# Outage Execution Training: Public Reference Register

These 17 public references support operating-experience context, not the fictional scenarios, technical acceptance, or modeled recovery effects. Publication dates and limitations are preserved. No current Vogtle clevis repair campaign was established by this research.

## S1: Baffle-Former Bolts (NRC Operating Experience topic page)

Date: undated page, content covers 2016-2019 events. Type: NRC public web page (operating experience).

In spring 2016 Indian Point Unit 2 and Salem Unit 1 identified large numbers of degraded baffle-former bolts during refueling-outage ultrasonic (UT) inspections; IP2 found 227 of 832 bolts potentially degraded; Salem 1 replaced 189 bolts in 2016 and in spring 2019 UT identified 228 potentially degraded bolts; D.C. Cook Unit 2 found 181 potentially degraded bolts in October 2016 and replaced 201. ([Original publication](https://www.nrc.gov/reactors/operating/ops-experience/baffle-former-bolts))

Applicability limits: Does not mention thermal shield support block bolts, thermal shield flexures, or clevis insert bolts. No page publication date. No EDM or removal-method information. No Vogtle information.

## S2: Westinghouse Nuclear Safety Advisory Letter NSAL-16-1, "Baffle-Former Bolts" (filed in Indian Point license renewal docket)

Date: July 5, 2016. Type: Vendor safety advisory letter, publicly filed in NRC ADAMS.

Inspections of reactor internals were recently performed at Indian Point Unit 2 and Salem Unit 1 (both Westinghouse NSSS units); D.C. Cook Unit 2 in fall 2010 identified 18 damaged bolts visually, with replacement work revealing 24 additional failed bolts (total 42); the letter groups the Westinghouse fleet into susceptibility tiers (e.g., Indian Point 2/3, Salem 1/2, D.C. Cook 1/2, Diablo Canyon 1 as Tier 1a). ([Original publication](https://www.nrc.gov/docs/ML1619/ML16196A245.pdf))

Applicability limits: Baffle-former bolts only. No mention of thermal shield support block bolts/flexures or clevis insert bolts. No EDM mention. Tier assignments are as of 2016 and may have changed.

## S3: PWROG Materials Subcommittee, "Clevis Insert Bolt OE and Guidance" (Technical Information Exchange slides)

Date: August 2021 (updated 8-9-21). Type: Industry owners-group presentation in NRC ADAMS.

First discovery of reactor vessel internals lower radial support clevis insert bolt degradation occurred in 2010, root-caused to PWSCC of Alloy X-750 with a susceptible heat treatment; at the affected unit all 29 bolts removed were either already separated, separated during removal, or had cracks present; guidance moved the inspection approach to UT with a proactive-replacement alternative (proposed implementation July 2023). ([Original publication](https://www.nrc.gov/docs/ML2122/ML21221A125.pdf))

Applicability limits: No plant names are stated in the fetched content. No EDM mention (only that bolts "separated during removal"). Does not address baffle-former bolts or thermal shield hardware. Status of the proposed 2023 implementation date is not established here.

## S4: Westinghouse InfoGram IG-10-1, "Reactor Internals Lower Radial Support Clevis Insert Cap Screw Degradation"

Date: March 31, 2010 (submitted to NRC docket July 22, 2013 / August 10, 2015). Type: Vendor InfoGram, publicly filed in NRC ADAMS.

During the March 2010 10-year in-service inspection at D.C. Cook Unit 1, an anomaly was observed in the lower radial support clevis inserts; at seven of 48 cap screw locations there was visual evidence that the cap screw head had detached from the shank; analysis supported one additional fuel cycle with no immediate physical modifications. ([Original publication](https://www.nrc.gov/docs/ML1533/ML15335A281.pdf))

Applicability limits: Single plant, 2010 vintage. Terminology is "cap screws," not "bolts." No EDM or removal-method content. Says nothing about Vogtle, baffle-former bolts, or thermal shield hardware.

## S5: Vogtle Units 1 and 2, License Renewal Commitment Item No. 20 primary reactor internals inspection plan (SNC letter NL-25-0013)

Date: January 16, 2025. Type: Licensee submittal in NRC ADAMS.

