ML24026A157

Relief Request CISl-03-01 for Relief Concerning Containment Unbonded Post-Tensioning System Inservice Inspection Requirements

ML24026A157
Person / Time
Site:	Point Beach
Issue date:	01/26/2024
From:	Strand D Point Beach
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
L-2024-001, CISI-03-01
Download: ML24026A157 (1)

Text

January 26, 2024 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 RE:

Point Beach Nuclear Plant, Units 1 and 2 Docket Nos. 50-266 and 50-301 Renewed Facility Operating Licenses DPR-24 and DPR-27 L-2024-001 10 CFR 50.55a Relief Request CISl-03-01 for Relief Concerning Containment Unbonded Post-Tensioning System lnservice Inspection Requirements In accordance with the provisions of 10 CFR 50.55a(z)(1 ), NextEra Energy Point Beach, LLC (NextEra) hereby requests NRC approval of the attached relief request for Point Beach Nuclear Plant (PBNP) Units 1 and 2.

Specifically, relief is requested from the applicable Section XI, Subsection IWL of the ASME Boiler and Pressure Vessel (B&PV) Code. The third Containment lnservice Inspection (CISI) Interval for PBNP Units 1 and 2 complies with ASME Code 2007 Edition through the 2008 Addenda. The third CISI interval for PBNP Units 1 and 2 began on September 9, 2016, and is currently scheduled to end September 8, 2026.

Approval is requested by July 31, 2024.

This submittal contains no new Regulatory Commitments or revisions to existing commitments.

If you have questions or require additional information, please contact Mr. Kenneth Mack, Licensing Manager at (561) 904-3635.

Sincerely, Dianne Strand General Manager Regulatory Affairs cc:

USNRC Regional Administrator, Region Ill Project Manager, USNRC, Point Beach Nuclear Plant Resident Inspector, USNRC, Point Beach Nuclear Plant Mr. Mike Verhagan, Department of Commerce, State of Wisconsin Attachment Enclosure NextEra Energy Point Beach, LLC 6610 Nuclear Road, Two Rivers, WI 54241

Attachment Point Beach Nuclear Plant 10 CFR 50.55a Relief Request CISl-03-01 for Point Beach Nuclear Plant, Units 1 and 2 Revision 0

10 CFR 50.55a Relief Request CISl-03-01 for Point Beach Nuclear Plant, Units 1 and 2 Revision 0 (Page 1 of 8)

Request for Relief for Containment Un bonded Post-Tensioning System lnservice Inspection Requirements in Accordance with 10 CFR 50.55a(z)(1)

1.

ASME Code Component(s) Affected Code Class:

Reference:

Examination Category:

Item Number:

==

Description:==

Component Number:

cc IWL-2421, IWL-2520, Table IWL-2500-1 Table IWL-2500-1, L-B L2.10, L2.20, L2.30, L2.40, and L2.50 Examination and Testing of Containment Unbonded Post-Tensioning System Point Beach Nuclear Plant, Units 1 and 2, Containment Building

2.

Applicable Code Edition and Addenda

3.

The third Containment lnservice Inspection (GISI) program is based on the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (BPV) Code,Section XI, 2007 Edition through the 2008 Addenda. The third GISI interval for Units 1 and 2 began on September 9, 2016, and is currently scheduled to end September 8, 2026.

Applicable Code Requirement

IWL-2421 (b) states that when the conditions of IWL-2421 (a) are met, the inspection dates and examination requirements may be as follows:

1.

For the containment with the first Structural Integrity Test, all examinations required by IWL-2500 shall be performed at 1, 3, and 10 years and every 10 years thereafter. Only the examinations required by IWL-2524 and IWL-2525 need be performed at 5 and 15 years and every 10 years thereafter.

2.

For each subsequent containment constructed at the site, all examinations required by IWL-2500 shall be performed at 1, 5, and 15 years and every 10 years thereafter. Only the examinations required by IWL-2524 and IWL-2525 need be performed at 3 and 10 years and every 10 years thereafter.

4.

10 CFR 50.55a Relief Request CISl-03-01 for Point Beach Nuclear Plant, Units 1 and 2 Revision 0 (Page 2 of 8)

In accordance with IWL-2420(c), the 10-year and subsequent examinations shall commence not more than 1 year prior to the specified dates and shall be completed not more than 1 year after such dates. If plant operating conditions are such that examination of portions of the post-tensioning system cannot be completed within this stated time interval, examination of those portions may be deferred until the next regularly scheduled plant outage.

Table IWL-2500-1 (L-B), Item Number L2.10 requires that selected tendon force and elongation be measured in accordance with IWL-2522.

Table IWL-2500-1 (L-B), Item Number L2.20 requires that tendon single wire samples be removed and examined for corrosion and mechanical damage as well as tested to obtain yield strength, ultimate tensile strength, and elongation on each removed wire in accordance with IWL-2523. The selected tendons are subsequently re-tensioned as required per IWL-2523.3 because wire removal requires de-tensioning in order to safely obtain wire samples.

Table IWL-2500-1 (L-B), Item Number L2.30 requires that a detailed visual examination be performed on selected tendon anchorage hardware and adjacent concrete extending 2 feet from the edge of the bearing plate in accordance with IWL-2524. The quantity of free water released from the anchorage end cap as well as any that drains from the tendon during examination shall be documented.

Table IWL-2500-1 (L-B), Item Numbers L2.40 and L2.50 require that samples of selected tendon corrosion protection medium (CPM) and free water be obtained and analyzed in accordance with IWL-2525 and IWL-2526.

Reason for Request

ASME Section XI requires periodic visual examination of Containment concrete as well as visual examination and physical testing of post-tensioning systems. The examination and testing to date has indicated that the post-tensioning system is expected to maintain its safety-related function through the period of extended operation. This relief request proposes to perform tendon examinations on a 10-year alternating basis as shown by the schedule presented in Section 5 below. Visual examination of the concrete Containment and accessible steel hardware visible without tendon cover removal will continue to be performed at 5-year intervals in accordance with Subsection IWL. Additional examination of tendons may be required based on the results of concrete and end anchorage visual examinations. The need for such additional examinations will be determined by the Responsible Engineer (IWL-2330).

A summary of the proposed CISI program changes can be found in Section 2 of the Enclosure. Extending the interval between post-tensioning system examinations and

10 CFR 50.55a Relief Request CISl-03-01 for Point Beach Nuclear Plant, Units 1 and 2 Revision 0 (Page 3 of 8) tests from 5 years to 10 years will continue to provide an acceptable level of quality and safety based on projected performance and implementation of physical testing, should visual examination results indicate a need for such testing.

While this relief request is based on maintaining an acceptable level of quality and safety, there are additional benefits to extending the frequency of visual examination and physical testing of unbonded post-tensioning systems. Physical testing requires exposing the involved personnel to industrial and radiological safety hazards. Removing the tendon end caps and load testing or de-tensioning/re-tensioning the tendons also unnecessarily cycles the tendons and exposes the system to an unsealed environment during testing.

Below are specific hazards and undesirable conditions that would be eliminated by this proposed relief request:

1.

Most tendons are located well above ground level which requires working at heights and the inherent risks associated with such work.

2.

Some areas are in difficult-to-reach locations that have only one small access point.

3.

The testing requires working with high pressure hydraulics.

4.

The testing requires working in the vicinity of high energy plant systems.

5.

The testing requires working with solvents and hot petroleum products and associated fumes.

6.

The testing requires working with containers and pressurized lines filled with heated corrosion protection medium (grease).

7.

The testing requires working in the vicinity of high levels of stored elastic energy in the tendons. Sudden rotation during force measurement has resulted in high-speed shim ejection.

8.

The work includes handling of heavy loads (i.e., test equipment) that expose test personnel and equipment to hazards.

9.

Many tendon examinations must be performed in a radiation-controlled area Performing examination/testing on a reduced frequency reduces the repetitive loading required for force measurement or de-tensioning and re-tensioning. Reducing the population of tendon end caps removed will minimize tendon hardware exposure to environmental conditions and will reduce environmental waste (e.g., solvents, used grease, other consumables).

5.

10 CFR 50.55a Relief Request CISl-03-01 for Point Beach Nuclear Plant, Units 1 and 2 Revision 0 (Page 4 of 8)

Proposed Alternative and Basis for Use Proposed Alternative In accordance with 10 CFR 50.55a(z)(1), NextEra Energy Point Beach, LLC (NextEra) is proposing alternative examination requirements on the basis that these alternative actions will provide an acceptable level of quality and safety.

The proposed alternatives to the currently approved ISi program are as follows:

Extend the interval for visual examination (Subsection IWL Table IWL-2500-1 Items L2.30, L2.40 and L2.50) of Unit 1 and Unit 2 tendon end anchorage areas from 5 years to 10 years as shown in the schedule below.

Extend the interval for complete Unit 1 and Unit 2 post-tensioning system examinations that include tendon force measurements (Subsection IWL Table IWL-2500-1 Items L2.10, L2.30, L2.40 and L2.50) in accordance with the following schedule.

Proposed Tendon Surveillance Schedule (includes the four most recent Unit 1 and Unit 2 surveillances for reference)

Units 1 & 2 Year Visual Examination, CPM Sampling Tendon Force

& Free Water Collection/ TestinQ Measurement 2003 Performed Performed - Unit 1 2009 Performed Performed - Unit 2 2014 Performed Performed - Unit 1 2019 Performed Performed - Unit 2 20308 Perform Perform - Unit 1 20408 Perform Perform - Unit 2 2050a,b Perform Perform - Unit 1 Note a: For scheduling purposes, each future surveillance is treated as due at mid-year and must be performed between 30 June of the year prior to the year shown and 30 June of the year following the year shown.

Note b: If applicable based on unit closure schedule.

Eliminate the requirement for de-tensioning / re-tensioning of tendons, wire removal and wire sample testing (Subsection IWL Table IWL-2500-1 Item L2.20).

Limit initial corrosion protection medium (CPM) laboratory tests (Subsection IWL Table IWL-2500-1 Item L2.40) to that which determines absorbed water content; perform the corrosive ion and reserve alkalinity tests only on those samples that

10 CFR 50.55a Relief Request CISl-03-01 for Point Beach Nuclear Plant, Units 1 and 2 Revision 0 (Page 5 of 8) have a water content above the acceptance limit, are collected at an anchorage where free water and / or corrosion is found or if specified by the IWL Responsible Engineer (RE).

The above proposed alternatives relate only to the post-tensioning system and the associated examinations that require close-in access to tendon end anchorage areas (Examination Category L-8). Visual examination of the exposed areas of the Containment concrete surface, exposed areas of the tendon bearing plates, and tendon end caps will continue to be performed at 5-year intervals in accordance with ASME Section XI, Subsection IWL requirements (Examination Category L-A).

The reduced frequency of physical testing of the post-tensioning system will continue to provide an acceptable level of quality and safety based on projected performance and implementation of physical testing should visual examination results indicate a need for such testing.

NextEra will continue to perform a General Visual examination and Detailed Visual examination (when required) of accessible concrete and exposed steel hardware as required by ASME Section XI, Table IWL-2500-1, Examination Category L-A, Item Numbers L 1.11 and L 1.12, as modified by 10 CFR 50.55a. The examination and physical testing requirements of ASME Section XI, Table IWL-2500-1, Examination Category L-8, Item Numbers L2.10, L2.20, L2.30, L2.40, and L2.50 will also be performed if the General Visual examination and Detailed Visual examination identify conditions indicative of possible degradation of tendon hardware, as documented by the Responsible Engineer in an engineering evaluation. Example conditions that could require removal of the tendon end cap and further examination per Item Numbers L2.10, L2.20, L2.30, L2.40, and L2.50 are:

Evidence of possible damage to the enclosed post-tensioning hardware as indicated by conditions such as end cap deformation found during external visual examination. Conditions observed by removal of the end cap would determine the extent of additional examinations per Item Numbers L2.10, L2.20, L2.30, L2.40, or L2.50.

Active corrosion on a bearing plate or end cap that requires further investigation as determined by the Responsible Engineer in an engineering evaluation.

Evidence of corrosion protection medium leakage will be evaluated, and a plan developed that requires further investigation and corrective actions as defined in an engineering evaluation documented by the Responsible Engineer.

NextEra will report any abnormal degradation of the concrete Containment structure in the lnservice Inspection Summary Report of the completed examinations required by the Pre-Stressed Concrete Containment Tendon Surveillance Program in accordance with

10 CFR 50.55a Relief Request CISl-03-01 for Point Beach Nuclear Plant, Units 1 and 2 Revision 0 (Page 6 of 8) 10 CFR 50.55a and ASME Section XI as required by Technical Specifications 5.6.7, "Tendon Surveillance Report."

Subsection IWL Post-Tensioning System Examination and Physical Testing Requirements and Justification for Alternative The Enclosure to this submittal provides a detailed discussion of the historical basis for examination and testing of post-tensioning systems. The Enclosure also includes the Point Beach Nuclear Plant (PBNP), Units 1 and 2, specific observations that provide a basis for the proposed alternative from the ASME Section XI examination and testing requirements included in Table IWL-2500-1, Examination Category L-B. In Sections 5.1 and 5.2 of the Enclosure, it was concluded that based on examination/testing results to date, combined with implementation of continuing actions, the proposed alternative will maintain an acceptable level of quality and safety.

Additional Supporting Actions The ASME Section XI, Subsection IWL programs at PBNP, Units 1 and 2 are credited for managing degradation of the Containment. The Examination Category L-A visual examinations (every 5 years) being performed adequately identify the conditions that would allow water intrusion into the tendons and leakage of CPM which would be precursors for providing an environment that could allow corrosion of the tendon wires or inaccessible tendon hardware covered by the tendon end cap. Such conditions would be evaluated by the Responsible Engineer to identify required additional actions to assure no corrosive environmental conditions exist.

The recommendations identified in Section 5.3 of the Enclosure, based on the results and conclusions in Sections 5.1 and 5.2 of the Enclosure, provide additional safety and related benefits. The recommendations that support this proposed relief request to perform Examination Category L-B examinations/tests on a less frequent basis offer additional assurance that performing the Examination Category L-B examinations/tests on a less frequent basis will continue to provide an acceptable level of quality and safety.

Summary and Conclusions The results of the 11 post-tensioning system lnservice examinations performed between 1971 and 2019 show that the Unit 1 and Unit 2 systems can be expected to perform their intended function through T = 100 years which is well past the presumed unit maximum operating lifetime of 80 years. Examination Category L-A visual examination will be adequate to determine if additional physical testing and examination per Examination Category L-B are required.

6.

10 CFR 50.55a Relief Request CISl-03-01 for Point Beach Nuclear Plant, Units 1 and 2 Revision 0 (Page 7 of 8)

Duration of Proposed Alternative This relief request will remain in effect through the remainder of the current third CISI interval for PBNP, Units 1 and 2, and will continue to remain in effect for all subsequent CISI intervals through the end of the operating lifetime of each unit or until such time as ASME Section XI requirements are revised to address similar examination scheduling that is approved in 10 CFR 50.55a. If similar ASME Section XI examination scheduling is implemented in later editions of Section XI, this relief request would be retired, and the Section XI requirements as amended by 10 CFR 50.55a would be adopted as required during subsequent CISI Interval updates. The expiration dates of the PBNP renewed operating licenses are October 5, 2030 (Unit 1) and March 8, 2033 (Unit 2).

7.

PRECEDENTS Letter from M. Markley (U.S. Nuclear Regulatory Commission) to C. Gayheart (Southern Nuclear Operating Co., Inc.), "Vogtle Electric Generating Plant, Units 1 and 2 - lnservice Inspection Alternative VEGP-ISI-ALT-19-01 For Containment Tendon lnservice Inspection Extension (EPID No. L-2019-LLR-0017)," dated July 11, 2019 (ML19182A077)

Letter from J. Danna (U.S. Nuclear Regulatory Commission) to B. Hanson (Exelon Generation Company, LLC), "Three Mile Island Nuclear Station, Unit 1 - Relief from the Requirements of the American Society of Mechanical Engineers Code RE:

Examination and Testing for Containment Unbonded Post-Tensioning System (EPID L-2018-LLR-0132)," dated September 19, 2019 (ML19226A023)

Letter from J. Danna (U.S. Nuclear Regulatory Commission) to D. Stoddard (Dominion Energy Nuclear Connecticut, Inc.), "Millstone Power Station, Unit No. 2 - Proposed Alternative RR-05-05 to the Requirements of the ASME Code Re: Containment Unbonded Post-Tensioning System lnservice Inspection Requirements (EPID L-2019-LLR-0120)," dated October 20, 2020 (ML20287A471)

Letter from N. Salgado (U.S. Nuclear Regulatory Commission) to D. Rhoades (Exelon Generation Company, LLC), "Braidwood Station, Units 1 and 2 and Byron Station, Unit Nos. 1 and 2 - Proposed Alternative to the Requirements of the American Society of Mechanical Engineers Boiler & Pressure Vessel Code (EPIDS L-2020-LLR-0099 and L-2020-LLR-0100)," dated August 3, 2021 (ML21134A006)

Letter from J. Danna (U.S. Nuclear Regulatory Commission) to D. Rhoades (Exelon Generation Company, LLC), "Calvert Cliffs Nuclear Power Plant, Units 1 and 2 -

Alternative to the Requirements of the ASME Section XI, Subsection IWL Concerning

10 CFR 50.55a Relief Request CISl-03-01 for Point Beach Nuclear Plant, Units 1 and 2 Revision 0 (Page 8 of 8)

Unbound Post-Tensioning Systems (EPID L-2020-LLR-0135)," dated September 2, 2021 (ML21190A004)

Letter from J. Dixon-Herrity (U.S. Nuclear Regulatory Commission) to M. Lacal (Arizona Public Service Company), "Palo Verde Nuclear Generating Station Units 1, 2, and 3 - Relief Request 67 for an Alternate Frequency to Containment Unbonded Post-Tensioning System lnservice Inspection (EPID L-2021-LLR-0050)," dated May 12, 2022 (ML22124A241)

8.

