05000382/LER-2019-005, Automatic Reactor Scram Due to Steam Generator 1 High Level Resulting from a Main Turbine Trip and Subsequent Reactor Power Cutback Due to Failed Diode Modules within the the Main Exciter
| ML19196A346 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 07/15/2019 |
| From: | Wood P Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| W3F1-2019-0046 LER 2019-005-00 | |
| Download: ML19196A346 (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) |
| 3822019005R00 - NRC Website | |
text
~Entergy.
W3F1-2019-0046 July 15, 2019 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001
Subject:
Licensee Event Report (LER) 2019-005-00 Entergy Operations, Inc.
17265 River Road Killona, LA 70057-3093 Tel (504) 464-3786 Paul Wood Manager, Regulatory Assurance 10 CFR 50.73 Automatic Reactor SCRAM due to Steam Generator #1 High Level Resulting from a Main Turbine Trip and Subsequent Reactor Power Cutback due to Failed Diode Modules within the Main Exciter Waterford Steam Electric Station, Unit 3 (Waterford 3)
NRC Docket No. 50-382 Renewed Facility Operating License No. NPF-38 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 the Regulatory Assurance Manager, Paul Wood, at (504) 464-3786.
I 1!
Respectftl I ~J~JUWJ Paul Wood PW/rd
Enclosure:
cc:
Waterford 3 Licensee Event Report 2019-005-00 NRC Region IV Regional Administrator NRC Senior Resident Inspector - Waterford Steam Electric Station, Unit 3 NRR Project Manager
ENCLOSURE W3F1-2019-0046 Entergy Operations, Inc.
Waterford 3 Licensee Event Report 2019-005-00
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/)
APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />.
Reported lessons learned are incorporated into the licensing process and fed back to industry.
Send comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S.
Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to Infocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 1. FACILITY NAME Waterford Steam Electric Station, Unit 3
- 2. DOCKET NUMBER 05000382
- 3. PAGE 1 OF 3
- 4. TITLE Automatic Reactor Scram due to Steam Generator #1 High Level Resulting from a Main Turbine Trip and Subsequent Reactor Power Cutback due to Failed Diode Modules within the Main Exciter
- 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 05 16 2019 2019 -
005
- - 00 07 15 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)(2)(ii) 50.73(a)(2)(i)(C)
OTHER Specify in Abstract below or in Steam Generator Level Deviation:
The cause of the Steam Generator Level deviation is still under investigation. The cause and corrective actions will be included as a planned update to this LER.
CORRECTIVE ACTIONS
A. Loss of Excitation:
Completed corrective actions include:
a.
The Main Exciter rectifier wheel was disassembled, cleaned, repaired including replacement of failed diode modules, and reassembled.
b.
Failed diodes were sent offsite for failure analysis.
c.
Corrected cooling water leak and door seal degradation inside Main Exciter housing.
Planned corrective actions include:
a.
Revise Main Exciter Preventive Maintenance strategy to clearly outline the scope for Major and Minor PMs of the Main Exciter based on industry best practices and vendor recommendations.
b.
Develop a Will sheet targeting the N/A of steps in accordance with fleet administrative procedure guidance including the justification expected/required per the procedure.
B. Steam Generator Level Deviation:
Completed corrective actions include:
a.
An Emergent Issue Team established during the forced outage confirmed that the Feedwater Control System performed as expected based on receiving a level deviation in both Steam Generator 1 and 2. The level deviation was not an expected plant response following a Reactor Power Cutback. Based on discussions with the replacement Steam Generator vendor, this may be an effect related to the Replacement Steam Generators Planned corrective actions include:
a.
Completing a vendor study to determine the cause of the Steam Generator Level Deviations following a Reactor Power Cutback. This study should also determine the appropriate corrective actions, with supporting documents that WF3 should implement. Once the study is completed a follow-up action to determine the appropriate corrective actions is to be initiated to track resolution of the condition adverse to quality.
SAFETY EVALUATION The actual consequences as stated in the problem statement were low. There were no other actual consequences to safety of the general public, nuclear safety, industrial safety and radiological safety for this event. The potential consequence to safety of the general public, nuclear safety, industrial safety and radiological safety of this event, if the Automatic Reactor Trip on High Steam Generator Water Level was removed, is low. High Steam Generator Water Level in Steam Generator #2 would have also generated an automatic Reactor Trip. Failing that, the Operators would have initiated a manual Reactor Trip or taken manual control to restore Steam Generator Water Level.
Steam Generator overfill is modeled in the PRA only as it relates to success of the Emergency Feedwater A/B pump, not the Main Feedwater Pumps. The overfill modeled in these PRA sequences occurs post-trip and is based on Emergency Feedwater being established for plant conditions, therefore, this PRA assessment is qualitative in nature.
PREVIOUS OCCURRENCES
CR-WF3-2017-5842: (Reported under LER 2017-002-00 and Supplement 2017-002-01.)
A reactor power cutback occurred on July 17, 2017 following a main turbine trip initiated from Isophase Bus Duct failure.
The same level deviations occurred in Steam Generators 1 and 2. However, this event did not result in Feed Water Control shifting to manual due to the subsequent reactor trip that was experienced (failure of Fast Dead Bus Transfer).