05000336/LER-2015-003, Regarding Valid Actuation of the Reactor Protection System

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Regarding Valid Actuation of the Reactor Protection System
ML16020A068
Person / Time
Site: Millstone Dominion icon.png
Issue date: 01/07/2016
From: Daugherty J
Dominion Nuclear Connecticut
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
16-002 LER 15-003-00
Download: ML16020A068 (8)


LER-2015-003, Regarding Valid Actuation of the Reactor Protection System
Event date:
Report date:
Reporting criterion: 10 CFR 50.73(a)(2)(iv)(A), System Actuation

10 CFR 50.73(a)(2)(i)

10 CFR 50.73(a)(2)(vii), Common Cause Inoperability

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)

10 CFR 50.73(a)(2)(iii)

10 CFR 50.73(a)(2)(ix)(A)

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)(i)(A), Completion of TS Shutdown

10 CFR 50.73(a)(2)(v), Loss of Safety Function

10 CFR 50.73(a)(2)(iv)(B), System Actuation
LER closed by
IR 05000245/2016003 (4 November 2016)
3362015003R00 - NRC Website

text

~Domlnion Dominion Nuclear Connecticut, Inc.

Rope Ferry Rd., Waterford, CT 06385 Mailing Address: P.O. Box 128 Waterford, CT 06385 dornI.com JAN 0 7 2016 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Serial No.

MPS Lic/LES Docket No.

License No.16-002 R0 50-336 DPR-65 DOMINION NUCLEAR CONNECTICUT! INC.

MILLSTONE POWER STATION UNIT 2 LICENSEE EVENT REPORT 201 5-003-00 VALID ACTUATION OF THE REACTOR PROTECTION SYSTEM This letter forwards Licensee Event Report (LER) 2015-003-00 documenting an event at Millstone Power Station Unit 2 on November 8, 2015. This LER is being submitted pursuant to 10 CFR 50.73(a)(2)(iv)(A).

If you have any questions or require additional information, please contact Mr. Thomas G.

Cleary at (860) 444-4377.

Sincerely, Joh R. Daug erty Sit( Vice President - Millstone Attachments: I Commitments made in this letter: None

Serial No.16-002 Docket No. 50-336 Licensee Event Report 2015-003-00 Page 2 of 2 cc:

U.S. Nuclear Regulatory Commission Region I 2100 Renaissance Blvd, Suite 100 King of Prussia, PA 19406-2713 R. V. Guzman NRC Project Manager Millstone Units 2 and 3 U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 0-2 11555 Rockville Pike Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station

Serial No.16-002 Docket No. 50-336 Licensee Event Report 201 5-003-00 bc page 2 of 2 Verification of Accuracy Basis:

1.

ROE 3015891, Unit 2 'C' RCP Oil Leak Causes Plant Shutdown

2.

CR1017568, P40C, 'C' RCP Oil Leaking in the Lower Oil Reservoir.

Action Plan: None Commitments made in this letter: None Required Changes to the UFSAR or QA Topical Report: None

Serial No.16-002 Docket No. 50-336 Licensee Event Report 2015-003-00 ATTACHMENT-LICENSEE EVENT REPORT 201 5-003-00 VALID ACTUATION OF THE REACTOR PROTECTION SYSTEM MILLSTONE POWER STATION UNIT 2 DOMINION NUCLEAR CONNECTICUT, INC.

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 0113112017 (02-014).,-'e'`='%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 />.

  • "*.*f"Reported lessons learned ame incorporated into the licensing process and ted back to industry.
  • .* 410,*,*Send comments regarding burden estimate to the FOIA, Privacy and Intormation Collections

-... LICENSEE EVENT REPORT (LER)

Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by itmte-mail to Intocellects.Resource@nrc.gov, and to the Desk Officer, Office ot Information and (See Page 2 for required number of Regulatory Affairs, NEOB-10202, (3150-0104), Office ot Management and Budget, Washington, DC digis/carater foreac blck)20503.

