05000400/LER-2018-003, Turbine Control System Auto-Stop Trip Solenoid Operated Valves Response Times Impacted
| ML18241A396 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 08/29/2018 |
| From: | Hamilton T Duke Energy Progress |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RA-18-0142 LER 2018-003-00 | |
| Download: ML18241A396 (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) |
| 4002018003R00 - 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 August 29, 2018 Serial: RA-18-0142 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 2018-003-00 Ladies and Gentlemen:
Duke Energy Progress, LLC, submits the enclosed Licensee Event Report 2018-003-00 in accordance with 10 CFR 50.73 for Shearon Harris Nuclear Power Plant, Unit 1 (HNP). This report details 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.
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 Jeffrey Robertson, Manager - Regulatory Affairs, at (919) 362-3137.
Sincerely, Tanya M. Hamilton Enclosure: Licensee Event Report 2018-003-00 cc:
J. Zeiler, NRC Senior Resident Inspector, HNP M. Barillas, NRC Project Manager, HNP C. Haney, 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 August 29, 2018 Serial: RA-18-0142 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 2018-003-00 Ladies and Gentlemen:
Duke Energy Progress, LLC, submits the enclosed Licensee Event Report 2018-003-00 in accordance with 10 CFR 50.73 for Shearon Harris Nuclear Power Plant, Unit 1 (HNP). This report details 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.
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 Jeffrey Robertson, Manager - Regulatory Affairs, at (919) 362-3137.
Sincerely, Tanya M. Hamilton Enclosure: Licensee Event Report 2018-003-00 cc:
J. Zeiler, NRC Senior Resident Inspector, HNP M. Barillas, NRC Project Manager, HNP C. Haney, 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.
required a turbine trip, the turbine would not have responded as expected. However, upon receipt of a turbine trip signal, the TCS generates an additional, although delayed, demand signal that would energize the OPC solenoids and close the governor valves, effectively tripping the turbine by isolating steam flow to it. For this reason, the turbine remained capable of being tripped on a delayed demand signal.
C. Causal Factors The direct cause of this event was that the periodic cycling of the AST SOVs was not performed at a periodicity which would prevent a common mode failure mechanism from rendering the turbine trip system non-functional. The valves must be periodically cycled to remove a varnish that gradually forms on internal surfaces of the valve at high temperatures. The June 29th instance was the initial on-line turbine trip test since successful power ascension testing of the newly replaced TCS, which was performed at 16 percent reactor power on May 10, 2018.
D. Corrective Actions
Immediate action was taken to exercise the AST valves and restore functionality. The frequency for performance of AST and OPC valve testing was adjusted to a weekly periodicity, consistent with vendor recommendations.
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 effectively 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 was performed to determine if the delayed turbine trip response time would have had an adverse effect on the analyzed transient responses. The conclusion of this assessment was 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 effectively 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
There have been no events related to this event at Harris within the past three years. There are no NRC commitments contained in this LER.
3 3
Shearon Harris Nuclear Power Plant, Unit 1 400 2018 003 00