ML14223B210

LER 14-002-00 for Shearon Harris Nuclear Power Plant, Unit 1, Regarding Inadequate DC Cable Protection Could Adversely Affect Safe Shutdown

ML14223B210
Person / Time
Site:	Harris
Issue date:	08/11/2014
From:	Waldrep B C Duke Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
HNP-14-089 LER 14-002-00
Download: ML14223B210 (5)

Text

ENERGYm August 11, 2014 Serial: HNP-14-089 Attn: Document Control Desk U.S. Nuclear Regulatory Commission Washington DC 20555-0001 Shearon Harris Nuclear Power Plant, Unit 1 Docket No. 50-400

Subject:

Licensee Event Report 2014-002-00 Ladies and Gentlemen:

Benjamin C. Waldrep Vice President Harris Nuclear Plant 5413 Shearon Harris Road New Hill NC 27562-9300 919.362.2502 10 CFR 50.73 Duke Energy Progress, Inc. submits the enclosed Licensee Event Report 2014-002-00 in accordance with 10 CFR 50.73 for Shearon Harris Nuclear Power Plant, Unit 1. This report describes an historical design issue regarding unfused electrical cables feeding to the Turbine Emergency Oil Pump. Corrective actions have been completed.

This document contains no regulatory commitments.

Please refer any questions regarding this submittal to Dave Corlett at (919) 362-3137.

Sincerely,

Enclosure:

LER 2014-002-00 cc: Mr. J. D. Austin, NRC Sr. Resident Inspector, HNP Ms. M. Barillas, NRC Project Manager, HNP Mr. V. M. McCree, NRC Regional Administrator, Region II NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (02-2014)

LICENSEE EVENT REPORT (LER)

APPROVED BY OMB: NO. 3150-0104 EXPIRES: 01/31/2017 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), U.S.

Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail to Infocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection. 1. FACILITY NAME Shearon Harris Nuclear Power Plant, Unit 1 2. DOCKET NUMBER 05000400 3. PAGE 1 OF 4 4. TITLE Inadequate DC Cable Protection Could Adversely Affect Safe Shutdown

5. EVENT DATE 6. LER NUMBER 7. REPORT DATE 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL NUMBER REV NO. MONTH DAY YEAR FACILITY NAME None DOCKET NUMBER 06 12 2014 2014

- 002 - 00 08 11 2014FACILITY NAME None DOCKET NUMBER

9. OPERATING MODE 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 1 20.2201(b) 20.2203(a)(3)(i) 50.73(a)(2)(i)(C) 50.73(a)(2)(vii) 20.2201(d) 20.2203(a)(3)(ii) 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A) 20.2203(a)(1) 20.2203(a)(4) 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B) 20.2203(a)(2)(i) 50.36(c)(1)(i)(A) 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A)

10. POWER LEVEL 20.2203(a)(2)(ii) 50.36(c)(1)(ii)(A) 50.73(a)(2)(iv)(A) 50.73(a)(2)(x) 100 20.2203(a)(2)(iii) 50.36(c)(2) 50.73(a)(2)(v)(A) 73.71(a)(4) 20.2203(a)(2)(iv) 50.46(a)(3)(ii) 50.73(a)(2)(v)(B) 73.71(a)(5) 20.2203(a)(2)(v) 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(C)

OTHER 20.2203(a)(2)(vi) 50.73(a)(2)(i)(B) 50.73(a)(2)(v)(D)

Specify in Abstract below or in NRC Form 366A12. LICENSEE CONTACT FOR THIS LER LICENSEE CONTACT Dave Corlett, Manager, Regulatory Affairs TELEPHONE NUMBER (Include Area Code) 9193623137 13. COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT CAUSE SYSTEM COMPONENT MANU-FACTURER REPORTABLETO EPIX CAUSE SYSTEM COMPONENT MANU-FACTURER REPORTABLE TO EPIX 14. SUPPLEMENTAL REPORT EXPECTED YES (If yes, complete 15. EXPECTED SUBMISSION DATE)

NO 15. EXPECTED SUBMISSION DATE MONTH DAY YEAR ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)

On June 12, 2014, while operating at 100 percent power in Mode 1, Harris plant personnel determined that inadequate cable protection existed in control cables for the Turbine Emergency Oil Pump.

The cables had no electrical protection devices (fuses) other than the circuit breaker. The control cables are routed through several fire areas, including the main control room, and under postulated conditions, could have created a common enclosure fire hazard situation. Compensatory measures (hourly fire watches) were implemented for affected areas of the plant to ensure continued public safety until electrical protection devices were installed. The apparent cause was the historical installation of an unfused section of cable in the control circuit of the Turbine Emergency Oil Pump.

NRC FORM 366 (02-2014)

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (02-2014)

LICENSEE EVENT REPORT (LER) CONTINUATION SHEET APPROVED BY OMB: NO. 3150-0104 EXPIRES: 01/31/2017 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), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail to Infocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection. 1. FACILITY NAME 2. DOCKET 6. LER NUMBER 3. PAGEShearon Harris Nuclear Power Plant, Unit 1 05000400YEAR SEQUENTIAL NUMBER REV NO. 2 OF4 2014 - 002 - 00 NARRATIVE Energy Industry Identification System (EIIS) and component codes are identified in the text as [XX].