It a means used to impose an intormation collection does not display a currentiy valid 0MB digis/carater foreac blck)control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

3. PAGE Millstone Power Station Unit 2 05000336 1 OF 3
4. TITLE Valid Actuation of the Reactor Protection System
5. EVENT DATE
6. LER NUMBER
7. REPORT DATE
8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL REV MONTH DAY YEAR05 0

FACILITY NAME DOCKET NUMBER 11 08 2015 2015 -

003

- 001 01 07 2016 05000
9. OPERATING MODE
11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 13 20.2201(b) 13 20.2203(a)(3)(i)

LI 50.73(a)(2)(i)(C) 13 50.73(a)(2)(vii) 13-20.2201(d) 13 20.2203(a)(3)(ii) 13 50.73(a)(2)(ii)(A) 13 50.73(a)(2)(viii)(A)

I[]

20.2203(a)(1) 13 20.2203(a)(4) 13 50.73(a)(2)(ii)(B) 13 50.73(a)(2)(vili)(B) 1 20.2203(a)(2)(i) 13 50.36(c)(1 )(i)(A) 13 50.73(a)(2)(iii) 13 50.73(a)(2)(ix)(A)

10. POWER LEVEL 13 20.2203(a)(2)(ii) 13 50.36(c)(1)(ii)(A)

[] 50.73(a)(2)(iv)(A) 13 50.73(a)(2)(x) 13 20.2203(a)(2)(iii) 13 50.36(c)(2) 13 50.73(a)(2)(v)(A) 13 73.71(a)(4)

LI 20.2203(a)(2)(iv)

LI 50.46(a)(3)(ii) 13 50.73(a)(2)(v)(B) 13 73.71 (a)(5) 19.0 13 20.2203(a)(2)(v) 13 50.73(a)(2)(i)(A) 13 50.73(a)(2)(v)(C) 13 OTHER

[]2.20(a()(i I

I5.3a)2()g

[]

5.3a()v()SpecifyN~

Frin Abstract36 below or in m12.

LICENSEE CONTACT FOR THIS LER LICENSEE CONTACT TELEPHONE NUMBER (Include Area Code)

Thomas Cleary, Manager Nuclear Station Licensing (860) 444-4377MANU-REPORTABLE CAS YTM CMOET MANU-REPORTABLE

CAUSE

SYSTEM COMPONENT FACTURER TO EPIX CUS SYFACTURER TO EPIX

14. SUPPLEMENTAL REPORT EXPECTED
15. EXPECTED MONTH DAY YEAR SUBMISSION 13 YES (If yes, complete 15. EXPECTED SUBMISSION DATE)

[] NO DATE ABSTRACT (Limit to 1400sapaces, iLe., approximately 15 single-spaced typewritten lines)

On November 8, 2015 during reactor start-up from refueling outage 2R23 with the reactor in mode I at approximately 57.5 percent power the operators received indication of an oil leak on the 'C' reactor coolant pump (RCP) motor lower oil reservoir. The operators monitored the 'C' RCP oil level and bearing temperatures. Upon noting the RCP oil level dropping at a rate of approximately 1.7percent per hour and the lower RCP guide bearing temperature rising, the operators entered abnormal operating procedure (AOP) 2575, Rapid Downpower, and commenced a rapid down-power. The operators manually tripped the reactor at approximately I19percent power in accordance with AOP 2575 and entered emergency operating procedures. The reactor trip was uncomplicated. All safety systems operated as designed.

The cause of the valid actuation of the reactor protection system (RPS) was the operators manually tripping the reactor via the manual reactor trip push button switches. The AOP was entered due to an oil leak from the tubing to the level transmitter on the 'C' RCP motor lower oil reservoir. The tubing failure mechanism was determined to be high cyclic fatigue. Repairs were completed, the unit was restarted, and returned to service. Additional corrective actions are being taken in accordance with the station's corrective action program.

