ML23150A138

Pre Submittal Meeting: Containment Inservice Inspection (Cisi) Relief Request, June 1, 2023

ML23150A138
Person / Time
Site:	Cooper
Issue date:	06/01/2023
From:	Nebraska Public Power District (NPPD)
To:	Thomas Wengert Plant Licensing Branch IV
Wengert T, NRR/DORL/LPLIV, 415-4037
References
Download: ML23150A138 (1)

Text

Pre-Submittal Meeting: Containment Inservice Inspection (CISI) Relief Request June 1, 2023

Agenda

• Introductions

• Purpose

• Background

• ASME Code Requirements

• Basis and Alternative

• Drywell Configuration

• Submittal Timeline

Purpose

• Discuss the need for relief from and alternative to Containment Inservice Inspection (CISI) ASME code requirements for Drywell shell flange to head assembly bolted connection examination

Background

• CNS Containment Inservice Inspection (ISI) Program is in accordance with the 2007 Edition/2008 Addenda of ASME Section XI, Category E-G, Item E8.10

• The CNS drywell shell flange to head assembly configuration contains 76 bolting assemblies comprised of a 2 1/4 diameter bolt, upper spherical washer, lower spherical washer, and nut

• The lower spherical washers and nuts were tack welded to the bottom side of lower drywell flange during original construction

• 70 lower spherical washers and 43 nuts are still welded to lower side of drywell shell flange limiting ability to obtain 100% VT-1 exam coverage

ASME Section XI, 2007 Edition 2008 Addenda Code Requirements

• Paragraph IWE-2313 (b), VT-1 Visual Examinations

- in accordance with IWE-2500 and Table IWE-2500- 1, Examination Category E-G, to assess the condition of containment pressure retaining bolting.

• Table IWE-2500-1 requires VT-1 of 100% of containment bolting when disassembled once in the interval

- Notes 1 and 2 state the following:

1. Examination shall include bolts, studs, nuts, bushings, washers, and threads in base material and flange ligaments between fastener holes.

2. Examination may be performed with the connection assembled and bolting in place under tension, provided the connection is not disassembled during the interval. If the bolted connection is disassembled for any reason during the interval, the examination shall be performed with the connection disassembled.

Basis and Alternative

• During Refueling Outage 32 (RE32) in the fall of 2022, CNS performed direct VT-1 examinations of disassembled bolting:

- 76 bolts, 76 upper washers, 33 nuts and 6 lower washers were examined SAT

- Coverage estimated at 63% based on number of components examined compared to total (not based on surface area)

• Lower nuts and washers achieved a best effort remote visual exam in place with assistance of In-Vessel Visual Inspection (IVVI) team after refueling cavity was flooded to minimize dose

• Purpose of relief request is to request NRC acceptance of the limited examination performed in RE32 based on 10CFR50.55a(g)(5)(iii) - Inservice inspection impracticality

- Hydrolazing lower nuts/washers in 2024 (RE33) would yield minimal increase in examination coverage. Dose estimated at 3.5 REM would not support ALARA principles

7 8

9 10 Submittal Timeline

• Submit to NRC June 2023

• Estimated 1-yr NRC review time

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