ML24266A003
| ML24266A003 | |
| 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, ASLBP 24-986-01-LA-BD01, 50-255-LA-3 | |
| Download: ML24266A003 (0) | |
Text
September 22, 2024 Docket No.: 50-255 of 1
9 Part Three, Supplemental Submission to the Petition Regarding the Safety Impact of Steam Generator Tube Plugging at Palisades Nuclear Plant:
The Need for NRC to Review the Palisades Design Basis of SSCs to Next Approve Accident Safety Analysis and Evaluate Steam Generator Tube Plugging Limits
Subject:
Part Three Supplemental Filing to Further Explain FSAR and Steam Generator Tube Plugging Limits in Support of Contention Two Docket No.: 50-255 Date: September 22, 2024 To the NRC Licensing Board, Introduction This supplemental, part three submission, is made in further support of Contention Two of the petition for a public hearing, specifically regarding the need for the NRC to approve a Final Safety Analysis Report (FSAR) for Palisades. The ongoing issue of steam generator (SG) tube plugging emphasizes the necessity for an NRC-approved FSAR to accurately assess accident safety analysis, defense-in-depth, and safety margins, by ensuring that the plants Structures, Systems, and Components (SSCs) function properly during both normal operations and accident conditions.
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9 Palisades Nuclear Plant was designed and licensed before the NRCs General Design Criteria (GDC) and Standard Review Plans (SRP) were established. As a result, the plant operates with less defense-in-depth than newer, GDC-compliant plants. The Systematic Evaluation Program (SEP) was introduced in 1985 to address the safety gaps caused by the plants pre-GDC design. However, despite these efforts, Palisades' safety margins remain less then GDC plants. Following the 2022 submission of the 50.82 certifications, marking the plants entry into decommissioning, the NRC is no longer bound by the backfit rule. This now allows the NRC to reconsider Palisades design basis using modern GDC and SRP standards, an essential step for ensuring that the plants SSCs, including steam generators, meet NRC safety requirements.
The Role of NUREG-0820 and the FSAR in Establishing Safety Margins NUREG-0820 was critical in transitioning Palisades from a conditional to a full-term operating license. It established the design basis that formed the foundation of the plants 1980 FSAR, outlining the SSCs necessary for safe operation. However, because Palisades was designed before GDC and SRP standards were introduced, its design lacks the defense-in-depth and redundancy that are now standard. The
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9 SEP addressed some of these issues but did not fully modernize the plant to GDC standards.
The FSAR is the foundational document that contains accident safety analyses, demonstrating how SSCs function during normal operations and accident conditions. Without an NRC approved FSAR, it is impossible to accurately assess the safety of the plants SSCs or evaluate critical safety concerns, such as the limits on SG tube plugging. The FSAR is essential for ensuring that Palisades operates within acceptable safety margins during all accident scenarios.
FSAR and the Importance of Accident Analysis The FSAR is integral to accident safety analysis, providing detailed evaluations of how the plants SSCs perform under various accident conditions. For Palisades, the accident analysis must account for the specific design of SSCs, including steam generators, which play a critical role in removing heat during accidents like Loss of Coolant Accidents (LOCA), Steam Generator Tube Ruptures (SGTR), and Main Steam Line Breaks (MSLB). Each of these scenarios depends on SSCs for maintaining their safety margins. The FSAR must specify the maximum allowable percentage of plugged SG tubes that can still ensure safe operation.
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9 As explained in the first supplement, the issue of SG tube plugging at Palisades highlights the need for a comprehensive FSAR review. Plugging SG tubes reduces the heat transfer capability of the steam generators, which is crucial for preventing overheating during accident scenarios. Without an NRC-approved FSAR, there is no validated safety basis for determining the maximum allowable level of plugged tubes, making it impossible to assess the plants ability to manage these critical functions safely.
Defense-in-Depth and the Role of SSCs Needs NRC Review The NRCs defense-in-depth strategy relies on multiple independent and redundant safety systems to prevent accidents and mitigate their consequences. At all plants, these systems include:
Fuel Cladding: The first barrier that prevents radioactive fission products from escaping.
Primary Coolant System: Maintains cooling of the reactor core to prevent overheating.
Containment Building: The final barrier that prevents the release of radioactive materials.
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9 These safety barriers work together to maintain safety margins during both normal and accident conditions. However, because Palisades was designed before the GDC, it lacks the redundancy and robustness of GDC-compliant plants. The FSAR must clearly demonstrate how SSCs, including the steam generators, contribute to the defense-in-depth strategy by maintaining safety margins during accident conditions. Specifically, the FSAR must document the maximum allowable percentage of plugged SG tubes to ensure that the plant can function safely during events like LOCA, SGTR, and MSLB.
The Inadequacy of the 50.59 Process for Addressing Critical Safety Issues Holtecs reliance on the 10 CFR 50.59 process to assess changes at Palisades, without submitting a PSAR for NRC approval, is insufficient for addressing the critical safety concerns associated with steam generator tube plugging. The 50.59 process allows operating plant licensees to make changes without prior NRC approval, provided that those changes do not introduce unreviewed safety questions to its NRC approved FSAR. However, SG tube plugging directly impacts the plants ability to manage accident conditions. As such, it must be evaluated
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9 within the context of an NRC-approved FSAR, aligned with all the SSCs, as described in the FSAR.
Holtecs failure to submit an updated FSAR and obtain NRC approval has created a regulatory gap, leaving the plant without a clear safety basis for the current level of SG tube plugging. The comprehensive accident analyses required by 10 CFR 50.34 and Appendix A to 10 CFR Part 50, documented in the FSAR, are essential for determining whether Palisades can continue to operate safely with the current level of plugged SG tubes. Bypassing the FSAR approval process neglects a key aspect of plant safety.
The Case for Updating Palisades FSAR Using Modern GDC and SRP Standards Palisades was designed and licensed before the establishment of the GDC and SRP, making it critical that the FSAR be updated to consider current GDC and SRP. The gaps in Palisades SSCs defense-in-depth, including reduced redundancy and seismic protections, must be addressed to ensure the plant can safely manage accident conditions. The FSAR must include updated accident analyses that
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9 account for the current state of SSCs, including the steam generators, and provide a validated basis for evaluating SG tube plugging limits.
The NRCs regulatory flexibility, following Palisades submission of the 50.82 certifications and entry into decommissioning, provides an opportunity to reconsider the plants design basis under current GDC and SRP standards.
Updating the FSAR to these standards would address important elements of defense-in-depth and strengthen the plants overall safety margins, particularly in light of ongoing challenges like SG tube degradation.
Conclusion The design basis of Palisades SSCs, as documented in the FSAR, is fundamental to ensuring the plants safety during both normal operations and accident conditions. Without an NRC-approved FSAR, it is impossible to accurately evaluate the impact of SG tube plugging or determine whether the plant can safely manage accident scenarios like LOCA, SGTR, and MSLB. The NRC must require Holtec to submit a PSAR and approve an updated FSAR that reflects the current state of the plants SSCs, accounting for current GDC and SRP standards. This will
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9 ensure that Palisades operates acceptable safety margins and that its defense-in-depth strategy is robust enough to protect public health and safety.
Respectfully submitted, Alan Blind Representative for the Joint Petitioners
September 22, 2024 Docket No.: 50-255 of 9
9 Declaration of Alan Blind in Support of Supplement Three Submission