05000272/LER-2013-004, Regarding Unfused DC Ammeter Circuits Result in an Unanalyzed Condition
| ML14013A095 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 01/10/2014 |
| From: | Jamila Perry Public Service Enterprise Group |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LR-N14-0002 LER 13-004-00 | |
| Download: ML14013A095 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v), Loss of Safety Function |
| 2722013004R00 - NRC Website | |
text
PSEG Nuclear LLC P.O. Box 236, Haricocks Bridge, NJ 08038-0236 JAN l 0 2014 LR-N14-0002 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 LER 272/2013-004-00 Ps=G NudeaY ILC 10 CFR 50.73 Salem Nuclear Generating Station Unit 1 and Unit 2
SUBJECT:
Renewed Facility Operating License Nos. DPR-70 and DPR-75 NRC Docket Nos. 50-272 and 50-311 Unfused DC Ammeter Circuits Result in an Unanalyzed Condition The Licensee Event Report, "Unfused DC Ammeter Circuits Result in an Unanalyzed Condition," is being submitted pursuant to the requirements of the Code of Federal Regulations, 10 CFR 50.73(a)(2)(ii)(B), "The nuclear plant being in an unanalyzed condition that significantly degraded plant safety".
The attached LER contains no commitments. Should you have any questions or comments regarding the submittal, please contact David Lafleur of Salem Regulatory Assurance at 856-339-1754.
Sincerely, c('.re'F.
John F. Perry
(/
Site Vice President - Salem Attachments (1)
Document Control Desk Page 2 10 CFR 50.73 LR8N1490002 cc Mr. W. Dean, Administrator-Region 1, NRC Mr. John Hughey, Licensing Project Manager-Salem, NRC Mr. P. Finney, USNRC Senior Resident Inspector, Salem (X24)
Mr. P. Mulligan, Manager IV, NJBNE Mr. T. Joyce, President and Chief Nuclear Officer-Nuclear Mr. T. Cachaza, Salem Commitment Tracking Coordinator Mr. L. Marabella, Corporate Commitment Tracking Coordinator Mr. D. Lafleur, Salem Regulatory Assurance Page 2 of3
NRC FORM366 U.S. NUCLEAR REGULATORY COMMISSION AP P ROVED BY OMB : NO. 3150-0104 EXPIRES: 10/31/2013 (10-2010)
, the N R C may not conduct or sponsor, and a person is not required to respond to, the information collection.
r* PAGE 1
Salem Generating Station - Unit 1 05000272 of 4
- 4. TITLE Unfused DC Ammeter Circuits Result in an Unanalyzed Condition
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED SEQUENTIAL REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBER NO.
MONTH DAY YEAR Salem Generating Station - Unit 2 05000311 DOCKET NUMBER 11 14 2013 2013 0 0
4 0
01 10 2014
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply)
D 20.2201(b)
D 20.2203(a)(3)(i) 1 D 20.22o1(d)
D 20.2203(a)(3)(ii)
D 20.2203(a)(1)
D 20.2203(a)(4)
D 20.2203(a)(2)(i)
D 50.36(c)(1 )(i)(A)
- 10. POWER LEVEL D 20.2203(a)(2)(ii)
D 50.36(c)(1 )(ii)(A)
D 20.2203(a)(2)(iii)
D 50.36(c)(2) 100%
D 20.2203(a)(2)(iv)
D 50.46(a)(3)(ii)
D 20.2203(a)(2)(v)
D 50. 73(a)(2)(i)(A)
D 50. 73(a)(2)(i)(C)
D 50.73(a)(2)(ii)(A) 181 50. 73(a)(2)(ii)(B)
D 50.73(a)(2)(iii)
D 50.73(a)(2)(iv)(A)
D 50. 73(a)(2)(v)(A)
D 50. 73(a)(2)(v)(B)
D 50. 73(a)(2)(v)(C)
D 50.73(a)(2)(vii)
D 50.73(a)(2)(viii)(A)
D 50. 73(a)(2)(viii)(B)
D 50.73(a)(2)(ix)(A)
D 50.73(a)(2)(x)
D 73.71(a)(4)
D 73.71(a)(5) 0 OTHER D 20.2203(a)(2)(vi)
D 50. 73(a)(2)(i)(B)
D 50.73(a)(2)(v)(D)
Specify in Abstract below or in
- 6. LER NUMBER I
I REVISI SEQUENTIAL ON YEAR NUMBER NUMBE
- 3. PAGE 2013
- - 0 0 4 -
00 3
of 4
Both Salem Units 1 and 2 are subject to the requirements of 10 CFR 50, Appendix R, Ill G., Fire Protection of Safe Shutdown Capability. A postulated fire that results in a short to ground concurrent with an opposite polarity short from the same battery could result in excessive current flow and heat in the ammeter wiring. With enough current flowing through the cable, the potential exists that the cable could self-heat to the point of causing a secondary fire in the electrical tray at some point along the path of the cable. This excessive current could result in a secondary fire in either the Control Room/Relay Room or the 460/230V Switchgear Room areas. The secondary fire in those areas could adversely affect safe shutdown equipment and cause a loss of alternate shutdown capability contrary to 10 CFR 50, Appendix R, Section III.G requirements.