Background On June 12, 2014, while operating at 100 percent power in Mode 1, Harris plant personnel determined that inadequate cable protection existed in the control cables for the Turbine Emergency Oil Pump (EOP) [P] during an evaluation of an Operational Experience (OE). DP-1-250-3 is a circuit breaker [BKR] which feeds the motor of the direct current (DC) Lube Oil Backup pump [P]. Directly off the motor starter are control switch cables [CBL] which had no electrical protection devices (fuses) other than the circuit breaker. Since the control cable is routed through several fire areas, including the main control room, postulated conditions could have allowed fires to ignite in multiple areas. Because the control cable is routed through cable trays that contain safe shutdown cables, the configuration creates a common enclosure situation. Additionally, failure of the EOP could cause significant main turbine damage. This event is reportable in accordance with 10 CFR 50.73(a)(2)(ii)(B), "The nuclear power plant being in an unanalyzed condition that significantly degraded plant safety."

Event Description On June 12, 2014, at approximately 1247 EDT, Harris plant personnel determined that inadequate cable protection existed in the control cables for the Turbine EOP. The cable protection was being reviewed as a result of an extent of condition identified in an OE evaluation. Control cables that are not protected from electrical faults could become a fire ignition source. The DC motor power is supplied through cables. Directly off the motor starter are control switch cables. There were no electrical protection devices (fuses) other than the circuit breaker protecting these cables. The large breaker did not provide adequate cable protection in case of a fault and did not meet Harris Nuclear Plant (HNP) design requirements. The installed cables were sized consistently with the original EBASCO specification for control cables, but because they are tied directly to a 250V DC bus [BU], they were actually installed like power cables.

In the event of an over-current situation, the cables could have heated up anywhere along their path, including at the switches. This could have caused and/or propagated fires in multiple fire areas.

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (02-2014)

LICENSEE EVENT REPORT (LER) CONTINUATION SHEET APPROVED BY OMB: NO. 3150-0104 EXPIRES: 01/31/2017 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), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail to Infocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection. 1. FACILITY NAME 2. DOCKET 6. LER NUMBER 3. PAGEShearon Harris Nuclear Power Plant, Unit 1 05000400YEAR SEQUENTIAL NUMBER REV NO. 3 OF4 2014 - 002 - 00 NARRATIVE These cables were designed and installed without proper electrical fault protection. This lack of fault protection could have created a common enclosure fire hazard in certain situations. This design is an historical issue that was part of the original plant design, and no discrepancies have been found that would indicate this should have been identified earlier than now. An extent of condition (EOC) evaluation was performed that was limited to DC powered motors, including safe shutdown (SSD) motors, and vendor-supplied motor control skids. The EOC evaluation concluded that the Air Side Back-up Pump Motor [MO] circuit has the same unfused condition.

However, it was not a fire protection concern since the cable remains in one area and would not allow fire propagation to other fire areas.

Causal Factors The apparent cause is the historical installation of an unfused section of cable in the control circuit of the Emergency Oil Pump.

Corrective Actions Completed Corrective Actions Immediate Compensatory Action - Established hourly fire watches in multiple areas. Installed fuses in each leg of the 250V DC control circuit for the EOP motor as per Engineering Change 96989. Safety Analysis There were no safety consequences associated with this event, as the equipment did not fail (the unfused cables did not burn). These cables were designed and installed without proper electrical fault protection. This lack of fault protection could have created a common enclosure fire hazard under postulated situations. NFPA 805 has two requirements to ensure that the fire damage is limited to one fire area. The first is having rated fire barriers between different divisions of equipment. The second is that fire damage cannot propagate outside the fire area due to electrical faults in the Common Enclosures. Those circuits that share enclosures with circuits required to achieve the nuclear safety performance criteria

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (02-2014)

LICENSEE EVENT REPORT (LER) CONTINUATION SHEET APPROVED BY OMB: NO. 3150-0104 EXPIRES: 01/31/2017 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), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail to Infocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection. 1. FACILITY NAME 2. DOCKET 6. LER NUMBER 3. PAGEShearon Harris Nuclear Power Plant, Unit 1 05000400YEAR SEQUENTIAL NUMBER REV NO. 4 OF4 2014 - 002 - 00 NARRATIVE and whose fire-induced failure could cause the loss of the required components must be identified to prevent propagating fires outside of the immediate fire area due to fire-induced electrical faults on inadequately protected cables or via inadequately sealed fire area boundaries. This creates a condition where the cable is not electrically protected such that a high impedance fault could cause the cable to overheat. If the cable reaches 400 degrees F, cable damage may occur to adjacent cables (Common Enclosure Concern). A temperature of 400 degrees F is the conservative value used for KERITE Fire Resistant cable, used in the Zone Of Influence calculations as specified in the HNP Safety Evaluation Report (SER) for the transition to NFPA 805. If the cable reaches the ignition temperature, a secondary fire can be created in areas anywhere along the cable path. Since these cables are routed through multiple fire areas, the secondary fire could be outside of the area where the original postulated fire occurs. This could expose the plant to cross train cable damage and is contrary to the requirements of NFPA 805. Other than the risks associated with fire and safe shutdown in the affected areas, there are no additional chemical, radiological, industrial, production, Emergency Preparedness, or Security impacts due to this condition. The nuclear safety significance lies in the potential for a fire to damage safe shutdown equipment in multiple fire areas, which would put the plant in an unanalyzed condition. Previous Similar Events No Operating Experience was found that would indicate the unfused cables should have been identified earlier. HNP became aware of the issue on January 9, 2014.

Commitments This report contains no regulatory commitments.