NL-16-132, Request for Relief Request IP3-ISI-RR-09 Alternative to the Depth Sizing Qualification Requirements
| ML16350A104 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 12/02/2016 |
| From: | Vitale A Entergy Nuclear Northeast |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NL-16-132 | |
| Download: ML16350A104 (8) | |
Text
- Entergx
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Enterqv Nuclear Northeast Indian Point Energy Center 450 Broadway, GSB P.O. Box 249 Buchanan, NY 10511-0249 Tel 914 254 6700 Anthony.J Vitale Site Vice President NL-16-132 December 2, 2016 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk 11555 Rockville Pike Rockville, MD 20852
SUBJECT:
Request for Relief Request IP3-ISl-RR-09 Alternative to the Depth Sizing Qualification Requirement Indian Point Unit Number 3 Docket No. 50-286 License No. DPR-64
Dear Sir or Madam:
Pursuant to 10 CFR 50.55a(g)(5)(iii), Entergy Nuclear Operations, Inc. (Entergy) requests relief to use an alternative to the 2001 edition with the 2003 Addenda of ASME Section XI requirements in Table IWB-2500-1 and in ASME Code Case N-770-1. Entergy proposes to use ASME Code Case N-695, approved as acceptable in Regulatory Guide 1.147, with relief for the qualification of equipment and personnel to the specified depth sizing.
This request is made for the upcoming 2017 spring refueling outage at IP3. Entergy plans to examine the Reactor Vessel Hot Leg and Cold Leg Nozzle to Safe-End dissimilar metal welds and safe-end to pipe elbow stainless steel welds. The examinations will be performed using techniques that are qualified for flaw detection and sizing using procedures, personnel, and equipment qualified by demonstration in all aspects except depth sizing. Therefore, as a contingency for depth sizing of any flaws detected, Entergy hereby requests approval of the proposed alternative. The basis for the request is provided in Attachment 1 to this letter.
Entergy is submitting the enclosed Relief Request No. 9 (IP2-ISl-RR-09) for Indian Point Unit No. 3 (IP3) in accordance with 10 CFR 50.55a(g)(5)(iii):
/SI program update: Notification of impractical /SI Code requirements. If the licensee has
. determined that conformance with a Code requirement is impractical for its facility the licensee must notify the NRC and submit, as specified in § 50.4, information to support the determinations. Determinations of impracticality in accordance with this section must be based on the demonstrated limitations experienced when attempting to comply with the Code requirements during the inservice inspection interval for which the request is being submitted. Requests for relief made in accordance with this section must be submitted to
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NL-16-132 Docket No. 50-286 Page 2 of 2 the NRC no later than 12 months after the expiration of the initial or subsequent 120-month inspection interval for which relief is sought.
If you have any questions or require additional information, please contact Mr. Robert Walpole, Manager, Regulatory Assurance at (914) 254-6710.
Sincerely, AJV/sp
Attachment:
10 CFR 50.55a Request No. IP2-ISl-RR-19 Proposed Alternative in Accordance With 10 CFR 50.55a(g)(5)(iii) cc: Mr. Douglas Pickett, Senior Project Manager, NRC NRR DORL Mr. Daniel H. Dorman, Regional Administrator, NRC Region 1 NRC Resident Inspectors Office Mr. Francis J. Murray, Jr., President and CEO, NYSERDA Ms. Bridget Frymire, New York State Dept. of Public Service
ATTACHMENT TO NL-16-1*32 10 CFR 50.55A REQUEST NO. IP3-ISl-RR-9 PROPOSED ALTERNATIVE IN ACCORDANCE WITH 10 CFR 50.55a(g)(5)(iii)
ENTERGY NUCLEAR OPERATIONS, INC.
INDIAN POINT NUCLEAR GENERATING UNIT NO. 3 DOCKET NO. 50-286
NL-16-132 Docket No. 50-286 Attachment Page 1 of 5 Indian Point Unit 3 Fourth 10-year ISi Interval Relief Request No: IP3-ISl-RR-9 Alternative to the depth sizing qualification requirement Proposed Alternative In Accordance with 10 CFR 50.55a(g)(5)(iii)
-Compliance is Impracticable-
- 1. ASME Code Component(s) Affected Code Class( 1
References:
Table IWB-2500-1 Examination Category: N-770-1 Item Number: A-2, B, R-A
==
Description:==
Reactor Vessel Hot Leg and Cold Leg nozzle to safe-end OM welds and safe-end to pipe elbow SIS welds
2. Applicable Code Edition and Addenda
The code of record for the Indian Point Unit 3 lnservice Inspection Fourth Interval is the ASME Section XI Code, 2001 Edition, 2003 Addenda.
