05000348/LER-2016-002, Regarding Automatic Reactor Trip and Safety Injection Due to Closure of Main Steam Isolation Valve
| ML16335A450 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 11/30/2016 |
| From: | Gayheart C Southern Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NL-16-2438 LER 16-002-00 | |
| Download: ML16335A450 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 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)(i) |
| LER closed by | |
| IR 05000348/2017001 (1 May 2017) | |
| 3482016002R00 - NRC Website | |
text
~ Southern Nuclear November 30, 2016 Docket Nos.: 50-348 Cheryl A. Gayheart Vice President - Farley Farley Nuclear Plant Post Office Box 470 Ashford, AL 36312 334.814.4511 tel 334.814.4575 fax cagayhea@ southernco.com NL-16-2438 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Joseph M. Farley Nuclear Plant-Unit 1 Licensee Event Report 2016-002-00 Automatic Reactor Trip and Safetv Injection Due to Closure of Main Steam Isolation Valve Ladies and Gentlemen:
This Licensee Event Report is being submitted pursuant to the requirements of the Code of Federal Regulations, 10 CFR 50.73(a)(2)(iv)(A), for an automatic actuation of the Reactor Protection System, ECCS actuation, and an automatic start of the Auxiliary Feedwater system.
This letter contains no NRC commitments. If you have any questions regarding the submittal, please contact Ms. Julie Collier at (334) 814-4639.
Sincerely, CAG/JAC Enclosure: Unit 1 Licensee Event Report 2016-002-00
U.S. Nuclear Regulatory Commission NL-16-2438 Page2 cc:
Southern Nuclear Operating Company Mr. S. E. Kuczynski, Chairman, President & CEO Mr. D. G. Bast, Executive Vice President & Chief Nuclear Officer Mr. M. D. Meier, Vice President-Regulatory Affairs Mr. D. R. Madison, Vice President-Fleet Operations Mr. B. J. Adams, Vice President-Engineering Mr. C. R. Pierce, Regulatory Affairs Director Ms. B. L. Taylor, Regulatory Affairs Manager-Farley Mr. J. E. Purcell, Operating Experience Coordinator-Farley RTYPE: CFA04.054 U. S. Nuclear Regulatory Commission Ms. C. Haney, Regional Administrator Mr. S. A. Williams, NRR Project Manager-Farley Mr. P. K. Niebaum, Senior Resident Inspector-Farley
Joseph M. Farley Nuclear Plant - Unit 1 Unit 1 Licensee Event Report 2016-002-00 Automatic Reactor Trip and Safety Injection Due to Closure of Main Steam Isolation Valve
~RC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 31~104 EXPIRES: 10131/2018 (11*2015) stimated, the NRC may not conduct or sponsor, and a person is no fe!~uired to respond to, the infonnation collection.
- 1. FACILITY NAME
~* DOCKET NUMBER
~*PAGE Joseph M. Farley Nuclear Plant, Unit 1 05000- I 348 1 OF 3
- 4. TITLE Automatic Reactor Trip and Safety Injection Due to Closure of Main Steam Isolation Valve
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED I
SEQUENTIAL I REV NO ACIUTYNAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBER MONTH DAY YEAR ACILITY NAME DOCKET NUMBER 10 1
2016 2016 002 -
00 11 30 2016
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 0 20.2201 (b) 0 20.2203(a)(3)(1) 0 50. 73(a)(2)(1i)(A) 0 50.73(a)(2)(vlli)(A) 1 0 20.2201 (d) 0 20.2203(a)(3)(11) 0 50.73(a)(2)(ii)(B) 0 50.73(a)(2)(vlli)(B) 0 20.2203(a)(1) 0 20.2203(a)(4) 0 50.73(a)(2)(ili) 0 50. 73(a)(2)(ix)(A) 0 20.2203(a)(2)(1) 0 50.36(c)(1 )(i)(A) 18150.73(a)(2)(iv)(A) 0 50.73(a)(2)(x)
- 10. POWER LEVEL 0 20.2203(a)(2)(11) 0 50.36(c)(1 )(li)(A) 0 50.73(a)(2)(v)(A) 0 73.71(a)(4) 0 20.2203(a)(2)(1ii) 0 50.36(c)(2) 0 50.73(a)(2)(v)(B) 0 73.71(a)(5) 99%
