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 1 of 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 "rst 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, petitioner s analysis of the regulatory structure concerning the evaluation of September 22, 2024 Docket No.: 50-255 2 of 9
steam generator tube plugging and the role of the Final Safety Analysis Report
(FSAR).
In the "rst supplement, I raised concerns about Holtecs "awed 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 3 of 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 "awed.
- 1. Introduction
In the "rst 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 4 of 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 signi"cant stress on the
reactor s cooling systems, including the steam generators. The FSAR evaluates the September 22, 2024 Docket No.: 50-255 5 of 9
plants ability to manage these accidents while assuming a speci"c 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
ef"ciency, which can affect the reactor s 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 6 of 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 suf"cient 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 signi"cantly 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 7 of 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 "rst 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 8 of 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 9 of 9
Declaration: Second Supplemental Submission to the Petition Regarding the Safety Impact of Steam Generator Tube Plugging at Palisades Nuclear Plant