ML21067A498

Relief Request No. RR 5-4 Proposed Alternative, Weld Reference System

ML21067A498
Person / Time
Site:	Palisades
Issue date:	09/07/2017
From:	David Wrona Plant Licensing Branch III
To:	Entergy Nuclear Operations
Rankin J
References
CAC MF8950
Download: ML21067A498 (8)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 September 7, 2017 Vice President, Operations Entergy Nuclear Operations, Inc.

Palisades Nuclear Plant 27780 Blue Star Memorial Highway Covert, Ml 49043-9530

SUBJECT:

PALISADES NUCLEAR PLANT - RELIEF REQUEST NO. RR 5 - 4 PROPOSED ALTERNATIVE, WELD REFERENCE SYSTEM (CAC NO. MF8950}

Dear Sir or Madam:

By letter dated December 20, 2016 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML16355A020), Entergy Nuclear Operations, Inc. (ENO, the licensee) submitted a request to the U.S. Nuclear Regulatory Commission (NRC) for the use of an alternative to certain American Society of Mechanical Engineers Boiler and Pressure Vessel (ASME Code),Section XI, "Rules for lnservice Inspection [ISi] of Nuclear Power Plant Components," requirements at Palisades Nuclear Plant (PNP).

Specifically, pursuant to Title 10 of the Code of Federal Regulations (1 O CFR) 50.55a(z)(2), the licensee requested to use a proposed alternative to the weld reference system as specified in Subarticle IWA-2600 on the basis of hardship without a compensating increase in the level of quality and safety. The NRC staff notes the letter dated December 20, 2016, also includes Relief Request No. RR 5-5 for a proposed alternative regarding under-vessel leakage examinations. By letter dated June 29, 2017 (ADAMS Accession No. ML17137A028), the staff authorized the use of RR 5-5, at PNP, during the fifth 10-year ISi interval from January 1, 2018, through December 12, 2025.

The NRC staff has reviewed the subject request and concludes, as set forth in the enclosed safety evaluation, that ENO has adequately addressed all the regulatory requirements set forth in 10 CFR 50.55a(z)(2). Therefore, the NRC authorizes the use of Relief Request No. RR 5-4 at PNP for the remainder of the fifth 10-year ISi interval from January 1, 2018, through December 12, 2025.

The NRC staff notes that all other ASME Code requirements for which relief was not specifically requested and approved in the subject request for relief remain applicable, including third-party review by the Authorized Nuclear lnservice Inspector.

If you have any questions, please contact the Project Manager, Jennivine Rankin at (301) 415-1530.

Sincerely, (J__ic 9 o/ ---

David J. Wrona, Chief Plant Licensing Branch Ill Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-255

Enclosure:

Safety Evaluation cc w/encl: Distribution via Listserv

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION FOR RELIEF REQUEST NO. RR 5-4 WELD REFERENCE SYSTEM PALISADES NUCLEAR PLANT ENTERGY NUCLEAR OPERATIONS, INC DOCKET NO. 50-255

1.0 INTRODUCTION

By letter dated December 20, 2016 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML16355A020), Entergy Nuclear Operations, Inc. (ENO, the licensee) submitted a request to the U.S. Nuclear Regulatory Commission (NRC or Commission) for the use of an alternative to certain American Society of Mechanical Engineers Boiler and Pressure Vessel (ASME Code),Section XI, "Rules for lnservice Inspection [ISi] of Nuclear Power Plant Components," requirements at Palisades Nuclear Plant (PNP).

Specifically, pursuant to Title 1O of the Code of Federal Regulations (1 O CFR) 50.55a(z)(2), the licensee requested to use a proposed alternative to the weld reference system as specified in Subarticle IWA-2600, "Weld Reference System," on the basis of hardship without a compensating increase in the level of quality and safety.

2.0 REGULATORY EVALUATION

Pursuant to 10 CFR 50.55a(g)(4), throughout the service life of a pressurized water-cooled nuclear power facility, components that are classified as ASME Code Class 1, 2, and 3 must meet the requirements, except the design and access provisions and preservice 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. Further, these regulations require that inservice examination of components and system pressure tests conducted during the first 10-year ISi 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 paragraph (a) of 10 CFR 50.55a, on the date 12 months prior to the start of the 120-month interval subject to the limitations and modifications listed therein.

