ML24200A161
| ML24200A161 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 07/19/2024 |
| From: | Jeffrey Whited Plant Licensing Branch III |
| To: | Coffey B Point Beach |
| Wall, S P | |
| References | |
| EPID L-2024-LLR-0005, CISI-03-01 | |
| Download: ML24200A161 (1) | |
Text
July 19, 2024 POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 - AUTHORIZATION AND SAFETY EVALUATION FOR ALTERNATIVE REQUEST NO. CISI-03-01 (EPID L-2024-LLR-0005)
LICENSEE INFORMATION Recipients Name and Address:
Bob Coffey Executive Vice President, Nuclear Division and Chief Nuclear Officer Florida Power & Light Company Mail Stop: EX/JB 700 Universe Blvd Juno Beach, FL 33408 Licensee:
NextEra Energy Point Beach, LLC Plant Name(s) and Unit(s):
Point Beach Nuclear Plant, Units 1 and 2 (Point Beach)
Docket No(s).:
50-266 50-301 APPLICATION INFORMATION Submittal Date: January 26, 2024 Submittal Agencywide Documents Access and Management System (ADAMS) Accession No.: ML24026A157.
Supplement Date(s): March 27, 2024.
Supplement ADAMS Accession No(s).: ML24089A119.
Applicable Inservice Inspection (ISI) and Interval Start/End Dates: The third 10-year containment inservice inspection (CISI) interval that started September 9, 2016, and is scheduled to end on September 8, 2026.
Alternative Provision: The applicant requested an alternative under Title 10 of the Code of Federal Regulations (10 CFR), paragraph 50.55a(z)(1).
ISI Requirement: American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, Subsection IWL, Table IWL-2500-1, Examination Category L-B, Unbonded Post-Tensioning System, Item Nos. L2.10, L2.20, L2.30, L2.40 and L2.50.
Applicable Code Edition and Addenda: ASME,Section XI, Subsection IWL, 2007 Edition with 2008 Addenda.
Brief Description of the Proposed Alternative: Pursuant to 10 CFR 50.55a(z)(1), the licensee submitted a relief request from the above ASME Code requirements for the current third 10-year CISI interval applicable between the most recently completed examination in 2019 to the subsequent examination in 2024 (+/- 1 year), and through the year 2030 surveillance for Point Beach. A summary is described below:
For Item No. L2.10, the proposed alternative is to extend the interval of the examination such that the tendon force measurement for Point Beach, Unit 1, originally scheduled for the year 2024 surveillance per IWL-2421(b), will be performed at the year 2030 (+/- 1 year) surveillance. Examination for Item No. L2.10 will be performed on Unit 1 at year 2030 instead of Unit 2.
For Item No. L2.20, the proposed alternative is to eliminate the requirement for de-tensioning / re-tensioning of tendons, wire removal and wire sample testing for the remaining duration of the current renewed facility operating license, which expires on October 5, 2030, for Point Beach, Unit 1, and March 8, 2033, for Point Beach, Unit 2.
For Item No. L2.30, the proposed alternative is to extend the interval for anchorage hardware examinations and surrounding concrete inspection for a one-time deferral from 5 years to 10 years for Point Beach and to perform the next examination in 2030
(+/- 1 year).
For Item Nos. L2.40 and L2.50, the proposed alternative is to extend the interval for the examination and testing of corrosion protection medium (CPM) and free water for a one-time deferral from 5 years to 10 years for Point Beach, Units 1 and 2, and to perform the next examination and testing in 2030 (+/- 1 year). The initial CPM laboratory tests required per Table IWL-2525-1 may be limited to that which determines absorbed water content and the remaining corrosive ions and reserve alkalinity tests are performed only on those samples that have a water content above the acceptance limit, and are collected at an anchorage where free/absorbed water and/or corrosion is found or if specified by the ASME Code,Section XI, Subsection IWL, Responsible Engineer (RE).