REFERENCES American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code,Section XI, 2007 Edition with the 2008 Addenda.

3rd Interval Concrete Containment lnservice Inspection Program for Point Beach Units 1 and 2, 3rd lnterval-lWL-PB-1/2-Program Plan Rev. 0.

Enclosure Point Beach Nuclear Plant Containment Post-Tensioning System lnservice Inspection Technical Report Revision 0

NEXTERA ENERGY, LLC POINT BEACH NUCLEAR PLANT UNITS 1 & 2 CONTAINMENT POST-TENSIONING SYSTEM INSERVICE INSPECTION BASIS FOR PROPOSED EXTENSION OF EXAMINATION INTERVAL TECHNICAL REPORT Report SL-018297 Revision 0 January 15, 2024 Project No.: A13329.151

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page i ISSUE

SUMMARY

AND APPROVAL PAGE This is to certify that this document has been prepared, reviewed, and approved in accordance with Sargent & Lundy's Standard Operating Procedure SOP-0405, which is based on ASQ/ANSI/ISO 9001 :2015: Quality Management Systems-Requirements.

Contributors Prepared by:

Name Title I

Signature Digitally signed by Howard T. Hill, PhD, P.E.

Senior Consultant H

d T H' I I Howard T. Hill OWar I

Date: 2024.01.15 15*13: 17 -06'00' Reviewed by:

I Name Title I

Signature Arthur Eberhardt, PhD, P.E., S.E.

Senior Consultant Arthur C.

Arthur C. Eberhardt 2024.01.1 5 15:39:19 Eberhardt

-06'00' Bryar Lindenmeyer Structural Associate

~

~~ byBlyar (Data Entry into Tables 2-13)

Dal : 2024.01.15 15:21:4&-06'00' Approved by:

Digitally signed by Andrew J.

Weihert Date: 2024.01.15 17:15:19 -06'00' See Signature Andrew Weihert, P.E., S.E., PMP Project Associate Date Date See signature Date See signature See Signature

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 TABLE OF CONTENTS SL Report No.: SL-018297 Rev. 0 01/15/2024 Page ii ISSUE

SUMMARY

AND APPROVAL PAGE............................................................................... i LIST OF ABBREVIATIONS....................................................................................................... vi

1.

PURPOSE, CONTAINMENT/ ISi PROGRAM DESCRIPTION AND ORGANIZATION.. 1 1.1 Containment Description.............................................................................................. 1 1.2 Containment ISi Program Summary Description........................................................ 3 1.3 Report Organization...................................................................................................... 4

2.

SUMMARY

OF PROPOSED ALTERNATIVES............................................................... 5

3.

BACKGROUND OF CURRENT ISi REQUIREMENTS AND BASIS FOR PROPOSED ALTERNATIVES............................................................................................................. 7 3.1 Regulatory Guide 1.35.................................................................................................. 7 3.2 ASME Section XI / Subsection IWL............................................................................. 8 3.3 USN RC Regulation 1 0CFR50.55a................................................................................ 8 3.4 Basis for Proposed Deviations/ Relief from 10CFR50.55a and IWL Requirements 8 3.4.1 Pre-Stressing Force Trend.............................................................................. 1 0 3.4.2 System Hardware Condition History.............................................................. 11 3.4.3 Wire/ Strand Test Results............................................................................... 12 3.4.4 Corrosion Protection Medium Test Results................................................... 13

4.

POINT BEACH EXAMINATION HISTORY AND RESULTS ANALYSIS/ EVALUATION.......................................................................................... 14 4.1 Tendon Force Trends and Forecasts......................................................................... 17 4.1.1 Hoop Tendon Mean Force Trends, LCL's and Margins................................. 19 4.1.2 Vertical Tendon Mean Force Trends, LCL's and Margins............................. 20 4.1.3 Dome Tendon Mean Force Trends, LCL's and Margins................................ 21 4.1.4 Pre-Stressing Force Summary and Conclusion............................................ 23 4.2 End Anchorage Condition.......................................................................................... 24 4.2.1 Corrosion.......................................................................................................... 24 4.2.2 Free Water........................................................................................................ 27 4.2.3 Broken Wires and Missing/ Unseated Button Heads.................................... 27 4.2.4 Load Bearing Components Damage I Distortion........................................... 32 4.2.5 Concrete Cracking Adjacent to Bearing Plates............................................. 32 4.2.6 Anchorage Condition Summary and Conclusions........................................ 32

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page iii 4.3 Wire Examination and Testing.................................................................................... 33 4.3.1 Wire Examination............................................................................................. 33 4.3.2 Wire Testing..................................................................................................... 35 4.3.3 Conclusions and Recommendation............................................................... 36 4.4 Corrosion Protection Medium Testing....................................................................... 36 4.4.1 CPM Test Results............................................................................................. 37 4.4.2 CPM Test Evaluation, Conclusions and Recommendations......................... 39

5.

OVERALL

SUMMARY

, CONCLUSIONS AND RECOMMENDATIONS.......................40 5.1 Surveillance Results Overall Summary..................................................................... 40 5.1.1 Tendon Force................................................................................................... 40 5.1.2 Condition of End Anchorage Hardware / Concrete and Extracted Wires.... 40 5.1.3 Tendon Wire Strength and Ductility............................................................... 41 5.1.4 Corrosion Protection Medium Characteristics.............................................. 41 5.2 Conclusions................................................................................................................. 41 5.3 Recommendations...................................................................................................... 42

6.

REFERENCES.............................................................................................................. 44

7.

TABLES AND FIGURES............................................................................................... 46

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 ACI ANS ANSI ASME ASTM CPM FSAR kip ksi LCL MRV NRC ORNL ppm SIT USNRC LIST OF ABREVIATIONS American Concrete Institute American Nuclear Society American National Standards Institute American Society of Mechanical Engineers American Society for Testing and Materials Corrosion protection medium Final Safety Analysis Report Kilo-pound (1,000 pounds)

Kips per square inch Lower confidence limit Minimum required value Nuclear Regulatory Commission Oak Ridge National Laboratory Parts per million Structural integrity test United States Nuclear Regulatory Commission SL Report No.: SL-018297 Rev. 0 01/15/2024 Page iv

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 1

1.

PURPOSE, CONTAINMENT/ ISi PROGRAM DESCRIPTION AND ORGANIZATION This report provides the technical evaluation / justification supporting a request for relief to allow alternatives to certain containment inservice inspection (ISi) requirements specified in USN RC Regulation 1 0CFR50.55a (Reference 6.1) and, by reference therein, ASME Section XI, Subsection IWL (Reference 6.2). The current Point Beach Nuclear Plant containment ISi program conforms to these regulatory and code requirements with modifications as allowed by approved relief requests.

1.1 Containment Description The Point Beach containments are essentially identical reinforced and post-tensioned concrete pressure vessels that serve as the final barriers (after fuel cladding and the reactor coolant system pressure boundary) against the release of radioactive material from the reactor core to the outside environment. The design basis internal pressure for both containments is 60 psig (Final Safety Analysis Report, Reference 6.3).

Each containment consists of a conventionally reinforced concrete flat base mat (with a central reactor cavity) connected to and supporting a pre-stressed concrete cylinder and a prestressed concrete shallow dome. The cylinder is thickened at six equally spaced locations with vertical buttresses that provide anchorage for the hoop prestressing tendons (see next page for a description of hoop tendons).

The dome consists of a central spherical cap and outer toroidal section that transitions into a massive ring girder which serves as a connection between the dome and cylinder.

The ring girder also provides anchorage for the dome prestressing tendons and the upper ends of the vertical tendons. The interior surface of the containment is lined with a 1/4 inch (thicker at penetration regions) steel plate for leak tightness. Principal containment dimensions are, as shown in References 6.3, 6.4 and 6.5:

Cylinder inside radius - 52 ft. 6 in.

Cylinder height top of mat to dome apex - 150 ft. 3in.

Cylinder wall concrete thickness (increases at the wall to mat haunch) - 3 ft. 6 in.

Dome thickness (increases at the transition to the ring girder) - 3 ft.

Base mat thickness -

11 ft. 6 in. at outer perimeter, 8 ft. at reactor cavity and greater elsewhere.

Both containments are completely enclosed by architectural fagades which provide protection from the outside environment. Wall and buttresses are fully exposed within the fagade; only the bottom and perimeter of the base mat are in contact with foundation material / backfill.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 2 The cylinder wall and dome are post-tensioned with 90 wire BBRV (wires anchored by cold formed button heads) tendons. The ASTM A421 (Reference 6.6) wires have a diameter of 0.250 inches and a specified minimum ultimate tensile strength of 240 ksi.

The cylindrical wall is pre-stressed with both circumferential (hoop) and vertical tendons.

Wall circumferential pre-stressing consists of 367 tendons arranged in 6 overlapping tendon sub-groups (and one additional tendon), each spanning 120 degrees plus the width of a buttress. Vertically adjacent sub-groups are offset by 60 degrees to provide continuous overlap of pre-stressing force. Circumferential (hoop) tendons anchor at the buttress faces. Circumferential tendon designations consist of two letters identifying the sub-group end anchorage buttresses and a sequence number identifying the elevation.

The order of the letters, which may differ depending on the source document, is not significant, i.e., tendon 20-AC and 20-CA identify the same tendon. Units 1 and 2 buttresses are designated A through F and G through M (there is no buttress I),

respectively.

Wall vertical pre-stressing consists of 168 tendons anchored at the top of the ring girder and the bottom of the base mat. A tunnel (the tendon access gallery) below the base mat provides access to the lower anchorages. Units 1 and 2 vertical tendons are numbered V-1 through V-168 and V-201 through V-368, respectively.

Dome pre-stressing consists of 147 tendons arranged in 3 layered sub-groups, each having 49 equally spaced and parallel (in plan-view) tendons. The layers intersect at 60 degrees. Dome tendons anchor at the vertical face of the ring girder. Unit 1 dome tendons are designated by a leading 'D', followed by the layer number and a number identifying the sequential position in the layer, e.g., D3-26 is a Unit 1 tendon in layer 3 at sequential position 26. Unit 2 dome tendons are designated by a '2' before the sequential position number, e.g., D1-209 is a Unit 2 tendon in layer 1 at sequential position 9.

Tendon forces decrease with time as a result of elastic shortening (the effect of sequential tensioning operations), concrete shrinkage, concrete creep, and pre-stressing wire relaxation losses. Mean tendon forces must remain above specified minima to ensure that concrete remains in a state of membrane compression under postulated accident pressure and temperature conditions. Minimum required group mean tendon forces, specified in Calculation 2000-0056 (Reference 6.7), are shown below. The calculation specifies the minima as stress levels in ksi. Corresponding minimum required group mean tendon force is computed for a tendon with 90 wires each having a 0.250-inch diameter.

Hoop Tendon Group:

Vertical Tendon Group:

Dome Tendon Group:

134.5 ksi -

594 kips / tendon 140.6 ksi -

621 kips/ tendon 137.4 ksi -

607 kips / tendon

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 1.2 Containment ISi Program Summary Description SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 3 Continuing structural1 integrity of the Point Beach containments is verified through regular examinations and tests (also referred to as surveillances) performed in accordance with the requirements of USN RC Regulation 1 0CFR50.55a (Reference 6.1) and, by reference therein, ASME Section XI, Subsection IWL (Reference 6.2) as modified by approved relief requests. The ISi program, as detailed in the 3rd Interval Concrete Containment lnservice Inspection Program (Reference 6.8), requires visual examination of the entire accessible concrete surface and examination and testing of random samples selected from the tendon population. Surface visual examinations follow the applicable guidelines given in the ACI reports referenced in Subsection IWL and are not considered further in this report, which addresses only the prestressing system.

Examination and testing of the post-tensioning system currently follows ASME B & PV Code (2007 Edition with 2008 Addenda)Section XI, Subsection IWL requirements as modified by approved relief requests. Examinations and tests, performed on a random sampling of tendons, are described below.

Visual Examination Anchorage area concrete and post-tensioning system hardware are visually examined for the following indications of damage or degradation.

o Cracking or spalling at the surface of concrete adjacent to bearing plates.

o Accumulation of water in end caps.

o Lack of corrosion protection medium (CPM) coverage on anchor heads, shims and buttonheads.

o Corrosion on bearing plates, anchor heads, shims and buttonheads.

o Protruding or missing buttonheads.

o End anchorage hardware cracking or distortion.

1 Containment liner ISi, performed to assess leak tight integrity, is covered by Subsection IWE, and is not addressed in this technical report.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 Tendon Force Measurement and Wire Testing2 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page4 The force at each end of a hoop or dome sample tendon and upper end of a vertical sample tendon is measured by applying jacking force just sufficient to loosen the shim stack (thus ensuring that all tendon load is carried by the calibrated jacks).

Also, a single wire (in addition to any found to be broken) is removed from one tendon in each group, examined for damage and corrosion and tested to determine yield strength, ultimate strength, and elongation at failure.

CPM Sampling and Testing Samples of CPM are collected at each end of each tendon and analyzed for water content, concentration of corrosive ions and reserve alkalinity.

Free Water Collection and Testing Free water, if found in sufficient quantity for sampling, is collected and tested to determine pH.

1.3 Report Organization The remainder of this report consists of the following 6 parts.

Part 2 - Summary of Proposed Alternatives Part 3 - Background of Current ISi Requirements and Basis for Proposed Alternatives Part 4 -Point Beach Examination History and Results Analysis / Evaluation Part 5 - Overall Summary, Conclusions and Recommendations Part 6 - References Part 7 - Tables and Figures 2 In accordance with the provisions of ASME Section XI Paragraph IWL-2421, tendon force measurements and wire extraction/ testing follow an alternating schedule as detailed in the Third-Ten-Year ISi Interval Containment Inspection Plan (Reference 6.8).

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151

2.

SUMMARY

OF PROPOSED ALTERNATIVES SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 5 The following alternatives to the currently approved ISi program are proposed and evaluated in this report.

Extend the interval for visual examination (Subsection IWL Table IWL-2500-1 Items L2.30, L2.40 and L2.50) of Unit 1 and Unit 2 tendon end anchorage areas from 5 years to 10 years as shown in the schedule below.

Extend the interval for complete Unit 1 and Unit 2 post-tensioning system examinations that include tendon force measurements (Subsection IWL Table IWL-2500-1 Items L2.10, L2.30, L2.40 and L2.50) in accordance with the following schedule.

Proposed Tendon Surveillance Schedule (includes the four most recent Unit 1 and Unit 2 surveillances for reference)

Units 1 & 2 Year Visual Examination, CPM Sampling Tendon Force

& Free Water Collection I Testing Measurement 2003 Performed Performed - Unit 1 2009 Performed Performed - Unit 2 2014 Performed Performed - Unit 1 2019 Performed Performed - Unit 2 20308 Perform Perform - Unit 1 20408 Perform Perform - Unit 2 2050a,b Perform Perform - Unit 1 Note a:

For scheduling purposes, each future surveillance is treated as due at mid-year and must be performed between 30 June of the year prior to the year shown and 30 June of the year following the year shown.

Note b:

If applicable based on unit closure schedule.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 6 Eliminate the requirement for de-tensioning / re-tensioning of tendons, wire removal and wire sample testing (Subsection IWL Table IWL-2500-1 Item L2.20).

