ML21089A010

Relief Request 66 to Defer Inservice Inspection of Containment Tendon by One Year Due to Covid-19 Pandemic

ML21089A010
Person / Time
Site:	Palo Verde
Issue date:	04/02/2021
From:	Jennifer Dixon-Herrity Plant Licensing Branch IV
To:	Lacal M Arizona Public Service Co
Lingam S, 301-415-1564
References
EPID L-2020-LLR-0145
Download: ML21089A010 (7)

Text

April 2, 2021 Mrs. Maria L. Lacal Executive Vice President/

Chief Nuclear Officer Arizona Public Service Company P.O. Box 52034, Mail Station 7605 Phoenix, AZ 85072-2034

SUBJECT:

PALO VERDE NUCLEAR GENERATING STATION, UNIT 2 - RELIEF REQUEST 66 TO DEFER INSERVICE INSPECTION OF CONTAINMENT TENDON BY 1 YEAR DUE TO THE COVID-19 PANDEMIC (EPID L-2020-LLR-0145 [COVID-19])

Dear Mrs. Lacal:

By electronic submittal dated November 5, 2020, Arizona Public Service Company (the licensee) submitted a COVID-19 relief request to extend containment tendon inspection at Palo Verde Nuclear Generating Station, Unit 2 (Palo Verde, Unit 2) by 1 year, in accordance with Title 10 of the Code of Federal Regulations (10 CFR) Section 50.55a(z)(2), Hardship without a compensating increase in quality and safety.

Specifically, pursuant to 10 CFR 50.55a(z)(2), the licensee requested U.S. Nuclear Regulatory Commission (NRC) approval of Relief Request 66 regarding the interval between containment tendon inspections as specified per paragraph IWL-2420 of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, Subsection IWL, Requirements for Class CC

[Concrete Containment] Concrete Components of Light-Water Cooled Plants, required by 10 CFR 50.55a. Relief is requested on the basis that compliance with the Code-specified inspection interval during the COVID-19 pandemic would result in hardship without a compensating increase in the level of quality and safety for Palo Verde, Unit 2 .

The U.S. Federal Government made a declaration of emergency due to COVID-19, under the Stafford Act on March 13, 2020, while the U.S. Centers for Disease Control and Prevention determined that COVID-19 poses a serious public health risk. Due to the COVID-19 pandemic, the licensee has enacted guidelines to limit outside contractors, including those that perform examinations for the inservice inspection program, in order to minimize the potential of inadvertently spreading the COVID-19 virus to Palo Verde personnel.

The licensee stated in its submittal dated November 5, 2020, that it currently does not have the internal capability and equipment to perform the containment tendon inspection, and that this must be done by the vendor that will need 10 contractors. In general, this work activity involves a team of people working in close proximity and does not allow for social distancing, which can be a large contributor towards the spread of the virus. The licensee is proposing a one-time, 1-year extension of the containment post-tensioning system inspection period to allow time to

M. Lacal safely and effectively accomplish the inspection. The duration of the proposed alternative would extend the current February 8, 2021, deadline for performing the Unit 2, 35th year IWL Containment Post-Tensioning System Inspection, until February 8, 2022. The licensee received verbal authorization from the NRC on November 19, 2020.

The NRC staff has reviewed the licensees submittal, and concludes, as set forth in the enclosed safety evaluation, that the licensees proposed alternative in Relief Request 66 has adequately addressed all the regulatory requirements set forth in 10 CFR 50.55a(z)(2).

Accordingly, the NRC staff determines that granting relief pursuant to 10 CFR 50.55a(z)(2) is authorized by law and will not endanger life or property or the common defense and security, and is otherwise in the public interest giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility. Therefore, the NRC staff authorizes the proposed alternative at Palo Verde, Unit 2, for the period beginning February 8, 2021, and ending February 8, 2022, during the Palo Verde, Unit 2, third 10-year Containment Tendon Inspection Program interval.

All other ASME Code Section XI requirements for which the alternative was not specifically requested and authorized in this proposed alternative remain applicable, including a third-party review by the Authorized Nuclear Inservice Inspector.

If you have any questions, please contact the Project Manager, Siva P. Lingam, at 301-415-1564 or by e-mail to Siva.Lingam@nrc.gov.

Sincerely, Jennifer L. Digitally signed by Jennifer L. Dixon-Herrity Dixon-Herrity Date: 2021.04.02 09:27:25 -04'00' Jennifer L. Dixon-Herrity, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. STN 50-529

Enclosure:

Safety Evaluation cc: Listserv

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELIEF REQUEST 66 REQUEST TO DEFER ASME CODE INSERVICE INSPECTION OF CONTAINMENT TENDON BY 1 YEAR DUE TO COVID-19 PANDEMIC ARIZONA PUBLIC SERVICE COMPANY PALO VERDE NUCLEAR GENERATING STATION, UNIT 2 DOCKET NO. STN 50-529

1.0 INTRODUCTION

By electronic submittal dated November 5, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20315A156), Arizona Public Service Company (APS, the licensee) submitted a COVID-19 relief request to extend the containment tendon inspection at Palo Verde Nuclear Generating Station, Unit 2 (Palo Verde, Unit 2) by 1 year, in accordance with the requirements of Title 10 of the Code of Federal Regulations (10 CFR) Section 50.55a(z)(2), Hardship without a compensating increase in quality and safety.