For additional details on the licensees request, refer to the documents located at the ADAMS Accession No(s). identified above.
STAFF EVALUATION The licensee proposed the request for alternative frequency, as modified by the supplement, to the containment unbonded post-tensioning system inservice inspection (CISI-03-01) for Point Beach. In response to the NRCs concern about the requests seeking multiple reliefs in subsequent intervals beyond the third 10-year CISI interval, the licensee clarified in the supplement that duration of the proposed alternative is a one-time extension applicable between the most recently completed examination in 2019 and the subsequent examination required by IWL. The licensee seeks NRCs approval through the 2030 surveillances and the relief request does not apply beyond the proposed 2030 examination. Specifically, the relief request concerns the following examination requirements in Table IWL-2500-1 (L-B) of ASME Code,Section XI, subsection IWL.
Item No. L2.10 requires that selected tendon force and elongation be measured every 5 years (10 years for two units or more meeting subparagraph IWL-2421(b) alternative scheduling requirements) in accordance with paragraph IWL-2522, Tendon Force and Elongation Measurements.
Item No. L2.20 requires that tendon single wire samples be removed and examined for corrosion examinations and mechanical damage as well as tested to obtain yield strength, ultimate tensile strength, and elongation on each removed wire. This inspection must be performed every 5 years (10 years for two units or more meeting subparagraph IWL-2421(b) alternative scheduling requirements) in accordance with paragraph IWL-2523, Tendon Wire and Strand Examination and Testing.
Item No. L2.30 requires that a detailed visual examination on selected tendon anchorage hardware and adjacent concrete extending 2 feet from the edge of the bearing plate be performed every 5 years (10 years for two units or more meeting subparagraph IWL-2421(b) alternative scheduling requirements) in accordance with paragraph IWL-2524, Examination of Tendon Anchorage Areas. In addition, the quantity of free water released from the anchorage end cap, as well as any free water that drains from the tendon during examination, must be documented.
Item No. L2.40 requires that samples of selected tendon CPM be obtained and analyzed every 5 years (10 years for two units or more meeting subparagraph IWL-2421(b) alternative scheduling requirements) in accordance with paragraph IWL-2525, Examination of Corrosion Protection Medium and Free Water.
Item No. L2.50 requires that samples of free water be obtained and analyzed every 5 years (10 years for two units or more meeting subparagraph IWL-2421(b) alternative scheduling requirements) in accordance with paragraph IWL-2525.
The NRC staff reviewed the information provided in the proposed alternative request, as modified by the supplement, and noted that the licensee will continue to conduct the general visual examinations and detailed visual examination of suspect areas, on a 5-year frequency as required in Table IWL-2500-1 (L-A) Examination Category L-A, Concrete. Any indications identified during these examinations may lead to additional examinations in accordance with Table IWL-2500-1 (L-B) Examination Category L-B, Unbonded Post-Tensioning System, as determined by the RE. As required by IWL-2511, Accessible Areas, this would include examination of the concrete surfaces and tendon end anchorage areas on a 5-year frequency to identify evidence of damage, degradation, deformation of the end cap, water intrusion, corrosion, concrete cracking, or CPM leakage. Tendon end caps are required to be removed for this examination if there is evidence of tendon end cap deformation or damage.
The NRC staff also reviewed the plant-specific information, and summary results of examinations conducted for each of the requirements of ASME Section XI, Subsection IWL, Table IWL-2500-1 (L-B), Item Nos. L2.10, L2.20, L2.30, L2.40, and L2.50. These examinations and tests were conducted during 11 inspections for Point Beach over almost a 50-year period (1970-2019) for each of the requirements. This information is specifically described in Section 4, Point Beach Examination History and Results Analysis/Evaluation, of the Enclosure to the proposed alternative. A summary of the NRC staffs evaluation of each item number is provided below.