Limit initial corrosion protection medium laboratory tests (Subsection IWL Table IWL-2500-1 Item L2.40) to that which determines absorbed water content; perform the corrosive ion and reserve alkalinity tests only on those samples that have a water content above the acceptance limit, are collected at an anchorage where free water and / or corrosion is found or if specified by the IWL Responsible Engineer3 This report and the Relief Request that it supports address only proposed alternatives to the post-tensioning system inservice inspection requirements covered by ASME Section XI, Subsection IWL Table IWL-2500-1 Examination Category L-B. The Category L-A concrete surface examinations will continue to be performed in accordance with Subsection IWL as modified by approved relief requests. Containment liner and penetration assembly examinations and tests will continue to be implemented in accordance with Subsection IWE as modified by approved relief requests.

Based on the evaluation of past examination results as discussed in subsequent sections of this report, it is concluded that implementation of the alternative containment in-service inspection program recommended herein will provide an equivalent level of assurance that the structural integrity of the Unit 1 and Unit 2 containments is maintained at the highest level.

3 A registered professional engineer having qualifications and responsibilities as identified in ASME Section XI Paragraph IWL-2330.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 7

3.

BACKGROUND OF CURRENT ISi REQUIREMENTS AND BASIS FOR PROPOSEDALTERNATWES Containment inservice inspection (also referred to herein as surveillance and inservice examination) requirements originated with the issuance of Regulatory Guide 1.35 (Reference 6.9) in the early 1970's and are currently mandated by ASME Section XI, Subsection IWL, which is incorporated by reference into USN RC regulation 1 0CFR50.55a.

A brief history of current requirement development is summarized in 3.1, 3.2 and 3.3 below. The basis for the proposed alternative program is discussed in 3.4.

3.1 Regulatory Guide 1.35 In February 1973, the U. S. Atomic Energy Commission issued the initial version of Regulatory Guide 1.35, lnservice Surveillance of Ungrouted Tendons in Prestressed Concrete Containment Structures (Reference 6.9). This document, drafted well before the accumulation of containment pre-stressing system performance data, described the following as an acceptable basis for system examinations.

Examination schedule - 1, 3 and 5 years after the pre-operational structural integrity test and every 5 years thereafter.

Examination sample size - 6 dome, 5 vertical and 1 0 hoop tendons.

Wire / strand extraction - one wire / strand from a tendon in each group {dome, vertical, hoop); extraction requires de-tensioning.

Visual examinations for damage, deterioration, and corrosion -

corrosion protection medium, end anchorage hardware, anchorage area concrete and extracted wires / strands.

Physical tests - tendon liftoff force and extracted wire / strand strength and elongation at failure.

The regulatory guide does not discuss the basis for the examination interval, the sample size or the various tests and examinations to be included in an acceptable program (these represent consensus opinions reached among the individuals involved in guide development). Also, it does not address the possible need for changes as future operating experience accumulates.

Subsequent revisions to Regulatory Guide 1.35 added procedures for corrosion protection medium chemical analyses (added in Revision 3), substantially changed the sampling process and included numerous other additions and clarifications but retained the examination interval and wire / strand testing program as described in the original 1973 issue. The final revision, Revision 3, was issued in July 1990.

Regulatory Guide 1.35 was withdrawn in August 2015 following the incorporation, by reference, of ASME Section XI, Subsection IWL into NRC regulation 10CFR50.55a.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 3.2 ASME Section XI/ Subsection IWL SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 8 The 1989 edition of the ASME Boiler and Pressure Vessel Code included in Section XI, for the first time, Subsection IWL which provided comprehensive and detailed requirements for a concrete containment inservice inspection program. During the development of IWL 4, which commenced in the 1970's, it was concluded that NRC acceptance and endorsement (by reference in 1 0CFR50.55a) of the document would be expedited if departures from the program described in Regulatory Guide 1.35 were minimized. For this reason, the examination interval, strength/ elongation testing of wire/

strand samples and relatively extensive chemical testing of corrosion protection medium samples mandated in IWL are unchanged from those identified in Regulatory Guide 1.35, Rev. 3.

Subsection IWL has been revised numerous times since its initial incorporation into Section XI in 1989. None of these revisions have altered the examination interval or the basic requirement to test wire / strand and corrosion protection medium samples.

3.3 USN RC Regulation 1 0CFR50.55a The 1996 amendment to 1 0CFR50.55a incorporated, by reference and with specified exceptions and additions, the ISi requirements given in the 1992 edition, with 1992 addenda, of ASME Section XI, Subsection IWL. Subsequent amendments have referenced later editions / addenda of IWL, but none have addressed changes to either the examination interval or the requirements for testing wire / strand and corrosion protection medium samples.

3.4 Basis for Proposed Deviations/ Relief from 10CFR50.55a and IWL Requirements

[Note:

This section of the technical report includes a generalized summary of post-tensioning system performance observed over almost 5 decades of periodic examinations conducted at 24 U. S. nuclear plant sites with 41 pre-stressed concrete containments. It is intended to show that containment post-tensioning systems, with few exceptions, are continuing to perform well and that, in general, system examination intervals could be significantly increased without compromising safe operation of the plant.]

The material covered in this section is based on the report author's experience as described below.

4 The author of this technical report has been a member of the IWL working group since the 1970's (when it was still being developed as an addition, CC-9000, to ASME Section Ill, Division 2) and served as chair of the working group during its later development and much of the period leading up to its incorporation into Section XI in 1989.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 9 Participation in containment post-tensioning system examinations at U. S. and foreign sites.

USNRC funded research, performed under contract to ORNL, on age-related decrease in pre-stressing force and other age-related effects at ~20 U. S.

containments.

Four decades of interacting with fellow members of the IWL working group.

Review of USNRC informational bulletins and generic letters.

Review of system performance history in connection with preparation of program basis documents for license renewal applications.

Forecasting tendon forces in connection with the preparation of minimum required pre-stressing force calculations.

Work on a USNRC-funded project to review and recommend updates to Regulatory Guides 1.35, 1.35.1 and 1.90, which address inservice inspection of pre-stressed containments.

A three-year association with the Crystal River 3 containment repair project; assignments included evaluating the condition of tendons not affected by the repair work.

The following summary is qualitative; specific references are not cited as the bases for the generalized statements regarding post-tensioning performance.

As noted in 3.1, 3.2 and 3.3 above, the examination intervals and wire / strand testing addressed in the 1973 original issue of Regulatory Guide 1.35 are now, almost 50 years later, still incorporated effectively unchanged into the current edition of ASME Section XI, Subsection IWL.

In addition, the current edition of ASME Section XI, Subsection IWL specifies corrosion protection medium chemical testing procedures that are effectively unchanged from those described in Regulatory Guide 1.35, Revision 3 (issued in July 1990).

The results of unbonded post-tensioning system examinations performed over the last 4 decades at 24 domestic sites with a total of 41 pre-stressed containments (listed in Table

1) provide ample evidence, as discussed below, that prescriptive requirements currently in IWL are, in many cases, overly conservative. These industry results as well as the subsequently discussed Point Beach plant-specific operating experience, support the implementation of alternative programs with fewer prescriptive requirements.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev.0 01/15/2024 Page 10 Reducing prescriptive requirements, as addressed in this report and the associated Relief Request that it supports, has the following advantages.

It reduces personnel and equipment safety hazards associated with working at heights, handling of heavy loads, working with high-pressure hydraulic equipment, working close to tendon end anchorages that can suddenly release stored mechanical energy, working with hot (>150 °F) corrosion protection medium that is under pressure, working in proximity to high-energy plant systems and working in radiation-controlled areas.

It reduces the potentially deleterious cycling of tendon loads that occurs during de-tensioning / re-tensioning for wire removal and to a lesser extent during the measurement of lift-off forces.

The technical justification for the proposed deviations is based on operating experience accumulated over the past 5 decades at the 24 domestic plants with containments having unbonded post-tensioning systems and the operating experience documented during the post-tensioning system examinations performed at Point Beach. The general conclusions regarding post-tensioning system performance are listed below. Conclusions specific to Point Beach are addressed in detail in subsequent sections of this report.

3.4.1 Pre-Stressing Force Trend Containment design criteria typically require that the post-tensioning system provide sufficient pre-stressing force at the end of 40 years (period of initial licensure considered to be the plant operating lifetime when design work on existing plants commenced) to maintain membrane compression in the walls and dome under specified accident conditions.

Post-tensioning system design was based on a postulated linear decrease in pre-stressing force with the logarithm of time (log-linear decrease). The log-linear function was selected as this provided a reasonably good fit to the results of relatively short-term creep, shrinkage and relaxation tests and was consistent with expectations based on the calculated response of theoretical models that represent materials as an assemblage of linear springs and dashpots. Concrete creep and shrinkage tests were typically conducted for 180 days and pre-stressing steel relaxation tests for 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> (~40 days). Designing for a 40-year plant operating lifetime required extrapolating concrete test durations by a factor of 80 and steel test durations by a factor of almost 400.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev.a 01/15/2024 Page 11 Post-tensioning system examination data have shown, with relative consistency, that the rate of change of pre-stressing force with the logarithm of time tends to decrease with time. Within 20 to 25 years after the completion of pre-stressing operations, the force time trend becomes essentially flat. Given this general trend, it can be stated with a high degree of confidence that the examination interval may be increased beyond 10 years with no compromise of safety function if the following conditions are satisfied.

The current mean pre-stressing force (hoop, vertical, dome, inverted U) computed using both the trend of individual tendon force data acquired to date and the mean of the most recently acquired data exceed the minimum required level by significant margins. The margin deemed significant is established through an evaluation by the Responsible Engineer.

The forecast means pre-stressing forces (hoop, vertical, dome, inverted U),

determined using the data acquired to date and computed, for conservatism, at the 95% lower confidence limit, remain above the minimum required levels until well past the deadline for completion of the subsequent surveillance.

3.4.2 System Hardware Condition History Industry wide, there have been relatively few significant issues associated with containment post-tensioning system hardware (tendon wire / strand5, anchor heads, wedges, shims and bearing plates).

Active corrosion is typically found only on the exposed parts of bearing plates. Free water at end anchorage areas, when found in quantities that are sufficient to allow collection and testing, has almost never been observed to cause corrosion.

Instances of deformation I damage I degradation are rare and almost always associated with singular construction events.

Most exceptions to the above are the result of unique situations that are plant specific and not indicative of an industry wide problem. Two widely reported exceptions, one involving wire corrosion and the other, anchor head material, are described below. Occurrences have been limited to the plants where these were first observed.

Debris blocked the drains at the perimeter of a shallow dome resulting in flooding that submerged the caps at the upper end of the vertical tendons. The hold down bolt holes in the tops of the caps were not well sealed. Storm water entered the caps through these holes and submerged the short lengths of uncoated wire just below the anchor heads. A number of wires were severely corroded and found to be no longer effective as pre-stressing elements.

5 The only U. S. containments with strand tendons, anchored with hardened wedges rather than cold formed button heads, are Rancho Seco, San Onofre (2 & 3) and Vogtle (1 & 2). Of these, only the Vogtle units are currently operating.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 12 New maintenance procedures to prevent future flooding above the ring girder were implemented. The condition has not recurred.

A unique combination of steel chemistry and high hardness led to the failure of anchor heads in both units of a two-unit plant. The problem, which is unique to the two units in question, has been addressed by implementing an enhanced examination and corrective action program.

3.4.3 Wire/ Strand Test Results Wire sample tests, performed by certified laboratories using appropriate equipment and procedures as specified in the applicable ASTM standards, show that strength and elongation at failure do not degrade with time. While past industry data often show reported strength and elongation to vary significantly from examination to examination, close evaluation of the data suggests that such fluctuations can generally be attributed to variations in the testing, specifically:

Many of the earlier tests were performed using vendor procedures that differ from those specified by the applicable ASTM standards.

Testing equipment was often vendor-fabricated and did not meet ASTM specifications.

Personnel assigned to the testing work did not always have the necessary experience.

In general, tests that conform to ASTM specifications and that are performed by experienced technicians show that both strength and elongation are close to, but exceed, the minima (240 ksi and 4.0%, respectively) specified for ASTM A421 (Reference 6.6) wire.

As there is no evidence that either strength or elongation (at failure) decrease with time under load, it is concluded that there is no benefit to ongoing tests for these parameters.

And it is to be noted that there is no precedent across the broader (beyond nuclear power plants) industry to periodically evaluate the continuing mechanical properties of pre-stressing system hardware and other steel structural members.

Relaxing the requirement for wire / strand tests, when justified by evaluation of specific plant operating experience, reduces the deleterious cycling of tendon force resulting from the de-tensioning and re-tensioning needed to allow wire removal. It also reduces the industrial hazard associated with the de-tensioning and re-tensioning operation.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 3.4.4 Corrosion Protection Medium Test Results SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 13 Effectively all US containments that have ungrouted tendons use a corrosion protection medium (CPM) product supplied by the Viscosity Oil Company. CPM formulations have changed over time, but the basic product remains the same, i.e., a microcrystalline wax that provides the following protective functions.

An essentially waterproof coating on tendon wires and end anchorage hardware.

A bulk fill to limit water intrusion into tendon ductwork.

A chemically built-in alkalinity to neutralize acid conditions that could lead to corrosion.

There is no industry operating experience to indicate that the CPM used in US containments has degraded over time in such a manner as to result in tendon or end anchorage hardware corrosion. Such hardware problems as have been found are attributable to either gross loss of medium from the ductwork, end anchorage design features that prevent full coverage of metallic components at the time of CPM injection or, metallurgical characteristics of certain anchor-head production batches.

Current CPM testing requirements mandate relatively complex procedures, as described or referenced in ASME Section XI (Reference 6.2) Table IWL-2525-1, to determine absorbed water content, corrosive ion concentration and residual reserve alkalinity. As corrosive ions cannot enter the ductwork in the absence of water intrusion and reserve alkalinity cannot be brought into play in the absence of acid ion presence in the bulk CPM, there is little, or no benefit gained by testing CPM samples for ion concentrations and reserve alkalinity unless there is evidence of free or absorbed water.

Consequently, industry experience would suggest that CPM samples collected during end anchorage examinations should be initially tested only to determine absorbed water content and that additional tests should be conducted only if there is evidence of sufficient water to establish potentially corrosive conditions or, if specific unit/ plant test data indicate a history of problems with the CPM. Modifying testing programs accordingly would reduce the environmental problems associated with disposal of the reagents used in these processes (the procedure for determining water content does not require use of reagents).

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 14

4.

POINT BEACH EXAMINATION HISTORY AND RESULTS ANALYSIS /

EVALUATION The visual examination results and test data used in the development of Sections 4.1 through 4.4 are those documented in Point Beach inservice inspection reports, References 6.1 0 through 6.22.

Point Beach has completed, to date, 11 surveillances of the Unit 1 and Unit 2 post-tensioning systems. These were performed in the years as shown in the following table.

The SIT years are also shown for reference. Examinations from 1984 onward were conducted in accordance with Regulatory Guide 1.35, Revision 3, or 1 0CFR50.55a I ASME Section XI Subsection IWL as noted, except that the initially established schedule was maintained as discussed below.

SIT and Year Year Surveillance Performed Performed Governing Document Number/

Year Unit 1 Unit 2 SIT 1970 1971 N/A 1 / 1 1971 1972 N/A 2/3 1973 1974 N/A 3/8 1979 N/A 4 / 13 1984 Reg Guide 1.35, Proposed Revision 3 5 / 18 1989 Reg Guide 1.35, Proposed Revision 3 6 / 23 1994 Reg Guide 1.35, Revision 3 7128 1999 Reg Guide 1.35, Revision 3 8 I 33 2003 10CFR50.55a / IWL 9 I 38 2009 10CFR50.55a / IWL 10 / 43 2014 1 0CFR50.55a I IWL 11 / 48 2019 1 0CFR50.55a I IWL

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 15 Regulatory guide 1.35 and ASME Section XI (paragraph IWL-2421) allow the measurement of lift-off forces (and tendon de-tensioning/ test wire extraction) to alternate between the two units, with Unit 1 lift-off forces measured in surveillance years 1, 5 and 10 and every 10 years thereafter and with Unit 2 lift-off forces measured in surveillance years 1, 5 and 15 and every 1 0 years thereafter.

As noted in the above table, Point Beach initially opted to perform surveillances 1, 3 and 8 years after the SIT and every 5 years thereafter. This schedule was retained through the 48th year surveillance in 2019. Also, Unit 1 and Unit 2 surveillances were performed concurrently during the 8th and subsequent years.

During the 1st, 3rd and 8th year surveillances, all sample tendons were de-tensioned, and a test wire was removed from each. Commencing with the 13th year surveillance in 1984, tendon force measurements and tendon de-tensioning / test wire extraction were performed in alternate years as shown below.

