ML24285A201

Memo Response - LTR-24-0212 - Response from Thomas Szabo - C-10 Board Member - David Lochbaum

ML24285A201
Person / Time
Site:	Seabrook
Issue date:	06/29/2022
From:	Lawrence Burkhart, Szabo T C-10 Research & Education Foundation
To:	Kent Howard Advisory Committee on Reactor Safeguards
References
LTR-24-0212
Download: ML24285A201 (1)

Text

Safety tor Clllzens

To: Advisory Committee on Reactor Safeguards Fuels, Materials, and Structures and Plant Operations, Radiation Protection, and Fire Protection Joint Subcommittees Email: Kent L. Howard, Sr. kent.howard@nrc.gov From: C-10 Research & Education Foundation, Inc., Amesbury, MA Re: ACRS Hearing April 27, 2022 - Joint Meeting on ASR at Seabrook Station, NH Date: June 29, 2022

C-10 appreciates the ACRS convening the Joint Subcommittee Hearing on the critical issue of Alkali-Silica Reaction (ASR) at the Seabrook Nuclear Power Plant. The questions posed by the ACRS members and the related responses by the NRC inspectors and staff revolve around a problem that is neither fully understood nor has a defined path to safe solutions. The hearing left many questions unanswered.

For example, unresolved issues included: the methodology, assessment and timeline needed for physical modifications to critical safety structures; the lack of consultation with established ASR experts; the significance of bulk structural deformation and the associated load demands; causes and consequences of NextEra staffing losses at the plant; the inadequacy of review and lack of deadlines for corrective actions, non-cited violations; questions on the limits of the Texas LSTP and whether ASR expansion will realistically remain within those bounds and what occurs if it does not; and unresolved operability determination. Finally, how can NRC regulations be timely updated to encompass these key factors, requiring NextEra to address each and the NRC to hold NextEra accountable on these vital processes and safety issues?

The following references are to the FINA~ ACRS Hearing Transcript issued on May 18, 2022

I. Page 4 "Robust Analytical Methodology"

Reference was made during the recent ACRS Subcommittee Hearing to the "robust analytical methodology" being used by NextEra Energy Resource, LLC (NextEra) in its assessment of ASR at Seabrook Station. In C-10's experience dating back to the 2019 AS~B Hearing on ASR in Newburyport, MA an important disclosure on the current testing methodology utilized by NextEra and Simpson, Gumpertz & Heger (SG&H) was shared. SG&H is still under contract with NextEra.

"We're not trying to understand where we.may go in the future and what the effects might be.

The fundamental piece of trying to stay within the design basis and the law that governs it is to see where we are now and within a reasonable amount of growth-that's exactly what the LSTP was designed to do-to define that box where we understand the properties of the concrete, we understand what is happening, and then we make sur<;? we stay within that box". (ASLB 11/8/2019 Transcript pgs.

816 -817).

More than a decade has passed since ASR's deleterious effects have been acknowledged by NextEra

1 1 a nd the NRf.1o'>~s¥fr8li ~Xu\\~~!hrw;1IJ.9.fli~h tJ111. d?~~u!~~9..riY!!s§!il/ir~li!iE_~d/ i~-'!/fo\\g C$ffi~!~Wl of ASR 1

1 demand loads, increasing deformation, a growing list of critical safety structures out-of-design-basis, license violations and the necessity of structural remediation while this nuclear facility is still under its original license term requires a rigorous ASR expert-driven evaluation as to where Seabrook's ASR is on its development curve and what those results foreshadow.

QUESTION 1.

Will the ACRS members recommend to the Commissioners a reassessment of the current ASR testing approach at Seabrook Station and encourage an ASR expert-driven methodology using state-of-the-art scientific methods? If not, why not?

II. Pages 34-37 Seismic Probabilistic Risk Assessment (PRA)

Given the damaging consequences of ASR we recognize that probabilistic risk assessment continues to play a critical role in refining and quantifying risk. C-10 is concerned, based on comments made at the ACRS hearing, that PRA may not be optimally utilized in seismic risk assessment at Seabrook.

