).

The requested information is being submitted as an enclosure to this letter and includes proprietary information. As such, a Proprietary and Non-Proprietary version of the enclosure is provided, along with AREVA's supporting affidavit for withholding the proprietary information in accordance to 10 CFR 2.390, paragraph (a)(4). In light of this , it is requested that the information marked as proprietary be withheld from public disclosure in accordance with 10 CFR 2.390.

Enclosure 1 contains proprietary information .

Upon removal of Enclosure 1, this document is uncontrolled .

ENCLOSURE 1 TO THIS LETTER CONTAINS PROPRIETARY INFORMATION TO BE WITHHELD FROM PUBLIC DISCLOSURE UNDER 10 CFR 2.390 ONS-2017-079 November 13, 2017 Page 2 If there are any questions or further information is needed you may contact David Haile of Oconee Regulatory Affairs at (864) 873-4742.

s~ ,d-H. Todd Grant General Manager, Nuclear Engineering Oconee Nuclear Station

Enclosures:

1. Supplemental Information Needed for NRC Review of Relief Request No . 17-0N-001 (Proprietary Version with Affidavit attached)

2. Supplemental Information Needed for NRC Review of Relief Request No. 17-0N-001 (Non-Proprietary Version)

Enclosure 1 contains proprietary information.

Upon removal of Enclosure 1, this document is uncontrolled .

ONS-2017-079 November 13, 2017 Page 3 cc:

Ms. Catherine Haney, Administrator, Region II U.S. Nuclear Regulatory Commission Marquis One Tower 245 Peachtree Center Ave ., NE, Suite 1200 Atlanta , GA 30303-1257 Ms. Audrey L. Klett, Project Manager (by electronic mail only)

U.S. Nuclear Regulatory Commission 11555 Rockville Pike Mail Stop 0-08B1A Rockville, MD 20852-2738 Mr. Eddy Crowe NRC Senior Resident Inspector Oconee Nuclear Station

AFFIDAVIT COMMONWEALTH OF VIRGINIA )

) ss.

CITY OF LYNCHBURG )

1. My name is Gayle Elliott. I am Deputy Director, Licensing & Regulatory Affairs, for AREVA Inc. (AREVA) and as such I am authorized to execute this Affidavit.

2. I am famil iar with the criteria applied by AREVA to determine whether certain AREVA information is proprietary. I am familiar with the policies established by AREVA to ensure the proper application of these criteria.

3. I am familiar with the AREVA information contained in an attachment to a letter from Duke Energy Carolinas , LLC (Duke Energy) to Document Control Desk (NRG) , with subject, "Supplemental information to support NRG review of Relief Request No. 17-0N-001 ; Alternative to extend the Code Case N-770, Inspection Item B Examination Frequency," ONS-2017-079, dated November 9, 2017, and referred to herein as "Document. " Information contained in th is Document has been classified by AREVA as proprietary in accordance with the policies established by AREVA for the control and protection of proprietary and confidential information.

4. This Document contains information of a proprietary and confidential nature and is of the type customarily held in confidence by AREVA and not made available to the public. Based on my experience, I am aware that other companies regard information of the kind contained in this Document as proprietary and confidential.

5. This Document has been made available to the U.S. Nuclear Regulatory Commission in confidence with the request that the information contained in this Document be withheld from public disclosure . The request for withholding of proprietary information is made in accordance with 10 CFR 2.390. The information for which withholding from disclosure is

requested qualifies under 10 CFR 2.390(a)(4) "Trade secrets and commercial or financial information ."

6. The following criteria are customarily applied by AREVA to determine whether information should be classified as proprietary:

(a) The information reveals details of AREVA's research and development plans and programs or their results.

(b) Use of the information by a competitor would permit the competitor to significantly reduce its expenditures, in time or resources , to design , produce, or market a similar product or service.

(c) The information includes test data or analytical techniques concerning a process, methodology, or component, the application of which results in a competitive advantage for AREVA.

(d) The information reveals certain distinguishing aspects of a process, methodology, or component, the exclusive use of which provides a competitive advantage for AREVA in product optimization or marketability.

(e) The information is vital to a competitive advantage held by AREVA, would be helpful to competitors to AREVA, and would likely cause substantial harm to the competitive position of AREVA.

The information in this Document is considered proprietary for the reasons set forth in paragraphs 6(c) , 6(d) and 6(e) above.

7. In accordance with AREVA's policies governing the protection and control of information, proprietary information contained in this Document has been made available, on a limited basis, to others outside AREVA only as required and under suitable agreement providing for nondisclosure and limited use of the information .

8. AREVA policy requires that proprietary information be kept in a secured file or area and distributed on a need-to-know basis.

9. The foregoing statements are true and correct to the best of my knowledge, information, and belief.

SUBSCRIBED before me this - - - -

day of ~ OY lW'--,,~ , 2017.

