ML26014A078
| ML26014A078 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 01/21/2026 |
| From: | Undine Shoop NRC/NRR/DORL/LPL1 |
| To: | Rhoades D Constellation Energy Generation, Constellation Nuclear |
| Sreenivas V, NRR/DORL/LPL1 | |
| References | |
| EPID L-2025-LLR-0042 | |
| Download: ML26014A078 (0) | |
Text
January 21, 2026 R.E. GINNA NUCLEAR POWER PLANT - AUTHORIZATION AND SAFETY EVALUATION FOR ALTERNATIVE REQUEST NO. I6R-11 FOR INSERVICE INSPECTION OF THE CONTAINMENT POST-TENSIONING SYSTEM COMPONENTS (EPID L-2025-LLR-0042)
LICENSEE INFORMATION Recipients Name and Address:
Mr. Christopher H. Mudrick Sr.
Senior Vice President Constellation Energy Generation, LLC President and Chief Nuclear Officer Constellation Nuclear 4300 Winfield Road Warrenville, IL 60555 Licensee:
Constellation Energy Generation, LLC Plant Name(s) and Unit(s):
R.E. Ginna Nuclear Power Plant (Ginna)
Docket No:
50-244 APPLICATION INFORMATION Submittal Date: March 25, 2025 Submittal Agencywide Documents Access and Management System (ADAMS) Accession No.: ML25086A205 Applicable Inservice Inspection (ISI) Program Interval and Interval Start/End Dates: The Third Containment lnservice Inspection (CISI) Interval; January 1, 2020, to December 31, 2029.
Alternative Provision: The applicant requested an alternative under Title 10 of the Code of Federal Regulations (10 CFR), paragraph 50.55a(z)(1) Acceptable level of quality and safety.
ISI Requirement: American Society of Mechanical Engineers (ASME) Code, section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, subsection IWL-2420, Unbonded Post-Tensioning Systems and 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 Boiler and Pressure Vessel (BPV) Code,Section XI, 2013 Edition Brief Description of the Proposed Alternative: March 25, 2025, submittal summarized visual and physical testing results. The proposed alternative, corresponding to the ASME Code inspection and dates and examination requirements are as follows:
- 1. Eliminating the performance of the 55th year examinations required by IWL-2520, and to perform only the visual examination of the accessible containment concrete surfaces and accessible tendon hardware visible without tendon cover removal during the 55th year surveillance, scheduled to be completed by September 10, 2026.
- 2. Use of the September 10, 2000, date to establish scheduling for the 5-year inspection frequency per IWL-2420(a) to perform the post-tensioning system examinations required by IWL-2500 For additional details on the licensees request, please refer to the documents located at the (ML25086A205) identified above.
STAFF EVALUATION The U.S. Nuclear Regulatory Commission (NRC) staff reviewed the information provided in the proposed alternative request and noted that the licensee will continue to conduct the general visual examinations and detailed visual examinations of suspect areas on a 5-year frequency, as required by Table IWL-2500-1 (L-A). Any indications identified during these examinations may lead to additional examinations in accordance with Table IWL-2500-1 (L-B). As required by paragraph IWL-2510, Surface Examination, 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 corrosion protection medium (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 reviewed the summary of results and the plant-specific surveillance data and figures for Ginna, examinations provided in Attachments 1 and 2 to the request. Ginna conducted examinations for each of the requirements of ASME Code,Section XI, Subsection IWL, Table IWL-2500-1 (L-B), Item Nos. L2.10, L2.20, L2.30, L2.40, and L2.50. The NRC staff conducted an online regulatory audit to examine the licensees non-docketed information with the intent of gaining a better understanding of the plants operating experience and to verify the alternative requests examination results to support the basis of the NRC staffs licensing decision.
The NRC staffs evaluation of each items number is provided below.
Item No. L2.10, Tendon Force Trends and Forecasts Section 5.2.2 of Attachment 1 to the proposed alternative request describes that all 160 of Ginnas vertical tendons have been retensioned since 2005 due to significant loss of prestress in early plant life, and since the retensioning, the performance of the post-tensioning system has been excellent. Attachment 2 of the proposed alternative contains Figures 1, 2, and 3, which are plots of measured tendon force trends for each set of tendons that were retensioned in 1969, 1980, and 2005.