0 20.2203(a)(2)(1v) 0 50.46(a)(3)(il) 0 50.73(a)(2)(v)(C) 0 73.77(a)(1) 0 20.2203(a)(2)(v) 0 50.73(a)(2)(i)(A) 0 50.73(a)(2)(v)(D) 0 73.n(a)(2)(1) 0 20.2203(a)(2)(vi) 0 50.73(a)(2)(i)(B) 0 50.73(a)(2)(vli) 0 73.n(a)(2)(1i) 0 50.73(a)(2)(i)(C) 0 OTHER Specify In Abstract below or In NRC Fonn 366A
- 12. LICENSEE CONTACT FOR THIS LER ICENSEE CONTACT ELEPHONE NUMBER (Include A111a Coda)
Julie Collier 334-814-4639 CAUSE SYSTEM COMPONENT MANU-REPORTABLE
CAUSE
SYSTEM COMPONENT MANU-REPORTABLE FACTURER TO EPIX FACTURER TOEPIX E
SB PSV A499 y
- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED MONTH DAY YEAR 0 YES (If yes, complete 15. EXPECTED SUBMISSION DATE) ~NO SUBMISSION DATE ABSTRACT (Umlt to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)
On 1 0/1/2016 at 0512 COT with Unit 1 at 99 percent power the plant experienced a turbine trip and automatic reactor trip as a result of inadvertent closure of the 1 A Steam Generator Main Steam Isolation Valve (MSIV).
This caused a rapid pressure reduction in the remaining two Steam Generators' steam lines, resulting in a Safety Injection (SI). The 1A MSIV closure was caused by failure of its test solenoid in conjunction with other air system leakage, which vented air pressure from the 1A MSIV actuator. An inadequate technical justification allowed the improper deactivation of the preventive maintenance (PM) task of the test solenoid valve in 2004. Decision making by control room personnel not to strictly adhere to an Annunciator Response Procedure was a contributing cause to the reactor trip being automatic versus manual, and led to the Sl.
Following the reactor trip and Sl the 1 A MSIV test solenoid was replaced and check valves on the 1 A MSIV steam line were tested and replaced. The technical justifications of a sample of previously extended or deleted PMs strategies will be reviewed and corrected. The PM for the Unit 1 solenoid will be reinstated.
Procedure use and adherence standards have been reinforced with Operations personnel, simulator just-in-time training was conducted for all crews, and further causal analysis is planned to investigate operations fundamental performance gaps. This event is reportable per 10 CFR 50.73(a}(2)(iv)(A) due to actuation of the reactor protection system, Emergency Core Cooling System (ECCS) injection into the Reactor Coolant System, and automatic actuation of the AFW system.
!=
A. PLANT AND SYSTEM IDENTIFICATION
Westinghouse-Pressurized Water Reactor
B. DESCRIPTION OF EVENT
- 2. DOCKET NUMBER 05000-348 YEAR
- 3. LER NUMBER SEQUENTIAL NUMBER 2016 002 On 10/1/2016 at 0512 COT with Unit 1 at 99 percent power and coasting down in power for a planned refueling outage, the Control Room received dual indication for the 1 A Steam Generator (SG) Main Steam Isolation Valve (MSIV), a closed indication for the 1 A MSIV test switch, and a Main Control Board (MCB) annunciator for main steam line isolation valve air pressure being low. Operations personnel implemented the Annunciator Response Procedure (ARP) for this annunciator and followed the first step, which was to attempt to recharge the accumulator by placing the switch for the 1 A MSIV to the 'open' position. Although the second step directed tripping the reactor if the alarm was in and dual indication was indicated, Operations instead dispatched licensed and non-licensed personnel into the plant to investigate the cause for the alarm. The normally closed test solenoid vent port was found to be releasing air. Operations initiated steps to isolate the leaking test solenoid valve; however, the leaking solenoid and check valves caused air pressure in the 1 A MSIV actuator to fall low enough to cause inadvertent 1 A MSIV closure. Actuation of the 1A MSIV turbine trip limit switch initiated a turbine trip and subsequent reactor trip.