This event is being reported pursuant to 10 CFR 50.73(a)(2)(iv)(A), as any event or condition that resulted in manual or automatic actuation of any of the systems (RPS) listed in paragraph 10 CFR 50.73 (a)(2)(iv)(B).

NRC FORM 386 (02-2014)

1. EVENT DESCRIPTION

On November 8, 2015 during Millstone Power Station Unit 2 (MPS2) reactor start-up from refueling outage 2R23 with the reactor in mode I at approximately 57.5 % power, the operators received indication of an oil leak on the 'C' reactor coolant pump (RCP) motor lower oil reservoir.

The operators monitored the 'C' RCP oil level and bearing temperatures. Upon noting the RCP oil level dropping at a rate of approximately 1.7% per hour and the lower RCP guide bearing temperature rising, the operators entered abnormal operating procedure (AOP) 2575, Rapid Downpower, and commenced a rapid down-power to return MPS2 to mode 3. The operators manually tripped the reactor at approximately 19% power in accordance with AOP 2575 and entered emergency operating procedures. The reactor trip was uncomplicated. All safety systems operated as designed.

The operators manually tripped the reactor, Dominion reported this event pursuant to 10 CFR 50.72(b)(2)(iv)(B) as any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical except when the actuation results from and is part of a pre-planned sequence during testing or reactor operation. (NRC Event Number: 51521).

The reactor trip was in response to degrading plant equipment, not preplanned, and the operator actions were directed by an AOP. Dominion is reporting this event pursuant to 10 CFR 50.73(a)(2)(iv)(A), as any event or condition that resulted in manual or automatic actuation of any of the systems (RPS) listed in paragraph 10 CFR 50.73 (a)(2)(iv)(B).

BACKGROUND:

The reactor trip pushbutton switches on the control panel causes interruption of the AC power to the control element drive mechanism (CEDM) power supplies. De-energizing the CEDM coils allows the shutdown and regulating Control Element Assemblies (CEAs) to drop into the core by gravity.

2. CAUSE

The cause of the valid actuation of the RPS was the operators manually tripping the reactor via the manual reactor trip push button. The AOP was entered due to an oil leak from the tubing to the level transmitter on the 'C' RCP motor lower oil reservoir. The tubing failure mechanism was determined to be high cyclic fatigue.

3. ASSESSMENT OF SAFETY CONSEQUENCES

The shutdown of MPS2 was conducted in accordance with plant procedure AOP 2575 and proceeded in an orderly controlled manner. As directed in the procedure, the reactor was manually tripped. The reactor trip was uncomplicated. All safety equipment operated as designed and as expected.

4. CORRECTIVE ACTION

Repairs were completed, the unit was restarted, and returned to service. Additional corrective actions are being taken in accordance with the station's corrective action program.

5. PREVIOUS OCCURRENCES

MPS2, & MPS3 LER 2014-006-00, Millstone Power Station Dual Unit Reactor Trip on Loss of Offsite Power MPS2, LER 2013-004-00, Reactor Trip While Backwashing 'D' Waterbox MPS3 LER 2013-007-00, Reactor Trip on Low-Low Steam Generator Level

6. Energy Industry Identification System (EllS) codes:

Reactor Coolant System - AB Control Rod Drive System - AA Pump-P Motor - MO

  • Transmitter, indicating level - LIT
  • Tubing -TBG

4. CORRECTIVE ACTION

Repairs were completed, the unit was restarted, and returned to service. Additional corrective actions are being taken in accordance with the station's corrective action program.

5. PREVIOUS OCCURRENCES

MPS2, & MPS3 LER 20 14-006-00, Millstone Power Station Dual Unit Reactor Trip on Loss of Offsite Power MPS2, LER 2013-004-00, Reactor Trip While Backwashing 'D' Waterbox MPS3 LER 2013-007-00, Reactor Trip on Low-Low Steam Generator Level

6. Energy Industry Identification System (EllS) codes:

Reactor Coolant System -AB Control Rod Drive System - AA Pump-P Motor - MO Transmitter, indicating level -

LIT

.T,,bing-_TBG

1. EVENT DESCRIPTION

On November 8, 2015 during Millstone Power Station Unit 2 (MPS2) reactor start-up from refueling outage 2R23 with the reactor in mode I at approximately 57.5 % power, the operators received indication of an oil leak on the 'C' reactor coolant pump (RCP) motor lower oil reservoir.

