05000333/LER-2019-002, Unanalyzed Condition Due to Unprotected Control Circuits Running Through Multiple Fire Areas
| ML19235A187 | |
| Person / Time | |
|---|---|
| Site: | FitzPatrick  |
| Issue date: | 08/23/2019 |
| From: | Timothy Peter Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| JAFP-19-0080 LER 2019-002-00 | |
| Download: ML19235A187 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition |
| 3332019002R00 - NRC Website | |
text
Exelon Generation JAFP-19-0080 August23,2019 United States Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555-0001 James A. FitzPatrick NPP P.O. Box 110 Lycoming. NY 13093 Tel 315-349-6024 Fax 315-349-6480 Timothy C. Peter Plant Manager - JAF James A. FitzPatrick Nuclear Power Plant Renewed Facility Operating License No. DPR-059 NRC Docket No. 50-333
Subject:
Dear Sir or Madam:
LER: 2019-002, Unanalyzed Condition Due to Unprotected Control Circuits Running Through Multiple Fire Areas This report is being submitted pursuant to 10 CFR 50.73(a)(2)(ii)(B).
There are no new regulatory commitments contained in this report.
Questions concerning this report may be addressed to Mr. William Drews, Regulatory Assurance Manager, at (315) 349-6562.
TCP/WD/mh
Enclosure:
LER: 2019-002, Unanalyzed Condition Due to Unprotected Control Circuits Running Through Multiple Fire Areas cc:
USNRC, Region I Administrator USNRC, Project Manager USNRC, Resident Inspector INPO Records Center (ICES)
NRC FORM 366 (04-2018)
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (04-2018)
LICENSEE EVENT REPORT (LER)
APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 1. Facility Name James A. FitzPatrick Nuclear Power Plant
- 2. Docket Number 05000333
- 3. Page 1 OF 3
- 4. Title Unanalyzed Condition Due to Unprotected Control Circuits Running Through Multiple Fire Areas
- 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 N/A Docket Number N/A 6
24 2019 2019 - 002 - 00 08 23 2019 Facility Name N/A Docket Number N/A
- 9. Operating Mode Month Day Year Yes (If yes, complete 15. Expected Submission date) No Abstract (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)
During a review of industry Operating Experience, James A. FitzPatrick Nuclear Power Plant (JAF) identified that unprotected control circuits for nonsafety-related oil pumps routed through different fire areas. The concern is that a postulated fire in one area can cause short circuits potentially resulting in secondary fires or cable failures in other fire areas where the cables are routed.
The control circuits for the Turbine Generator Emergency Bearing Lube Oil pump (94P-2), Emergency Seal Oil Pump (94P-13), and Reactor Feed Pump Turbine Emergency Oil Pumps (31P-7A and 31P-7B) are unfused and would not be protected. Cables for these control circuits are routed in safety-related trays with safety-related cables thru fire zones in Battery Charger Rooms, Battery Room Corridor, Cable Spreading Room, Relay Room, and Control Room.
The cause of the condition is the original plant design, prior to 10 CFR 50 Appendix R, did not include overcurrent protection for control circuits in all applicable Safe Shutdown Analysis circumstances. Compensatory actions were established for the affected Fire Zones and corrective actions to evaluated and modify all applicable control circuits are planned.
(See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
(See Page 2 for required number of digits/characters for each block)
=
Background===
The James A. FitzPatrick Nuclear Power Plant (JAF) 10 CFR 50 Appendix R Safe Shutdown Analysis is based on the occurrence of a single fire. The only failures that are considered are those directly attributable to the fire, and spurious operations that can be postulated to occur as a result of the fire. No other failures are assumed to occur (i.e., single failure).
Fire areas are established to meet the separation requirements of Section III.G of Appendix R for safe shutdown systems. The 25 fire areas at JAF are further subdivided into fire zones. The fire zones affected by the condition described in this report are:
BR-4: Train "B" Battery Charger Room 4 BR-5: Battery Rooms Corridor CS-1: Cable Spreading Room RR-1: Relay Room CR-1: Main Control Room However, it is postulated that a fire in one fire area could cause a short-circuit, cause overcurrent, overheat cables, then possibly result in secondary fires in other fire areas where the cables are routed. Fuses were designed in electrical circuits to prevent this type of fire propagation. Secondary fires or cable failures are outside the assumptions of the 10 CFR 50 Appendix R Safe Shutdown Analysis.