For example: "On your last slide, I think that was 14, you show the seismic gap in the upper right between buildings. And I don't know if there's anybody here that can address this, Seabrook had a rather extensive PRA performed, and included seismic PRA. Has this information been factored back into that risk assessment? And if so, what are those results showing?" (Member Bley} p.34:6-13

After some discussion "We can verify that, and we can get back to you for sure". (Mr. Newport} p.36:21

QUESTION 2.

a. Has the NRC Staff been able to confirm to the ACRS Subcommittee whether or not seismic gaps have been factored into seismic PRA in NextEra's evaluations?

b. If not, will the ACRS recommend that these computations be factored into not only the design safe shutdown earthquake paradigm but also for additional safety that they be factored into "... the earthquakes that go beyond the design earthquakes that lead to significant damage". (Member Bley} p. 36:15-16

Ill. Pages 55-64 an "organizational review" or perhaps a "root cause" analysis

The expectation was floated by the ACRS Subcommittee members that an "organizational review" or "root cause" analysis was perhaps warranted for NextEra's failure to complete required ASR load computations as reported in Seabrook's quarterly inspection report [IIR dated August 11, 2021}

for the period ending 6/30/2021 (05000443/2021002}.

Compounding the above action, NextEra was proven to have failed to complete required computations as reported in Seabrook's (IIR dated February 10, 2022 for the period ending 12/31/2021 (05000443/2021004)}. The report noted: "Per the Structures Monitoring Program ASR methodology document, an evaluation of the impacted areas of the CIS structure should have been conducted which would have included additional ASR load demands for comparison to the total structural load in accordance with the code of record, ACI 318-71, to ensure that the structure remained in compliance with the design code of record." "There was also an opportunity for NextEra staff to document and

2 evaluate these conditions as part of their 2018 structures monitoring walkdown." In C-10's opinion, there was a questionable attribution of the failure to evaluate the CIS structure back to the year 2017, as the NRC deemed that it did " not reflect present licensee performance".

"I'm just wondering if the procedure was difficult for them to follow... and it would be interesting to better understand the root cause to make sure that maybe some bigger flags are needed, or something."... "you want it to be as easy as possible for the staff to follow it."(Member Rempe).

p.59:7-11

C-10 has repeatedly called for the establishment of well-defined ASR regulations as an aid to NextEra staff in performing their responsibilities and as a pathway to accountability.

The above omissions point to an urgent concern - NextEra's intractable failure to compute ASR load demands. In C-l0's opinion, citing the staffing changes made by NextEra was an unconvincing response.

Public safety is the NRC' s chief mission. Why does NextEra fail to provide answers to NRC's inquiries as to why these computations are not performed?

QUESTION 3.

a. Will the ACRS recommend to the Commissioners that Seabrook Inspectors approach NextEra for a "root cause" analysis of these failures? Will the ACRS recommend that all findings be documented?

b. Given the ongoing failures by NextEra to compute additional ASR loads (related margin and future ASR expansion) and while all parties await the results of finite element analysis, the week of May 9th 2022 ASR assessment and CIS assessments including liner conditions, will the ACRS commit to recommending that the NRC certify that NextEra is timely computing all quarterly ASR factors at Seabrook as currently required and that this information will be made public?

c. What has caused so many elective personnel departures from NextEra? Do the "staffing levels of licensed operators after the unexpected retirement and departure of several licensed reactor operators" at Seabrook affect the ACRS's view of the need for an organizational review as Seabrook shifts into an increasingly compromised condition? (IIR May 2, 2022

[05000443/2022001)

The timely insistence of computing additional load demands and their impact on margin and safety are a "reasonable" request to h elp mitigate the expanding risk imposed on the public by a nuclear plant that is undergoing ASR remediation activities in critical safety structures while attempting to maintain qualified personnel staffing levels.

IV. Pages 69-71; 45-47 - Corrective Action Procedures and Prompt Operability Determination (POD)

In previous inquiries to the NRC it has been explained that there are no interim or other finite

3 deadlines imposed on POD's or corrective actions. Although inspectors review CA's daily, the principal method of oversight for the status of CA's (which the NRC admits number in the thousands) is the process whereby for two weeks every other year they are reviewed for deletions, omissions, etc.