Alternatives to requirements under 10 CFR 50.55a(g) may be authorized by the NRC pursuant to 10 CFR 50.55a(z)(1) or 10 CFR 50.55a(z)(2). In proposing alternatives or requests for relief, Enclosure

the licensee must demonstrate that: (1) the proposed alternatives would provide an acceptable level of quality and safety; or (2) compliance with the specified requirements would result in hardship or unusual difficulty, without a compensating increase in the level of quality and safety.

Based on the above, and subject to the following technical evaluation, the NRC staff finds that regulatory authority exists for the licensee to request, and the Commission to authorize, the proposed alternative requested by the licensee.

3.0 TECHNICAL EVALUATION

3.1 Code Requirements for Which Relief Is Requested The Code of Record for the fifth ISi interval at PNP is the 2007 Edition through the 2008 Addenda of the ASME Code, which will end on December 12, 2025.Section XI, of the Code of Record, subparagraph IWA-2610, "General," states, "[a] reference system shall be established for all welds and areas subject to surface or volumetric examination. Each such weld and area shall be located and identified by a system of reference points. The system shall permit identification of each weld, location of each weld centerline, and designation of regular intervals along the length of the weld." Subparagraph IWA-2620, "Piping" refers to requirements outlined in Article 111-4300 and subparagraph IWA-2630, "Vessels," accepts requirements of Appendix A of Article 4 for vessels examined in accordance with Article 4 of ASME Code,Section V. With regard to ultrasonic examination of piping, Article 111-4000, "Examination," paragraph 111-4320, "Marking" states, "[l]ow stress stamps or vibratooling, or both may be used to permanently identify each weld. Marking applied shall not be deeper than 3/64 inch." Paragraph 111-4330 "Reference System" states, "[a] reference system shall be established to locate the weld centerline. Circumferential and longitudinal welds requiring volumetric examination shall be marked once before or during the preservice examination to establish a reference point."

Pursuant to 10 CFR 50.55a(z)(2), the licensee requests authorization to use an alternative to the requirements of the weld reference system as specified in Subarticle IWA-2600.

3.2 System/Component(s) for which Relief Is Requested The requested relief from the ASME Code,Section XI, IWA-2600 requirements applies to the ISi examination of piping, vessel, and component welds.

3.3 Licensee's Basis for Requesting Relief In the application dated December 20, 2016, the licensee stated the following in regards to the basis for requesting relief.

The PNP construction permit was issued on March 14, 1967. At that time, the construction code did not require that a weld reference system be established. This included the marking of welds inside ISi boundaries before or during the preservice examination.

Establishment of a weld reference system in accordance with the Subarticle IWA-2600 cannot be practically attained based on the number and location of the welds. To meet the Subarticle IWA-2600 requirements, each and every weld

within the ISi boundary would have to be accessed in order to install permanent markings using low stress stamps or vibratooling, or both. The majority of the subject welds are located in radiation areas and covered under insulation.

Therefore, accessing them for the sole purpose of installing the required markings would require significant man-hours in radiation areas, resulting in unnecessary high radiation exposure to workers without a compensating increase in the level of quality and safety.

Hence, the licensee has proposed the use of an alternative weld reference system in Relief Request No. RR 5-4.

3.4 Licensee's Proposed Alternative As an alternative to a weld reference system, the licensee proposes to implement the following requirements to locate and identify subject weld areas.

ENO will use isometric drawings at PNP to provide a detailed identification and location of each weld requiring examination.

In addition, the following will be performed:

Surface Examination - Where surface examination is specified,Section XI requires that 100% of the selected weld or area be examined. Unlike the performance of volumetric examination, there is no need to indicate the direction of examination to assure uniformity in reporting results. In these cases, no marks will be placed on the weld or area. The location of any accepted surface indications will be documented by the use of a map or photograph that permits accurate identification of areas on the examination surface.

