ML22259A122
| ML22259A122 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 09/08/2022 |
| From: | Kenneth Kolaczyk NRC/NRR/DRO/IRAB |
| To: | |
| Kenneth Kolaczyk, NRR/DRO/IRAB | |
| Shared Package | |
| ML22259A115 | List: |
| References | |
| Download: ML22259A122 (26) | |
Text
Challenges With Arkansas Nuclear One Service Water System Aging Management 1
WE POWER LIFE
Some of the information contained in this presentation is pre-decisional in nature.
Do not discuss with individuals outside of the NRC.
Comparison of Units Unit One Unit Two Generating capacity of Generating capacity of 930 846 megawatts megawatts Commercial Operations started Commercial Operations started December 19, 1974 March 26, 1980 Licensed to operate through May Licensed to operate through July 20, 2034 17, 2038 Nuclear reactor was supplied Nuclear reactor was supplied by Babcock & Wilcox by Combustion Engineering Releases heat into Lake Uses a cooling tower to dissipate Dardanelle heat Began the period of extended Began the period of extended operation after midnight operation after midnight on July on May 20, 2014 17, 2018
Existing Service Water System Piping Concern with discharge Supply to Intake Return to ECP Chemically GL 89-13 Treated areas treated
Existing Service Water System Piping Layout
ANO Inspection
- Buried piping not inspected over life of the plant (supply lines, one return)
- Concern with internal condition - lack of chemical treatment (supply)
- Evaluate license basis for the buried pipe and service water programs
- Evaluate if programs to manage aging effects have been effective
- Identify if gaps exist in regulatory basis, program implementation, or both
- Facility faces enterprise risk - plan to implement a CFRP wrap (2026)
- Recent Allegation in this area
ASME Code Pressure Testing Requirements for Buried Class 3 Piping IWA-5244 Buried Components (b) For buried components without an annulus, the following examination requirements shall be met:
(1) A VT-2 visual examination shall be performed to identify evidence of leakage on ground surfaces in the vicinity of the buried components and in areas where leakage might be channeled or accumulated. The examination shall be performed after the component has been pressurized to system leakage test pressure for at least 24 hr.
Portions of buried components where a VT-2 examination is impractical (e.g.,
component is buried beneath impermeable material or encased in concrete) are exempt from VT-2 examination.
(2) A test that determines the rate of pressure loss, a test that determines the change in flow between the ends of the buried components, or a test that confirms that flow during operation is not impaired shall be performed. Personnel performing these tests need not be qualified for VT-2 visual examination.
Inspection History U1 return:
3/2010 WO completed internal cleaning, UT, and installed Epoxy liner. 4 coats of epoxy liner installed - 10 year recommended inspection following installation.
11/5/2016 video inspection of the Unit 1 Service Water to ECP return line.
U1 supply:
4/10 - 5/09/2021 Visual and Ovality Inspection during 1R29 in support of CFRP Rehabilitation Installation in 1R33 Results: MIC was noted within the pipe and the visual crawler was only able to travel 642 ft into the pipe Unable to determine pipe ovality due to degraded condition of the pipe
Inspection History U2 soft pigging:
Supply - WO-478947 - Fall 2021 Return - WO-549458 - Fall 2021 U2 supply Video crawler inspection
Microbiologically Influenced Corrosion accounts for 20% of all corrosion damages MIC mitigation relies on biocide and scrubbing (pigging)
A tubercle is a mound created on the metals surface that creates a micro-environment for the various species of bacteria to thrive together in a colony chemistry controls for MIC in the presence of heavy tuberculation significantly less effective. Colony is protected from biocide Fire main pipe that licensee used as comparable sample
Guide stem that was removed in pen and Ink modification. It fell off during work due to corrosion of 3/4 inch anchor bolt Support bars credited for holding gate open
This is a picture from the 2016 visual inspection Of Unit 1 ECP Return Line. There is no evaluation of the significance of this degradation.
Degradation to pipe
As justification for condition of the service water pipe, the licensee cited analysis on a section of fire water system that had been inspected Microscopic View of Pipe Wall Fire Main Pipe Section
Continuing Delays Original plans to replace all the buried piping Multiple delays /
deferrals of the permanent repairs No technical justification, just cost considerations
How Did They Get Here Corporate/Site confusion on program management Handoff from SWIP -
> MIC program &
chemistry program Changes made to their MIC program Changes made to their ISI program Engineering report used as procedure
Concerns with Licensees Monitoring Program Last thickness measurement inspection was 2010. 67 locations were close to minimum wall thickness allowance.