Corrective Action Procedures

"The observation that they didn't have trend data to inform the timing of their long term corrective actions. So the example here, again, I'll go back to the control, and diesel generator building. They showed an observable growth on a few of their ASR grids, but they didn't have a physical modification plan until out in the year 2026. So based off that trend, I looked at the timing of the corrective actions like well, you're not really going to meet that time line. And so part of the corrective action in response to our finding, and observation, they now have trend projections for each of the monitored structures now. I think that was their original intent, but we saw it, and we brought it up to their attention, and that's how we got to the findings. So now going forward, while they correct trend data, they're also projecting setting trend data, and that will inform the timeliness of their future corrective actions." (Mr. Floyd) p.69:1-21

"Nil<, this is kind of a disconnect in my mind, and maybe you can provide some help. It seems very fundamental to do this, either in another process called scheduling, and planning of modifications, or just in the assessing of the risk of a corrective action, how long it can be open. So, this seems fundamental to corrective action process, to modification planning process, accountable engineering. A system engineer type person, are you confident that the changes they made in the organization have been re-sensitized to this, where these fundamental issues like what you just found are going to get covered in the future?"

(Co-Chair-Halnon) p. 70:19-25 p.71:1-7

Prompt Operability Determination (POD)

"Before you go on, the prompt operability determination, it's not typical to have a POD that goes on forever. What is the end point of this operability determination, or will there be one? Is this. going to be something that's a living document to the end of life for the plant? (Co-Chair Halnon} p. 45:19-24

"So the original idea was previous to the license amendment that we approved back in 2019. Basically all the structures affected by ASR were under the licensee's prompt operability determination. After getting that license amendment, the idea was now you have a methodology for evaluating ASR such that you're now in compliance. And so after the application of the structure evaluations, which included ASR, the idea was you ' d be out of operability determination space. Well, that didn't turn out to be the case here. In fact, we didn't know it at the time, but as they were applying this methodology, you added ASR loads, and it's not as simple as just adding the ASR loads, you also added load factors, which is a margin. Plus you have to account for that future ASR expansion. And so when you do that,

4 you add in a significant portion of load to that structure, and what the licensee found during that is that there were several areas in these six structures that weren't able to meet that load criteria. So really the end point of this is going to be once the licensee completes - and in these cases, reanalysis is not an option. So they're going to have to complete physical modifications. Once those physical modifications are complete, they'll reanalyze it, taking into account the increased strength, which ups the capacity to account for that ASR load. And then they'll be able to get out of operability determination space. So it's not going to be a forever thing, and certainly we do not want them to stay in that space." (Mr. Floyd) p.46:1-25 p. 47:1-8

"Physical degradation such as concrete cracking and spalling, excessive deflection or deformation of structures, water leakage, corrosion of rebar, cracked welds, corrosion of steel members, corrosion of anchor bolts, bent anchor bolt(s) or structural bolting of a structure or component may be evaluated in accordance with generally accepted industry standards and guidance documents. Where consensus standards or guidance documents are not *consistent with the physical degradation (e.g., alkali-silica reaction (ASR)) the NRC inspector should consult with NRR staff." (IMC 0326 10/1/2019 page 24 Sec.

08.14 Structural Requirements).

QUESTION 4:

a. What modifications to NRC inspections have been instituted to ensure that NextEra is proactively preparing projection trends?

b. Will the ACRS recommend the establishment by the NRC of deadlines (interim and final) for various tasks and enforcement actions including but not limited to: corrective actions, remediation plans and modificatiC:,ns for ASR, structure monitoring program {SMP) issues and non -cited violations (NCV/Green) that require correction? Will the above include enforcement actions if deadlines are not met?

c. Completed physical modifications ("will likely take several years" per NRC Chairman Hanson's Letter to C-10 dated 5/16/22) appear to be the only option to eliminate the POD at Seabrook. Are the requirements of IMC 0326 Section 8.14 being met? i.e. "For structures and related support functions, OD evaluations need to include applicable design and licensing basis loads and load combinations". Is the "continuous assessment of operability" being performed per IMC Section 06.01? Is the NRR utilized as warranted? Are these compliance actions fully documented? When will this information be made public?

d. As the impact of ASR is more rapid and pervasive than expected has NextEra's maintenance program been re-evaluated for completeness since 2019? Similarly, have NRC inspection protocols been updated to account for the more rapid progression?

v. Pages 79-81; 84-85; 118-119; 113 - "Backfill Concrete" and "Steel Liner"