Unit 1: Surveillance years 1, 3, 8, 13, 23, 33 and 43 Unit 2: Surveillance years 1, 3, 8, 18, 28, 38 and 48 The following sections, 4.1 through 4.4 of this report provide a comprehensive evaluation of Point Beach post-tensioning system examination results as documented in the applicable surveillance reports.

Section 4.1 - Tendon force trends and forecasts Unit 1 and Unit 2 hoop tendon force trends and forecasts Unit 1 and Unit 2 vertical tendon force trends and forecasts Unit 1 and Unit 2 dome tendon force trends and forecasts Section 4.2 - End anchorage condition Section 4.3 - Extracted wire condition and mechanical properties Section 4.4 - Corrosion protection medium chemical properties and free water analysis The proposed extension of the tendon examination interval to 10 years is justified if the extension can be separately justified for each of the 4 post-tensioning system performance categories listed above.

In this report surveillances are generally referred to by calendar year and I or time, T, since the applicable unit SIT date. Plots of time-dependent parameters use T for the time axis.

Tables listing time dependent parameters show both the calendar year of the surveillance and the applicable value of T.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 16 Tis calculated as the difference between the surveillance mid-point date and the SIT mid-point date, each expressed as decimal years. Mid-points are determined as decimal years midway between the event (SIT or surveillance) starting and ending dates as shown in the applicable reports. To simplify computations, starting and ending dates are treated as the middle of the month during which the surveillance (or SIT) begins and ends. Values of T computed for Units 1 and 2 are shown in the following tables6.

PBNP Unit 1 SIT & Surveillance Dates and Time, T, Since SIT SIT/ Surv.

Start End T', Mid-Point T,

Year Year Month Year Month Year & Fraction Years Since SIT SIT 1970 6

1970 6

1970.46 0.0 1

1971 7

1971 8

1971.58 1.1 3

1973 7

1973 8

1973.58 3.1 8

1979 6

1979 8

1979.54 9.1 13 1984 6

1984 8

1984.54 14.1 18 1989 6

1989 8

1989.54 19.1 23 1994 6

1994 8

1994.54 24.1 28 1999 5

1999 7

1999.46 29.0 33 2003 8

2003 10 2003.71 33.3 38 2009 2

2009 4

2009.21 38.8 43 2014 3

2014 5

2014.29 43.8 48 2019 4

2019 6

2019.38 48.9 PBNP Unit 2 SIT & Surveillance Dates and Time, T, Since SIT SIT/ Surv.

Start End T', Mid-Point T,

Year Year Month Year Month Year & Fraction Years Since SIT SIT 1971 3

1971 3

1971.21 0.0 1

1972 5

1972 5

1972.38 1.2 3

1974 7

1974 8

1974.58 3.4 8

1979 6

1979 8

1979.54 8.3 13 1984 6

1984 8

1984.54 13.3 18 1989 6

1989 8

1989.54 18.3 23 1994 6

1994 8

1994.54 23.3 28 1999 5

1999 7

1999.46 28.3 33 2003 8

2003 10 2003.71 32.5 38 2009 2

2009 4

2009.21 38.0 43 2014 3

2014 5

2014.29 43.1 48 2019 4

2019 6

2019.38 48.2 6 Due to the 9-month difference in SIT dates, the Unit 2 calendar date corresponding to a given value of Tis 0.75 years later than the Unit 1 calendar date corresponding to the same value of T.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 4.1 Tendon Force Trends and Forecasts SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 17 In the following discussions and evaluations, all computed mean forces and LCL's are rounded to a whole kip value. Computed values ending in (.5) are rounded to the nearest even number.

Units 1 and 2 tendon forces were measured during the surveillances noted in the table below.

Unit Surveillance Year-Tendon Force Measurement Yes/ No 1

3 8

13 18 23 28 33 38 43 1

Yes Yes Yes Yes No Yes No Yes Noa Yes 2

Yes Yes Yes No Yes No Yes Nob Yes No Note a: Unit 1 common tendon only forces measured during the 38th year surveillance.

Note b: Unit 2 common tendon only forces measured during the 33rd year surveillance.

48 No Yes Force (lift-off force or the force required to separate the anchor head from the shim stack) in designated sample tendons, and additional tendons as mandated by procedure or specified by the Responsible Engineer, is measured during each examination. Measured force trends and forecasts provide ample evidence that mean pre-stressing in the containment wall and dome will remain at or above the lower limits shown in report Section 1.1 until at least T = 100 years and, well beyond the currently expected 80-year maximum operating lifetime of the units.

The purpose of a lift-off force measurement is to determine how the initial seating force in a tendon (seating force is used as a measure of the pre-stressing force contributed by the tendon) has been reduced by elastic shortening and time dependent losses. Reported hoop or dome tendon force is the average of the lift-off forces measured at the two anchorages.

Reported vertical tendon force is that measured at the upper end. The mean of many tendon forces then serves as a reasonable estimate of the overall mean pre-stressing force provided by the applicable tendon group (i.e., hoop, vertical or dome).

Forces measured at tendon anchorages reflect the losses due to elastic shortening7, concrete creep, concrete shrinkage, and tendon wire stress relaxation.

7 Elastic shortening loss is the loss in tendon force resulting from the compressive strain induced in the concrete by subsequent tendon tensioning. It is generally greatest for the first tendon tensioned and zero for the last tendon tensioned.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 18 Concrete creep strain, concrete shrinkage strain and pre-stressing steel stress relaxation are shown by relatively short-term tests8 to vary approximately linearly with the logarithm of time. The log-linear characteristics established by these tests are used in containment design. For this reason, mean pre-stressing force trends are treated in this report as log-linear functions.

[Note: The log-linear trend slope and intercept as well as LCL values discussed below, are computed using the methods developed in Probability and Statistics for Engineers by Irwin Miller and John E. Freund (Reference 6.23).]

A log-linear mean force trend is computed for each of the Unit 1 and Unit 2 tendon groups using all applicable lift-off force data acquired during the 1st year through 48th year surveillances.

Lift-off forces (and log-linear trend lines) are plotted on Figures 1 through 6. Each of these plots exhibits a significant degree of scatter, a phenomenon typical of lift-off force plots generated for other containments. As the number of tendons included in surveillance samples is a small fraction of the total, the mean force represented by a trend line fitted to scattered data is only an estimate of the true mean pre-stressing force provided by the tendon group. A meaningful lower limit on the true mean at any point in time is computed as the 95% lower confidence limit (95% LCL)9 on the trend line ordinate.

Both the trend lines and LCL curves are extrapolated to T = 100 years, a major grid line on the plot abscissa.

Units 1 and 2 hoop, vertical and dome force trends are addressed in 4.1.1 through 4.1.3.

8 Creep and shrinkage tests are typically conducted for 6 months and relaxation tests for 1,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> Uust under 42 days). These time frames are short relative to the expected service life of a containment (40, 60 or possibly even 80 years if a subsequent license extension is granted).

9 The use of a 95% confidence limit is based on a precedent set in the standard (ANSI / ANS 56.8, Reference 6.24) that governs the conduct of another safety related activity, the containment integrated leakage rate test.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 4.1.1 Hoop Tendon Mean Force Trends, LCL's and Margins 4.1.1.1 Unit 1 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 19 Unit 1 hoop tendon mean force trend and LCL are illustrated by the Figure 1 plot. Both the trend and LCL remain above the 594-kip minimum required value (MRV) beyond T = 100 years. Mean force trend and LCL values at T = 100 years and margins above the MRV are tabulated below. Trend values are based on the following log-linear regression line equation, which is shown on the plot.

F(T) = 670.9 - 21. 73

• Log1o(T)

Unit 1 Hoop Tendon Group F(100), kip Margin, kip LCL(100), kip Margin, kip 627 33 618 24 4.1.1.2 Unit 2 Unit 2 hoop tendon mean force trend and LCL are illustrated by the Figure 2 plot. Both the trend and LCL remain above the 594-kip minimum required value (MRV) beyond T = 100 years. While the plotted forces exhibit a significant degree of scatter, these do support a conclusion that the force trend tends to flatten over time.

Mean force trend and LCL values at T = 100 years and margins above the MRV are tabulated below. Trend values are based on the following log-linear regression line equation, which is shown on the plot.

F(T) = 699.9-41.07

• Log10(T)

Unit 2 Hoop Tendon Group F(100), kip Margin, kip LCL(100), kip Margin, kip 618 24 608 14

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 4.1.2 Vertical Tendon Mean Force Trends, LCL's and Margins 4.1.2.1 Unit 1 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 20 Unit 1 vertical tendon mean force trend and LCL are illustrated by the Figure 3 plot. Both the trend and LCL remain above the 621-kip minimum required value (MRV) beyond T =

100 years. While the plotted forces exhibit a significant degree of scatter, those plotted for the 23rd through 43rd year surveillances do support a conclusion that the force trend tends to flatten over time.

Mean force trend and LCL values at T = 100 years and margins above the MRV are tabulated below. Trend value is based on the following log-linear regression line equation, which is shown on the plot.

F(T) = 691.3 - 18.49

• Log10(T)

Unit 1 Vertical Tendon Group F(100), kip Margin, kip LCL(100), kip Margin, kip 654 33 643 22 4.1.2.2 Unit 2 Unit 2 vertical tendon mean force trend and LCL are illustrated by the Figure 4 plot. Both the trend and LCL remain above the 621-kip minimum required value (MRV) beyond T =

100 years. While the plotted forces exhibit a significant degree of scatter, those plotted for the 28th through 43rd year surveillances do support a conclusion that the force trend tends to flatten over time.

Mean force trend and LCL values at T = 100 years and margins above the MRV are tabulated below. Trend value is based on the following log-linear regression line equation, which is shown on the plot.

F(T) = 695.0 - 29.62

• Log10(T)

Unit 2 Vertical Tendon Group F(100), kip Margin, kip LCL(100), kip Margin, kip 636 15 626 5

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 4.1.3 Dome Tendon Mean Force Trends, LCL's and Margins 4.1.3.1 Unit 1 SL Report No.: SL-018297 Rev.0 01/15/2024 Page 21 Unit 1 dome tendon mean force trend and LCL are illustrated by the Figure 5 plot. Both the trend and LCL remain above the 607-kip minimum required value (MRV) beyond T =

100 years. While the plotted forces exhibit a significant degree of scatter, these do support a conclusion that the force trend tends to flatten over time.

Mean force trend and LCL values at T = 100 years and margins above the MRV are tabulated below. Trend value is based on the following log-linear regression line equation, which is shown on the plot.

F(T) = 675.0 - 23.05

• Log10(T)

Unit 1 Dome Tendon Group F(100), kip Margin, kip LCL(100), kip Margin, kip 629 22 612 5

4.1.3.2 Unit 2 Unit 2 dome tendon mean force trend and LCL are illustrated by the Figure 6 plot. The trend remains above the 607-kip minimum required value (MRV) beyond T = 100 years.

The LCL crosses the MRV line at T = 66.5 years and falls to 597.9-kip at T = 100 years.

However, the LCL remains above the MRV at T = 60.3 years which is the deadline for completion of the next surveillance as shown on the schedule 10 proposed in Part 2 of this report. Again, the plotted forces exhibit a significant degree of scatter, but support a conclusion that the force trend tends to flatten over time.

Mean force trend margin above the 607-kip MRV at T = 100 years and LCL margin above the MRV at T = 60.3 years are tabulated below. Trend value is based on the following log-linear regression line equation, which is shown on the plot.

F(T) = 690.8 - 38.47

• Log10(T) 10 The deadline for completion of the 60th year surveillance is 30 June 2031, one year after the 30 June 2030 mid-point date shown on the schedule. This is 60.3 years after the Unit 2 SIT.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 F(100), kip 614 Unit 2 Dome Tendon Group Margin, kip LCL(60.3), kip 7

609 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 22 Margin, kip 2

The 735-kip 1st year surveillance lift-off force plotted on Figure 6 is well above the maximum forces shown for 1st year surveillances in Figures 1 through 5. While this is not a statistical justification for designating the 735-kip force an outlier (i.e., an erroneous reading), deleting this one lift-off data point from the trend and LCL computations does raise the T = 100-year LCL value up to an acceptable level, which adds additional confidence throughout the 100 year span as shown in the Figure 7 plot. Alternative trend and LCL values and margins based on the truncated data set are shown below. Trend value is based on the following log-linear regression line equation, which is shown on the plot.

F(T) = 667.3 - 22.98

• Log1o(T)

Unit 2 Dome Tendon Group - Alternative Analysis F(100),

Margin, LCL(100),

Margin, kip kip kip kip 621 14 608 1

The tendon force data plotted in Figures 6 and 7, while scattered, do support the expectation that the trend after T = 20 years is essentially flat and well above the 607-kip MRV.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 23 4.1.4 Pre-Stressing Force Summary and Conclusion The tendon force trends and LCL's presented in 4.1.1 through 4.1.3 above are summarized in the following table.

Lift-Off Data Trend and LCL Summary Value, kip, & Margin, kip, Over MRV Group/

Unit At T = 100 (UNO) Years MRV Trend Margin LCL Margin Hoop 1

627 33 618 24 594 kip 2

618 24 608 14 Vertical 1

654 33 643 22 621 kip 2

636 15 626 5

1 629 22 612 5

Dome 2

614 7

609a 2a 607 kip 2 altb 621 14 608 1

Note a:

LCL margin is negative at T = 100 years. LCL & margin shown are computed for T = 60.3 years (30 June 2031 ), the deadline for completing the next surveillance per the schedule in Part 2.

Note b:

"2 alt" provides the Trend and LCL computed for the alternative data set that excludes the highest 1st year data point per discussion in 4.1.3.2 relating to Figure 7.

Margins shown in the above table, in conjunction with the Figures 1 through 7 plots, support the conclusion that the mean pre-stressing force will remain above the applicable group MRV through T = 100 years which is beyond the postulated 80-year maximum operating lifetime of the units. The Unit 2 dome group LCL margin, when computed using all lift-off data, does fall below the MRV at T ~ 66.5 years but this is over 5 years after the deadline for completion of the next surveillance per the schedule in Part 2. The dome group LCL remains above the MRV at T = 100 years, as shown on Figure 7, when a questionable 1st year surveillance tendon force measurement is eliminated from the computations.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 24 Based on the above, it is concluded that the examination interval may be extended per the Part 2 schedule without compromising the safe operation of the Point Beach Units.

It is noted, without impact on the above conclusion, that margins computed for Unit 2 are consistently less than those for Unit 1. It is possible that the wire used to fabricate the Unit 2 tendons has a greater relaxation characteristic, which, if true, would explain the lesser margins. Wire tests (see 4.3 below) show that Unit 1 and Unit 2 wires have, on average, the same tensile strength but, that Unit 2 wire is more ductile. This supports a conclusion that the Unit 1 and Unit 2 wires, while both conforming to ASTM A421, differ somewhat in composition and/ or manufacturing process, which could explain a difference in relaxation characteristics.

4.2 End Anchorage Condition During each of the surveillances, end anchorage areas were visually examined for evidence of corrosion, presence of free water, broken wires or missing button heads, damage to I distortion of load bearing components and cracks in concrete adjacent to bearing plates. Results of these examinations are summarized in 4.2.1 through 4.2.5.

4.2.1 Corrosion Severity of load bearing item corrosion, as documented in surveillance reports, is defined by numeric or alphabetic levels as noted below.

Corrosion Levels Level Definition 1 or A No visible corrosion 2 or B Reddish-brown color; no pitting 3 ore 0.000" <pitting< 0.003" 4 or D 0.003" <pitting< 0.006" 5 or E 0.006" < pitting < 0.01 0" 6 or F Pitting > 0.01 0" Documented corrosion levels of 3 or greater represent examiner judgment as to the depth of pitting, which is not measured.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 25 Inactive Level 2 (B) corrosion on wires (addressed in Section 4.3 below), button heads, anchor heads and bushings is considered acceptable. Inactive Level 3 (C) corrosion on shims and bearing plates (both flame-cut from hot rolled plate) is generally considered acceptable. More severe or active corrosion on bearing plates is acceptable by repair (cleaning to bright metal and recoating) of the corroded area.

Most corrosion documented during surveillances conducted to date is Level 1 (A) or 2 (B).

Higher levels of corrosion found during these surveillances are summarized below. None of the observed corrosion was noted as being active and is considered to have existed at the time of construction.

End Anchorage Corrosion Surveillance I Calendar Unit 1 Unit 2 Year Level 3 and 4 corrosions 1 /

documented for bearing plates.

Corrective action, if any, taken to Level 3 corrosion documented Unit 1 -1971 remediate the Level 4 bearing for shims and bearing plates.

Unit 2 - 1972 plate corrosion is not addressed in the 1st year report.

Level 3 corrosion documented Level 3 corrosion documented 3/

for shims and bearing plates.

for shims and bearing plates.