Sherry L. McFaden NOTARY PUBLIC, COMMONWEALTH OF VIRGINIA MY COMMISSION EXPIRES: 10/31/18 Reg.# 7079129 SHERRY L. MCFADEN Notary Public Commonwealth of Virginia 7079129 My Qomml11lon Expires Oct 31, 2018

I Non-Proprietary Enclosure 2 to ONS-2017-079 Duke Energy Carolinas, LLC Oconee Nuclear Station, Units 1 and 2 Supplemental Information Needed for NRC Review of Relief Request No. 17-0N-001

Non-Proprietary 1 Oconee Nuclear Station, Units 1 and 2 Supplemental Information Needed for NRC Review of Relief Request No. 17-0N-001 The 4 requests contained in the NRC's submittal had subparts imbedded in each request. Duke Energy's responses address each subpart of each of the 4 NRC requests.

NRC Request:

1. a) The staff requests the licensee to provide detailed drawings of the welds in question. The drawings, or additional supplemental data, should include the pipe outside diameter size, the weld thickness and the weld width as defined by slide 6 of the NRC presentation identified above (ADAMS Accession No. ML17138A002).

Duke Energy Response to 1(a):

~ - 'Sketch 1._ _ _ _ _ _ _ _ _ _ __

Sketch 1 is provided to give perspective of the general configuration of the pipe, nozzle and welds . The supporting data for the response is provided below.

Core Flood Nozzle, Pipe, & DMBW Dimensions: Value 14" Sch140 SS Pipe Wall Thickness : 1.25" Note: DMBW = Dissimilar Metal Butt Weld NRC Request:

b) The drawings, or additional supplemental data , should also include details of any safe end weld , as well as the length from centerline of the dissimilar metal butt weld to the safe end weld .

(__ _____________

Duke Energy Response to 1(b):

Page 1 of 5 ONS 2017 Enclosure 2

Non-Proprietary 1

• Oconee Nuclear Station, Units 1 and 2 Supplemental Information Needed for NRC Review of Relief Request No. 17-0N-001 NRC Request:

c) Further, any pipe bends or branch connections should be identified with distances from any and all such items to the centerline of the weld.

Duke Energy Response to 1(c):

There are no pipe bends or branches in the vicinity of the CF Nozzle or Safe End and the closest piping elbow in the Core Flood line has a centerline that is 9'-3" from the DMBW.

NRC Request:

d) The staff also requests the licensee to specify whether these components (i.e., pipe bends, branch connections , and safe end welds) have been evaluated as part of the licensee's weld residual stress profile for the dissimilar metal butt welds .

Duke Energy Response to 1(d):

The safe end and the stainless steel safe end weld adjacent to the DMBW were included in the finite element models.

NRC Request:

2. The staff requests the licensee to:

(a) provide the weld residual stress inputs used for the licensee's flaw evaluation ;

Duke Energy Response to 2(a):

Residual stresses for the Circumferential Flaw: Table 1 provides the axial residual stresses and includes a conservative assumption of a 50% Through Wall Weld Repair even though there is no record that any weld repair was performed for the DMBWs.

Residual stresses for the Axial Flaw: Table 2 provides the residual hoop stresses at the DMBW Centerline (Does not include an assumed weld repair).

NRC Request:

(b) include a description of the methodology used to generate the weld residual stresses; Duke Energy Response to 2(b ):

Circumferential Flaw Methodology:

The weld 's fabrication and operating sequence was modeled as follows :

1. The low alloy steel nozzle was buttered with lnconel Alloy 82 material.

2. Post weld heat treatment (PWHT) of the buttered nozzle was performed.

(Note: creep was not accounted for in the simulation of the PWHT.)

3. lnconel Alloy 82/182 filler was used for the nozzle-to-safe end dissimilar metal weld .

4. An assumed inner diameter repair of the DMW was imposed as having a repair depth of 50% of the weld thickness over 100% of the circumference (360°).

Followed by:

5. A shop hydrostatic test.

6. A field weld of the stainless steel safe end-to-pipe weld .

7. A field hydrostatic test.

8. Three operating cycles to simulate shakedown.

Page 2 of 5 ONS 2017 Enclosure 2

Non-Proprietary Oconee Nuclear Station, Units 1 and 2 Supplemental Information Needed for NRC Review of Relief Request No. 17-0N-001 Axial Flaw Methodology:

The weld residual stress analyses utilized thermal analysis to determine the temperature distribution followed by a stress analysis to determine the resulting stresses.

The analytical sequence described below is used in the finite element analysis.

1. Deposit nozzle-to-safe end weld (dissimilar metal weld )

2. Deposit safe end-to-pipe weld (stainless steel weld) .

3. Perform hydrostatic test.

4. Impose five cycles of "shake down" with normal operating temperature and pressure to stabilize the residual stress fluctuations and redistribute peak residual stresses .