Vogtle's reactor internals inspection schedule lists "Lower Radial Support Clevis Insert X-750 Bolts" for UT examination and "Baffle Former Assembly - Baffle to Former Bolts" (Item W6) for UT, and marks the thermal shield flexure item (W9) not applicable because Vogtle Units 1 and 2 use a neutron panel design and therefore have no thermal shield flexures; extended operation begins January 2027 (Unit 1) and February 2029 (Unit 2). ([Original publication](https://www.nrc.gov/docs/ML2501/ML25016A339.pdf))

Applicability limits: A forward-looking inspection plan only. Does not report any Vogtle clevis insert bolt degradation, replacement, or EDM work. Does not establish that any clevis UT has yet been performed at Vogtle.

## S6: NRC letter, Vogtle Units 1 and 2 - License Renewal Commitment Item No. 20 fulfilled (staff assessment)

Date: April 30, 2025. Type: NRC staff letter / assessment in ADAMS.

NRC staff reviewed SNC's January 16, 2025 submittal as supplemented April 4, 2025 and concluded the Vogtle Units 1 and 2 reactor internals inspection plan (LRC Item No. 20) is acceptable and the commitment fulfilled; the plan supplements ASME Section XI B-N visual examinations with examinations per Westinghouse Technical Bulletin TB 14-5, "Reactor Internals Lower Radial Support Clevis Insert Cap Screw Degradation"; Vogtle units have 832 baffle-former bolts each and volumetric BFB examinations were completed (fall 2024 and spring 2025). ([Original publication](https://www.nrc.gov/docs/ML2511/ML25113A190.pdf))

Applicability limits: Regulatory acceptance of a plan; it does not report Vogtle clevis insert bolt inspection results, degradation, or any repair/EDM activity. Unit-to-season assignment of the BFB exams differs between this letter and the licensee RAI response (S7).

## S7: Vogtle Units 1 and 2, Response to Request for Additional Information regarding LRC Item No. 20 (SNC letter NL-25-0070)

Date: April 4, 2025. Type: Licensee RAI response in NRC ADAMS.

Vogtle Units 1 and 2 are Westinghouse upflow designs with 832 baffle former bolts per unit (1,664 total); of these, 1,651 were confirmed without indications, 1 had a rejectable indication, 5 were uninspectable and 7 could not be completed due to equipment challenges, with all not-confirmed bolts treated as failures and no clustering failures; reinspection interval per MRP-2017-009 is six years. ([Original publication](https://www.nrc.gov/docs/ML2509/ML25094A206.pdf))

Applicability limits: Establishes baffle-former bolt examination outcome only. Does not report clevis insert bolt results, does not mention EDM, and does not establish any 2026 Vogtle internals bolt work. Unit/season pairing of the exams is stated inconsistently versus S6.

## S8: Beaver Valley Power Station Unit 1 - Notification of Deviation from MRP-227, Revision 1-A, Section 7.5 Regarding the Disposition of Examination Results for Thermal Shield Flexures (Vistra letter L-25-084)

Date: April 23, 2025. Type: Licensee NEI 03-08 deviation notification in NRC ADAMS.

MRP-227 examinations during Beaver Valley Unit 1 outage 1R29 (spring 2024) identified five fractured/degraded thermal shield flexures and two degraded thermal shield support block (TSSB) bolts; 1,088 BVPS-1 baffle bolts had been volumetrically examined in 1R28 (fall 2022); the flexures and degraded TSSB bolts were to be replaced in outage 1R30 (scheduled October 5 - November 21, 2025); an NEI 03-08 deviation was developed and submitted because the examination results could not be dispositioned per MRP-227 Rev 1-A Section 7.5. ([Original publication](https://www.nrc.gov/docs/ML2511/ML25113A165.pdf))

Applicability limits: Does not mention EDM. Does not address clevis insert bolts (it discusses the lower radial support system clevises only as an impact-load recipient). Forward-looking on 1R30 scope; S16 separately reports examination review, not replacement completion. Plant-specific; not generalizable to other designs.

## S9: SONGS Unit 1 - response on issues regarding degraded fasteners for thermal shield support blocks (license amendment support, "Cycle X Thermal Shield Monitoring Program")

Date: 1989 (references February 12, 1988 through February 1989). Type: Licensee/NRC correspondence in NRC ADAMS (legacy).