Unit 1 -1973 Note that these same items Note that these same items were Unit 2 - 1974 were examined during the 1st examined during the 1st year year surveillances.

surveillances.

Level 3 corrosion noted on No level 3 or higher corrosion shims and bearing plates. Note noted in the surveillance report.

8 I 1979 that these same items were Note that these same items were examined during the 1st and 3rd examined during the 1st and 3rd year surveillances.

year surveillances.

13 / 1984 No level 3 or higher corrosion No level 3 or higher corrosion noted in the surveillance report.

noted in the surveillance report.

18 / 1989 No level 3 or higher corrosion No level 3 or higher corrosion noted in the surveillance report.

noted in the surveillance report.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 Surveillance/

Calendar Year 23 I 1994 28 I 1999 33 I 2003 38 I 2009 43 I 2014 48 / 2019 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 26 End Anchorage Corrosion Unit 1 Unit2 No level 3 or higher corrosion No level 3 or higher corrosion noted in the surveillance report.

noted in the surveillance report.

No level 3 or higher corrosion No level 3 or higher corrosion noted in the surveillance report.

noted in the surveillance report.

No level 3 or higher corrosion No level 3 or higher corrosion noted in the surveillance report.

noted in the surveillance report.

No level 3 or higher corrosion No level 3 or higher corrosion noted in the surveillance report.

noted in the surveillance report.

No level 3 or higher corrosion No level 3 or higher corrosion noted in the surveillance report.

noted in the surveillance report.

No level 3 (C) or higher No level 3 (C) or higher corrosion corrosion noted in the surveillance report.

noted in the surveillance report.

End anchorage examinations performed during surveillance year 13 ( calendar year 1984) and later have uncovered no load bearing item corrosion greater than Level 2 (B), rusting without evident pitting. The higher levels noted in the earlier reports may be the result of more conservative judgment calls by examination personnel. Based on subsequent surveillance findings, conditions observed during the 1st, 3rd and 8th year surveillances that were reported as Level 3 or 4 corrosion may have been close to the next lower level.

Because the Point Beach containments are protected from the outside environment and no free water in tendon ducting or end anchorage areas has been noted since the 1st year surveillance (see 4.2.2 below), it is concluded that corrosion of post-tensioning system load bearing items is not a concern at Point Beach.

This conclusion supports the recommendation to extend post-tensioning system end anchorage examination intervals from five years to ten.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 4.2.2 Free Water11 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 27 Each Point Beach containment is enclosed in a fagade that provides protection from the outside environment. In addition, there is no backfill against the containment walls, only against the perimeter of the base mat. For this reason, rain / snow and ground water are not considered potential sources of water intrusion into tendon ductwork and end anchorage areas. The only water that might be found in ductwork or end anchorage areas would have accumulated at the time of construction. As noted below, a minor amount of free water was observed during the first-year surveillances. None has been found since.

The Unit 1 first year (1971) surveillance report noted that a small amount (sic) of free water was found on the wire removed from tendon V-120. The wire was reported to be free of corrosion.

The Unit 2 first year (1972) surveillance report noted that a small amount (sic) of free water was found on the wires at the field end of tendon MH-54 and stated that the wires showed no evidence of significant corrosion.

The containments were exposed to the outside environment during construction and prior to completion of the fagades. This early exposure to rain / snow could account for the small amount of free water found during the first-year surveillances. As noted in the preceding paragraphs, no adverse effects were found to have resulted from the presence of the free water found during the first-year surveillances. Subsequent surveillance reports either do not mention free water or (beginning with the 28th year report) state that no free water was found.

It can be concluded that free water is not a concern at Point Beach for the following reasons: 1) Point Beach containments are protected from the outside environment, 2) there is no backfill against the walls and 3) no free water has been found in tendon ducting or end anchorage areas since the first-year surveillance.

This conclusion supports the recommendation to extend post-tensioning system end anchorage examination intervals from five years to ten.

4.2.3 Broken Wires and Missing/ Unseated Button Heads During each surveillance, sample tendon end anchorages were examined for evidence of broken wires and for missing / unseated button heads. During the 1st, 3rd and 8th year surveillances, all sample tendons were de-tensioned, and the individual wires were pulled to verify end-to-end continuity. During the 13th and later year surveillances, only tendons designated for wire removal were de-tensioned; wire was presumed to be continuous unless the examination uncovered evidence (e.g., an unseated button head) to suggest otherwise. However, unseated button heads were not documented until the 28th year surveillance.

11 The term 'free water' is used to distinguish that which can be observed / collected in a liquid condition from that absorbed into the corrosion protection medium.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 28 It is to be noted that an unseated button head does not necessarily indicate a broken (discontinuous) wire. Tendons are twisted during fabrication to ensure that wire stress is equalized during tensioning. Without this twist, stress in wires at the outer edge of a tendon in a curved duct would be greater than that in wires at the inner edge of the duct. One unintended consequence of the twist is that force can be transferred to a wire through friction rather than through contact between button head and stressing washer. This can result in an occasional continuous wire, which is fully effective in carrying load, having an unseated button head. As there is no way to verify continuity of a wire with an unseated button head without de-tensioning the tendon (which was not routinely done after the 8th year surveillance), wires with unseated button heads are treated in this report as discontinuous and, therefore, ineffective in carrying load.

Results of button head examinations are summarized in the following table.

Broken Wires and Missing/ Unseated Button Heads Surveillance /

Calendar Unit 1 Unit2 Year No missing wires or Tendon D2-227 field end - 2 1 /

buttonheads not previously missing button heads (see Unit 1-1971 documented / Unseated discussion in the following Unit 2 - 1972 button heads, if any, not text) I Unseated button heads, noted in report if any, not noted in report 3/

No missing wires or button No missing wires or button heads not previously heads not previously Unit 1 -1973 documented / Unseated documented / Unseated button Unit2-1974 button heads, if any, not heads, if any, not noted in noted in report report No missing wires or button No missing wires or button heads not previously heads not previously 8 I 1979 documented / Unseated documented / Unseated button button heads, if any, not heads, if any, not noted in noted in report report No missing wires or button No missing wires or button heads not previously heads not previously 13 / 1984 documented / Unseated documenteda I Unseated button heads, if any, not button heads, if any, not noted noted in report in report

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 29 Broken Wires and Missing/ Unseated Button Heads Surveillance I Calendar Unit 1 Unit 2 Year One missing button head No missing wires or button (tendon BD-53 field end) heads not previously 18 / 1989 not previously documented documented I Unseated button

/ Unseated button heads, if heads, if any, not noted in any, not noted in report report No missing wires or button One missing button head heads not previously (tendon HK-48 shop end) not 23 I 1994 documented I Unseated previously documented /

button heads, if any, not Unseated button heads, if any, noted in report not noted in report V-299 field end - one missing button head No missing wires or missing MH-56 field end - one missing button head 28 I 1999

/ unseated button heads not previously documented MH-56 shop end - one unseated button head None of the above previously documented No missing wires or missing V-243 shop & field ends - one 33 I 2003

/ unseated button heads not missing button each end not previously documented previously documented No missing wires or missing No missing wires or missing /

38 I 2009

/ unseated button heads not unseated button heads not previously documented previously documented One missing button head One unseated button head 43 I 2014 (tendon V-92 shop end) not (tendon D1-214 field end) not previously documented previously documented

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. O 01/15/2024 Page 30 Broken Wires and Missing / Unseated Button Heads Surveillance /

Calendar Unit 1 Unit2 Year No missing wires or missing No missing wires or missing /

48 I 2019

/ unseated button heads not unseated button heads not previously documented previously documented Note a:

13th year surveillance report (Reference 6.15) Table 6 shows 88 button heads at each end of tendon MH-54. This is incorrect as test wires were pulled from this tendon during each of the first three surveillances.

Two wires in Unit 2 tendon 02-227 were identified as broken during the 1st year surveillance. The description in the surveillance report is not completely clear as to whether these wires were missing button heads or were broken somewhere along the length. The report does state that at least one of the wires was identified as discontinuous at the time of stressing. It is presumed, for the purpose of the present technical report, that both were in the observed condition when stressing was complete and that the breaks and

/ or missing button heads are not service/ age related.

No additional broken wires were reported for Unit 2 No broken wires were reported for Unit 1.

Findings of missing / unseated buttonheads that were not previously documented, as shown in the above table, are summarized below.

Unit 1 Surveillance Tendon/ End: Button Head Condition Year 18th 80-53 / field: One missing 43rd V-92 / shop: One unseated

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 Surveillance Year 23rd 28th 33rd 43rd Unit2 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 31 Tendon I End: Button Head Condition HK-48 / shop: One missing V-299 I field: One missing MH-56 / field: One missinga MH-56 / shop: One unseateda V-243 / shop: One missinga V-243/ field: One missinga 01-214 / field: One unseated Note a:

Since the tendon was not de-tensioned to check wire continuity (and possibly verifying that the missing and unseated button heads are at opposite ends of the same wire), the observed condition is conservatively treated as two ineffective wires.

It is assumed, for conservatism, that the conditions noted above, other than the Unit 2 tendon 02-227 broken wires, are service / age related and that these did not exist at the time of tensioning. However, it is possible that Unit 2 tendon MH-56 (28th year surveillance) had one wire that was originally button headed at one end only (or that detached during tensioning) and/ or that Unit 2 tendon V-243 (33rd year surveillance) was missing one wire at the time of tensioning, but, proceeding on the basis that the construction records are correct, and conservatively treating MH-56 and V-243 as each having 2 ineffective wires, results in the following count of (not previously documented) ineffective wires as found to date (through the 48th year surveillance in 2019).

Unit 1: 2 ineffective wires (one hoop tendon, one vertical tendon)

Unit 2: 7 ineffective wires (3 hoop tendons, 3 vertical tendons, 1 dome tendon)

During the 11 surveillances completed to date, 92 Unit 1 tendons and 94 Unit 2 tendons were examined. Of these, 3 Unit 1 and 7 Unit 2 tendons were examined at only one end.

Treating each tendon with single end examination as equivalent to half a tendon, results in an effective 90.5 tendons examined in each unit. As tendons have 90 wires, 90.5 tendons account for 90.5

• 90 = 8,145 wires.

During the Unit 1 examinations, 2 of 8, 145 wires, or 0.025% of the wires were found to be ineffective.

During the Unit 2 examinations, 7 of 8, 145 wires, or 0.086% of the wires were found to be ineffective.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev.0 01/15/2024 Page 32 The above fractions, which represent presumed service/ age related failures over a period of 5 decades, are structurally insignificant. Also, the Broken Wire and Missing / Unseated Button Heads table shows no evident increase in the incidence of ineffective wires (broken wires or those with missing button heads) found during consecutive surveillances.

Therefore, based on the results of surveillances conducted to date, it is concluded that the fraction of ineffective wires in the Unit 1 and Unit 2 containment tendons has, and will continue to have, no structural significance. This conclusion supports the extension of time between system examinations as presented in Part 2 of this technical report.

4.2.4 Load Bearing Components Damage I Distortion Examinations performed during surveillances conducted to date (through the 48th year surveillance in 2019) have uncovered no indications of damage (distortion, cracking) to anchor heads, shims or bearing plates.

4.2.5 Concrete Cracking Adjacent to Bearing Plates Concrete extending out 24 inches from the edges of tendon bearing plates was visually examined for cracking during the 18th year and subsequent six surveillances. Only 1 crack having a width in excess of 0.010 inches (the lower limit of recordability) was documented in the reports covering these surveillances. This crack, observed on the Unit 2 tendon gallery ceiling and addressed in the 43rd year report, had a width of 0.015 inches and a length of 4 ft. It extended from a point on the inboard (toward the containment center) edge of the V-218 bearing plate to a point on the inboard edge of the V-216 bearing plate. The crack was previously documented (also with a 0.015-inch width) on a 1973 plant drawing (Reference 6.25) and is probably the result of initial shrinkage of the concrete. There was no growth between 1973 and 2014 (the most recent Unit 2 surveillance addressing this crack); therefore, it is not considered to be the result of an aging mechanism.

4.2.6 Anchorage Condition Summary and Conclusions Tend on end anchorage hardware and adjacent concrete have performed well throughout the life of the plant (through the most recent surveillance in 2019) and show no trends of deteriorating condition.

There have been no reports of active corrosion on bearing plates, anchor heads, shims, or button heads. Inactive corrosion is, with the exceptions noted in the table in Section 4.2.1, limited to light rusting.

No free water has been found since the small amounts reported during the Unit 1 and Unit 2 first year surveillances.

No adverse effects were found to have resulted from the presence of the free water found during the first-year surveillances.

The fractions of ineffective wires (wires presumed to have failed in service) found for Unit 1, 0.025%, and Unit 2, 0.086%, are structurally insignificant and show no trend with time.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 33 No damage, cracking or distortion has been found during visual examinations of bearing plates, anchor heads and shims.

Only one concrete crack having a width greater than 0.010 inches was documented during the surveillances performed to date. This crack, found during the 2014 surveillance, measured 0.015 inches in width and was previously recorded on a 1973 drawing. There was no evidence of growth over the 41 years between the initial documentation of the crack in 1973 and the 2014 surveillance. Therefore, it is concluded to be an original shrinkage crack and not the result of an aging mechanism.

End anchorage visual examination trends, as discussed above, show that the condition of both post-tensioning system hardware and concrete adjacent to tendon end anchorage bearing plates is stable and unlikely to experience significant change over the operating lifetime of the plant.

The results of the tendon end anchorage examinations, as discussed above, support the extension of system examination intervals as presented in Part 2 of this technical report.

4.3 Wire Examination and Testing Specified test wires and broken wires were extracted from surveillance tendons, examined for corrosion / damage, and tested to verify continuing strength and ductility. One or more wires were extracted from each surveillance tendon during the 1st, 3rd* and 8th year surveillances. During subsequent surveillances 12, a single wire was extracted from only one tendon in each group (hoop, vertical and dome). Visual examination of extracted wires, testing, test results and conclusions are addressed below.

4.3.1 Wire Examination Extracted wires were visually examined for damage and corrosion. No damage, other than minor scratch marks resulting from tendon fabrication and installation, was found. While wires were generally free of corrosion, some light rusting and minor pitting were noted in the surveillance reports. The following table summarizes corrosion as documented in these reports. The corrosion levels shown are the highest observed on the extracted wire or test specimen and typically are limited to small, sparsely scattered areas.

12 Test wires were extracted only from tendons in the containment designated for complete examinations that include measurement of lift-off force, i.e., Unit 1 tendons during surveillance years 1, 3, 8 13, 23, 33 and 43 and Unit 2 tendons during surveillance years 1, 3, 8, 18, 28, 38 and 48.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 34 Extracted Wire Corrosiona as Summarized / Tabulated in Surveillance Report Surveillance Unit 1 Unit 2 Year 1

8 extracted wires Level 1 ; 1 All extracted wires Level 3 or lower extracted wire Level 2 3 extracted wires Level 1; 5 5 extracted wires Level 1; 4 3

extracted wires Level 2; 3 extracted wires Level 3 extracted wires Level 2 to Level 3 8

8 test specimens Level 1; 1 test 5 test specimens Level 1; 4 test specimen Level 2 specimen Level 2 13 2 extracted wires Level 1; 1 N/A extracted wire Level 2 18 N/A All extracted wires Level 1 23 Wire corrosion not addressed in N/A surveillance report 28 N/A 8 test specimens Level A; 1 test specimen Level B 33 All test specimens Level A N/A 38 N/A 8 test specimens Level 1; 1 test specimen Level 2 43 All test specimens Level 1 N/A 48 N/A All test specimens Level 1 Note a:

Levels 1 or A - bright metal; 2 or B - red/ brown oxide with no pitting; 3 or C - pitting with depth <0.003".

Wires extracted during surveillance years 8 through 48 were found to be free of corrosion (Level 1 or A) or with isolated areas of minor rusting (Level 2 or B). Both Level 1 (A) and Level 2 (B) conditions are considered acceptable without further evaluation. The Level 3 corrosion documented in the 1st and 3rd year surveillance reports is presumed to represent conservative categorization with Level 2 rust probably recorded as Level 3. No pitting was documented in the later reports. Also, there is nothing in the surveillance reports to suggest that observed corrosion is active. In most cases, it was concluded to have existed at the time of tendon installation.

The examination results tabulated above support the conclusion that wire corrosion is not increasing over time.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 4.3.2 Wire Testing SL Report No.: SL-018297 Rev.a 01/15/2024 Page 35 Testing consisted of determining the tensile strength and ductility (as measured by test specimen elongation at failure) of specimens cut from each extracted wire. Typically, three specimens were cut from the extracted wire, one close to each end and one close to the center. In a few cases more specimens were cut and tested and, only one specimen was cut from each of the two broken wires extracted from Unit 2 dome tendon D2-227 during the 1st year surveillance.