This event is reportable in accordance with 10 CFR 50. 73(a)(2)(ii)(B) as a condition that resulted in the nuclear power plants being in unanalyzed conditions that significantly degraded safety in that the overloaded ammeter wiring could damage cables in multiple fire areas and result in a loss of associated safe shutdown capability.
CAUSE OF OCCURRENCE The cause of the reported condition is that the original design of the DC ammeter circuits did not include fuses to protect ammeter cables. This design has been in place at Salem Units 1 and 2 since construction and was only recently identified as an issue through the Salem Operating Experience Program.
PREVIOUS SIMILAR OCCURRENCES A review of LERs at Salem Station dating back to 2010 identified no similar design deficiencies in Post Fire Safe Shutdown Analyses.
SAFETY CONSEQUENCES AND IMPLICATIONS
There were no actual safety consequences of this condition and the event did not result in a challenge to fission product barriers or the release of radioactive materials. The event did not adversely affect the safe operation of the plant or the health and safety of the public.
The secondary Fire Areas of concern are the Units 1 and 2 Control Room, Relay Rooms and the 460/230V Switchgear Rooms. The Unit 1 and 2 Control Room is equipped with ionization smoke detectors. The Unit 1 and 2 Relay Rooms contain smoke detectors with automatic Halon fire suppression systems. The Unit 1 and 2 460/230V Switchgear Rooms contain smoke and thermal detectors with preaction sprinkler systems. The Control Room is continuously manned and operators can promptly respond to fire events in the plant.
The postulated secondary fire is a very slow fire progression event. The credited operator manual actions implemented in a potentially affected secondary Fire Area are typically completed within minutes following the confirmation of the fire event.
The condition of a negative ground fault can exist until a subsequent ground on the positive and neutral leg of a circuit from the same source occurs. The neutral ground will make the system grounded and any hot leg grounds will result in the control power fuses blowing and loss of control power to all affected circuits.
The affected cables at Salem Units 1 and 2 are thermoset cables with bronze or copper metal shields. In addition. to the postulated ground fault hot short and intra-cable interactions, additional ground interactions due to the metal shielding would be likely. Therefore, the potential for only negative grounds without the positive ground are unlikely since the metal shield represents a more readily accessible ground plane. The metal shield tape will introduce additional electrical ground pathways which would result in lower current flow in the ammeter cable.
The factors discussed above support a conclusion that the combination of a significant fire event and the specific wiring faults required to produce a secondary fire that affects the availability of equipment required for safe shutdown is very unlikely.
The design deficiency did not impact the performance of any other component functions and no other safety functions were impacted as a result of this event. A review of this event determined that a Safety System Functional Failure (SSFF) as defined in Nuclear Energy.Institute (NEI) 99-02 did not occur.
CORRECTIVE ACTIONS
- 1.
Compensatory measures have been implemented in the affected areas of the plant.
- 2.
Implementation of a modification to add isolation devices for the Ammeter circuits is in progress.
COMMITMENTS
No commitments are made in this LER.