Item No. L2.10, Tendon Force Trends and Forecasts Section 4.1.4, Pre-stressing Force Summary and Conclusion, of the Enclosure to the proposed alternative contains the Lift-Off Data Trend and LCL [Lower Confidence Limit] Summary table for each of the tendons for Point Beach. The summary table provides the log-linear regression tendon force trends at T=100 years, the 95 percent LCL, and margins of the trended values over the minimum required value (MRV). Except for Point Beach, Unit 2, dome tendons, the licensee concluded that the mean tendon forces 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 licensee also describes that the Point Beach, Unit 2, dome tendon projected force is expected to remain above MRV until T~66.5 years, which is over 5 years after the deadline for completion of the next surveillance.
The NRC staff reviewed the lift-off force data presented in Sections 4.1.1 through 4.1.4 and Figures 1 through 7 of the Enclosure to the proposed alternative and verified that the projected lift-off forces remain above the MRV (i.e., 594 kip for hoop, 624 kip for vertical, and 607 kip for dome tendons) beyond the deferred next inspection and through the end of the current operating license term. Based on the statistical analyses of past surveillance results, and the ample margin between the measured force trend (forecast) values and the MRV, the NRC staff finds it acceptable to defer the post tensioning system examinations and tests (ASME Code,Section XI, Table IWL 2500-1 (L-B), Item No. L2.10) for a one-time deferral for Point Beach, Unit 1, scheduled for the year 2024 surveillance, and to perform the next tendon force measurement on Unit 1 in 2030 (+/- 1 year) instead of Point Beach, Unit 2.
Item No. L2.20, Wire Examination and Test Results Section 4.3, Wire Examination and Testing, of the Enclosure to the proposed alternative describes that specified test wires and broken wires were extracted from each tendon that was scheduled for surveillance. The wires were examined for corrosion and tested for strength and ductility.
Section 3.4.3, Wire/Strand Test Results, of the Enclosure to the proposed alternative states, 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 minimum (240 kilopound per square inch (ksi) and 4.0 percent, respectively) specified for ASTM A421, and There is no evidence that either strength or elongation (at failure) decrease with time under load.
The NRC staff reviewed the tendon wire test results described in Section 4.3.1, Wire Examination, of the Enclosure to the proposed alternative and noted the following:
The licensee stated that the few occurrences of level 3 corrosion (pitting with depth
< 0.003 inch) observed only occurred during the 1-and 3-years surveillance, and nothing in the surveillance reports suggest that the observed corrosion is active.
Two tendon wires that did not meet the elongation criteria averaged 3.8 percent elongation during the year 1 surveillance for Unit 1, and one tendon wire in Unit 1 that did not meet the ultimate strength criteria measured at 236 ksi average.
The NRC staff finds the level 3 corrosion noted in the first 3 years acceptable because the corrosion is inactive, and as the Enclosure stated, most of the corrosion cases existed at the time of tendon installation. The NRC staff reviewed Tables 8 through 11 of the Enclosure to the proposed alternative and observed that all wires tested during surveillance years 3 through 48 resulted in mean elongation (greater than 4 percent) and ultimate stress (greater than 240 ksi) above the ASTM A421 acceptance criteria. Although there is a scatter of measured tensile strength, the NRC staff notes that the examination and testing of extracted sample wires has shown no degradation of condition, strength, or elongation over a time period of 48 years.
Therefore, the NRC staff finds it acceptable to eliminate tendon wire examinations and tests (ASME Code,Section XI, Table IWL 2500-1 (L-B), Item No. L2.20) for Point Beach with the condition that the RE should consider wire removal and examination and testing if observed end anchorage conditions indicate the possibility of wire degradation.
Item No. L2.30, Anchorage Hardware and Surrounding Concrete Inspection Section 4.2, End Anchorage Condition, of the Enclosure to the proposed alternative summarizes the results of examinations for corrosion, presence of free water, broken wires or missing button heads, damage to or distortion of load bearing components, and cracks in the concrete adjacent to bearing plates. The NRC staff reviewed the results of these examinations summarized in Subsections 4.2.1 through 4.2.5 of the Enclosure to the request and noted the following:
Level 3 and 4 corrosion of the anchorage bearing shims and plates is limited to ones observed during the year 1 surveillance, which supports the licensees statement that these existed during construction and are not active.