3. Applicable Code Requirement
ASME Section XI, Code Case N-770-1, Items A-2, Unmitigated Hot Leg Butt Welds, specifies that a visual inspection is performed every refueling outage and a volumetric examination is performed every five (5) years. ASME Section XI, Code Case N-770-1, Item B, Unmitigated Cold Leg Butt Welds specifies that a visual examination is performed once per interval and a volumetric examination must be performed every second inspection period, not to exceed 7 years. And Risk Informed R-A requires volumetric examination of safe-end to pipe/elbow S/S welds every ten years.
4. Reason for Request
ASME Code Case N-695, "Qualification Requirements for Dissimilar Metal Piping Welds,Section XI, Division 1, is shown as acceptable for use in Regulatory Guide (RG) 1.147, Revision 17, dated August 2014. This code case provides alternatives to the requirements of Appendix VIII, Supplement 10, but Paragraph 3.3(c) of this case requires that "Examination procedures, equipment, and personnel are qualified for depth-sizing when the RMS error of the flaw depth measurements, as compared to the true flaw depths, do not exceed 0.125 inches (3 mm)."
The requirement for the 0.125-inch root mean square error (RMSE) depth sizing accuracy criteria of Code Case N-695 is impractical for IP3 to comply with. To date, although examination vendors
NL-16-132 Docket No. 50-286 Attachment Page 2 of 5 Indian Point Unit 3 Fourth 10-year ISi Interval
. Relief Request No: IP3-ISl-RR-9 Alternative to the depth sizing qualification requirement Proposed Alternative In Accordance with 10 CFR 50.55a(g)(5)(iii)
-Compliance is Impracticable-have qualified for detection and length sizing in accordance with the requirements for examinations from the inside diameter (ID), the vendors have not met the established RMSE of 0.125 inch for indication depth sizing for inside diameter inspections. Several process enhancements including new delivery systems, new*search units, and software modifications have been implemented, but did not achieve the desired improvements in performance given the challenges of weld geometry, rough surfaces, multiple materials, and microstructural anisotropies. This result shows that the Code accuracy standard is impractical for use with the ID ultrasonic examination technology employed in the qualification efforts.
The numerous attempts by inservice inspection (ISi) vendors to meet the RMSE value for depth sizing required by Supplement 10 and Code Case N-695 when examining from the inside diameter have been unsuccessful. Furthermore, the configuration of the IP3 Hot Leg/ Cold Leg nozzle to safe end welds is not suitable for examination from the outer surface due to the limited accessibility to the outside diameter (OD) of the component; examination from the OD would require extensive effort and result in significant and unnecessary personnel radiation exposure.
- 5. Proposed Alternative and Basis for Use For dissimilar metal weld applications (Supplement 10), the NRC has issued RIS-2003-01 that allows the use of procedures that do not meet all of the Supplement 10 criteria, provided that the best available technology is applied.
Entergy proposes to use Code Case N-695 with a RMSE of 0.189 inches and 0.245 inches instead of the 0.125 inches specified for depth sizing in the Code Case. The examination vendor contracted to perform the safe end examinations at IP3 has demonstrated the ability to depth size indications in dissimilar metal welds with a RMSE of 0.189 inches for the RPV nozzle to safe-end DM welds (Appendix VIII, Supplement 10) and 0.245 inches RMSE for the safe-end to pipe S/S welds (Appendix VIII, Supplements 2 and 10 combined (Supplement 14)) instead of the 0.125 inches RMSE required by Appendix VI 11 Supplement 10 and Code Case N-695. If the examination vendor demonstrates an improved depth sizing RMSE prior to the examination, improved RMSE will be used in any flaw sizing instead of the 0.189-inch and 0.245-inch RMSE.
If a reportable flaw is detected and determined to be ID surface connected during examination of the welds in accordance with this relief request, Entergy will provide a flaw evaluation including the measured flaw size as determined by ultrasonic examination for NRC review. Eddy current testing will be used to determine if flaws are surface connected. Additional data including details of the
NL-16-132 Docket No. 50-286 Attachment Page 3 of 5 Indian Point Unit 3 Fourth 10-year ISi Interval Relief Request No: IP3-ISl-RR-9 Alternative to the depth sizing qualification requirement Proposed Alternative In Accordance with 10 CFR 50.55a(g)(5)(iii)
-Compliance is Impracticable-surrounding ID surface contour in the region of the flaw and percentage of the examination area **
where ultrasonic testing (UT) probe lift-off is evident, if any, will be included.