"There's no ASR in this vertical wall, there's a steel liner plate behind it, so there's no ground water in that wall, no humidity impact on that wall, it's a very dry spac e. But what potentially could be happening is tha t that backfill concrete that's behind this wall, sandwiched between the bedrock, and the wall, that backfill concrete potentially doe s have ASR in it. And it potentially is exerting a force on that wall, which would c ause it to bow out like you're seeing there, and impact the deck plate. The licensee's contra c tor, 5

they assessed this, like I said, and they said this was not due to the building deformation, this was due to shrinkage, and due to the differential temperatures. But our assessment was your program says if you see these things you shall do an evaluation. Taking into account any potential loads that those forces might be putting on the wall, and they didn't do that, and their procedure required them to do that. And that's in a nut shell, what our finding was." {Mr. Floyd) p. 79:1-25 p. 80:1-3

"Well, if you look at the side view here, you see this thin black line? So one of the primary purposes of containment is it acts as a giant pressure vessel. And there's a huge, airtight, steel liner plate that surrounds all of containment, and that's what holds the pressure in. (Mr. Newport) p. 80:7-12

"So was the evaluation they did based on the deformation, apparently it's pushing against that steel liner, has that steel liner as well been evaluated as acceptable to continue being in containment?

{Co-Chair Halnon} p.80:18-22

"Yeah, that's a separate --you're talking about, because the purpose of the steel liner is to prevent, during an accident with fuel damage, to prevent radionuclides from getting out to the public". (Mr.

Newport). p. 80:23-25 p.81:1-2

"I guess my point is, and maybe I heard it wrong, that the back fill is pushing against the steel liner, which is pushing against the internal concrete, which is causing it to spa II. So the liner must be moving as well, so if there's deformation in the liner, has that been evaluated? {Co-Chair Halnon)

p. 81:14-19

"They did not specifically address any impacts to the containment liner (Mr. Floyd) p. 84... it was not formally evaluated by the licensee (Mr. Floyd) p. 84 "... they did not evaluate specifically the liner in a prompt operability determination". (Mr. Newport) p. 84:7-8 and 24 p. 85:15-16

11 S0 the only thing getting looked at this time around, will be the actual containment internal structure itself, which will include the foundation". "Now certainly if they start seeing measurements, or changes in measurements on the CEB that would impact that, or vice versa, they should take into consideration all of those". (Mr. Floyd) p. 118:15-21

"Have they seen any settling, or movement of the CEB in terms of how it sits there on that, that underlying concrete?" (Member Kirchner} p. 118:22-24

"CEB is, I believe, a standalone structure. But that being said, they have done that full what they call stage three analysis of the CEB, which is the most in-depth, finite element analysis they do. And that analysis would show any of that settling. They are seeing quite a bit of movement in the CEB, and that's from kind of this cumulative effect of the strain, There is ASR actually in that containment enclosure building, and that strain that cumulatively pushes bulges and causes forces on that. And that shows up in their output of their models. And any kind of that settlement and other things would show up, as they correlate the model to the actual measurements they've taken". (Mr. Newport) p. 119:7-23

QUESTION 5:

a. What specific methods have been established for the assessment of the liner? What date?

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b. Without any further analysis can the NRC, ACRS and NRR currently warrant that the liner is safe in protecting the public from radionuclides?

c. Will the ACRS encourage the Commissioners to prioritize the evaluation of all critical safety structures and the "backfill concrete"?

d. Will the ACRS recommend to the Commissioners that the NRC Staff take an active role throughout NextEra's evaluation of the CIS and foundation? It would appear that the completeness and accuracy of assumptions, oversight and interim assessment of NextEra/SG&H throughout the process would lead to a more efficient process and more accurate information as opposed.to the current plan that calls for the NRC conducting "a detailed inspection of that product" i.e. an analysis of "the fall 2022 report". p.113:5-7

e. If, as quoted a~ove, "there is quite a bit of movement in the CEB due to ASR" (and as it has not been evaluated since 2018), will the ACRS advise the Commissioners to provide for the I

expansion of thelcurrent plan (slated for summer/fall 2022) to include a current assessment of the CEB? Would this example alone not point to the importance of active ongoing oversight by the NRC?