Because the containment is protected from the outside environment, no free water has been found in the tendon ducting or end anchorage areas since the first-year surveillance - which occurred during construction.
During the 11 surveillances completed to date, only 2 wires from Unit 1 tendons, and 7 wires from Unit 2 tendons were observed to be in ineffective, and no individual tendon had more than two ineffective wires.
Only one crack greater than 0.01-inch wide (0.015-inch) was observed occurring at Unit 2 near tendon V-218. The crack is passive considering it has not grown between 1973 to 2014.
The NRC staff evaluated the information related to the anchorage hardware examinations and noted that there is no active or significant corrosion since the year-1 surveillance, free water is not present as explained above, the 7 ineffective tendon wires (0.086 percent) at Unit 2 is insignificant to the performance of the tendons, and the one 0.015-inch crack is shrinkage related during construction. Furthermore, no damage, cracking, or distortion has been found on bearing plates, anchor heads, and shims. The surveillance findings to-date do not appear to indicate the presence of active degradation mechanisms that will cause significant degradation if the inspection interval is extended. Therefore, the staff finds it acceptable to extend the interval of anchorage hardware examinations and surrounding concrete inspection (ASME Code,Section XI, Table IWL2500-1(L-B), Item No. L2.30 for a one-time deferral from 5 years to 10 years for Point Beach, for the third 10-year CISI interval. Accordingly, the next tendon anchorage hardware and adjacent concrete examination will be conducted in 2030 (+/- 1 year) on both Point Beach units.
Item Nos. L2.40 and L2.50, Corrosion Protection Medium and Free Water Testing Section 4.4, Corrosion Protection Medium Testing, of the Enclosure to the proposed alternative states that CPM was collected at the ends of sample tendons during each surveillance and tested for chlorides, nitrates, sulfides, absorbed water content, and reserve alkalinity (base number). Section 4.4.1 of the Enclosure also stated, CPM test results, except those shown for several nitrate ion concentrations during the 23rd and 28th year surveillance reports, met the acceptance limits set in the ASME Code,Section XI, Subsection IWL, Table IWL-2525-1. The anomalous nitrate ion test results observed during the 23rd and 28th year surveillances were concluded by the licensee to be a result of sample contamination or procedural errors during testing. Section 4.4.1.1 of the Enclosure further noted that the ion concentration data give no indication that the contaminant levels are increasing over time.
The NRC staff reviewed Tables 12 and 13 of the Enclosure to the proposed alternative for Point Beach CPM sample tests results, and confirmed the statements in the proposed alternative that the CPM analysis results, with the noted exceptions, have met the acceptance limits required by ASME Code,Section XI, Subsection IWL, Table IWL-2525-1. The testing of free water for the pH value is not applicable as there has not been any water collected since year 1 as described under Item No. L2.30.
Based on the adequate test results, and no indication that the conditions will degrade over time, the NRC staff finds it acceptable to extend the interval of the examination of CPM and free water (ASME Section XI, Subsection IWL, Table IWL2500-1(L-B), Item Nos. L2.40 and L2.50) for a one-time deferral from 5 years to 10 years for both Point Beach for the third 10-year CISI interval. In addition, based on past examination results from 1999 to date, the CPM test results have been consistently well below acceptance limits and the CPM appears to be retaining its corrosion protection function. Therefore, the NRC staff finds it is acceptable to limit the initial CPM laboratory tests required per Table IWL-2525-1 to that which determines absorbed water content, and to perform the remaining corrosive ions and reserve alkalinity tests only on those samples that have a water content above the acceptance limit and are collected at an anchorage where free/absorbed water and / or corrosion is found or if specified by the ASME Section XI, Subsection IWL, RE. No such conditions exist as of the last inspection. Accordingly, the next CPM and free water examination and testing will be conducted in 2030 (+/- 1 year) on both Point Beach.