After Westinghouse informed the licensee in late 1987/February 1988 of degraded reactor vessel thermal shield supports found at Haddam Neck, San Onofre Unit 1 inspected its thermal shield supports; five of six flexures were known broken and support-block bolt degradation was evaluated, with analyzed cases running from three degraded blocks with one intact flexure to a worst-credible case of all flexures and bolts broken, each dispositioned as acceptable. ([Original publication](https://www.nrc.gov/docs/ML1331/ML13311B148.pdf))

Applicability limits: Legacy 1988-1990 plant-specific record; SONGS 1 and Haddam Neck are permanently shut down. No baffle-former or clevis insert bolt content. Thermal shield support block bolts are a distinct component from baffle-former bolts and clevis insert bolts; no interchangeability is implied.

## S10: SONGS Unit 1 - Nonproprietary "Thermal Shield Support System Design & Replacement Plan"

Date: circa 1989-1990 (references October 6, 1989 commitment and Cycle 11 outage beginning by June 30, 1990). Type: Licensee/vendor replacement plan in NRC ADAMS (legacy).

The SONGS 1 thermal shield support system replacement work was to involve electric discharge machining (EDM) tooling together with water-operated hydraulic positioners and jacks; the sequence included as-found inspection, flexure removal, support block replacement, in-situ dimensional measurement before final part machining, and machining of inspection ports in the core barrel flange for future inspections; support block bolt failures were attributed to high-cycle fatigue from flow-induced vibration. ([Original publication](https://www.nrc.gov/docs/ML1331/ML13316A540.pdf))

Applicability limits: This is the clearest public EDM-to-thermal-shield-support-bolt link found, but it is a legacy plan document for a now-shutdown unit. It does not establish EDM use for thermal shield support block bolts at any currently operating plant, and it contains no acceptance criteria or machining parameters relied upon here.

## S11: Framatome, "RPV internals (incl. Baffle Bolts and Clevis Bolts) replacement" (product A0137)

Date: page dated 2025-10-22 in search index; no date stated on page. Type: Primary vendor service publication.

The vendor states its RPV internals bolt replacement solution uses EDM (Electric Discharge Machining) to address broken bolt/shank removal and installation as well as broken bolt/oversize threading and bolt installation, within a "Reactor Internals Asset Management approach" that plans examination intervals, replacement patterns and outage duration. ([Original publication](https://www.framatome.com/solutions-portfolio/product/a0137/))

Applicability limits: Vendor marketing content: no plants, dates, or counts. Covers baffle bolts and clevis bolts; it does not mention thermal shield support block bolts. Establishes capability, not that EDM was used in any specific campaign.

## S12: Framatome product sheet, "Clevis Bolt Replacement"

Date: 2024 (copyright © 2024 Framatome Inc.). Type: Primary vendor service publication.

The vendor states it optimized its electrical discharge machining (EDM) process to incorporate one-step functions and that all machining operations use the EDM process to avoid foreign material concerns; cited experience includes successful removal of 28 bolts and replacement of 23 standard and 5 oversized LRSS clevis bolts at a utility in 2013 and a clevis repair solution at a utility in 2020. ([Original publication](https://www.framatome.com/solutions-portfolio/docs/default-source/default-document-library/product-sheets/a0163-ps-us-r-en-800-07-24-clevis-bolt-replacement.pdf?sfvrsn=48f84929_0))

Applicability limits: No plant names. Vendor-reported experience. Applies to lower radial support (clevis) bolts, not to thermal shield support block bolts or baffle-former bolts. Tooling details and torque values are deliberately excluded from the brief.

## S13: Westinghouse blog, "First-of-a-Kind Identification and Replacement of Failed Thermal Shield Flexures"

Date: September 8, 2021 (page date from index). Type: Vendor publication (blog).

During a scheduled 2019 refueling outage at Salem Unit 1, vendor field personnel identified four failed thermal shield support block bolts (TSSBBs) and cracks on the outer welds of two thermal shield flexures; fuel grid strap damage on two peripheral assemblies was attributed to protruding baffle-former bolt heads and subsequent BFB inspection identified 232 new UT indications; visual inspections later confirmed five of eight thermal shield flexures completely severed, and replacement flexures were installed. ([Original publication](https://info.westinghousenuclear.com/blog/first-of-a-kind-identification-and-replacement-of-failed-thermal-shield-flexures))

Applicability limits: Vendor narrative, not a regulatory record; no EDM mention; no acceptance criteria. It documents co-occurrence of thermal shield support degradation and baffle-former bolt indications at one plant, not a generic causal rule.