VI. Pages 95-97; 100-102-NRC Slides 7/18 "BuyBack Margin": Physical Modifications

"As long as they stay within the bounds of that Texas testing with the measurements they're taking, they're safe by their current license". (Mr. Newport) p. 95:10-12

"So they're continuously looking at these measurements, and as they approach some of those limits, they have to either do more advanced modeling. Or they have to do modifications to the structures to get that margin, which we'll talk about in the next slide". (Mr. Newport} p. 95:22-25 p. 96:1-3

"Correct, so it's the contractor, the vendor that does all of the finite element modeling. They don't have that ability to do that in-~ouse, and they are using an Ansys based software". (Mr. Floyd} p. 97 :10-14

"The stage -- they've done all of the evaluation they can do, and they're still approaching the limits, or what happens if, like we ;briefed earlier, they've gone outside of those limits, and they need to restore compliance. The NRC traditionally gives you two, you either have to restore compliance, or change the license". (Mr. Newport) p. 100:13-19

"So for those six structures that we talked about that are outside of licensing basis, and also some structures that they believe might be approaching those limits at some point in the future. The licensee has elected to perform physical modifications". (Mr. Newport) p. 100:24-25 p. 101:1-5

"But we wanted to touch on just some examples of some of the structural -- there's dozens, and dozens of different ways where you can buy back margin by doing physical modifications like reinforced concrete walls". (Mr. Newport} p. 101:9-11

7 QUESTION 6:

a. What was the NRC's role in the development and review of the physical modification plan(s)? Were national and international structural solutions to similar ASR degradation studied in the development of SG&H's proposed modifications? Was the success of the results reviewed? Did the NRC Staff at Seabrook review this critical information? When will the change (increase or decrease) in the strength of the modified structures, determined through applicable engineering computations be made public?

b. Does the ACRS find any conflict of interest in NextEra using SG&H to establish the "box theory", to then measure ASR degradation within the "box limits" and to eventually also develop the "analysis" and "plans" for the physical modifications needed at Seabrook?

c. What does NextEra "doing more advanced modeling" to "get that margin" they are seeking indicate? One would expect they are doing the appropriate and valid level of assessment each time. How does "doing more advanced modeling" change the facts of the ASR degradation that is actually occurring?

d. Does the ACRS concur that completing structural modifications and having success with the results are two separate outcomes? There should be no pre-conceived opinion by NextEra or the NRC that physical modifications will necessarily result in the "buyback of margins".

e. The NRC staff emphasize "ensuring structures remain functional" and "continued functionality". In C-l0's opinion the emphasis should be that the structures remain "safely operable". This position is supported by IMC 0326 Operability Determinations Section 08.14 Structural Requirements which states "If a condition with a structure is identified, the licensee should assess the capability of the structure to perform its specified safety functions".

f. What is the endpoint (i.e. timed deadline) for the Nuclear Regulatory Commission to prohibit a nuclear reactor from continuing operations when it is noncompliant with its licensing requirements?

In C-10's opinion, the public would benefit from ASR experts evaluating current conditions at Seabrook and offering proven solutions (if any) based on similar fact patterns in the national and international ASR arena. The public living near Seabrook Station has no idea what safety margins exist for even the ASR compromised critical safety structures or how quickly they may be receding.

Summary: C-10 thanks the ACRS Subcommittee for convening the April 27, 2022 meeting on ASR and

'allowing public access and verbal and written comments to be considered. It is an important part of our mission to stay informed.

We urge the ACRS Subcommittee to assess the information that is being developed as a result of the May 9th assessment of ASR at Seabrook, the ongoing ASR analysis of the CIS and foundation by NextEra and the documented results of structural modifications being instituted. We encourage the members to hold a similar meeting in the fall of 2022 when this information has been produced and evaluated.

8 Our concern is genuine because we have so much at stake in the validity and success of your actions.

Sincere~~

Patricia L. Skibbee, Board President C-10 Research & Education Foundation, Inc.