Summary Based on the above evaluation, the NRC staff determined that the licensee has demonstrated adequate performance of the unbonded post-tensioning system by presenting adequate plant-specific post-tensioning system inspection results, operating experience and corrective actions, and technical evaluations demonstrating applied tendon prestress level will remain acceptable beyond the deferred next inspection. Therefore, the NRC staff finds that the use of the proposed alternative CISI-03-01 for Point Beach, for the third 10-year CISI interval provides an acceptable level of quality and safety.
The NRC staff authorizes the alternatives for the third 10-year IWL CISI interval for Point Beach as follows:
Defer the post tensioning system examinations and tests (ASME Code,Section XI, Table IWL 2500-1 (L-B), Item No. L2.10) for Point Beach, Unit 1 scheduled for the year 2024 surveillance, for a one-time deferral, to perform the next tendon force measurement in 2030 (+/- 1 year) instead of Point Beach, Unit 2.
Eliminate tendon wire examinations and tests (ASME Code,Section XI, Table IWL 2500-1 (L-B), Item No. L2.20) for Point Beach for the remaining duration of the current renewed facility operating license, which expires on October 5, 2030, for Point Beach, Unit 1, and March 8, 2033, for Point Beach, Unit 2, with the condition that the RE should consider wire removal and examination and testing if observed end anchorage conditions indicate the possibility of wire degradation.
Extend the interval of anchorage hardware examinations and surrounding concrete inspection (ASME Code,Section XI, Table IWL2500-1(L-B), Item No. L2.30) for a one-time deferral from 5 years to 10 years for Point Beach to perform the next examination in 2030 (+/- 1 year).
Extend the interval of the examination of CPM and free water (ASME Code,Section XI, Subsection IWL, Table IWL2500-1(L-B), Item Nos. L2.40 and L2.50) for a one-time deferral from 5 years to 10 years for Point Beach to perform the next examination and testing in 2030 (+/- 1 year). The initial CPM laboratory tests required per Table IWL-2525-1 may be limited to that which determines absorbed water content; perform the remaining corrosive ions and reserve alkalinity tests only on those samples that have a water content above the acceptance limit, and are collected at an anchorage where free/absorbed water and/or corrosion is found or if specified by the ASME Code,Section XI, Subsection IWL, RE.
If deferred inspections from the third interval are conducted in the fourth CISI interval, the ASME Code edition used for the inspection shall be in accordance with 10 CFR 50.55a (g)(4)(ii),
Applicable ISI Code: Successive 120-month intervals.
CONCLUSION As set forth above, the NRC staff determines that the licensees proposed alternative provides for an acceptable level of quality and safety. Accordingly, the NRC staff concludes that the licensee has adequately addressed all the regulatory requirements set forth in 10 CFR 50.55a(z)(1). Therefore, the NRC staff authorizes the use of the alternative request, CISI-03-01, at Point Beach for the third 10-year CISI interval, as stipulated in the staff evaluation summary section above.
All other ASME Code,Section XI, requirements, for which an alternative was not specifically requested and authorized remain applicable, including third -party review by the Authorized Nuclear Inservice Inspector.
Principal Contributor(s): S. Lai, NRR Date: July 19, 2024 Jeffrey A. Whited, Chief Plant Licensing Branch III Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation cc: Listserv Jeffrey A.
Whited Digitally signed by Jeffrey A. Whited Date: 2024.07.19 11:57:50 -04'00'
- via memo NRR-028 OFFICE NRR/DORL/LPL3/PM NRR/DORL/LPL3/LA NRR/DEX/ESEB/BC NAME SWall SRohrer ITseng DATE 07/17/2024 07/18/2024 07/15/2024 OFFICE NRR/DORL/LPL3/BC NRR/DORL/LPL3/PM*
NAME JWhited SWall DATE 07/19/2024 07/19/2024