Volumetric Examination (Manual) - If a weld is accepted for continued service that contains volumetric indications accepted under the criteria of ASME BPV

[Boiler and Pressure Vessel] Code,Section XI, Subarticles IWB-3500, Acceptance Standards, and IWB-3600, Analytical Evaluation of Flaws, for Class 1 components, or IWC-3500, Acceptance Standards and IWC-3600, Analytical Evaluation of Flaws, for class 2 components, then the indications will be identified by appropriate reference marks to ensure that the indications can be located during subsequent examinations. At PNP, the reference marks may be permanently fixed on the weld, or documented on a map or photograph of the weld or the component surface, in order to accurately locate areas on the examination surface (e.g., reference points, orientation and/or proximity to other welds) where volumetric indications were previously discovered. This method positively identifies the weld or area in question and determines the examination starting point. Further, the examination starting point is established by using a zero reference point as instructed by written guidance.

Volumetric Examination (Automated Vessel) - The automated vessel tool establishes its examination location using an existing zero reference point on the reactor vessel. The zero reference point allows the tool to repeat examinations in the same location without the need for an additional reference system. The

automated vessel tool determines its location by the use of an electronic encoder system which provides reasonable assurance of repeatability.

3.5 Staff Evaluation The weld reference system, as stated under subparagraph IWA-2610 of the ASME Section XI Code, 2007 edition with addenda through 2008, requires identification of each weld for ISi, location of its centerline, and designation of regular intervals along the length of the weld to ensure repeatability of the examination. The ASME Code requires that each weld be permanently identified by marking on the weld using low stress stamps or vibratooling or both.

The NRC staff concurs with the licensee that at the time of construction of PNP, the application of a reference system, which included the marking of welds before or during the preservice examination, was not required by the ASME Code and, accordingly welds were not marked. In order to meet the current requirements, the NRC staff also notes that the licensee must access each and every weld within the ISi boundary to establish permanent markings in accordance with IWA-2600. Given that a significant number of these welds are located in radiation areas, the NRC staff acknowledges the radiological dose hardship associated with the time to setup scaffolding, remove insulation, and perform all of the required markings required by IWA-2600.

Given the radiological hardship above, the NRC staff reviewed the licensee's proposed alternative. The licensee noted that they will provide a detailed identification and location of each weld requiring examination on isometric drawings. While this alternative action does not met the full defense-in-depth of the marking identification system, the NRC staff notes that licensee drawings are required to be complete and up to date in accordance with 10 CFR, Appendix B, Section Ill, "Design Control." Additionally, the licensee will, if a weld is found to contain an indication during ISi, apply the appropriate reference marks on the weld to repeat future examination of the weld. The licensee will further document such indications on a weld map or with photograph(s) of the weld that will assist in identifying any indication in relation to the examination starting point and the area on the examination surface (e.g., reference points, orientation and/or proximity to other welds) of the weld. The NRC staff found for the limited continued operational period of PNP, which does not currently include another full 10-year ISi interval following the current ISi interval, and the frequency of these examinations, typically, once per 10-year ISi period, that the licensee's proposed alternative to the weld reference system of IWA-2600 would attain the same objective of ensuring effective examination, if indications are found during examination.

The NRC staff, therefore, finds that the licensee's proposed alternative provides a reasonable assurance of the structural integrity of the subject welds which require inspection through the remaining period of operation of PNP. Accordingly, the NRC staff has determined that establishment of a weld reference system in accordance with paragraph IWA-2600 for all welds within the ISi boundary, would result in hardship to the licensee without a compensating increase in the level of quality and safety.

4.0 CONCLUSION

As set forth above, the NRC staff determines that compliance with the ASME Code requirement, in lieu of the proposed alternative of RR 5-4, would result in hardship without a compensating increase in the level of quality and safety. The licensee's proposed alternative to use isometric

drawings and perform surface and volumetric examinations, using maps or photographs, provides reasonable assurance of structural integrity of the subject welds. Accordingly, the NRC concludes that the licensee has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a(z)(2). Therefore, the NRC staff authorizes Relief Request No.

RR 5-4 at PNP for the remainder of the fifth 10-year ISi interval from January 1, 2018, through December 12, 2025.

All other requirements of the ASME Code,Section XI for which relief has not been specifically requested and approved remain applicable, including a third party review by the Authorized Nuclear lnservice Inspector.

Principal Contributors: J. Collins C. Fairbanks Date of issuance: September 7, 2017

ML17216A173 *via email OFFICE DORL/LPL3/PM DORL/LPL3/LA DE/EPNB/BC* DORL/LPL3/BC NAME JRankin SRohrer DAiiey DWrona DATE 08/08/17 08/07/17 08/02/2017 09/07/17