Event Description
On June 24, 2019, during a review of industry operating experience, Electrical Engineering identified similar conditions at JAF where nonsafety-related direct current (DC) control circuits lack adequate overcurrent protection. Circuit breakers associated with these control circuits are insufficient to prevent a postulated overcurrent event from damaging additional cables or propagating secondary fire because the circuit breakers are designed to protect the power supply to each pump, not the control circuit portion. Specifically, the control circuit for the Turbine Generator Emergency Bearing Lube Oil (EBOB) pump (94P-2) is unfused. This condition also exists for the Emergency Seal Oil Pump (ESOP) (94P-13) and Reactor Feed Pump Turbine (RFPT) DC Emergency Oil Pumps 31P-7A and 31P-7B.
It was determined that these nonsafety-related control cables are routed in safety-related trays with safety-related cables thru Fire Zones BR-4, BR-5, CS-1, RR-1, and CR-1.
This event was reported to the NRC on June 24, 2019 per 10 CFR 50.72(b)(3)(ii)(B) (ENS 54130). The required actions of the Technical Requirement Manual (TRM) 3.7.M were implemented.
Event Analysis
Based on a review of the cables contained within common enclosures, additional failures resulting from postulated secondary fires or cable failures were evaluated. Where failures invalidate the credited fire safe shutdown success paths, the following fire areas and fire safe shutdown systems were impacted:
Fire Area 03: Automatic Depressurization System (ADS) [EIIS identifier: SB], Control Room Ventilation [VI],
and High Pressure Coolant Injection System (HPCI) [BJ] are impacted by unprotected control cables for 31P-7A and 94P-13. U.S. NUCLEAR REGULATORY COMMISSION (04-2018)
LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. LER NUMBER James A. FitzPatrick Nuclear Power Plant 05000 - 333 YEAR SEQUENTIAL NUMBER REV N0.
2019
- - 002
- - 00 Page 3 of 3 (See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
Fire Area 1E: Failures similar to those identified in Fire Area 03. A manual review identified that if the circuits for pump 31P-7B were left unprotected, it could also contribute to concerns in certain failure combinations including the control circuits of 31P-7A, 94P-2 and 94P-13.
Other fire areas 04, 06 and 17 will experience additional failures as a result of the unprotected circuits, but the fire safe shutdown methodology remains unaffected in these areas.
Since the degree of separation for redundant safe shutdown trains is lacking, the event would be reportable as an unanalyzed condition that significantly degraded plant safety. Therefore, this report is being submitted in accordance with 10 CFR 50.73(a)(2)(ii)(B), a condition that resulted in the plant being in an unanalyzed condition that significantly degraded plant safety.
Cause
The cause of this condition was overcurrent protection was not installed in all applicable control circuits which can impact the 10 CFR 50 Appendix R Safe Shutdown Analysis. This condition has existed since original plant design.
Similar Events
FitzPatrick, LER: 2013-003-00, Unfused DC Ammeter Circuits Result in Unanalyzed Condition, JAFP-13-0158, dated December 26, 2013.
Corrective Actions
Completed Corrective Actions Established compensatory actions in Fire Areas 03 in accordance with the TRM and initiated Operations Standing order for the condition in Area 1E.
Future Corrective Actions Modification to all applicable control circuit cables will be completed to protect the separation of Fire Zones and Areas as required by Appendix R Safe Shutdown Analysis.
Safety Significance
Nuclear safety - There were no actual consequences caused by this condition. The potential consequence of this condition is for a fire damage in one fire area to damage other cables or create a secondary fire in more than one fire area. This may cause a loss of safe shutdown capability outside the analysis of the Safe Shutdown Analysis. However, the risk of fire damage is minimize by fire protection equipment and the availability of Fire Brigade members trained to respond to fire accident scenarios.
Industrial safety - No safety event or abnormal increase to personnel risk results from this condition Radiological safety - No radiological impact or impact on dose is associated with this condition.
References JAF Issue Report - IR 04259118, June 26, 2019 JAF-RPT-FPS-01975, Revision 5, 10CFR50 Appendix R Safe Shutdown Analysis Report (SSAR)