Specifically, pursuant to 10 CFR 50.55a(z)(2), the licensee requested U.S. Nuclear Regulatory Commission (NRC) approval of Relief Request 66 regarding the interval between containment tendon inspections as specified per paragraph IWL-2420 of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, Subsection IWL, Requirements for Class CC

[Concrete Containment] Concrete Components of Light-Water Cooled Plants, required by 10 CFR 50.55a, Codes and standards.

Relief is requested on the basis that compliance with the Code-specified inspection interval during the COVID-19 pandemic would result in hardship without a compensating increase in the level of quality and safety for Palo Verde, Unit 2. The duration of the proposed alternative would extend the current February 8, 2021, deadline, for performing the Unit 2, 35th year, IWL Containment Post-Tensioning System Inspection, until February 8, 2022.

By teleconference call on November 19, 2020, the NRC provided verbal authorization to APS for the subject relief request for Palo Verde, Unit 2 (ADAMS Accession No. ML20325A039).

Enclosure

2.0 REGULATORY EVALUATION

Pursuant to 10 CFR 50.55a(g)(4), Inservice inspection standards requirement for operating plants, throughout the service life of a nuclear power facility, components that are classified as ASME Class CC pressure retaining components must meet the requirements set forth in Section XI of the ASME Code, Subsection IWL, as incorporated by reference in paragraph (a)(1)(ii), ASME Boiler and Pressure Vessel Code,Section XI, subject to the conditions listed in paragraph (b)(2)(ix),Section XI condition: Metal containment examinations, of 10 CFR 50.55a.Section XI, Subsection IWL of the ASME Code, provides rules for inservice inspection (ISI) and repair/replacement activities of the reinforced concrete and post-tensioning system components of Class CC containment structures. The appropriate edition of the code to be used for successive 120-month inspection intervals is determined under paragraph (g)(4)(ii), Applicable ISI Code: Successive 120-month intervals, of 10 CFR 50.55a. Alternatives to the requirements of 10 CFR 50.55a(g), Preservice and inservice inspection requirements, may be authorized by the NRC under 10 CFR 50.55a(z)(2) if the licensee demonstrates that the specified requirement would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

Pursuant 10 CFR 50.55a(g)(4)(ii), the licensees Code of record for the third 10-year containment ISI interval is the 2007 Edition with the 2008 Addenda, of ASME Code,Section XI, Subsection IWL. Subarticle IWL-2420 Unbonded Post-Tensioning Systems, paragraph (a) states that Unbonded post-tensioning systems shall be examined in accordance with IWL-2520 at 1, 3, and 5 years following the completion of the containment Structural Integrity Test and every 5 years thereafter. Subarticle IWL-2420 further states in paragraph (c) that The 10-year and subsequent examinations shall commence not more than 1 year prior to the specified dates and shall be completed not more than 1 year after such dates. If plant operating conditions are such that examination of portions of the post-tensioning system cannot be completed within this stated time interval, examination of those portions may be deferred until the next regularly scheduled plant outage. Table IWL-2500-1, Examination Category L-B, Unbonded Post-Tensioning System, provides the examination and test requirements for the post-tensioning system components.

Palo Verde Unit 2s specified date for the 35th surveillance year subsequent examination under IWL-2420(a) is February 8, 2020. Therefore, per IWL-2420(c), Palo Verde Unit 2s deadline for the completion of the 35th year inspection is February 8, 2021. For this relief request, the licensee requests postponing the completion date for the 35th year surveillance to no later than February 8, 2022, under 10 CFR 50.55a(z)(2), because of hardship or unusual difficulty imposed by the national emergency declaration due to the COVID-19 pandemic.

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 NRC to authorize, the alternative requested by the licensee.

3.0 TECHNICAL EVALUATION

3.1 Licensees Proposed Alternative The licensees alternative request applies to the containment unbonded post-tensioning system inspections. Specifically, the request applies to the requirement in subparagraph IWL-2420(c) as stated above.

The licensees proposed alternative corresponding to the above code requirement is a one-time, 12-month extension to the completion date of the unbonded post-tensioning system examination for the 35th year inspection. The licensees 35th surveillance date began on February 8, 2020, and the Palo Verde, Unit 2, deadline for the completion of the inspection was until February 8, 2021. The proposed alternative would postpone the required inspections to be completed no later than February 8, 2022. The licensee requested authorization for use of the proposed alternative under 10 CFR 50.55a(z)(2), on the basis that complying with the specified requirement would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety, due to the ongoing national emergency related to the COVID-19 pandemic.