## S14: PWROG Materials Committee Update (2025 NRC/industry meeting slides)

Date: 2025 (ADAMS ML25163A014). Type: Industry owners-group presentation in NRC ADAMS.

An anonymized fleet survey of PWR lower radial support clevis insert X-750 bolt inspections reports recordable indications across multiple plant types, including one plant where only 7 bolts were found degraded during visual inspections but 29 were found degraded when removed during the replacement campaign, and one case detected via a dislodged clevis insert with no visual signs of lock bar or bolt head degradation; clevis replacements per outage season are expected to increase significantly beginning in 2026, making early vendor engagement necessary. ([Original publication](https://www.nrc.gov/docs/ML2516/ML25163A014.pdf))

Applicability limits: Plants are anonymized (Plant A-O), so no claim can be tied to Vogtle or any named unit. Expectations for 2026 are industry projections, not confirmed work. No EDM mention. Numbers in the survey table are as-reported and partly ambiguous in column alignment.

## S15: Vogtle Electric Generating Plant, Units 1 and 2 - Integrated Inspection Report, inspection period January 1 - March 31, 2026

Date: April 13, 2026 (inspection completed March 31, 2026). Type: NRC inspection report in ADAMS.

NRC inspectors reviewed Vogtle Unit 1 refueling outage 1R26 (which began February 22, 2026) including in-service inspection activities from February 24 to March 12, 2026, with ISI results presented to the licensee on March 12, 2026; among documents reviewed is "Site Requirements Document for Vogtle Unit 1 & 2 RVCH Inspections, Cavitation Peening, and EDM," 03-8153011 Rev. 001. ([Original publication](https://www.nrc.gov/docs/ML2609/ML26092A010.pdf))

Applicability limits: The only 2026 Vogtle EDM reference found is in the title of a reviewed site requirements document associated with reactor vessel closure head (RVCH) work; the report does not state what EDM was used for and does not mention baffle-former bolts, thermal shield hardware, or clevis insert bolts. It therefore does not establish any 2026 Vogtle clevis or baffle bolt removal/replacement activity.

## S16: Beaver Valley Power Station, Units 1 and 2 - Integrated Inspection Report 05000334/2025004, inspection period October 1 - December 31, 2025

Date: January 28, 2026. Type: NRC inspection report in ADAMS.

During Beaver Valley Unit 1 refueling outage 1R30, NRC inspectors reviewed (November 17 - December 12, 2025) remote UT of ten remaining thermal shield support block bolts and remote EVT-1 of reactor vessel internals including the 330-degree thermal shield flexure and core barrel upper girth weld, and verified the examinations were performed appropriately; 1R30 ISI results were presented to licensee management on December 12, 2025. ([Original publication](https://www.nrc.gov/docs/ML2602/ML26028A061.pdf))

Applicability limits: Confirms examination scope and NRC review during 1R30; it does not state EDM use, replacement counts, or acceptance results, and does not mention clevis insert bolts or baffle bolts. It is the most recent thermal-shield-bolt evidence found and does not establish any activity in 2026.

## S17: American Nuclear Society, "A proactive approach to reactor vessel aging management" (Nuclear News)

Date: October 25, 2024. Type: Industry society news article.

Prairie Island Unit 2 underwent a fall 2023 outage that included extensive reactor vessel work using a novel approach to replace baffle-former bolts and lower radial clevis insert bolts, with extensive prior analysis determining which bolts to replace and only new bolts structurally credited, an approach described as eliminating the need for costly inspection-related contingencies. ([Original publication](https://www.ans.org/news/article-6449/a-proactive-approach-to-reactor-vessel-aging-management/))

Applicability limits: Trade press, not a regulatory record. No EDM mention, no counts, no thermal shield content, and no metrology/tooling detail. It shows that baffle-former and clevis workstreams can be combined in one outage but establishes no schedule or cost figures.