Office phone: (978) 465-6646

Addendum to:

To: Advisory Committee on Reactor Safeguards Fuels, Materials, and Structures and Plant Operations, Radiation Protection, and Fire Protection Joint Subcommittees Email: Kent L. Howard, Sr. kent.howard@nrc.gov From: C-10 Research & Education Foundation, Inc., Amesbury, MA Re: ACRS Hearing April 27, 2022 - Joint Meeting on ASR at Seabrook Station, NH Date : June 29, 2022

We appreciate the ACRS hosting the recent hearing on Seabrook Station's ASR issues. About forty years have passed since the construction of the Seabrook Nuclear Power Plant began and much has changed in the industry since the development of original designs, and the management and regulation of nuclear power has evolved. The implications of the unique ASR at Seabrook was unknown at the time of construction. Present processes are being adjusted to monitor its extraordinary behavior and unanticipated challenges.

Unfortunately, ASR expertise appears to be missing at NextEra and w ithin the NRC, so why not call on independent, non-biased ASR consultants with specific ASR expertise? Next Era has structural proficiency but not in ASR. From the viewpoint of the public, there is a potential conflict of interest:

NextEra is subject to federal safety regulation but is also invested in keeping the plant active and profitable. Consider that NextEra is called upon to perform its own ASR study, determine corrective actions, and yet has no staff with ASR expertise. Nor are there ASR experts in the NRC. Clearly, independent impartial assessment is needed. Science is self-correcting through peer review. A new approach is needed to accommodate the serious safety issues already uncovered at Seabrook.

Monitoring the progressive deterioration and deformation of the plant and adjusting current safety guidelines may not be enough. A valid means of assessing the structural integrity of the containment structure with ASR and predicting its future performance are essential.

The present approach uses finite element programming with ANSYS software which apparently treats the ASR infected concrete structures as homogeneous linear elastic solids which are thermally expanding. Kirchner (p. 96: 17-25) asked if ANSYS is an approved model. Yes, experts at NRC reviewed it in its use context. ANSYS is a popular FEM program used internationally. However has ANSYS ever been validated independently for ASR analysis under peer review? As Bryce Lehman pointed out NextEra undertook an ASR study program at the University of Texas at Austin from 2013 to 2016. This study

9 correlated thermal expansion predictions with lab samples of ASR mixtures. Per Inspector Newport's perspective (p. 87:15-25, p. 88:1-11),... "they (NextEra) saw these cracks, they knew that that deck plate had spalled up previously, the bowing grate was there... They said this is not due to ASR. They incorrectly used their-procedures required them to do this, they didn't use that procedure correctly, they said we believe this is just due to thermal expansion, they did a traditional evaluation, but they did not do that formal evaluation back in 2017, that's when the mistake happened so to speak."

This happened after their Texas study. The present process is that building deformations and other measurements are monitored and then calculations are adjusted to check safety. Newport (p. 95:13-17) continues:.. "then with the building deformation aspect of this, they have to continuously look at these models, the outputs of these models, and they have to continuously be feeding in the changes that they're seeing in the plant." Clearly, this is a reactive approach.

For ASR at Seabrook, a more accurate predictive approach is needed to develop an aging management plan. For example, given measurements made over time, can parameters such as nonlinear rate of elastic modulus decrease be extrapolated into the future to estimate future loading failures and plant longevity? As structures at the plant weaken, and prescribed limits are exceeded, in the present plan "physical modifications" are proposed. Suggestions include (p. 101:12-25) restraining bolts and braces.

Have studies been done to determine the effect of driving a bolt into micro-fractured concrete under load? Can these micro-effects be sufficiently modeled with the present approach?

ASR degradation is progressive, however, when Co-Chair Halnon asked when Seabrook was built (p. 22:4-9), guesses were the 90's. No one seemed to know. He concluded "I would add that while Seabrook went critical in the 90s, I guess that's true, the construction period was much, much longer than that." In fact, the concrete in many structures dates from the 1980's.

In most industries a failure analysis is conducted. In fact, this is a critical aspect of device and system design. For example, typically a mean-time-between-failure (MBTF) is computed. Is there a comparable approach for nuclear power plants? Given that ASR was not anticipated in original designs, a comprehensive failure analysis would be extremely useful.

As the community living close to the Seabrook Nuclear Power Plant, we are concerned that the reactive monitoring approach, NextEra's noncompliance and lack of ASR competence, and the serious ASR and building deformations pose serious safety concerns that need to be addressed. The ACRS hearing was an excellent opportunity to air safety issues, however, many questions remain unanswered.

Sincerely,

--no~,,(_ Sz.J-o Thomas Szabo, Ph.D.

C-10 Board Member

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