The licensees November 5, 2020, letter stated that the U.S. Federal Government had made a declaration of emergency due to COVID-19, under the Stafford Act, on March 13, 2020, while the U.S. Centers for Disease Control and Prevention (CDC) determined that COVID-19 posed a serious public health risk. Due to the COVID-19 pandemic, the licensee had enacted guidelines to limit outside contractors, including those that perform examinations for the ISI program, in order to minimize the potential of inadvertently spreading the COVID-19 virus to Palo Verde personnel.

The licensees November 5, 2020, letter also stated that currently, APS did not have the internal capability and equipment to perform the inspection, and this must be done by the vendor. The letter stated that 10 contractors were needed to perform the containment tendon inspections. In general, this work activity involves a team of people working in close proximity and does not allow for social distancing which could be a large contributor towards the spread of the virus.

Therefore, the licensee requested a 12-month extension.

In its request, the licensee stated that the prior containment post-tensioning surveillances had been completed successfully with no abnormal degradation. The recent inspection results of 25th and 30th years inspections were included as an attachment to the relief request and the report in the attachment concluded that the structural and functional integrity of the post tensioning system was acceptable. The licensees November 5, 2020, letter further stated that a visual examination of the Unit 2 Concrete Containments exterior surface was completed in August of 2017. The inspection results indicated that no conditions which would require structural repair or more frequent examinations were identified, and the condition of the exterior concrete surface was deemed acceptable, per paragraph IWL 3211, Acceptance by Examination.

3.2 NRC Staff Evaluation The NRC staff reviewed the information provided in the proposed alternative request, as well as general information available regarding the COVID-19 pandemic, and noted that the CDC has identified social distancing as a method for mitigating the spread of the COVID-19 virus and defines social distancing as remaining out of congregate settings, avoiding mass gatherings, and maintaining distance (approximately 6 feet or 2 meters) from others when possible. The NRC staff also noted that the subject containment inspections require a significant number of contractors to be onsite working closely with licensee personnel in conditions that may not be conducive to social distancing. Therefore, the NRC staff finds that completing the inspections as required would result in a hardship or unusual difficulty.

Summary results of the 25th and 30th years Tendon Surveillances, performed on Palo Verde, Unit 2, was attached to the licensees November 5, 2020, submittal. The tendon surveillances

results confirmed that the functional integrity of the selected post-tensioning system met the applicable code requirements. The NRC staff reviewed the licensees Tendon Surveillances results and noted that the inspections have been completed successfully with no indications of degradation to the post-tensioning system that would compromise the structural integrity of the containment building. Specifically, the NRC staff finds that the licensee performed all the ASME Code,Section XI, Table IWL-2500-1 (L-B) inspection requirements of the containment post-tensioning system and met the requirements as specified in the Code.

Since the previous inspection results were all acceptable, the regression analysis shows that the tendon forces in the post-tensioning system is expected to exceed the minimum prescribed lower limit value for each tendon type for the duration of the current license, and the 2017 visual inspection showed no significant signs of degradation. The NRC staff finds that conducting the required inspections of the unbonded post-tensioning system by the February 8, 2021, deadline would not have provided an increase in quality or safety commensurate with the increased hardship.

Based on its review, the NRC staff finds it is acceptable for the licensee to defer completion of the required ASME Section XI, Table IWL-2500-1 (L-B) inspections of the containment post-tensioning system for 1 year, or until no later than February 8, 2022. The NRC staff also finds that there is reasonable assurance that the structural integrity of the containment building will be maintained until February 8, 2022, when the required ASME Code inspections will be completed.

4.0 CONCLUSION

As set forth above, the NRC staff determines that complying with the specified requirement would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. The NRC staff concludes that the licensees proposed alternative in Relief Request 66 has adequately addressed the regulatory requirements set forth in 10 CFR 50.55a(z)(2). Accordingly, the NRC staff determines that granting relief pursuant to 10 CFR 50.55a(z)(2) is authorized by law and will not endanger life or property or the common defense and security, and is otherwise in the public interest giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility.

Therefore, the NRC staff authorizes the proposed alternative at Palo Verde, Unit 2 for the period beginning February 8, 2021, and ending February 8, 2022, during the Palo Verde, Unit 2, third 10-year Containment Tendon Inspection Program interval.

All other ASME Code Section XI requirements for which the alternative was not specifically requested and authorized in this proposed alternative remain applicable, including a third-party review by the Authorized Nuclear Inservice Inspector.

Principal Contributor: J. Ma Date: April 2, 2021

ML21089A010 *by e-mail OFFICE NRR/DORL/LPL4/PM* NRR/DORL/LPL4/LA* NRR/DEX/ESEB/BC* NRR/DORL/LPL4/BC*

NAME SLingam PBlechman JColaccino JDixon-Herrity DATE 3/29/2021 4/1/2021 3/26/2021 4/2/2021