ML21165A183

RR-67 6-16-21 Pre-Submittal Public Meeting Presentation Slides

ML21165A183
Person / Time
Site:	Palo Verde
Issue date:	06/14/2021
From:	Arizona Public Service Co
To:	Siva Lingam NRC/NRR/DORL/LPL4
Lingam S, 301-415-1564
References
Download: ML21165A183 (12)

Text

Proposed IWL Inspection Alternative Relief Request 67 - Pre-submittal Meeting Palo Verde Nuclear Generating Station (PVNGS)

June 16, 2021

Agenda

• Introduction

• Relief Request Summary

• Current Requirements

• Alternative Requirements

• Alternative Justifications

• Duration of Proposed Alternatives

• Precedents

• Schedule

Relief Request Summary

• Reason for the request:

• The alternative modified schedule proposed will reduce resources required and safety risks associated with performing the exams while still providing reasonable assurance the containment post-tensioning systems will continue to perform their function.

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Relief Request Summary

• ASME BPV Section XI, Subsection IWL requires certain scheduling frequencies and specific tests of post-tensioning system tendons

• APS is seeking a relief request in accordance with 10 CFR 50.55a(z)(1)

• Units 1 and 3: Alternatives are being requested from IWL-2520 ten year surveillance scheduling requirements Unit 2 will be addressed in a subsequent submittal after the next surveillance is completed in Dec 2021 / Jan 2022.

• Units 1, 2, and 3: Alternatives are being requested from certain IWL-2523 tendon wire and strand testing 4

Current Requirements

• IWL-2421 - PVNGS Units 1, 2, and 3 are currently using the alternative scheduling requirements of IWL-2421(b):

• (1) For the containment with the first structural integrity test, all examinations required by IWL-2520 shall be performed at 1, 3, and 10 years, and every 10 years thereafter. In addition, the examinations required by IWL-2524 and IWL-2525 shall be performed at 5 and 15 years, and every 10 years thereafter.

• (2) For each subsequent containment constructed at the site, all examinations required by IWL-2520 shall be performed at 1, 5, and 15 years, and every 10 years thereafter. In addition, the examinations required by IWL-2524 and IWL-2525 shall be performed at 3 and 10 years, and every 10 years thereafter.

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Current Requirements IWL-2523.1

• Requires tendon detensioning and wire sample removal, as follows:

• One sample tendon of each type shall be completely detensioned. A single wire or strand shall be removed from each detensioned tendon.

IWL-2523.2

• Requires that tension tests be performed on each removed wire or strand, as follows:

• Tension tests shall be performed on each removed wire or strand: one at each end, one at mid-length, and one in the location of the most corroded area, if any. []

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Alternative Requirements - IWL-2421

• Units 1 and 3:

• (1) For the containment with the first structural integrity test, all examinations required by IWL-2520 shall be performed every 20 years thereafter.

• (2) For each subsequent containment constructed at the site, all examinations required by IWL-2520 shall be performed every 20 years thereafter.

NOTE: Unit 2 is currently excluded from this scheduled alternative, and is planned to be addressed in 2022 after the next scheduled Unit 2 surveillance is completed.

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Alternative Requirements -IWL-2523.1 and IWL-2523.2

• For Units 1, 2, and 3:

• IWL-2523.1: Detension a tendon and remove a single wire for examination only if a tendon anchorage visual examination in accordance with IWL-2524 detects a loss of wires in excess of that permitted by the design, or if required as a result of an engineering evaluation

• IWL-2523.2: Eliminate tension testing to determine the yield strength, ultimate tensile strength, and elongation of tendon wires. Visual examinations shall continue to be performed when detensioning is required.

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Alternative Justifications

• Previous IWL examination results indicate excellent performance of the post-tensioning system.

• Tendon Force trendlines indicate tendons for Units 1 and 3 will remain above the minimum required value beyond the next alternative scheduled surveillance (Code requirement), and even beyond 100 years from initial tensioning.

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Duration of Proposed Alternatives

• The proposed alternatives are requested for the third and subsequent intervals until the end of PVNGS plant life.

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Precedents

• Millstone Power Station, Unit 2 [ML20287A471]

• Vogtle Electric Generating Plant, Units 1 and 2 [ML19182A077]

• Three Mile Island Nuclear Station, Unit 1 [ML19226A023]

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Schedule

• Planning to submit in early July 2021

• NRC approval requested in June 2022 12