Tensile strength and ductility test results are documented in Tables 8 through 11 and summarized in Figures 8 through 11 which are plots of minimum, mean and maximum values found during each surveillance. Values shown in shaded cells in the tables do not meet the ASTM A421 acceptance criteria, which are 240 ksi minimum tensile strength and 4% minimum elongation at failure.

Early wire tests were performed in the field or shop (not in a certified testing laboratory13) on 100-inch specimens, rather than the 10-inch specimens specified in the ASTM standards, by individuals with little or no previous materials testing experience. Later tests were performed in accordance with ASTM standards by certified laboratories. Elongations (expressed as a percentage of test specimen length) are expected to be lower for the longer specimens since the high strain in the necked-down failure region is distributed over 100 inches rather than 10. In addition, failure at the specimen attachment points, which, in earlier tests, did not always meet ASTM gripping standards, can result in lower measured tensile strength. This is reflected in the test data shown in the tables.

While wire tensile strength and ductility data exhibit a significant degree of scatter as well as irregular variations from surveillance to surveillance, there is nothing in the plots to suggest that either parameter is trending down with time. Based on the tabulated data and plots, it is concluded that the tensile strength and ductility of the ASTM A421 wire are not affected by time under load.

Scatter, as measured by the difference between plotted maxima and minima, of both tensile strength and ductility values is seen to be less pronounced during later surveillances. This can be attributed to improvement in test procedures and equipment as well as experience gained by test personnel over time.

13 Some confirmatory tests on 1st and 3rd year surveillance wire samples were performed by laboratories using ASTM specified 10-inch gage length specimens. All laboratory test results, except two excluded from consideration due to fracture outside the gage length, met the ASTM A421 acceptance criteria. Results of the laboratory confirmatory tests have been excluded from this report to ensure a consistent basis for presenting strength and ductility data.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev.0 01/15/2024 Page 36 As noted in the tables and on the plots, the results of all tests performed on wires extracted during the 13th year and subsequent surveillances meet the ASTM A421 acceptance criteria and are both reasonable and consistent with the results of tests performed on wire specimens extracted from tendons in containments at other nuclear plants. Test failures documented for the 1st, 3rd* and 8th year surveillances (shaded cells in the tables) are attributed to testing techniques that did not meet ASTM requirements and lack of test personnel experience as discussed above.

4.3.3 Conclusions and Recommendation The results of tests performed on Unit 1 and Unit 2 tendon wire specimens, as shown in the tables and on the plots, do not give any indication that tensile strength and ductility are decreasing over time. And, with the limited exceptions addressed above, the results show that strength and ductility meet the ASTM A421 acceptance criteria. Finally, visual examination results show that tendon wires are free of damage and are not corroding over time. This supports the proposed extension of examination interval.

In addition, the stable nature of the test results (i.e., no apparent change over time) supports the conclusion that there is no need to continue extracting and testing wires.

Therefore, it is recommended that requirements for routine de-tensioning of tendons for the purpose of extracting of test wires and subsequent testing of those wires be eliminated from the post-tensioning system surveillance program, with the provision that the Responsible Engineer will specify such testing when conditions (e.g., broken wires, active corrosion or low pH water) found at an anchorage indicate the possibility of wire degradation.

4.4 Corrosion Protection Medium Testing Corrosion protection medium (CPM) was collected at the ends of sample tendons during each surveillance. CPM samples from one or both ends of each tendon were tested for the presence of three corrosive ions (chlorides, nitrates, and sulfides), absorbed water content and reserve alkalinity (expressed as neutralization number or base number). Tests were generally performed in accordance with procedures14 recommended by the CPM manufacturer, Viscosity Oil Corp.

Absorbed water content and base number are determined for bulk samples of CPM. The laboratory procedure used to determine water content is standardized and easily performed. It should yield reasonably accurate results. That used to determine base number is complex; results tend to exhibit more variability than would be expected for the material being analyzed.

Corrosive ion concentrations are not determined for bulk samples of CPM but, rather, for water maintained in contact with a defined CPM surface area under specified conditions.

14 These procedures were subsequently incorporated into ASME Section XI Subsection IWL Table IWL-2525-1.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 37 More recently conducted tests tend to yield the expected results, i.e., that corrosive ions are essentially absent from the CPM samples. Earlier tests gave erratic results, particularly for nitrate ion concentrations. The erratic results may have resulted from errors in specimen preparation or application of the procedures used to quantify concentrations in the water extractions, or both.

CPM initially installed at Point Beach is the Visconorust 2090-P2 formulation. Tendons examined during more than one surveillance, those with CPM top-off and those with end cap gasket replacement may have been re-filled or topped off with the 2090-P4 formulation which has a higher base (minimum of 35 as-manufactured) number than the P2 formulation (minimum of 5 as-manufactured). This is reflected in test results, which show many reported base numbers in the range expected for the 2090-P4 CPM formulation.

4.4.1 CPM Test Results Unit 1 and Unit 2 test results are summarized in Tables 12 and 13, respectively, which show the maximum and minimum values of corrosive ion concentrations, water contents and base numbers found for the CPM samples collected during each surveillance 15.

CPM test results, except those shown for several nitrate ion concentrations in the 23rd and 28th year surveillance reports, met the ASME Sub-Section IWL Table IWL-2525-1 acceptance criteria shown below.

Chloride ion concentration in the water extraction: :::;10 ppm Nitrate ion concentration in the water extraction: :::;1 0 ppm Sulfate ion concentration in the water extraction: :::;1 0 ppm Water content: :::;10% of sample dry weight Base number: >0 (Table IWL-2525-1 criterion applicable to Visconorust 2090-P2) 15 As noted on the tables, no test results were found for Unit 1 3rd year surveillance or Unit 2 1st and 3rd year surveillances.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 4.4.1.1 Corrosive Ion Concentrations SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 38 Results of corrosive ion tests performed on samples collected during the 28th year and later surveillances are generally in line with those reported for samples collected at other nuclear power facilities. Almost all concentrations are below the lower limit of reportability (0.5 ppm for chlorides and sulfides and 0.5 or 1.0 ppm for nitrates16). This is expected since there is no credible means for contaminants containing these ions to mix with the CPM in tendon ducts and end anchorage areas.

Reported concentrations significantly greater than the lower limits of reportability are concluded result from sample contamination or procedural errors made during preparation and testing of the water extractions. Results of early (prior to 2000) of tests for nitrate ions are often questionable, probably because of errors made in sample preparation and / or in determining the concentration in the water extraction. For this reason, the high nitrate ion concentrations reported for several of the 23rd and 28th year surveillance samples are deemed invalid.

The ion concentration data shown in Tables 12 and 13 give no indication that contaminant levels are increasing over time.

4.4.1.2 Absorbed Water Content All reported water contents are below the 10% acceptance limit and almost all are below 1 %. This is an expected result since the Point Beach containments are enclosed in fagades that provide a dry environment and since the walls are not in contact with backfill and associated ground water intrusion.

The data shown in the tables give no indication that water contents are increasing over time.

4.4.1.3 Neutralization (Base) Number The minimum base numbers listed in Tables 12 and 13 are all above the lower acceptance limit of zero.

The data shown in the tables give no indication that minimum base numbers are decreasing over time.

16 The lower limit of reportability for nitrates was recently increased from 0.5 ppm to 1.0 ppm. The reason for the increase is not addressed in the surveillance reports.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 4.4.2 CPM Test Evaluation, Conclusions and Recommendations SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 39 The results of Unit 1 and Unit 2 CPM tests show that concentrations of corrosive ions (except the reported nitrate concentrations deemed invalid) and absorbed water content have remained well below the specified acceptance (upper) limits and, in addition, exhibit no adverse trends over time. Neutralization (base) numbers remained above the specified lower acceptance limit of zero and exhibited no consistent trends over time. When evaluated in conjunction with the tendon end anchorage and wire examination findings, these results demonstrate that the CPM is continuing to perform its corrosion protection function. In addition, the test results give no indication that the protective properties of the CPM have degraded to unacceptable levels since initial installation in the 1970's.

An evaluation of the CPM test results, as summarized above, leads to the conclusion that the interval between collecting samples and performing such tests can be extended to 10 years with no adverse consequences.

In addition, unless evidence of active corrosion is found during visual examinations of end anchorage hardware and I or extracted wires, free water is found or there is evidence that the quantity of absorbed water has increased over time, there should be no need to perform the tests for corrosive ions and neutralization number. It is concluded that these tests need be done only if corrosion or moisture conditions favoring corrosion are found.

If free water is found, it will be collected and analyzed to determine pH.

Therefore, it is recommended that future CPM testing be limited to determining absorbed water content, unless the Responsible Engineer specifies otherwise based on evaluation of Point Beach surveillance findings or industry operating experience.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 40

5.

OVERALL

SUMMARY

, CONCLUSIONS AND RECOMMENDATIONS A summary of surveillance results, conclusions based thereon and recommendations for future changes to the surveillance program are outlined Sections 5.1, 5.2 and 5.3 below.

5.1 Surveillance Results Overall Summary The results of the post-tensioning system surveillances conducted at Point Beach between 1971 and 2019 show that the systems are continuing to perform the intended functions and can be expected to do so until well beyond the maximum expected 80-year operating lifetime of the units. Performance of the Unit 1 and Unit 2 systems, determined by evaluations of the visual examination findings / test results as detailed in Part 4 of this technical report, is summarized below.

5.1.1 Tendon Force The mean force in each of the Unit 1 and Unit 2 tendon groups is projected by log-linear regression to remain above the specified minimum required values through T = 100 years

{after the unit SIT), which is well beyond the maximum expected 80-year operating lifetime of the units. In addition, and with one exception, the 95% lower confidence limits on group mean force also remain above the minimum required values through T = 100 years.

The lone exception is the confidence limit constructed for the Unit 2 dome tendon group.

This limit crosses the minimum required value line at T ~ 66.5 years which is just over 6 years after the deadline (30 June 2031) for completing the next surveillance shown in the schedule proposed in Part 2. An alternative LCL, constructed using a data that excludes a questionable 1st year surveillance force measurement, remains above the MRV line at T = 100 years.

5.1.2 Condition of End Anchorage Hardware / Concrete and Extracted Wires Enclosed end anchorage hardware and tendon wires extracted for tensile testing show no signs of active corrosion. The minor (acceptable) rusting that has been observed is concluded to have occurred prior to filling of the tensioned tendon duct with corrosion protection medium or following extraction for testing. Corrosion on the exposed surface of bearing plates is also minor and, with one questionable exception reported for the Unit 1 examination performed during the 1st year surveillance, meets acceptance criteria.

No broken wires, other than those noted in construction records, have been found. Missing

/ protruding button heads not documented in construction records or that represent wires removed for testing, represent only a miniscule fraction (less than 0.1 % ) of the number of installed tendon wires.

Small amounts of free water were found in two of the tendons examined during the Unit 1 first year surveillance. No free water was found in any other tendon during this surveillance, and none has been found during subsequent surveillances.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 41 Only 1 anchorage area concrete crack wider than 0.01 inches was reported. This crack, documented in the 43rd year (2014) surveillance report, ran approximately 4 feet between two Unit 2 vertical tendon bottom end bearing plates. Crack width was reported as 0.015 inches. It was previously documented at the same length and width on a 1973 drawing and is concluded to be an original shrinkage crack.

5.1.3 Tendon Wire Strength and Ductility Tensile tests on specimens cut from extracted wires show, with unique exceptions limited to tests performed during the first 3 surveillances, that ultimate strength and ductility (quantified by the measured elongation at failure) remain above specified minimum values. Test results also show that strength and ductility are not decreasing over time. The unacceptable results shown for several of the tests performed during the 1st, 3rd and 8th year surveillances were concluded to incorporate procedural or other errors and are not considered credible.

5.1.4 Corrosion Protection Medium Characteristics Results of corrosion protection medium (CPM) tests to determine corrosive ion concentrations, absorbed water content, and neutralization number confirm (with limited exceptions for reported nitrate ion concentrations deemed invalid) that acceptance criteria have been met. There are no discernible trends to these parameters and no indication that the protective characteristics of the CPM are degrading to an unacceptable level over time.

5.2 Conclusions Based on the evaluations detailed in Part 4 of this technical report and summarized above, it is concluded that the Point Beach post-tensioning system will continue to perform its design function until well beyond the maximum expected operating lifetime of the units.

And specifically, that:

Tendon group mean forces will remain above the specified minima.

End anchorage hardware and tendon wire will remain free of active corrosion. Corrosion on exposed surfaces of bearing plates will remain minor.

Tendon wire strength and ductility will not change over time and will remain acceptable throughout the operating lifetime of the plant.

Corrosion protection medium will retain its protective properties with no unacceptable degradation over time.

And free water will not be a concern.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 42 5.3 Recommendations Based on the above conclusions, there are four recommendations.

1. Increase the interval between post-tensioning system surveillances from the present 5 years to 10 years in accordance with the schedule presented in Part 2 of this report.

This includes examinations identified in Reference 6.2, Table IWL-2500-1, Examination Category L-B, Items L2.10, L2.30, L2.40 and L2.50.

2. Adjust the interval between tendon force measurements, Item L2.10, from the present 1 0 years in accordance with the alternating program shown in the proposed schedule.

3. Discontinue de-tensioning of sample tendons, removal of test wires and examining /

testing of those wires (Item L2.20) with the condition that the Responsible Engineer should consider wire removal and examination / testing if observed end anchorage conditions indicate the possibility of wire degradation.

4. Limit testing of corrosion protection medium (Item L2.40) to only include the determination of absorbed water content with the condition that the Responsible Engineer should consider performing additional tests if any of the following are found:

1) active corrosion of CPM coated hardware, 2) free water or 3) sample absorbed water contents is increasing over time.

Implementing these changes will provide the following safety and related benefits.

Reducing personnel exposure to several industrial safety hazards associated with system examination/ testing. These include:

o Working at heights; o

Working in a de facto confined space (the tendon gallery);

o Working with high-pressure hydraulic systems; o Working around high-energy plant systems; o Working around solvent and hot petroleum product fumes; o

Working around containers and lines filled with hot petroleum products; o

Close in exposure to high levels of stored elastic energy in tendons (sudden rotation during force measurement has resulted in rapid shim ejection);

o Handling heavy loads, often in the vicinity of critical plant components;

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 43 Reducing potentially damaging repetitive loading on tendons during de-tensioning / re-tensioning as well as during implementation of force measurement procedures; Reducing time spent working in a radiation-controlled area; And, eliminating need for disposal of hazardous reagents used in testing CPM for ion concentrations and base number.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151

6.

REFERENCES 6.1 USNRC Regulation 10CFR50.55a, Codes and standards.

SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 44 6.2 ASME Boiler and Pressure Vessel Code,Section XI, Subsection IWL, Requirements for Class CC Concrete Components of Light-Water-Cooled Plants, (editions /

addenda as noted in the above text).

6.3 Point Beach Nuclear Plant Units 1 and 2 Updated Final Safety Analysis Report, Section 5.1, Containment System Structure, updated 2018.

6.4 Point Beach Drawing C-108, Containment Structure/ Base Slab Outline/ Plans and Sections, Revision 5.

6.5 Point Beach Drawing C-117, Containment Structure / Prestress Requirements /

Typical Details, Revision 5.

6.6 ASTM A421, Specification for Uncoated Stress Relieved Wire for Prestressed Concrete, Published by the American Society for Testing and Materials.

6.7 Point Beach Calculation 2000-0056, Tendon Prestress Acceptance Limits, approved 20 October 2000.

6.8 3rd Interval / Point Beach Units 1 and 2 I Reactor Containment Building / Concrete Containment lnservice Inspection Program, Revision 0, 29 December 2017.

6.9 USNRC Regulatory Guide 1.35, lnservice Inspection of Ungrouted Tendons in Prestressed Concrete Containments, (revisions as noted in the above text).

6.10 Wisconsin Electric Power Company I Wisconsin Michigan Power Company / Point Beach Nuclear Power Plant Unit No. 1 / Containment Building/ Post-Tensioning System / One-Year Surveillance, Revision 1, June 1972, report prepared by Bechtel Power Corporation.

6.11 Wisconsin Electric Power Company I Wisconsin Michigan Power Company I Point Beach Nuclear Power Plant Unit No. 2 I Containment Building/ Post-Tensioning System I One-Year Surveillance, November 1972, report prepared by Bechtel Power Corporation.

6.12 Addendum No. 1 / Wisconsin Electric Power Company/ Wisconsin Michigan Power Company I Point Beach Nuclear Power Plant Unit No. 1 / Containment Building /

Post-Tensioning System / Three-Year Surveillance, February 25, 1974, report prepared by Bechtel Power Corporation.

