05000266/LER-2020-001, Re Reactor Coolant System Pressure Boundary Leak on Steam Generator Bowl Drain Line Results in Operation Prohibited by Technical Specifications
| ML20330A283 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 11/25/2020 |
| From: | Strope M Point Beach |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NRC 2020-0038 LER 2020-001-00 | |
| Download: ML20330A283 (3) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(1) 10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(viii)(B) |
| 2662020001R00 - NRC Website | |
text
November 25, 2020 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Point Beach Nuclear Plant, Unit 1 Docket 50-266 Renewed License Nos. DPR-24 Licensee Event Report 266/2020-001-00 POINT BEACH NRG 2020-0038 10 CFR 50.73 Enclosed is Licensee Event Report (LER) 266/2020-001-00 for Point Beach Nuclear Plant, Unit 1. NextEra Energy Point Beach, LLC is providing this LER regarding a Reactor Coolant System Pressure Boundary Leak on the Steam Generator Channe[head Drain Line that resulted in an operation prohibited by Technical Specifications.
This letter contains no new regulatory ~ommitments.
If you have any questions please contact Mr. EriC Schultz, Licensing Manager, at 920-755-7854.
Sincerely,
~~op M lchael Strope C lra1ffJ20 jfl)
Site Vice President NextEra Energy Point Beach, LLC Enclosure cc:
Administrator, Region 111 1 USNRC Project Manager, Point Beach Nuclear Plant, USNRC Resident Inspector, Point Beach Nuclear Plant, USNRC PSCW NextEra Energy Point Beach, LLC 6610 Nuclear Road, Two Rivers, Wl 54241
NRG FORM 366 (06-2020)
U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 08131/2023 vP'"nt.,11, l~*
1
"{,lt LICENSEE EVENT REPORT (LER) a ~ti( ~
(See Page 3 for required number of digits/characters for each block)
\\~V~I (See NUREG-1022, R.3 for Instruction and guidance for complelfng U1ls
- fl tt f olTll httos:llvvwvl.nrc.gov/readlng-ITllidoc-collecUons/nureos/staff/sr1022fr3[)
- 1. Facility Name Point Beach Nuclear Plant Unit 1
- 4. Title EsUrnaled
- 2. Docket Number 05000266 3.Page 1 OF2 Reactor Coolant System Pressure Boundary Leak on Steam Generator Bowl Drain Line results in operation prohibited by Technical Specifications
- 5. Event Date
- 6. LER Number Year Month Pay Year sequential Rev Number No.
10 3
2020 2020 001 00
- 9. Operating Mode 3
- 7. Report Pate Month Day 11 25 Facility Name Year NA 2020 Facility Name NA
- 10. Power Level 0.0%
-~-........ --.. -............
- 8. Other Facilities Involved Docket Number 05000NA Docket Number 05000NA uiremen(S of 1 O CFR Check all that a f D 50.73(a)(2)(iv)(A)
D 20.2201 (b)
D 50.46(a)(3)(1i) 0 50.73(a)(2)(v)(A)
D 20.2201 (d) 0 50.69(g)
D 50.73(a)(2)(v)(B)
D 73.7t(a)(4)
O 20.2203(a)(1) 0 50.73(a)(2)(i)(A)
D 50.73(a)(2)(v)(C)
D 73.7t(a)(5)
O 20.2203(a)(2)(i)
[8J 50.73(a)(2)(1)(B) 0 50.73(a)(2)(v)(D)
D 73.77(a)(1)(i)
D 20.22os(a)(2)(il)
D 50.73(a)(2)(1)(G)
D 50.73(a)(2)(vil)
D 73.77(a)(2)(i)
D 20.2203(a)(2)(iii)
[8J 50.73(a)(2)(ii)(A)
D 50.73(a)(2)(viii)(A)
D 73. 77(a)(2)(ii)
D 20.2203(a)(2)(1v)
D 50.73(a)(2)(il)(B) 0 50.73(a)(2)(viii)(B) 0 20.2203(a){2)(v)
D so.73(a)(2)(ill) 0 50.73(a)(2)(1x)(A)
D Other (Specify here1 in Abstract1 or In NRC 366A).
