05000382/LER-2019-007, (Waterford 3), Plant Shutdown Required by Technical Specifications Due to Charging Pump Suction Line Flaw
| ML19269D869 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 09/26/2019 |
| From: | Wood P Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| W3F1-2019-0070 LER 2019-007-00 | |
| Download: ML19269D869 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(x) 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)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) |
| 3822019007R00 - NRC Website | |
text
Entergy Operations, Inc.
17265 River Road Killona, LA 70057-3093 Tel 504-464-3786 Paul Wood Manager, Regulatory Assurance 10 CFR 50.73 W3F1-2019-0070 September 26, 2019 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 The enclosed report is being sent pursuant to 10 CFR 50.73.
This letter contains no new regulatory commitments.
If you have any questions or require additional information, please contact Paul Wood, Regulatory Assurance Manager, at 504-464-3786.
Respectfully, Paul Wood PIW/jkb cc:
NRC Region IV Regional Administrator NRC Senior Resident Inspector - Waterford Steam Electric Station, Unit 3 NRR Project Manager
Subject:
Licensee Event Report (LER) 2019-007-00 Plant Shutdown Required by Technical Specifications Due to Charging Pump Suction Line Flaw Waterford Steam Electric Station, Unit 3 (Waterford 3)
NRC Docket No. 50-382 Renewed Facility Operating License No. NPF-38
Enclosure:
Waterford 3 Licensee Event Report 2019-007-00
ENCLOSURE W3F1-2019-0070 Entergy Operations, Inc.
Waterford 3 Licensee Event Report 2019-007-00
NRC FORM 366 (04-2018)
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (04-2018)
LICENSEE EVENT REPORT (LER)
(See Page 2 for required number of digits/characters for each block)
(See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc/gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
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- 1. FACILITY NAME Waterford Steam Electric Station, Unit 3
- 2. DOCKET NUMBER 05000382
- 3. PAGE 1 OF 3
- 4. TITLE Plant Shutdown Required by Technical Specifications Due to Charging Pump Suction Line Flaw
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL NUMBER REV NO.
MONTH DAY YEAR FACILITY NAME DOCKET NUMBER 07 31 2019 2019 -
007
- - 00 09 26 2019 FACILITY NAME DOCKET NUMBER
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 1 20.2201(b) 20.2203(a)(3)(i) 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A) 20.2201(d) 20.2203(a)(3)(ii) 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B) 20.2203(a)(1) 20.2203(a)(4) 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A) 20.2203(a)(2)(i) 50.36(c)(1)(i)(A) 50.73(a)(2)(iv)(A) 50.73(a)(2)(x)
- 10. POWER LEVEL 20.2203(a)(2)(ii) 50.36(c)(1)(ii)(A) 50.73(a)(2)(v)(A) 73.71(a)(4) 100 20.2203(a)(2)(iii) 50.36(c)(2) 50.73(a)(2)(v)(B) 73.71(a)(5) 20.2203(a)(2)(iv) 50.46(a)(3)(ii) 50.73(a)(2)(v)(C) 73.77(a)(1) 20.2203(a)(2)(v) 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(D) 73.77(a)(2)(i) 20.2203(a)(2)(vi) 50.73(a)(2)(i)(B) 50.73(a)(2)(vii) 73.77(a)(5)(ii) 50.73(a)(2)(i)(C)
OTHER Specify in Abstract below or in Planned Actions: Perform weld build-up or other activity to harden the CVC suction lines that are susceptible to fatigue failure. These activities are planned to be completed by the end of the next scheduled refueling outage.
SAFETY EVALUATION The actual consequences were all three Charging Pumps and the associated boration flow path were declared inoperable. This resulted in a potential loss of safety function, entry into Technical Specification 3.0.3, and a plant shutdown. There were no other actual consequences to safety of the general public, nuclear safety, industrial safety and radiological safety for this event. While the line was determined to be inoperable due to the crack size, the line did not fail and the boric acid makeup suction path to the Charging Pumps was not lost.
The potential consequence to safety of the general public, nuclear safety, industrial safety and radiological safety of this event if the line would have failed is a loss of the suction path to the Charging Pumps.
The risk if no action is taken is low. The basis for this determination is as follows:
Probabilistic Risk Analysis (PRA) does not specifically model the CVC drain line in the station model but the impact would be to the boric acid inventory through the charging system. The loss of the boric acid makeup tank capacity would result in a change in the core damage frequency (CDF) of 1.57E-7/year. This change in core damage frequency falls within the Regulatory Guide 1.174 acceptance guidelines for very small changes to CDF.
The immediate/interim/mitigating actions to reduce the frequency or consequence (pending implementation of final actions) are: 1) The line was replaced; and, 2) weld buildup was performed to increase the connection strength and prevent future fatigue failures.
PREVIOUS OCCURRENCES
In 2007 and 2013, Entergy identified a cracked weld in an instrument line connected to the outlet of the Chemical Volume Control System Volume Control tanks. The leak was caused by high-cycle low-stress fatigue which initiated at the root of the weld (inside diameter of the pipe) at an area of Lack of Fusion. Cantilever design resulted in a stress riser and fatigue failure. The source of cyclic stress is believed to be flow induced vibration due to Chemical and Volume Control system operation. A support was added to reduce the vibration level at the failure location.
In 2000, Entergy identified a cracked socket weld on a Chemical Volume Control piping connection that is part of the common header for all three charging pumps. The leak was determined to be caused by high-cycle low-stress fatigue due to vibrations induced by the nearby charging pump pulsations.
Note: Energy Industry Identification System (EIIS) codes and component codes are identified in the text as [XX].