In the event that any flaw(s) requiring depth sizing are detected during examination of welds in accordance with this relief request, the following criteria shall be implemented:
- Flaws detected and measured as less than 50 percent through-wall in depth shall be adjusted by adding a correction factor to the flaw depth such that the adjusted flaw depth is equal to the measured flaw depth+ (applicable vendor RMSE - 0.125 in.), prior to comparison to the applicable acceptance criteria;
- For flaws detected and measured as 50 percent through-wall depth or greater and to remain in service without mitigation or repair, Entergy will submit flaw evaluation(s) for review and approval prior to reactor startup. The flaw evaluation will include:
- 1. Information concerning the mechanism that caused the flaw
- 2. Information concerning the inside surface roughness and/or profile of the region surrounding the flaw in the examined piping weld
- 3. Information concerning areas where UT probe lift-off is observed, if any.
The activities included in the relief request are subject to third party review by the Authorized Nuclear In-service Inspector.
Basis for Use During the upcoming 2017 Spring refueling outage at IP3 (3R19), Entergy will perform ultrasonic examination of the four (4) Hot Leg safe-end to nozzle dissimilar metal welds and during the 2019 outage the four (4) Cold Leg safe-end to nozzle dissimilar metal welds will be ultrasonically examined . These examinations will be performed from the ID of the weld utilizing robotics, Code Case N-695 will be used as the basis for performing these examinations.
To date, the contracted vendor qualified for detection and length sizing on these welds, have not met the RMSE requirement for depth sizing. Entergy's contracted examination vendor has demonstrated ability to meet the depth sizing qualification requirement with an RMSE of 0.189 inches for the RPV nozzle to safe-end OM welds and 0.245 inches RMSE for the safe-end to pipe SIS welds instead of the 0.125 inches required by the Code Case.
For the case of flaws measured to be less than 50 percent through-wall, the addition of the difference in allowable depth sizing tolerance to the measured-flaw depths to that actually
NL-16-132 Do'cket No. 50-286 Attachment Page 4 of 5 Indian Point Unit 3 Fourth 10-year ISi Interval Relief Request No: IP3-ISl-RR-9 Alternative to the depth sizing qualification requirement Proposed Alternative In Accordance with 10 CFR 50.55a(g)(5)(iii)
-Compliance is Impracticable-measured during the examination will compensate for the possible variance in the measured depth. Flaws measured to be more than 50 percent through-wall are proposed to be given special treatment because of the concern for the magnitude of depth sizing errors specific to such deep flaws.
The proposed alternative assures that the safe end-to-nozzle dissimilar metal (DM) welds and the safe end to pipe stainless steel (S/S) welds will be fully examined by procedures, personnel, and equipment qualified by demonstration in all aspects except depth sizing. For depth sizing of flaws measured to be less than 50 percent through-wall, the proposed addition of the difference between the qualified and demonstrated sizing tolerance to any flaw required to be sized compensates for the potential variation. For depth sizing of flaws measured to be 50 percent through-wall or greater, Entergy will submit a flaw evaluation to NRC for review and approval prior to reactor startup from the refueling outage. Therefore, the proposed alternative provides an acceptable level of quality and safety by providing reasonable assurance of structural integrity of the subject welds.
Given the impracticality of the applicable depth-sizing requirement, Entergy requests that the proposed alternative be approved in accordance with 10 CFR 50.55a(g)(5)(iii).
- 6. Duration of Proposed Alternative Relief is requested for the Fourth Ten Year Interval (effective from July 2009 thru July 2019).
- 7. Precedents Similar relief requests have been previously approved for:
(1) NRC Letter to Entergy dated August 29, 2016, Arkansaa Nuclear One, Unit 1 - Relief Request No. AN01-ISl-025, Relief from American Society of Mechanical EngineersSection XI Table IWB-2500-1 Requirements (CAC No. MF7625)
(2) NRC letter to Diablo Canyon dated November 4, 2015, "Diablo Canyon Power Plant, "
Unit No. 2, lnservice Inspection Program Relief Request NDE-RCS-SE-2R19, Associated with the Use of Alternate Sizing Qualification Criteria Through a Protective Clad Layer (TAC No. MF5348)," (ML15299A034)
(3) NRC letter to Catawba dated October 26, 2015, "Proposed Relief Request 14-CN-003, American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (ASME Code), Code Case N-695 (CAC NO. MF5447)," (ML15286A326)
NL-16-132 Docket No. 50-286 Attachment Page 5 of 5 Indian Point Unit 3 Fourth 10-year ISi Interval Relief Request No: IP3-ISl-RR-9 Alternative to the depth sizing qualification requirement Proposed Alternative In Accordance with 10 CFR 50.55a(g)(5)(iii)
-Compliance is Impracticable-