ML24266A002
| ML24266A002 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 09/22/2024 |
| From: | Blind A - No Known Affiliation |
| To: | Atomic Safety and Licensing Board Panel |
| SECY RAS | |
| References | |
| RAS 57113, 50-255-LA-3, ASLBP 24-986-01-LA-BD01 | |
| Download: ML24266A002 (0) | |
Text
September 22, 2024 Docket No.: 50-255 of 1
9 Part Two, Supplemental Submission to the Petition Regarding the Safety Impact of Steam Generator Tube Plugging at Palisades Nuclear Plant
Subject:
Part Two Supplemental Filing to Further Explain FSAR and Steam Generator Tube Plugging Limits in Support of Contention Two Docket No.: 50-255 Date: September 21, 2024 To the NRC Licensing Board, This part two 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.
Petitioners acknowledge that we cannot know for sure what Holtec or the NRC may currently be using as the basis for evaluating accident safety analysis, nor the exact safety analysis in use. However, this supplement aims to explain, in general terms, petitioners analysis of the regulatory structure concerning the evaluation of
September 22, 2024 Docket No.: 50-255 of 2
9 steam generator tube plugging and the role of the Final Safety Analysis Report (FSAR).
In the first supplement, I raised concerns about Holtecs flawed use of the 50.59 process and its failure to submit an PSAR for NRC approval, to address the accident safety analysis needs posed by the increasing number of plugged steam generator (SG) tubes at the Palisades Nuclear Plant.
This part two supplement further explains how an NRC-approved FSAR is indispensable for analyzing the impact of steam generator tube plugging limits, as it contains accident analyses that ensure the plant can safely respond to various operational and accident conditions.
Additionally, the regulations referenced here for FSAR accident analysis stem from 10 CFR Part 50, which governs both construction and operational requirements for nuclear plants. It is important to note that there is no Part 50 category for decommissioned plants. Given Palisades' extended period outside the NRC Regulatory Oversight Program (ROP)since 2022, this paper assumes, as similarly argued in the full petition, that the FSAR regulations for new plant construction are more applicable. However, this question is ultimately for the NRC
September 22, 2024 Docket No.: 50-255 of 3
9 Adjudicatory Board to determine how the NRC staff determines and approves the appropriate category. This question alone demonstrates how using the Holtec proposed within regulatory framework, clause is flawed.
- 1. Introduction In the first supplement, I highlighted the regulatory gap created by Holtecs failure to submit a PSAR for NRC approval, and Holtecs inappropriate reliance on the 50.59 process for assessing critical safety issues, such as steam generator tube plugging. This second supplement delves deeper into how accident analyses in the FSAR are tied to assumptions about SG tube plugging limits and why the FSAR is essential for evaluating the safety impact of these plugged tubes.
Steam generator tube plugging is an inevitable part of plant operation due to tube degradation. However, plugging reduces the heat transfer capability, which is crucial for the safe operation of a Pressurized Water Reactor (PWR). The FSAR contains accident analyses that account for assumed SG tube plugging limits, ensuring the plant can safely respond to various operational and accident conditions.
September 22, 2024 Docket No.: 50-255 of 4
9 Holtecs failure to have an NRC-approved FSAR means there is no valid, NRC-approved basis for assessing whether the plant can safely operate with any level of plugged tubes, especially since these tubes are critical during key accident scenarios such as Loss of Coolant Accidents (LOCA), Steam Generator Tube Ruptures (SGTR), and Main Steam Line Breaks (MSLB).
- 2. The FSAR's Role in Accident Analysis and Steam Generator Tube Plugging The FSAR serves as the foundation for all safety-related analyses at a nuclear power plant. For steam generators, the FSAR outlines how the plant is designed to handle various accident scenarios while accounting for the plugging of steam generator tubes. As more tubes are plugged over time, the plant's heat removal capacity decreases, and the accident scenarios outlined in the FSAR must account for this reduction. This is done by the analysis specifying a maximum number of plugged tubes. Licensees may submit new analyses, for NRC approval, if they elect to operate at higher levels of SG tube plugging.