The closure of the 1 A MSIV caused a rapid pressure reduction in the remaining two Steam Generators' steam lines and resulted in actuation of a Safety Injection (SI). The Emergency Core Cooling System (ECCS) actuated and injected into the Reactor Coolant System (RCS). Auxiliary Feedwater (AFW) auto-started. All Control rods fully inserted and all equipment actuated as designed. The unit was stabilized in Mode 3 with decay heat removed through the condenser.
The test solenoid had last been replaced in 2003. The Preventive Maintenance (PM) task for this component was improperly deactivated in 2004 due to inadequate technical justification.
Decision making by control room personnel not to strictly adhere to the ARP was a contributing cause to the reactor trip being automatic versus manual, and led to the Sl. Manual actuation of a reactor trip pripr to the closure of the 1 A MSIV would have prevented the Sl from occurring.
C. UNIT STATUS AT TIME OF EVENT Unit 1, Mode 1, 99 percent power Unit 2, Mode 1, 1 00 percent power
D. CAUSE OF EVENT
The 1 A MSIV closure was caused by failure of its test solenoid in conjunction with other air system leakage, which vented the air pressure from the 1 A MSIV actuator. An inadequate technical justification allowed the improper deactivation of the PM task of the test solenoid valve in 2004 and led to the component failure. Decision making by control room personnel not to strictly adhere to the ARP was a contributing cause to the reactor trip being automatic versus manual, and led to the Sl.
REV NO.
00
E. REPORT ABILITY ANALYSIS AND SAFETY ASSESSMENT
- 3. LER NUMBER YEAR 2016 SEQUENTIAL NUMBER 002 This event is reportable per 10 CFR 50. 73(a)(2)(iv)(A) due to actuation of the reactor protection system, actuation and injection of ECCS into the RCS, and automatic actuation of the AFW system.
The 1 A MSIV closing caused steam flow in steam line A to decrease, and steam flow increased and steam pressure decreased in steam lines 8 and C. The rate of steam pressure decrease in steam lines 8 and C resulted in the initiation of the safety injection signal. All systems responded as required, including all control rods fully inserting into the core, AFW system auto-starting to supply the Steam Generators, and decay heat removal occurring through the condenser. This system response to the event was as designed for turbine trip, reactor trip, and Sl actuation.
Because all systems responded as required and there were no actual adverse effects on the health and safety of the public, the safety significance of this event is considered very low.
F. CORRECTIVE ACTION
The 1 A MSIV test solenoid was replaced. In addition, all of the test solenoids for all Unit 1 MSIVs were replaced. The check valves on the 1 A MSIV steam line were tested and replaced. The PM for the Unit 1 solenoid will be reinstated. The technical justifications of a sample of previously extended or deleted PM strategies will be reviewed and corrected. Prior to Unit 1 entering Mode 3 all Unit 1 MSIV test solenoid isolation valves were closed to prevent a loss of air through the test portion of the lines.
The Unit 2 main steam system was walked down for similar issues, and needed test solenoid replacements will be completed by the end of the next refueling outage. In addition, the Unit 2 MSIV test solenoid isolation valves were closed to prevent a loss of air through the test portion of the lines.
Procedure use and adherence standards have been reinforced with Operations personnel, simulator just-in-time training was conducted for all crews, and further causal analysis is planned to investigate operations fundamental performance gaps.
G. ADDITIONAL INFORMATION
- 1) Failed Components: Loop A test solenoid valve for the 1 A MSIV
- 2) Previous Similar Events:
Nooe
- 3) Other system affected:
None
- 4) Commitment Information: None
- 5) Energy Industry Identification System Code:
[JC]- Reactor Protection System [BA] -Auxiliary Feedwater [SB] - Main Steam System REV NO.
00