05000317/LER-2014-006, Regarding Reactor Trip Due to Reactor Protective System Matrix Relay Testing Pushbutton Failure

Regarding Reactor Trip Due to Reactor Protective System Matrix Relay Testing Pushbutton Failure

ML14182A662
Person / Time
Site:	Calvert Cliffs  (DPR-053)
Issue date:	06/26/2014
From:	Flaherty M Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
LER 14-006-00
Download: ML14182A662 (5)

LER-2014-006, Regarding Reactor Trip Due to Reactor Protective System Matrix Relay Testing Pushbutton Failure

Event date:
Report date:
Reporting criterion:	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)(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)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
3172014006R00 - NRC Website

text

-O Mark Flaherty ExeLon Generation Plant Manager Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, MD 20657 410 495 5205 Office 443-534-5475 Mobile www.exeloncorp.com mark.flaherty@exeloncorp.com 10 CFR 50.73 June 26, 2014 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Calvert Cliffs Nuclear Power Plant, Unit No. 1 Renewed Facility Operating License No. DPR-53 NRC Docket No. 50-317

Subject:

Licensee Event Report 2014-006, Revision 00 Reactor Trip Due to Reactor Protective System Matrix Relay Testing Pushbutton Failure The attached report is being sent to you as required by 10 CFR 50.73.

There are no regulatory commitments contained in this correspondence.

Should you have questions regarding this report, please contact Mr. Douglas E. Lauver at (410) 495-5219.

Respectfully, Mark D. Flaherty Plant Manager MDF/SMR/bjd

Attachment:

As stated cc:

NRC Project Manager, Calvert Cliffs NRC Resident Inspector, Calvert Cliffs NRC Regional Administrator, Region I S. Gray, MD-DNR

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 01/31/2017 (02-2014)

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 FOIA, Privacy and Information Collections Branch (T-5 F53),

LICENSEE EVENT REPORT (LER)

U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail to lnfocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office (See Page 2 for required number of of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB digits/characters for each block) control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

3. PAGE Calvert Cliffs Nuclear Power Plant, Unit 1 05000 317 1 OF 4

4. TITLE Reactor Trip Due to Reactor Protective System Matrix Relay Testing Pushbutton Failure

5. EVENT DATE

6. LER NUMBER

7. REPORT DATE

8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL REV MONTH DAY Y

FACILITY NAME DOCKET NUMBER NUMBER NO.

05000 FACILITY NAME DOCKET NUMBER 05 01 2014 2014

- 006 -

001 06 26 2014 05000

9. OPERATING MODE

11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply) 11 20.2201(b)

[I 20.2203(a)(3)(i)

El 50.73(a)(2)(i)(C)

[I 50.73(a)(2)(vii) 1l 20.2201(d) 0l 20.2203(a)(3)(ii)

[I 50.73(a)(2)(ii)(A)

[I 50.73(a)(2)(viii)(A)

El 20.2203(a)(1) 0l 20.2203(a)(4)

[I 50.73(a)(2)(ii)(B)

[I 50.73(a)(2)(viii)(B)

El 20.2203(a)(2)(i) 0l 50.36(c)(1)(i)(A)

El 50.73(a)(2)(iii)

[I 50.73(a)(2)(ix)(A)

10. POWER LEVEL El 20.2203(a)(2)(ii) 0l 50.36(c)(1)(ii)(A) 0 50.73(a)(2)(iv)(A)

[I 50.73(a)(2)(x)

El 20.2203(a)(2)(iii) 0l 50.36(c)(2)

El 50.73(a)(2)(v)(A)

[1 73.71(a)(4) 100 El 20.2203(a)(2)(iv) 0- 50.46(a)(3)(ii)

El 50.73(a)(2)(v)(B)

[1 73.71(a)(5)

El 20.2203(a)(2)(v) 0l 50.73(a)(2)(i)(A)

[I 50.73(a)(2)(v)(C)

[I 50.73(a)(2)(vii)

El 20.2203(a)(2)(vi)

El 50.73(a)(2)(i)(B)

[E 50.73(a)(2)(v)(D)

Specify in Abstract below or in May 2, 1620 Matrix relay trip test pushbuttons AD and BD, the test power supply, and the test power supply socket were replaced. Post-maintenance testing was performed and the system was returned to service.

May 4, 0900 Unit 1 was returned to 100 percent power.

E.

OTHER SYSTEMS OR SECONDARY FUNCTIONS AFFECTED

There were no other systems or secondary functions affected.

F.

METHOD OF DISCOVERY

The event was self-revealing.

G.

MAJOR OPERATOR ACTION:

None.

H.

SAFETY SYSTEM RESPONSES:

The RPS operated as designed. There were no safety system functional failures.

II.

CAUSE OF EVENT

The Unit 1 reactor trip is documented in station condition report number CR-2014-004215.

Troubleshooting identified intermittent operation of the matrix relay trip test pushbuttons due to the buildup of silver sulfide on the contacts. The root cause determined that no maintenance strategy had been applied to an unrecognized single point vulnerability. The matrix relay trip test pushbutton does not have a maintenance strategy that ensures the pushbutton is replaced before its decline in performance contributes to erratic continuity.

Ill.

ANALYSIS OF EVENT

This event resulted in a valid actuation of the RPS. The actuation was not part of a pre-planned sequence during testing or reactor operation. Therefore, this event is reportable in accordance with 10 CFR 50.73(a)(2)(iv)(A).. Immediate notification of this event (Event Number 50078) was made on May 1, 2014, at 1150 in accordance with 10 CFR 50.72(b)(2)(iv)(B) and 10 CFR 50.72(b)(3)(iv)(A).

The Nuclear Regulatory Commission Performance Indicator for Unit 1 unplanned scrams per 7,000 critical hours is expected to increase to approximately 1.8 and-remain green. No other performance indicators were impacted.

This event did not result in any actual nuclear safety consequences. The RTCBs performed as designed. The RPS performed as designed. An estimated conditional core damage probability

of 9.5E-07 and an estimated conditional large early release probability of 4.7E-08 were calculated for this event.

IV.

CORRECTIVE ACTIONS

A.

ACTION TO RETURN AFFECTED SYSTEMS TO PRE-EVENT NORMAL STATUS:

Matrix relay trip test pushbuttons AD and BD, test power supply and test power supply socket were replaced. Post-maintenance testing was performed and the system was returned to service.

B.

ACTION TAKEN OR PLANNED TO PREVENT RECURRENCE:

1.

No location code (Unique Equipment Identifier) exists for the matrix relay trip test pushbuttons. This pushbutton did not have nor receive a Functional Importance Determination Classification per AP-913. Further, no preventive maintenance template applies to pushbuttons. The corrective action to prevent recurrence is to assign a location code, functional importance determination, and maintenance strategy to all Unit 1 and Unit 2 matrix relay trip test pushbuttons.

2.

Replace the remaining Unit 1 and Unit 2 RPS matrix relay trip test pushbuttons.

V.

ADDITIONAL INFORMATION

A.

FAILED COMPONENTS:

Matrix Relay Test Pushbutton manufactured by Eaton Cutler Hammer.

B.

PREVIOUS LERS ON SIMILAR EVENTS:

None C.

THE ENERGY INDUSTRY IDENTIFICATION SYSTEM (EIIS) COMPONENT FUNCTION IDENTIFIER AND SYSTEM NAME OF EACH COMPONENT OR SYSTEM REFERRED TO IN THIS LER:

IEEE 803 IEEE 805 COMPONENT FUNCTION ID SYSTEM ID Matrix Relay Trip Test Pushbutton SEL TG D.

SPECIAL COMMENTS:

None