ML24277A006
| ML24277A006 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 10/03/2024 |
| From: | Blind A - No Known Affiliation |
| To: | Atomic Safety and Licensing Board Panel |
| SECY RAS | |
| References | |
| RAS 57129, ASLBP 24-986-01-LA-BD01, 50-255-LA-3 | |
| Download: ML24277A006 (0) | |
Text
October 3, 2024 Docket No.: 50-255 of 1
10 Third Supplemental Filing to Highlight the Critical Need to Use a FSAR Based on Current General Design Criteria, Unlike Holtec's Proposed Use of 50.59 to Build a FSAR: Before Analysis of the Significant Stress Corrosion Cracking (SCC) in Steam Generator Tubing Findings Docket No.: 50-255 Date: October 2, 2024
Subject:
Third Supplemental Filing to Emphasize the Need for an Updated FSAR Using Current GDC and SRP Standards Before Any Use of the 50.59 Process to Address the Significant SCC Findings in Steam Generator Tubing To the NRC Licensing Board, This Part Three supplemental submission is intended to clarify and expand upon the arguments made in the first supplement, titled "Supplemental Submission to the Petition Regarding the Safety Impact of Steam Generator Tube Plugging at Palisades Nuclear Plant," submitted on September 19, 2024, in further support of Contention Two, Holtec's flawed regulation to submit the Final Safety Analysis Report (FSAR)
October 3, 2024 Docket No.: 50-255 of 2
10 The focus of this submission is to highlight the critical need for a fully updated Final Safety Analysis Report (FSAR), based on current General Design Criteria (GDC) and Standard Review Plans (SRP), before any safety analysis can be conducted regarding the significant Stress Corrosion Cracking (SCC) findings in the steam generator tubing. Holtecs proposal to use the 10 CFR 50.59 process to build the FSAR is flawed, as it relies on outdated safety margins, and lack of defense in depth from a 1969 design basis, which predate the GDC and SRP. Petitioners argue that Holtec must not be allowed to proceed with the 50.59 process until a comprehensive FSAR is first established, reflecting the current regulatory framework and safety standards.
Holtecs Public Statement: Repair Plan for the Steam Generators Holtec recently shared its strategy for addressing the degraded steam generator tubes, reinforcing the need for a modern, NRC-approved FSAR. Patrick OBrien, a company spokesperson, stated that the tube degradation "was not entirely unpredicted" due to deviations from the standard "layup process" during the plant's shutdown. Despite this, Holtec maintains that the Palisades restart is still on schedule for late 2025.
October 3, 2024 Docket No.: 50-255 of 3
10 OBrien outlined that Holtec intends to repair, rather than replace, the steam generators. The plan includes "unplugging" approximately 300 tubes per steam generator that were plugged during the original installation and addressing the remaining damaged tubes by plugging about 20% and sleeving 80%a proven repair technique expected to extend the life of the generators by 30 years.
While Holtecs public statement addresses the immediate repair strategy, it underscores the necessity of a modern, updated FSAR to properly evaluate the long-term impacts of these repairs on plant safety margins. Only after updating the FSAR in line with current GDC and SRP standards can the full implications of the SCC findings, and the proposed repairs, be thoroughly analyzed.
Source: Gardner, Timothy. Corrosion exceeds estimates at Michigan nuclear plant US wants to restart, regulator says.Reuters, October 2, 2024 A further word on "unplugging" approximately 300 tubes per steam generator that were plugged during the original installation. Reference ML050560010, STEAM GENERATOR INSPECTION SCOPE FOR 2004 REFUELING OUTAGE:
Prior to the installation of these steam generators CE advised Consumers Energy that the area around the center stay cylinder region was potentially susceptible to fretting wear at the bat wing locations. This region was preventatively plugged. A total of 308 tubes were preventatively plugged in Steam Generator A and 309 tubes were preventatively plugged in Steam Generator B.
October 3, 2024 Docket No.: 50-255 of 4
10 This historical reference for preventive plugging, further amplifies the complexity and need for updated safety analysis for NRC to properly review and approve Holtecs proposed repair plans 1.
Introduction:
The Need for a Modern FSAR Before Any Safety Analysis Although it is widely accepted that the NRC has established methods for evaluating steam generator tube plugging safety impacts, the central issue lies in Holtecs intent to use the 50.59 process to build the underlying FSAR. If Holtec is allowed to proceed with the 50.59 process, using the 1965 era design basis as the reference for no unreviewed safety questions, the plant's defense-in-depth and safety margins will be based on outdated assumptions predating even the oldest GDC and SRP framework.
