05000400/LER-2019-001, Turbine Control System Auto-Stop Trip Solenoid Operated Valves Response Times Impacted
| ML19168A008 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 06/17/2019 |
| From: | Hamilton T Duke Energy Progress |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RA-19-0222 LER 2019-001-00 | |
| Download: ML19168A008 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 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)(i) 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(iii) 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)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(x) |
| 4002019001R00 - NRC Website | |
text
(_ DUKE ENERGY Tanya M. Hamilton Vice President Harris Nuclear Plant 5413 Shearon Harris Road New Hill, NC 27562-9300 919.362.2502 10 CFR 50.73 June 17,2019 Serial: RA-19-0222 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Shearon Harris Nuclear Power Plant, Unit 1 Docket No. 50-400/Renewed License No. NPF-63 Subject: Licensee Event Report 2019-001-00 Ladies and Gentlemen:
Duke Energy Progress, LLC, submits the enclosed Licensee Event Report (LER) 2019-001-00 in accordance with 10 CFR 50.73 for Shearon Harris Nuclear Power Plant, Unit 1 (HNP). This report describes an event in which both channels of the HNP Turbine Control System Auto-Stop Trip Quadvoter pilot-operated solenoid valves were unable to function as expected. The root cause evaluation is ongoing and this LER will be supplemented following completion of the evaluation. This event had no significance with respect to the health and safety of the public.
There are no regulatory commitments contained within this report.
Please refer any questions regarding this submittal to Sarah McDaniel at (919) 362-2002.
Sincerely, Tanya M. Hamilton Enclosure: Licensee Event Report 2019-001-00 cc:
J. Zeiler, NRC Senior Resident Inspector, HNP M. Barillas, NRC Project Manager, HNP NRC Regional Administrator, Region II
Tanya M. Hamilton Vice President Harris Nuclear Plant 5413 Shearon Harris Road New Hill, NC 27562-9300 919.362.2502 10 CFR 50.73 June, 2019 Serial: RA-19-0222 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Shearon Harris Nuclear Power Plant, Unit 1 Docket No. 50-400/Renewed License No. NPF-63 Subject: Licensee Event Report 2019-001-00 Ladies and Gentlemen:
Duke Energy Progress, LLC, submits the enclosed Licensee Event Report (LER) 2019-001-00 in accordance with 10 CFR 50.73 for Shearon Harris Nuclear Power Plant, Unit 1 (HNP). This report describes an event in which both channels of the HNP Turbine Control System Auto-Stop Trip Quadvoter pilot-operated solenoid valves were unable to function as expected. The root cause evaluation is ongoing and this LER will be supplemented following completion of the evaluation. This event had no significance with respect to the health and safety of the public.
There are no regulatory commitments contained within this report.
Please refer any questions regarding this submittal to Sarah McDaniel at (919) 362-2002.
Sincerely, Tanya M. Hamilton Enclosure: Licensee Event Report 2019-001-00 cc:
J. Zeiler, NRC Senior Resident Inspector, HNP M. Barillas, NRC Project Manager, HNP NRC Regional Administrator, Region II
NRC FORM 366 (04-2018)
U.S. NUCLEAR REGULATORY COMMISSION 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
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
NRC FORM 366 (04-2018) 05000
- 3. Page 1
OF
- 4. Title
- 5. Event Date Month Day Year
- 6. LER Number Year Sequential Number Rev No.
- 7. Report Date Month Day Year
- 8. Other Facilities Involved Facility Name Docket Number 05000 Facility Name Docket Number 05000
- 9. Operating Mode
- 10. Power Level
- 11. This Report is Submitted Pursuant to the Requirements of 10 CFR §: (Check all that apply) 20.2201(b) 20.2201(d) 20.2203(a)(1) 20.2203(a)(2)(i) 20.2203(a)(2)(ii) 20.2203(a)(2)(iii) 20.2203(a)(2)(iv) 20.2203(a)(2)(v) 20.2203(a)(2)(vi) 20.2203(a)(3)(i) 20.2203(a)(3)(ii) 20.2203(a)(4) 50.36(c)(1)(i)(A) 50.36(c)(1)(ii)(A) 50.36(c)(2) 50.46(a)(3)(ii) 50.73(a)(2)(i)(A) 50.73(a)(2)(i)(B) 50.73(a)(2)(i)(C) 50.73(a)(2)(ii)(A) 50.73(a)(2)(ii)(B) 50.73(a)(2)(iii) 50.73(a)(2)(iv)(A) 50.73(a)(2)(v)(A) 50.73(a)(2)(v)(B) 50.73(a)(2)(v)(C) 50.73(a)(2)(v)(D) 50.73(a)(2)(vii) 50.73(a)(2)(viii)(A) 50.73(a)(2)(viii)(B) 50.73(a)(2)(ix)(A) 50.73(a)(2)(x) 73.71(a)(4) 73.71(a)(5) 73.77(a)(1) 73.77(a)(2)(i) 73.77(a)(2)(ii)
Other (Specify in Abstract below or in Page of 05000-
- 3. LER NUMBER YEAR SEQUENTIAL NUMBER REV NO.
reason, the turbine remained capable of being tripped on a delayed demand signal.
C. Causal Factors The root cause evaluation is ongoing. Once the evaluation is complete, a supplemental report will be issued containing the root cause for this event.
D. Corrective Actions
Immediate action was taken to exercise the AST valves and restore functionality. The frequency for performance of AST valve testing was increased to twice per week and cycling of the solenoid valves was increased to five strokes for each test. Operations guidance was issued to maintain turbine housing doors open for additional cooling as allowed by procedure. Pilot valve springs were replaced with a stronger spring in all AST valves to increase margin. Additional planned actions will be determined following completion of the ongoing root cause evaluation.
E. Safety Analysis
The TCS utilizes two on-line maintainable trip block assemblies (AST/OPC Quadvoters) that hydraulically trip the turbine on overspeed conditions or upon receipt of a turbine trip signal. The AST Quadvoter SOVs would not have been able to function upon receiving a signal; however, the OPC Quadvoter SOVs were functional, and would have tripped the turbine on the subsequent delayed demand if a trip signal had been received. The ability of the TCS to send or receive trip signals was not impacted, only the physical opening of the AST Quadvoter SOVs once de-energized.
An assessment of the HNP Final Safety Analysis Report (FSAR) Chapter 6 and Chapter 15 transient accident analyses has been performed to determine if a delayed turbine trip response time would have an adverse effect on the analyzed transient responses. The conclusion of this assessment is that the FSAR Chapter 6 and 15 analyses are not adversely affected by the lack of turbine isolation through throttle valve closure.
TCS maintained the ability to trip the turbine on the subsequent delayed command to the OPC Quadvoter SOVs and there was no significant impact to the health and safety of the public. Based on this evaluation, this condition will not be counted as a safety system functional failure against Performance Indicator MS05, Safety System Functional Failure.
F. Additional Information
A similar condition occurred previously at HNP on July 3, 2018, which was described in LER 2018-003-00. The ongoing root cause evaluation will address reoccurrence as well.
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