Subsequent inspections have been visual and partial.
License Renewal Aging Management Programs vague and limited (pre-GALL for Unit 1; GALL, Revision 0 for Unit 2
https://youtu.be/KZIP7JKw3Zg PIG: Pipeline Inspection Gauge or Gadget Crawler used for inspection in 2021
Enforcement Challenges With ANO License Conditions License condition specifies completing inspection activities prior to date of entering PEO Concerned about a challenge related to the date being limiting rather than the requirement Broader agency concern with enforcement in PEO
Code Case 752 Risk-Informed Categorization and Treatment for Repair/Replacement Activities in Class 2 and 3 SystemsSection XI, Division 1 Licensees application of CC N-752 Use approved through relief request Application to ultimate heat sink through engineering change, results in low safety significance classification for UHS suction piping and commercial procurement of new piping, etc.
Licensee estimates cost savings for pipe materials of 60 percent
Code Case 752 Concerns IWA 1420: LSS Items LSS items are exempt from the requirements of IWA-1320, IWA-1400(g), IWA-1400(k), IWA-1400(o), IWA-4000, IWA-6211(d), IWA-6211(e), IWA-6211(f), IWA-6212, IWA-6220, and IWA-6350.
In lieu of these requirements, the Owner shall define (d) Items used for repair/replacement activities shall meet the Owners Requirements or revised Owners Requirements as permitted by the licensing basis.
Past and Present Proposals Epoxy Coat interior of pipe Excavate and replace with Section III Code pipe Carbon Fiber Reenforce Polymer Wrap entire length of pipe Install noncoded pipe under Code Case 752 for entire length, abandon and backfill old pipe Install noncoded pipe under Code Case 752 for portions of piping and use Carbon Fiber Reenforce Polymer Wrap at the ends of each pipe. Backfill abandon sections.
Latest Proposal Trend of IP71003 violations in past 20 years ANO 1 4/11/2022 NCV License Condition 2.c(3) IP71003 Phase 4 ANO 1 3/13/2014 NCV 10 CFR 50 App B Criterion V IP71003 Phase 2 Dresden 11/18/2009 NCV 10 CFR 50 App B Criterion V IP71003 Phase 1 & 2 Dresden 11/18/2009 FIN n/a IP71003 Phase 1 & 2 10 CFR 50 App B Criterion Dresden 11/18/2009 NCV III IP71003 Phase 1 & 2 Dresden 11/18/2009 FIN n/a IP71003 Phase 1 & 2 LaSalle 3/5/2021 FIN n/a IP71003 Phase 1 LaSalle 3/5/2021 NCV 10 CFR 50 App B Criterion V IP71003 Phase 1 LaSalle 3/5/2021 NCV 10 CFR 50 App B Criterion V IP71003 Phase 1 Millstone 2 12/17/2021 NCV License Condition 2.c(11) IP71003 Phase 4 Monticello 3/4/2010 NCV 10 CFR 50 App B Criterion V IP71003 Phase 1 Turkey Point 3 & 10 CFR 50 App B Criterion Resident quarterly 4 3/31/2019 NCV XVII report Turkey Point 3 & Resident quarterly 4 3/31/2019 NCV 10 CFR 50 App B Criterion V report
Proposed Enforcement Action
- 10 CFR 50 Appendix B Criterion III for not performing thickness monitoring as described in USAR SWIP program
- Criterion III, UFSAR Supplement, MIC monitoring program (EN-DC-340) , monitoring points not established for buried portions of piping.
Going Forward Issue June IP 71003 Phase 4 inspection report with enforcement action Fall 2022 ISI Unit 1 Spring 2023 ISI Unit 2 Licensee is developing through an Engineering Change to help OPS interpret wall thinning results vs. operability, etc. - note that both the fall and spring inspections will be informed by the play book NRC (region and HQ) need to closely monitor licensees preparations for corrective action, including use of CC 752 Trenching new piping run through PA (25 feet deep, 15 feet wide, about 1800 linear feet)
Application of CFRP to ends of piping, dissimilar metal connections between existing piping and new stainless piping
Questions?