Accidents such as LOCAs, SGTRs, and MSLBs place significant stress on the reactors cooling systems, including the steam generators. The FSAR evaluates the
September 22, 2024 Docket No.: 50-255 of 5
9 plants ability to manage these accidents while assuming a specific limit on how many tubes can be plugged before safety margins are compromised. Key analyses include:
Loss of Coolant Accident (LOCA)
In a LOCA, a break in the reactor coolant system leads to a rapid loss of coolant, requiring the Emergency Core Cooling System (ECCS) to remove residual heat. Plugging steam generator tubes reduces heat transfer efficiency, which can affect the reactors ability to remain safely cooled during a LOCA. The FSAR includes this analysis to ensure the ECCS can function effectively even with a certain percentage of plugged tubes.
Steam Generator Tube Rupture (SGTR)
An SGTR involves the failure of one or more steam generator tubes, allowing primary coolant to leak into the secondary system. As more tubes are plugged, the remaining tubes are under greater stress, which could exacerbate the severity of an SGTR. The FSAR provides detailed analyses to ensure the plant can handle SGTR events without exceeding safety limits.
September 22, 2024 Docket No.: 50-255 of 6
9 Main Steam Line Break (MSLB)
In an MSLB, the pressure on the secondary side of the steam generators drops rapidly, challenging the plants ability to remove heat from the reactor.
Plugging steam generator tubes reduces their heat transfer capacity, which could impair the plants ability to manage an MSLB. The FSAR ensures that the plant can still remove sufficient heat, even with a portion of the tubes plugged.
Each of these scenarios relies on a maximum allowable number of plugged tubes, which is determined through the accident analysis included in the FSAR. Without an updated and NRC-approved FSAR, it is impossible to accurately determine whether the plant remains within these safety limits.
- 3. Why Holtec's Reliance on the 50.59 Process is Inadequate For operating plants, the 10 CFR 50.59 process allows for certain changes to plant operations without prior NRC approval if the changes do not significantly affect safety. However, in the case of steam generator tube plugging, this process is inadequate. The plugging of steam generator tubes directly affects the plants
September 22, 2024 Docket No.: 50-255 of 7
9 ability to manage critical accident scenarios, making it essential to assess these impacts within the context of the FSAR.
Holtecs failure to submit a PSAR and seek NRC approval means there is no approved baseline for evaluating the current condition of the steam generators and their ability to meet safety standards. The 50.59 process cannot replace the comprehensive safety analyses required by 10 CFR 50.34 and Appendix A to 10 CFR Part 50, which are documented in the FSAR. By bypassing the FSAR approval process, Holtec has neglected a key aspect of plant safety, particularly in regard to the maximum number of steam generator tubes that can be plugged without compromising the plant's response to accident conditions.
- 4. Conclusion This second supplement builds on the first by further explaining the critical role the FSAR plays in the evaluation of steam generator tube plugging limits. The FSAR contains the accident analyses necessary to determine whether the plant can safely operate with plugged steam generator tubes. Without it, both Holtec and the NRC are operating without a clear understanding of the plant's safety margins. Holtecs
September 22, 2024 Docket No.: 50-255 of 8
9 reliance on the 50.59 process is inadequate for addressing such a fundamental safety issue.
I respectfully request that the NRC address Contention Two by requiring Holtec to submit a PSAR and use an approved FSAR before any further evaluation of the Palisades Nuclear Plant restart, particularly in relation to SG tube plugging limits.
This will ensure that all necessary safety analyses are performed and that the plants operations remain in full compliance with NRC regulations.
Sincerely, Alan Blind Representative for the Joint Petitioners
September 22, 2024 Docket No.: 50-255 of 9
9 Declaration: Second Supplemental Submission to the Petition Regarding the Safety Impact of Steam Generator Tube Plugging at Palisades Nuclear Plant