The mechanical boundary conditions for the stress analyses (thermal and pressure) are symmetric boundary conditions applied to the free end of the vessel/clad material. In addition , the nodes at the free end of the attached pipe are coupled in the axial direction to simulate continuity.

NRC Request:

(c) provide any references used to develop the through-weld th ickness residual stresses, as well as all stress profiles used Duke Energy Response to 2(c):

Inputs used in the Residual Stress and Fracture Mechanics Crack Growth Evaluations Circumferential Flaw:

1. Enveloped the ONS Units 1, 2 & 3 external piping moments,

2. Used MRP-287 guidance and MRP-115 PWSCC crack growth rates ,

3. Temperature: 557 °F, I ----~--

5. Used an initial 10% through wall flaw,

6. Used residual stresses from a 50% ID through wall repair.(see Table 1)

Axial Flaw:

1. Used MRP-115 PWSCC crack growth rates,

2. Temperature: 557 °F,

3. Used Flaw aspect ratios of 1: 1, 2: 1 & "Variable" ('natural' crack growth due to hoop stress and stress intensities).

4. Used an initial 10% through wall flaw,

5. Used residual stresses from the no weld repair case . (see Table 2)

NRC Request:

(d) document for each profile if it included effects of pressure, temperature, shakedown and hydro pressure testing, and the value used for pressure, temperature and hydro, including the number of shakedown evolutions evaluated .

Page 3 of 5 ONS 2017 Enclosure 2

1

• Non-Proprietary Oconee Nuclear Station, Units 1 and 2 Supplemental Information Needed for NRC Review of Relief Request No. 17-0N-001 Duke Energy Response to 2(d):

Circumferential Flaw Evaluation Inputs: Value Axial Flaw Evaluation Inputs: Value

• Initial 10% Wall Flaw Depth: 0.16875"

• 1: 1 Aspect Ratio, with Handbook Methods: 0.16875" (Initial Flaw Length)

• 2: 1 Aspect Ratio, with Handbook Methods: 0.3375" (Initial Flaw Length)

• 1: 1 Aspect Ratio* see note: 0.16875" (Initial Flaw Length)

• Operating Temperature : 557 Of

• Operating Pressure: 2155 psig

• Hydro Pressure: 3125 psig

• Imposed five operating cycles to simulate shakedown .

• Note: The initial aspect ratio is shown. The residual Hoop Stresses and Stress Intensities (Ks) were used to grow the axial flaw without dictating a single value for the aspect ratio during flaw growth.

NRC Request:

3. a) The staff requests the loadings used to perform the licensee's flaw analysis . In terms of forces, the staff requests the licensee to provide forces from deadweight, thermal ,

operational basis earthquake, safe shutdown earthquake , and loss of coolant accident.

Duke Enerqv Response to 3(a :

Axial (Fx) Shear Torsion (Mx) Bending Envelope Piping Loads (Kips) (Kips) (Ft-Kips) (Ft-Kips)

Gravity: 0.50 3.00 1.00 13.00 Thermal Range: 6.00 15.00 65 .00 130.0 OBE: 2.50 3.00 17.00 16.00 SSE: 5.00 6.00 37.00 34.00 No LOCA Loads Calculated:

NRC Request:

b) If stresses are provided , the staff requests the licensee to document the axial membrane stress and global bending stress used for analysis.

Duke Energy Response to 3(b):

Not applicable, Individual loads were provided in 3(a) above.

Page 4 of 5 ONS 2017 Enclosure 2

Non-Proprietary Oconee Nuclear Station, Units 1 and 2 Supplemental Information Needed for NRC Review of Relief Request No. 17-0N-001 Table 1 Table 2 Circumferential Flaw Axial Stress in psi Axial Flaw Residual Hoop Stress in psi Distance from alt(%) Stress (psi)

ID Surface 0.00" 0.00 15458 0.07" 4.17 17164 0.14" 8.33 21782 0.21 " 12.50 29788 0.28" 16.67 37784 0.35" 20.83 39379 0.42" 25.00 40814 0.49" 29.17 44005 0.56" 33.33 42178 0.63" 37 .50 42529 0.70" 41.67 46932

0. 77" 45.83 49892 0.84" 50.00 52415 0.91 " 54.17 54745 0.98" 58.33 53819 1.05" 62.50 55975 1.13" 66.67 55997 1.20" 70.83 57276 1.27" 75.00 58454 1.34" 79.17 58467 1.41 " 83.33 62398 1.48" 87.50 63721 1.55" 91.67 62162 1.62" 95.83 64885 1.69" 100.00 65991 Page 5 of 5 ONS 2017 Enclosure 2