- 12. Licensee Contact for this LER 1-----~~~
.. ~--..... __,,,... -~~------------------
licensee Contact hone Numbar (Include Area Cod(!)
ho mas P. Schnerder ~ Senior Licensin En ineer 1920~ 755~ 7797 I'----------------~~.____--~~*--*~-----------"------~-~-~-__
in-..th_is_R_eport~--~------,-----------1
Cause
System Component Manufacturer Reportable To IRIS Ca us a System Component Manufacturer Reportable To IRIS NA NA NA NA NA.
NA NA NA NA NA
- ~~--
- 14. Supplemental Report Expected Montfl Pay Year lZ1 No D Yes (If yes, complete 15. Expected Submission Dale)
- 15. Expected Submission Date NA NA NA
Abstract
On October 3, 2020, Point Beach Unit 1 was shut down for refueling outage U1 R39. At 0913 hours0.0106 days <br />0.254 hours <br />0.00151 weeks <br />3.473965e-4 months <br /> while performing inspections during the MODE 3 descending walkdown 1 a through-weld leak was identified on the steam generator (SG) 1 B channelhead drain line at the drain isolation valve weld.
The cause of the condition was high cycle fatigue that initiated from a small weld defect at the root of the socket fillet weld.
Corrective actions included the removal of the weld defect and the drain valve and Installing a cap on the SG channel head drain line 1 B.
This event is reportab[e in accordance with 10 CFR 50. 73(a)(2)(ii)(A) and 1 O CFR 50. 73(a)(2)(i)(B).
NRC PORM 366A (08-2020)
U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 SXPIRES: 08/31/2023 EsUmaled
- 3. LER NUMBER Point Beach Nuclear Plant Unit 1 05000266 Description of the Event:
YEAR 2020 SEQUENTIAL NUMBER 001 REV NO.
0 On October 3, 2020 1 Point Beach Unit 1 was shut down for refueling outage U1 R39. At 0913 hours0.0106 days <br />0.254 hours <br />0.00151 weeks <br />3.473965e-4 months <br /> while performing Inspections during the MODE 3 descending walkdown, a through~weld leak was identified on the steam generator (SG) 1 B channelhead drain line [AB] at the drain isolation valve, 1RC~00526B weld.
Operations entered Technical Specification (TS) Limiting Condition for Operation (LCO) 3.4.13, 11RCS Operational LEAKAGE,1 1 Condition B, "Pressure boundary LEAKAGE exists." Condition B requires the unit be in Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Mode 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. On October 3, 2020 at 1713 Unit 1 exited the Mode of Applicability for LCO 3.4.13.
This event is reportable in accordance with 10 CFR 50.73(a)(2)(H)(A) and 10 CFR 50.73(a}(2}(i)(B). This LER is being submitted in follow-up to ENS 54930 made on October 3, 2020.
Analysis of the Event
The drain lines had been replaced on both Unit 1 SGs in the 2017 refueling outage (U1R37). This change was based on Industry experience, to eliminate a concern with Alloy 600 steel primary water stress corrosion cracking identified at other utilities. On February 20, 2020 a potential primary leak was identified during Unit 1 operator rounds when a change in the Containment Air Particulate Monitor trend was noted. Containment Inspections were conducted but the amount of leakage
'Was very small, and no definitive source could be identified. lt has been determined that the !eakage experienced during the cycle was a Pressure Boundary leak upstream of 1 RC"526B, HX-1 B SG Channelhead Drain valve1 which was not accessible during the at-power walkdowns.
Cause of the Event
The cause of the event was high cycle fatigue cracking that initiated from a small weld defect at the root of the socket fillet weld.
Safety Significance
The event was determined to be of very low safety significance. The flaw location was on small bore piping. The Flnal Safety Analysis Report (FSAR) describes a small break loss of coolant accident (SBLOCA) 1 which is a break of the reactor coolant pressure boundary with a total cross-sectional area less than 1.0 square foot. The SG bowl drain line Jeal<
was downstream of a drain coupling with an orifice not exceeding 0.37 4 inches and is bounded by the evaluations d'1scussed in the FSAR. There was no loss of any safety systems, structures or components needed to shut down the reactor, maintain safe shutdown conditions. remove residual heat control the release of radioactive material or miUgate the consequences of an accident. Therefore. there would have been no safety consequences during a design basis event1 and no impact on the health and safety of the public as a result of this condition.
Similar Events
There have not been similar events of this degraded condition In the past three years from a similar cause.
Component Failure Data
None NRG FORM 3668 (08-2020)