The NRC staff evaluated section 5.2.1 of the proposed alternative request, reviewed the lift-off force data in Figures 1, 2, 3-1, and 3-2 of the enclosure to the request, and verified that the projected forces remain above the minimum required value (MRV) (i.e., 636 kilo-pound (kip) for the vertical tendons) beyond the deferred next inspection and through the end of the current 60-year operating license. The NRC staff also verified that: (1) the visual examination of anchorage components such as tendon wires, buttonheads on anchorheads, and sacrificial tendon wire, as well as collected corrosion protection medium (tendon grease), provides evidence that no unacceptable degradation has occurred in the tendons; (2) during the lift-off force measurements, as well as the overstress force measurements at 106 percent of the measured lift-off force, no significant tendon elongation occurs, regardless of the post-tensioning systems at Ginna not being designed to periodically be detensioned and retensioned during surveillance testing. 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 extend the interval of 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 Constellation Energy Generation (CEG) to perform the next tendon testing from 5 to 10 years for the third 10-year CISI interval.
Item No. L2.20, Wire Examination and Test Results Section 5.2.4 of Attachment 1 to the request states: (1) Visual examination of all wires removed from tendons since initial tendon installation has shown no signs of corrosion or physical damage; and (2) Results of tension tests on all wires removed from tendons have met applicable acceptance standards, including material specification requirements for ultimate tensile strength ( 240 ksi) and elongation at failure ( 4 percent).
The NRC staff reviewed the test results of tendon wire specimens and observed that the results of all tendon wire specimens were above the minimum ultimate strength of 240 ksi. The lowest recorded wire tested stress was 249 ksi. Additionally, the NRC staff observed that the recorded elongation values of the tested specimens were all above the minimum 4.0 percent. Because the examination and testing of extracted sample wires have shown no signs of degradation of condition, strength, or elongation over a period of approximately 55 years, the NRC staff finds it acceptable to extend the interval of the tendon wire examination and tests (ASME Code,Section XI, Table IWL-2500-1 (L-B), Item No. L2.20) for a one-time deferral for CEG to perform the next tendon wire examination and testing from 5 to 10 years for the third 10-year CISI interval.
Item No. L2.30, Anchorage Hardware and Surrounding Concrete Inspection Section 5.2.3 of Attachment 1 to the request summarizes the results of periodic end anchorage examinations at Ginna. The examinations described follow the requirements of ASME BPVC Section XI, Subsection IWL-2524, which governs periodic visual inspections of post-tensioning systems in Class CC containment structures.
CEG summarized the tendon anchorage area concrete and tendon anchorage hardware examination results as follows:
Cracking concrete adjacent to bearing plates at several tendon end anchorages has been evaluated as typical in structures of this age and does not represent evidence of abnormal degradation of the containment or post-tensioning system. Necessary maintenance is performed to prevent further cracking resulting from freeze-thaw conditions.
Visual examinations of tendon anchorage hardware (anchorhead, shims, buttonheads, and bearing plates) have met the applicable acceptance standards, with exceptions as noted in the following bullet. Cracks have not been detected in any tendon anchorage component.
Level III corrosion (visible oxidation with pitting) has been observed on bearing plates of most tendons, specifically found beneath tendon end cap gasketing where the gasket is compressed against the bearing plate. The gaskets used to seal grease from leaking at the grease can-to-bearing plate interface have maintained their function at the locations exhibiting corrosion/pitting.
No broken, missing, or protruding wires have been detected in any tendon, except for wires in Tendon V-075, which were damaged during surveillance activities in 1983.
During the regulatory audit, the NRC staff confirmed surveillance results during the 40th year, 45th year, and 50th year are consistent with the acceptance criteria of ASME BPVC Section XI, Subsection IWL-2524. The Level III corrosion is localized and superficial, with no evidence of material loss that would challenge the load-carrying capacity or functionality of the bearing plates. In accordance with the visual examination requirements of IWL-2525-1 and the condition evaluation criteria of IWL-3221.3, the inspections appropriately addressed the presence of corrosion, free water, broken or missing wires or buttonheads, damage or distortion of load-bearing components, and cracking in concrete adjacent to bearing plates. The conditions observed were evaluated and determined to be acceptable without repair, they have not resulted in degradation of tendon anchorage and have not had an adverse impact on the structural integrity of the containment.
Based on the anchorage hardware and surrounding concrete inspection, the NRC staff finds it acceptable to extend the interval of the tendon wire examination and tests (ASME Code,Section XI, Table IWL-2500-1 (L-B), Item No. L2.20) for a one-time deferral for CEG to perform the next tendon wire examination and testing from 5 to 10 years for the third 10-year CISI interval.