6.13 Wisconsin Electric Power Company I Wisconsin Michigan Power Company I Point Beach Nuclear Power Plant Unit No. 2 I Containment Building / Post-Tensioning System/ Three-Year Surveillance, October 1974, report prepared by Bechtel Power Corporation.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 45 6.14 Wisconsin Electric Power Company/ Point Beach Nuclear Power Plant Units No. 1 and 2 I Containment Building / Post-Tensioning System I Eight-Year Surveillance, September 1979, report prepared by Bechtel National, Inc.

6.15 Wisconsin Electric Power Company/ Point Beach Nuclear Power Plant Units No. 1 and 2 I Containment Building / Post-Tensioning System / Thirteen-Year Surveillance, 15 May 1985, report prepared by Bechtel Power Corporation.

6.16 Eighteen-Year lnservice Tendon Surveillance Test Report / Units 1 and 2 Containment Building / Post-Tensioning System / Point Beach Nuclear Plant /

Wisconsin Electric Power Company, Revision 0, report prepared by VSL Corporation.

6.17 Final Report/ Point Beach Nuclear Power Plant/ 23 Year Post Tensioning System Surveillance, WEPCO Contract No. 247680, September 1994, report prepared by DYWIDAG Systems International, USA, Inc.

6.18 Twenty-Eighth Year Physical Surveillance of Unit 1 and Visual Surveillance of Unit 2 at the Point Beach Nuclear Generating Station, Revision 0, 27 December 1999, report prepared by Precision Surveillance Corporation. [Note:

Report title is incorrect; physical surveillance performed on Unit 2 and visual on Unit 1.]

6.19 33rd Year Unit 1 Physical and Unit 2 Visual Tendon Surveillance at the Point Beach Niclear {sic) Plant/ Post Tensioning Surveillance Report, Revision 1, 15 April 2004, report prepared by Precision Surveillance Corporation.

6.20 Final Report FPL Point Beach Power Plant Unit 1 Visual 38th Year & Unit 2 Physical 38th Year Containment Building Tendon Surveillance, Revision 0, 17 June 2009, report prepared by Precision Surveillance Corporation.

6.21 Final Report for the 43rd Year Tendon Surveillance at Point Beach Nuclear Power Plant/ Unit 1 and Unit 2, Revision 1, 30 June 2014, report prepared by Precision Surveillance Corporation.

6.22 Final Report for the 48th Year Tendon Surveillance at Point Beach, Revision 0, 19 September 2019, report prepared by Precision Surveillance Corporation.

6.23 Miller, Irwin and John E. Freund, Probability and Statistics for Engineers, Prentice-Hall, Englewood Cliffs, NJ, 1965.

6.24 ANSI/ANS-56.8, Containment System Leakage Testing Requirements, published by the American Nuclear Society.

6.25 Point Beach Drawing No. PB02S01000201501, Ceiling Cracks - Tendon Gallery/

Point Beach Unit 2 Cont., Revision 1, 1973.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev.0 01/15/2024 Page 46

7.

TABLES AND FIGURES Tables and figures cited in the above text follow.

Table 1 - List of US Containments1 with Ungrouted Pre-stressing Systems Plant/ Unit Containment Type2 / Notation3 Millstone 2 Shallow dome w / hoop, vertical & dome tendon groups; B Ginna Vertical tendons only; anchored in rock; B TMI 1 Shallow dome w / hoop, vertical & dome tendon groups; B; N Calvert Cliffs 1 & 2 Shallow dome w / hoop, vertical & dome tendon groups; B V. C Summer Shallow dome w / hoop, vertical & dome tendon groups; B Oconee 1, 2 & 3 Shallow dome w / hoop, vertical & dome tendon groups; B Vogtle 1 & 2 Hemispherical dome w / hoop & inverted U tendon groups; S Crystal River 3 Shallow dome w / hoop, vertical & dome tendon groups; B; N Turkey Point 3 & 4 Shallow dome w / hoop, vertical & dome tendon groups; B Farley 1 & 2 Shallow dome w / hoop, vertical & dome tendon groups; B Palisades Shallow dome w / hoop, vertical & dome tendon groups; B; N Zion 1 & 2 Shallow dome w / hoop, vertical & dome tendon groups; B; N Braidwood 1 & 2 Shallow dome w / hoop, vertical & dome tendon groups; B Byron 1 & 2 Shallow dome w / hoop, vertical & dome tendon groups; B LaSalle 1 & 2 BWR Mark II (cylinder-cone) containment w / hoop & vertical tendon groups; B Point Beach 1 & 2 Shallow dome w / hoop, vertical & dome tendon groups; B Callaway Hemispherical dome w / hoop & inverted U tendon groups; B ANO 1 & 2 Shallow dome w / hoop, vertical & dome tendon groups; B South Texas 1 & 2 Hemispherical dome w / hoop & inverted U tendon groups; B Wolf Creek Hemispherical dome w / hoop & inverted U tendon groups; B

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 47 Table 1 - List of US Containments1 with Ungrouted Pre-stressing Systems Plant/ Unit Containment Type2 / Notation3 Ft. Calhoun Shallow dome with spiral and dome tendon groups; B; N Palo Verde 1, 2 & 3 Hemispherical dome w I hoop & inverted U tendon groups; B San Onofre 1 & 2 Hemispherical dome w I hoop & inverted U tendon groups; S; N Rancho Seco Shallow dome w I hoop, vertical & dome tendon groups; S; N Trojan Hemispherical dome w I hoop & inverted U tendon groups; B; N Note 1: Bellefonte 1 & 2, which are still under construction, Midland 1 & 2, which were terminated prior to fuel load and Robinson & TMI 2, which have grouted tendon systems, are not listed.

Note 2: All units are PWR's except LaSalle (BWR).

Note 3: B - BBRV system with button headed wires; S - strand system with wedge anchors; N -

unit(s) no longer in operation.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 48 Table 2 - Summary of Unit 1 Hoop Tendon Forces Surveillance T, Time FM, Measured I Calendar Since SIT, Tendona Year Years Force, kip BD-38 661 I

1 / 1971 1.1 BF-23

/658*

DF-54 680 3 I 1973 3.1 Note b 8 / 1979 9.1 Note b AC-52 666 CE-11 664 13d / 1984 14.1 BD-42 634 DF-61 658 18 / 1989 19.1 Visual examination only DF-17 622 CE-34 650 23d I 1994 24.1 AC-39 662 BD-46 626 28 / 1999 29.0 Visual examination only AC-19 648 BF-25c 619 33 I 2003 33.3 CE-7 659 DF,55 633 EA-45 629

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 49 Table 2 - Summary of Unit 1 Hoop Tendon Forces Surveillance T, Time FM, Measured

/ Calendar Since SIT, Tendona Year Years Force, kip 38 I 2009 38.8 BF-25c 627 I

BD-16 622 BF-25c 619 43 I 2014 43.8 CE-23 650 DF-57 630 EA-62 641 48 I 2019 48.9 Visual examination only Note a: Shaded cell tendons de-tensioned / re-tensioned during indicated surveillance.

Note b: The 3rd and 8th year surveillance samples are identical to the 1st year samples. All sample tendons were de-tensioned and re-tensioned during the 1, 3 and 8 year surveillances. As discussed in the text, the 3rd and 8th year lift-off forces cannot be used in the trend analyses and, in the interest of clarity, are not shown in the tables.

Note c:

Common tendon.

Noted: Tendon BF-23, included in the 13th and 23rd year samples, was de-tensioned/ re-tensioned during the 1st, 3rd, and 8th year surveillances. Lift-off force cannot be used in trend analysis and is, in the interest of clarity, omitted from the table.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 50 Table 3 - Summary of Unit 1 Vertical Tendon Forces Surveillance T, Time FM, Measured I Calendar Since SIT, Tendona Force, kip Year Years V-3 691 1 / 1971 1.1

• V-58 700 V-120 673 3 I 1973 3.1 Note b 8 I 1979 9.1 Note b V:-23 679 13d / 1984 14.1 V-79 695 V-135 676 18 / 1989 19.1 Visual examination only V-59 657 23d I 1994 24.1

\\.. I<

V-'fl5 644 28 I 1999 29.0 Visual examination only V-5c 680 V-32 670 33 I 2003 33.3 V-'88 672 V-144 635 38 / 2009 38.8 v.. 5c 664 v.. 5c 664 V-36 645 43 I 2014 43.8 V-92 675 V-148 652

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 51 Table 3 - Summary of Unit 1 Vertical Tendon Forces Surveillance T, Time FM, Measured I Calendar Since SIT, Tendona Year Years Force, kip 48 / 2019 48.9 Visual examination only Note a: Shaded cell tendons de-tensioned/ re-tensioned during indicated surveillance.

Note b: The 3rd and 8th year surveillance samples are identical to the 1st year samples. All sample tendons were de-tensioned and re-tensioned during the 1st, 3rd, and 8th year surveillances. As discussed in the text, the 3rd and 8th year lift-off forces cannot be used in the trend analyses and, in the interest of clarity, are not shown in the tables.

Note c:

Common tendon.

Noted: Tendon V-3, included in the 13th and 23rd year samples, was de-tensioned I re-tensioned during the 1, 3 and 8 year surveillances. Lift-off force cannot be used in trend analysis and is, in the interest of clarity, omitted from the table.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 52 Table 4 - Summary of Unit 1 Dome Tendon Forces Surveillance T, Time FM, Measured

/ Calendar Since SIT, Tendona Year Years Force, kip D1-25 675 1 / 1971 1.1 D2-23 673 D3--25 686 3 / 1973 3.1 Note b 8 / 1979 9.1 Note b D1.;.32 658 13d / 1984 14.1 D3-14 613 18 / 1989 19.1 Visual examination only D1-31 638 D3-17 657 23d / 1994 24.1 D3.;.18 58.5 D3-19 656 28 / 1999 29.0 Visual examination only D1-36 656 33 / 2003 33.3 D2-25c 632 D3-15 664 38 / 2009 38.8 D2-25c 634 D1-02 649 43 / 2014 43.8 D2-25c 630 D3-48 656 48 / 2019 48.9 Visual examination only

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 53 Note a: Shaded cell tendons de-tensioned / re-tensioned during indicated surveillance.

Note b: The 3rd and 8th year surveillance samples are identical to the 1st year samples. All sample tendons were de-tensioned and re-tensioned during the 1st, 3rd, and 8th year surveillances. As discussed in the text, the 3rd and 8th year lift-off forces cannot be used in the trend analyses and, in the interest of clarity, are not shown in the tables.

Note c:

Common tendon.

Note d: Tendon D2-23, included in the 13th and 23rd year samples, was de-tensioned / re-tensioned during the 1st, 3rd, and 8th year surveillances. Lift-off force cannot be used in trend analysis and is, in the interest of clarity, omitted from the table.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 54 Table 5 - Summary of Unit 2 Hoop Tendon Forces Surveillance T, Time FM, Measured I Calendar Since SIT, Tendona Force, kip Year Years HK-22 700 1 / 1972 1.2 MKC:.39 705*

MH"'.54-705 3 I 1974 3.4 Note b 8 / 1979 8.3 Note b 13 / 1984 13.3 Visual examination only HK-31 622 KM-55 633 18d / 1989 18.3 GJ-1 634 JL-15 620 23 I 1994 23.3 Visual examination only GJ-59 638 HK-49 644 28 / 1999 28.3 JL:;37 621 KM-10 644 MH-56c 657 33 I 2003 32.5 MH-56c 639 HK-23 640 GL-61 641 38 I 2009 38.0 JL-9 637 KM-7 655

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 55 Table 5 - Summary of Unit 2 Hoop Tendon Forces Surveillance T, Time FM, Measured

/ Calendar Since SIT, Tendona Force, kip Year Years MH-56c 624 43 I 2014 43.1 Visual examination only GJ-4 673 GL-31 631 48 I 2019 48.2 JL-22 631 MH-29 634 MH-56c 623 Note a: Shaded cell tendons de-tensioned / re-tensioned during indicated surveillance.

Note b: The 3rd and 8th year surveillance samples are identical to the 1st year samples. All sample tendons were de-tensioned and re-tensioned during the 1st, 3rd* and 8th year surveillances. As discussed in the text, the 3rd and 8th year lift-off forces cannot be used in the trend analyses and, in the interest of clarity, are not shown in the tables.

Note c:

Common tendon.

Note d: Tendon MH-54, included in the 18th year sample, was de-tensioned / re-tensioned during the 1st, 3rd, and 8th year surveillances. Lift-off force cannot be used in trend analysis and is, in the interest of clarity, omitted from the table.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 56 Table 6 - Summary of Unit 2 Vertical Tendon Forces Surveillance T, Time FM, Measured I Calendar Since SIT, Tendona Force, kip Year Years V-226 710.

1 / 1972 1.2 V-278 680.

V-339 700 3 I 1974 3.4 Note b 8 I 1979 8.3 Note b 13 / 1984 13.3 Visual examination only V-208 637 18d I 1989 18.3 V264 626 23 I 1994 23.3 Visual examination only V,-243 662 28 I 1999 28.3 V-299 665 V-337c 649 33 I 2003 32.5 V-337c 646 V-224 643 V-239 669 38 I 2009 38.0 V-"282 639 V-337c 643 V-368 635

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 57 Table 6 - Summary of Unit 2 Vertical Tendon Forces Surveillance T, Time FM, Measured

/ Calendar Since SIT, Tendona Year Years Force, kip 43 / 2014 43.1 Visual examination only V-237 664 V-293 652 48 I 2019 48.2 V-337c 649 V-349 652 Note a: Shaded cell tendons de-tensioned / re-tensioned during indicated surveillance.

Note b: The 3rd and 8th year surveillance samples are identical to the 1st year samples. All sample tendons were de-tensioned and re-tensioned during the 1st, 3rd, and 8th year surveillances. As discussed in the text, the 3rd and 8th year lift-off forces cannot be used in the trend analyses and, in the interest of clarity, are not shown in the tables.

Note c:

Common tendon.

Noted: Tendon V-339, included in the 18th year sample, was de-tensioned / re-tensioned during the 1st, 3rd, and 8th year surveillances. Lift-off force cannot be used in trend analysis and is, in the interest of clarity, omitted from the table.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 58 Table 7 - Summary of Unit 2 Dome Tendon Forces Surveillance T, Time FM, Measured

/ Calendar Since SIT, Tendona Force, kip Year Years01-223 685 1 / 1972 1.2 02-'227 735 03.;225 655 3 I 1974 3.4 Note b 8 I 1979 8.3 Note b 13 / 1984 13.3 Visual examination only 01-205 628 18d / 1989 18.3 03-214 612 23 I 1994 23.3 Visual examination only 01-238 625 02-228 648 28 / 1999 28.3 02-229 594 O2-23oc 642 03-21.3 652 33 I 2003 32.5 O2-23oc 634 01-'203 640 38 / 2009 38.0 O2-23oc 626 03-203 654

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 59 Table 7 - Summary of Unit 2 Dome Tendon Forces Surveillance T, Time FM, Measured

/ Calendar Since SIT, Tendona Force, kip Year Years 43 I 2014 43.1 Visual examination only D1-237 632 48 / 2019 48.2 D2-230C 623 D3-231 639 Note a: Shaded cell tendons de-tensioned / re-tensioned during indicated surveillance.

Note b: The 3rd and 8th year surveillance samples are identical to the 1st year samples. All sample tendons were de-tensioned and re-tensioned during the 1st, 3rd, and 8th year surveillances. As discussed in the text, the 3rd and 8th year lift-off forces cannot be used in the trend analyses and, in the interest of clarity, are not shown in the tables.

Note c:

Common tendon.