The FSAR must be updated first, using the current GDC and SRP frameworks, in accordance with the NUREG-0820 Systematic Evaluation Program (SEP) process, as was the case in 1985. Only then can the true safety margins and risks posed by the increased tube plugging and the elevated likelihood of a steam generator tube rupture be accurately assessed. Without a modern FSAR, any analysis of these risks will be incomplete and based on outdated safety standards.
- 2. Significant Findings from the 2024 Inspection Report
October 3, 2024 Docket No.: 50-255 of 5
10 The 2024 steam generator tube inspection revealed alarming levels of stress corrosion cracking (SCC). Specifically, the inspection identified 1,417 SCC indications, with 853 axial outside diameter stress corrosion cracking (ODSCC) indications at the tube support plates (TSPs) in Steam Generator A. The number of ODSCC indications at TSPs increased dramatically from 4 in 2020 to 1,163 in 2024.
Such a rapid increase in tube degradation represents a major safety concern. The extent of SCC indicates that the current tube plugging limits may be inadequate to ensure the plants safe operation, especially under accident conditions such as Loss of Coolant Accidents (LOCA) or Steam Generator Tube Ruptures (SGTR).
Without an updated FSAR, these new findings cannot be properly incorporated into the plants safety evaluations, potentially underestimating the true risks to the plants safety margins.
- 3. Holtecs Flawed Use of the 50.59 Process Without a Modern FSAR The 10 CFR 50.59 process allows for plant operational changes without prior NRC approval, provided those changes do not result in a significant increase in the probability or consequences of previously analyzed accidents. However, the
October 3, 2024 Docket No.: 50-255 of 6
10 significant SCC findings from the 2024 steam generator inspections represent a substantial new risk that must be properly factored into the plants safety analysis.
Holtecs proposal to use the 50.59 process without first updating the FSAR is flawed, as it will base the plant's defense-in-depth and safety margins on outdated 1969 safety assumptions. These assumptions do not account for the modern safety requirements established by the GDC and SRP frameworks, which are critical for providing accurate safety evaluations. Proceeding without a fully updated FSAR risks underestimating the true risks to the plant's safety margins and accident response capabilities.
- 4. The Critical Role of the FSAR in Establishing True Safety Margins The Final Safety Analysis Report (FSAR) is the cornerstone of nuclear plant safety. It provides the detailed accident analyses, safety margins, and defense-in-depth strategies needed to ensure safe plant operations. However, Holtec proposed basis FSAR, they would use for building a new FSAR for Palisades is based on outdated assumptions that predate the introduction of the GDC and SRP.
For example:
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10 Loss of Coolant Accident (LOCA): The FSAR evaluates the plants ability to manage a LOCA with a certain number of plugged tubes. However, with the increased tube plugging and degradation due to SCC, it is uncertain whether the emergency core cooling system (ECCS) can still perform effectively under modern accident conditions.
Steam Generator Tube Rupture (SGTR): The FSAR must account for the heightened risk of an SGTR caused by the extensive SCC identified in the 2024 inspections. The current FSAR does not adequately assess the risks posed by this widespread tube degradation.
Main Steam Line Break (MSLB): The FSARs evaluations of the plants ability to handle an MSLB must be revisited, considering the significant tube plugging and Holtec's proposed repair strategies.
These scenarios cannot be properly evaluated until the FSAR is updated in line with current GDC and SRP standards. Any evaluation conducted using outdated FSAR assumptions will fail to capture the true risks posed by the SCC findings and the proposed steam generator repairs.
5.
Conclusion:
The FSAR Must Be Updated First
October 3, 2024 Docket No.: 50-255 of 8
10 The significant degradation of steam generator tubes discovered in 2024 highlights the urgent need to update the FSAR before any use of the 50.59 process. Allowing Holtec to use the 50.59 process to build the FSAR would base the plant's safety analysis on outdated 1969 assumptions, failing to reflect modern safety margins established under the General Design Criteria and Standard Review Plans.
As petitioners, we respectfully request that the NRC:
1.
Resolve Contention Two by requiring Holtec to submit a fully updated FSAR for NRC approval, incorporating the latest data on steam generator tube degradation and reflecting the modern GDC and SRP standards.
2.
Suspend any further evaluations of the plants restart until the FSAR has been fully updated and approved by the NRC, ensuring that safety margins and defense-in-depth are accurately quantified before the SCC degradation is addressed.
This will ensure that the plants operations remain in full compliance with NRC regulations and that all necessary safety analyses are performed using modern safety standards.
October 3, 2024 Docket No.: 50-255 of 9
10 Sincerely, Alan Blind Representative for the Joint Petitioners
October 3, 2024 Docket No.: 50-255
of 10 10 Declaration of Alan Blind