Item No. L2.40 and L2.50, CPM and Free Water Testing Section 5.2.6 of Attachment 1 to the request describes the design of the Ginna prestressed tendons attached to rock anchors at the bottom ends, which makes tensioning of tendons from the bottom end impossible, and CPM is not drained or removed from tendons during surveillances. For this reason, only a small quantity of CPM is removed and replaced during surveillance (approx. < 5 gallons), and measurement of grease volumes removed/replaced is not normally performed. Section 5.2.5 of Attachment 1 summarized that the examination of CPM analyses has met acceptable standards during all examinations, and free water has only been detected at the following tendons: V-026 (approx. 2 ounces); V-087 (very small quantity);
and V-160 (approx. 8 ounces).
The NRC staff reviewed the information provided in section 5.2.5 and 5.2.6 of Attachment 1 to the request and noted that for tendons with excessive CPM leakage, CPM is added as necessary to ensure coverage remains acceptable and that unacceptable or tendon conditions resulting from inadequate grease coverage have not been detected. The NRC staff confirmed that anchorage components and wires have remained sufficiently coated with CPM to protect the components from corrosion, regardless of the level of CPM observed within the tendon and cap. The licensee also performed the chemistry sample analysis testing for the CPM which includes mixing and analyzing for alkalinity, water content, and concentrations of water soluble chlorides, nitrates, and sulfides. The NRC staff verified that the alkalinity, water content, and concentration results of the CPM testing were within acceptable limits of ASME Section XI, Subsection IW-2525.
Based on the review of CPM condition monitoring, surveillance results, the absence of corrosion-related degradation, and chemistry sample analysis the NRC staff finds the examinations are consistent with the ASME Code requirements and finds it acceptable to not perform 55th year physical examinations of the concrete containment unbonded post-tensioning system from the requirements of Section XI, Subsection IWL-2520.
Scheduling Section 5.2.1 of the request describes the adjusted schedule for performing physical examinations of the Containment Post-Tensioning System. While April 14, 1969, is the original baseline date for scheduling these examinations, CEG has conducted the required examinations and tests in accordance with ASME Section XI, Subsection IWL, specifically Table IWL-2500-1, by the date of September 10, 2000. The examinations scheduled at the 200-month interval have been performed at a frequency consistent with the requirements of IWL-2420.
The NRC staff reviewed the inspection history and confirmed that the examinations and surveillance results are consistent with ASME Code criteria. Therefore, the NRC staff finds the adjusted date for the visual examination of the unbonded post-tensioning system to be acceptable.
Summary Based on the above evaluation, the NRC staff determines 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 the applied tendon prestress level will remain acceptable beyond the deferred next inspection. Therefore, the NRC staff finds that the use of the proposed alternative for Ginna, for the third CISI Interval Program, which began on January 1, 2020, and is currently scheduled to end on December 31, 2029, is acceptable.
The NRC staff finds it reasonable to approve the proposed alternative based on its review of the plant-specific inspection results, operating experience, and corrective actions taken, including the most recent inspection results from the current CISI interval provided in the licensees request. Specifically, the NRC staff finds it acceptable to: (1) eliminate the performance of the 55th-year examinations required by IWL-2520 and instead perform only the visual examination of the accessible containment concrete surfaces and accessible tendon hardware visible without tendon cover removal during the 55th-year surveillance, scheduled to be completed by September 10, 2026; and (2) use the September 10, 2000, date to establish scheduling for the 5-year inspection frequency per IWL-2420(a) to perform the post-tensioning system examinations required by IWL-2500.
CONCLUSION The NRC staff has determined that the proposed alternative in the licensees request referenced above would provide an acceptable level of quality and safety. The NRC staff concludes that the licensee has adequately addressed the regulatory requirements set forth in 10 CFR 50.55a(z)(1). The NRC staff authorizes the use of proposed alternative I6R-11 at the R.E. Ginna Nuclear Power Plant for the third CISI Interval, which began on January 1, 2020, and is currently scheduled to end on December 31, 2029. All other ASME BPV 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: Aaron Gallman Date: January 21, 2026 Undine Shoop, Acting Branch Chief Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation cc: Listserv UNDINE SHOOP Digitally signed by UNDINE SHOOP Date: 2026.01.21 12:26:09 -05'00'
ML26014A078 NRR-028 OFFICE NRR/DORL/LPL1/PM NRR/DORL/LPL3/LA NRR/DEX/ESEB /BC NAME VSreenivas SLent Ian Tseng DATE 01/13/2026 1/15/26 01/09/2026 OFFICE NRR/DORL/LPL1/BC NRR/DORL/LPL1/PM NAME Undine Shoop VSreenivas DATE 1/21/2026 1/21/2026