The operators monitored the 'C' RCP oil level and bearing temperatures. Upon noting the RCP oil level dropping at a rate of approximately 1.7% per hour and the lower RCP guide bearing temperature rising, the operators entered abnormal operating procedure (AOP) 2575, Rapid Downpower, and commenced a rapid down-power to return MPS2 to mode 3. The operators manually tripped the reactor at approximately 19% power in accordance with AOP 2575 and entered emergency operating procedures. The reactor trip was uncomplicated. All safety systems operated as designed.

The operators manually tripped the reactor, Dominion reported this event pursuant to 10 CFR 50.72(b)(2)(iv)(B) as any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical except when the actuation results from and is part of a pre-planned sequence during testing or reactor operation. (NRC Event Number: 51521).

The reactor trip was in response to degrading plant equipment, not preplanned, and the operator actions were directed by an AOP. Dominion is reporting this event pursuant to 10 CFR 50.73(a)(2)(iv)(A), as any event or condition that resulted in manual or automatic actuation of any of the systems (RPS) listed in paragraph 10 CFR 50.73 (a)(2)(iv)(B).

BACKGROUND:

The reactor trip pushbutton switches on the control panel causes interruption of the AC power to the control element drive mechanism (CEDM) power supplies. De-energizing the CEDM coils allows the shutdown and regulating Control Element Assemblies (CEAs) to drop into the core by gravity.

2. CAUSE

The cause of the valid actuation of the RPS was the operators manually tripping the reactor via the manual reactor trip push button. The AOP was entered due to an oil leak from the tubing to the level transmitter on the 'C' RCP motor lower oil reservoir. The tubing failure mechanism was determined to be high cyclic fatigue.

3. ASSESSMENT OF SAFETY CONSEQUENCES

The shutdown of MPS2 was conducted in accordance with plant procedure AOP 2575 and proceeded in an orderly controlled manner. As directed in the procedure, the reactor was manually tripped. The reactor trip was uncomplicated. All safety equipment operated as designed and as expected.

4. CORRECTIVE ACTION

Repairs were completed, the unit was restarted, and returned to service. Additional corrective actions are being taken in accordance with the station's corrective action program.

5. PREVIOUS OCCURRENCES

MPS2, & MPS3 LER 2014-006-00, Millstone Power Station Dual Unit Reactor Trip on Loss of Offsite Power MPS2, LER 2013-004-00, Reactor Trip While Backwashing 'D' Waterbox MPS3 LER 2013-007-00, Reactor Trip on Low-Low Steam Generator Level

6. Energy Industry Identification System (EllS) codes:

Reactor Coolant System - AB Control Rod Drive System - AA Pump-P Motor - MO

  • Transmitter, indicating level - LIT
  • Tubing -TBG

4. CORRECTIVE ACTION

Repairs were completed, the unit was restarted, and returned to service. Additional corrective actions are being taken in accordance with the station's corrective action program.

5. PREVIOUS OCCURRENCES

MPS2, & MPS3 LER 20 14-006-00, Millstone Power Station Dual Unit Reactor Trip on Loss of Offsite Power MPS2, LER 2013-004-00, Reactor Trip While Backwashing 'D' Waterbox MPS3 LER 2013-007-00, Reactor Trip on Low-Low Steam Generator Level

6. Energy Industry Identification System (EllS) codes:

Reactor Coolant System -AB Control Rod Drive System - AA Pump-P Motor - MO Transmitter, indicating level -

LIT

.T,,bing-_TBG