Noted: Tendon D2-227, included in the 18th year sample, was de-tensioned/ re-tensioned during the 1st, 3rd, and 8th year surveillances. Lift-off force cannot be used in trend analysis and is, in the interest of clarity, omitted from the table.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 Table 8 - Unit 1 Wire Test Results/ Ultimate Tensile Strength Exam/

Tendon I Ultimate Tensile Strength*, ksi Calendar Wire (if Specimen Specimen Specimen Specimen Specimen Year applicable) 1 2

3 4

5 BO-38 242 243 244 NIA NIA BF-23 237 235 237 NIA NIA OF-54 249 251 244 NIA NIA V-3 252 247 256 254 NIA 1 / 1971 V-58 245 249 240 245 242 V-120 244 247 254 NIA NIA 01-25 247 255 256 NIA NIA 02-23 249 Note b 248 255 NIA 03-25 247 240 251 249 NIA BO-38 252 242 253 NIA NIA BF-23 256 250 245 NIA NIA OF-54 253 250 241 NIA NIA V-3 258 264 254 NIA NIA V-58 / 1 229 252 241 238 244 3 / 1973 V-58 / 2 244 250 248 NIA NIA V-120/1 254 254 262 NIA NIA V-120 / 2 249 248 241 NIA NIA 01-25 259 258 253 NIA NIA 02-23 253 256 258 245 NIA 03-25 258 261 261 NIA NIA BO-38 241 247 252 NIA NIA BF-23 233 245 244 243 240 OF-54 255 252 256 NIA NIA V-3 247 249 251 NIA NIA 8 / 1979 V-58 246 246 247 NIA NIA V-120 249 244 247 247 249 01-25 257 258 257 NIA NIA 02-23 252 254 257 NIA NIA 03-25 251 249 251 NIA NIA AC-52 257 254 254 NIA NIA 13 / 1984 V-23 259 263 263 NIA NIA 01-32 260 257 259 NIA NIA OF-17 260 260 258 NIA NIA 23 / 1994 V-115 251 250 255 NIA NIA 03-18 258 256 256 NIA NIA OF-55 260 260 262 NIA NIA 33 / 2003 V-88 265 266 264 NIA NIA 03-15 266 266 269 NIA NIA BO-16 250 251 251 NIA NIA 43 / 2014 V-36 252 252 254 NIA NIA 01-02 252 251 249 NIA NIA Note a: Values in shaded cells are below the lower acceptance limit.

Note b: Test results for the specimen not shown in the surveillance report.

SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 60 Wire Exam Specimen

Mean, Mean, 6

ksi ksi NIA 243 NIA 236 NIA 248 NIA 252 NIA 244 247 NIA 248 NIA 253 NIA 251 NIA 247 N/A 249 NIA 250 NIA 248 NIA 259 243 241 NIA 247 251 NIA 257 NIA 246 NIA 257 NIA 253 NIA 260 NIA 247 242 241 NIA 254 NIA 249 NIA 246 249 NIA 247 NIA 257 NIA 254 NIA 250 NIA 255 NIA 262 258 NIA 259 NIA 259 NIA 252 256 NIA 257 NIA 261 NIA 265 264 NIA 267 NIA 251 NIA 253 251 NIA 251

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 Table 9 - Unit 2 Wire Test Results I Ultimate Tensile Strength Exam I Tendon I Ultimate Tensile Strength*, ksi Calendar Wire (if Specimen Specimen Specimen Specimen Specimen Year applicable) 1 2

3 4

5 MK-39 236

.i 235 248 NIA NIA HK-22 236 C

253 260 NIA NIA HM-54 256 259 255 NIA NIA V-226 254 248 244 NIA NIA V-27811 235 258 246 NIA NIA V-27812 255 253 251 NIA NIA 1 11972 V-339 252 253 252 NIA NIA D1-223 260 252 258 NIA NIA D2-227 11 272 269 271 NIA NIA D2-22712 258 NIA NIA NIA NIA D2-22713 270 NIA NIA NIA NIA D3-225 263 265 258 NIA NIA HK-22 253 255 255 NIA NIA MK-39 247 251 252 NIA NIA MH-54 253 251 253 NIA NIA V-226 250 248 248 NIA NIA 311974 V-278 255 251 253 NIA NIA V-339 251 249 251 NIA NIA D1-223 250 253 250 NIA NIA D2-227 264 263 263 NIA NIA D3-225 254 251 253 NIA NIA HK-22 248 252 249 NIA NIA MK-39 247 244 241 240 240 MH-54 243 245 247 NIA NIA V-226 241 241 241 NIA NIA 811979 V-278 242 241 241 NIA NIA V-339 243 244 242 NIA NIA D1-223 244 244 243 NIA NIA D2-227 251 247 247 NIA NIA D3-225 243 245 247 NIA NIA HK-31 248 251 250 NIA NIA 1811989 V-208 241 240 240 NIA NIA D1-205 244 246 242 NIA NIA JL-37 261 260 259 NIA NIA 28 / 1999 V-243 257 258 260 NIA NIA D3-213 260 260 260 NIA NIA HK-23 269 271 270 NIA NIA 3812009 V-282 265 258 261 NIA NIA D1-203 260 260 260 NIA NIA GL-4 251 252 252 NIA NIA 48 I 2019 V-237 259 260 258 NIA NIA D1-237 248 246 247 NIA NIA Note a: Values in shaded cells are below the lower acceptance limit.

SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 61 Wire Exam Specimen

Mean, Mean, 6

ksi ksi NIA 240 NIA 250 NIA 257 NIA 249 NIA 246 NIA 253 254 NIA 252 NIA 257 NIA 271 NIA 258 NIA 270 NIA 262 NIA 254 NIA 250 NIA 252 NIA 249 NIA 253 253 NIA 250 NIA 251 NIA 263 NIA 253 NIA 250 NIA 242 NIA 245 NIA 241 NIA 241 244 NIA 243 NIA 244 NIA 248 NIA 245 NIA 250 NIA 240 245 NIA 244 NIA 260 NIA 258 259 NIA 260 NIA 270 NIA 261 264 NIA 260 NIA 252 NIA 259 253 NIA 247

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 Table 10 - Unit 1 Wire Test Results/ Elongation at Failure Exam/

Tendon I Elongation*, %

Calendar Wire (if Specimen Specimen Specimen Specimen Specimen Year applicable) 1 2

3 4

5 BD-38 3.6 4.3 3.6 NIA NIA BF-23 4.9 5.0 5.1 NIA NIA DF-54 5.2 5.2

... 3;8<... *.

NIA NIA V-3 4.8 2.7 3.5 4.1 NIA 1 / 1971 V-58 4.5 4.5 3:8 5.1 4.1 V-120

• • 3.7 4.2 4.5 NIA NIA D1-25 4.7 4.9 4.1 NIA NIA D2-23 p.<23,5.. ****

Note b

• 3.6 5.3 NIA D3-25 3.9...

• • .. *.* 3Jf.

5.0 4.9 N/A BD-38 4.8 5.8 5.7 N/A NIA BF-23 5.6 5.7 5.0 N/A N/A DF-54 5.2 5.7 5.0 N/A N/A V-3 4.4 4.5 4.1 N/A N/A V-58 / 1 4.9 5.0 4.9 5.3 5.1 3 / 1973 V-58 / 2 5.9 4.4 4.9 N/A N/A V-120/1 5.1 4.2 4.4 N/A N/A V-120 / 2 4.5 4.9 4.8 NIA NIA D1-25 4.6 4.6 4.7 NIA NIA D2-23 4.1 4.4 4.2 3.8 NIA D3-25 4.0 4.2 4.9 N/A NIA BD-38 4.4 4.9 4.8 N/A N/A BF-23 5.0 5.1 4.0 4.7 4.1 DF-54 5.0 5.2 4.8 N/A N/A V-3 4.1 4.0 4.2 N/A N/A 8 / 1979 V-58 4.3 5.0 4.1 N/A N/A V-120 5.1 3.7 3.0 *.**

4.0 5.1 D1-25 5.8 5.9 5.6 N/A N/A D2-23 5.6 4.9 5.1 NIA NIA D3-25 5.2 5.0 4.8 NIA N/A AC-52 5.0 4.8 5.0 N/A N/A 13 / 1984 V-23 4.1 4.9 4.8 N/A N/A D1-32 5.6 5.2 5.0 N/A N/A DF-17 4.9 5.4 5.4 N/A N/A 23 / 1994 V-115 5.4 5.7 5.7 NIA N/A D3-18 5.6 5.3 5.0 NIA N/A DF-55 4.2 4.0 4.3 N/A N/A 33 / 2003 V-88 4.1 4.2 4.1 N/A N/A D3-15 4.8 4.6 5.0 NIA N/A BD-16 4.5 4.1 4.6 N/A NIA 43 / 2014 V-36 4.7 4.5 4.2 N/A N/A D1-02 5.9 5.2 4.5 N/A N/A Note a: Values in shaded cells are below the lower acceptance limit.

Note b: Elongation test results for the specimen not shown in the surveillance report.

SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 62 Wire Exam Specimen

Mean, Mean, 6

NIA 3.8 NIA 5.0 NIA 4.7 NIA 3.8 NIA 4.4 4.3 NIA 4.1 N/A 4.6 N/A 4.1 N/A 4.2 N/A 5.4 N/A 5.4 N/A 5.3 N/A 4.3 4.4 4.9 N/A 5.1 4.8 N/A 4.6 N/A 4.7 N/A 4.6 N/A 4.1 N/A 4.4 N/A 4.7 5.2 4.7 N/A 5.0 N/A 4.1 NIA 4.5 4.7 NIA 4.2 N/A 5.8 N/A 5.2 N/A 5.0 N/A 4.9 NIA 4.6 4.9 N/A 5.3 NIA 5.2 N/A 5.6 5.4 N/A 5.3 N/A 4.2 NIA 4.1 4.4 N/A 4.8 N/A 4.4 N/A 4.5 4.7 NIA 5.2

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 Table 11 - Unit 2 Wire Test Results/ Elongation at Failure Exam/

Tendon I Elongation*, %

Calendar Wire (if Specimen Specimen Specimen Year applicable) 1 2

3 MK-39 6.2 5.3 5.8 HK-22 5.6 4.5 5.7 HM-54 5.6 4.5 4.7 V-226 5.5 5.7 5.5 V-278 / 1 5.2 5.9 5.0 1 / 1972 V-278 / 2 6.2 5.4 5.8 V-339 5.8 6.3 5.7 D1-223 4.9 4.4 4.5 D2-227 / 1 5.8 4.9 4.9 D2-227 / 2 4.7 N/A NIA D2-227 / 3 5.4 NIA NIA D3-225 5.3 5.2 3.9 HK-22 5.3 5.8 5.9 MK-39 4.3 5.7 5.4 MH-54 4.9 4.0 4.8 V-226 4.2 5.6 5.5 3 I 1974 V-278 5.5 5.7 6.3 V-339 5.1 4.4 4.6 D1-223 4.6 5.1 5.0 D2-227 4.8 4.6 4.3 D3-225 5.5 5.4 4.6 HK-22 4.6 5.2 4.8 MK-39 5.1 5.1

.********* 3.7 MH-54 4.1 5.2 5.4 V-226 5.7 5.4 5.5 8 / 1979 V-278 5.4 5.8 5.8 V-339 5.1 5.7 4.2 D1-223 5.5 4.6 5.3 D2-227 5.0 4.8 5.4 D3-225 4.4 4.7 5.3 HK-31 18 / 1989 V-208 Note b D1-205 JL-37 5.6 5.4 5.7 28 / 1999 V-243 5.3 5.9 4.4 D3-213 5.9 5.8 5.6 HK-23 5.1 5.6 4.9 38 / 2009 V-282 5.2 4.9 5.0 D1-203 5.6 5.2 5.7 GJ-4 6.0 6.5 5.8 48 / 2019 V-237 6.9 6.5 6.4 D1-237 6.0 5.2 5.0 Note a: Values in shaded cells are below the lower acceptance limit.

Note b: Elongation test results not shown in the sU1veillance report.

Specimen 4

N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A NIA NIA N/A N/A N/A N/A

. 3:E) **..

• N/A NIA NIA N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A Specimen 5

N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A NIA NIA N/A NIA N/A N/A N/A N/A 5.0 N/A N/A N/A N/A N/A N/A N/A N/A N/A NIA N/A N/A NIA N/A NIA N/A NIA N/A N/A SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 63 Wire Exam Specimen

Mean, Mean, 6

N/A 5.8 N/A 5.3 N/A 4.9 N/A 5.6 N/A 5.4 N/A 5.8 5.3 NIA 5.9 N/A 4.6 N/A 5.2 N/A 4.7 N/A 5.4 N/A 4.8 N/A 5.7 N/A 5.1 N/A 4.6 N/A 5.1 N/A 5.8 5.1 NIA 4.7 NIA 4.9 NIA 4.6 N/A 5.2 N/A 4.9 N/A 4.5 N/A 4.9 N/A 5.5 N/A 5.7 5.0 N/A 5.0 N/A 5.1 N/A 5.1 N/A 4.8 N/A N/A N/A N/A N/A N/A N/A N/A 5.6 N/A 5.2 5.5 N/A 5.8 N/A 5.2 N/A 5.0 5.2 N/A 5.5 N/A 6.1 N/A 6.6 6.0 N/A 5.4

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 Number Surveillance I of Calendar Year Samples Tested 1 / 1971 9

3 / 1973 8 I 1979 9

13 / 1984 24 18 / 1989 2

23 I 1994 11 28 / 1999 11 33 / 2003 17 38 / 2009 29 43 / 2014 28 48 / 2019 24 Table 12-Unit 1 CPM Sample Test Results Chloride Ion Nitrate Ion Sulfide Ion Concentration, Concentration, Concentration, ppm ppm ppm Min Max Min Max Min Max 0.4 1.2

<0.1 0.2

<0.1 0.7 Test results not found

<0.1 0.8 0.1 2.7

<0.1

<0.1 0.5 1.3 0.67 3.56 0.038 0.213 1.4 3.4 0.04 0.04

<1.0

<1.0

<1 5

<0.4 8.7

<0.2 9.4

<0.50

<0.50 0.85 40.4a

<0.50

<0.50

<0.50 1.00

<0.50

<0.50

<0.50

<0.50

<0.50 1.00

<0.50

<5.00

<0.50

<3.00

<0.50 1.5

<0.50

<0.50

<0.50

<0.50

<0.50 1.00

<1.0

<1.0

<0.50

<0.50 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 64 Water Content, %

Base Number (of dry weight)

Min Max Min Max

<0.1 0.4

<0.1

<0.3

<0.1 0.1 0.07 23.31 0.05 0.10 3.9 6.1 0.5 0.5

<0.02 0.02 0.12 0.92 0.17 59.56

<0.10 0.45

<0.50 8.30

<0.10 0.32

<0.50 10.5

<0.10 1.80

<0.50 84.3

<0.10 0.58

<0.500 35.3

<0.10 5.7b

<0.500 51.6 Note a: Additional samples from the opposite ends of 2 tendons were tested for nitrates only. Maximum documented concentration was 64.2 ppm. This and other nitrate test results are considered questionable as discussed in text sub-section 4.4.1.

Note b: No other 48th year Unit 1 sample water content exceeded 0.46%.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 Number Surveillance /

of Calendar Year Samples Tested 1 / 1972 3 / 1974 8 / 1979 9

13 / 1984 28 18 / 1989 11 23 / 1994 13 28 / 1999 11 33 / 2003 14 38 / 2009 31 43 I 2014 27 48 / 2019 26 Table 13-Unit 2 CPM Sample Test Results Chloride Ion Nitrate Ion Sulfide Ion Concentration, Concentration, Concentration, ppm ppm ppm Min Max Min Max Min Max Test results not found Test results not found

<0.1 0.1

<0.1 1.2

<0.1

<0.1 0.5 1.3 0.70 3.06 0.035 0.213

<1.0 3.5

<0.01 0.27

<0.1 1.0

<1 1

<0.4 10.5

<0.2 7.5

<0.50

<0.50 0.66 24.08

<0.50

<0.50

<0.50 0.50

<0.50

<0.50

<0.50

<0.50

<0.50

<0.50

<0.50

<0.50

<0.50

<5.00

<0.50 2.0

<0.50

<0.50

<0.50 0.53

<0.50

<0.50

<1.0

<5.0

<0.50

<2.50 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 65 Water Content, %

Base Number (of dry weight)

Min Max Min Max

<0.1 0.1 0.05 0.31 0.05 0.05 3.9 6.2

<0.5

<0.5 0.03 0.38 0.12 0.88 3.65 53.39

<0.10 0.62

<0.50 5.50

<0.10 0.30

<0.50 11.4

<0.10 1.70 2.50 70.5

<0.10 1.1

<0.500 46.5

<0.10 0.74 2.11 53.1 Note a: An additional sample from the opposite ends of 1 tendon was tested for nitrates only. Maximum documented concentration was 8.96 ppm. This and other nitrate test results are considered questionable as discussed in text sub-section 4.4.1.

NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 66 Figure 1 - Unit 1 Hoop Tendon Force Trend & LCL C.

1 Q) 0 750 700 LL 650 C

0

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NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 67 Figure 2 - Unit 2 Hoop Tendon Force Trend & LCL Q..

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NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 C.

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NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 Figure 6 - Unit 2 Dome Tendon Force Trend & LCL

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NextEra Energy, LLC Point Beach Nuclear Plant A13329.151 SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 72 Figure 7 - Unit 2 Dome Tendon Force Trend & LCL / All Data ex Outlier Q.

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SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 73 100

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A,...

SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 74 100

• Mean Max Min

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-=

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10 T, Time Since SIT, Years (Logarithmic Scale)

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SL Report No.: SL-018297 Rev. 0 01/15/2024 Page 76 100 Max

.& Mean l!!l Min