05000440/LER-2011-001, Fire Protection Design Vulnerability Results in an Unanalyzed Condition
| ML11243A051 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 08/23/2011 |
| From: | Bezilla M FirstEnergy Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-11-268 LER 11-001-00 | |
| Download: ML11243A051 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 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)(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 |
| 4402011001R00 - NRC Website | |
text
FENOC FirstEnergy Nuclear Operating Company Perry Nuclear Power Plant 10 Center Road Perry Ohio 44081 Mark B. Bezilla Vice President 440-280-5382 Fax: 440-280-8029 August 23, 2011 L-1 1-268 10 CFR 50.73(a)(2)(ii)(B), 10 CFR 21.2(c)
ATTN: Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555-0001
SUBJECT:
Perry Nuclear Power Plant, Unit 1 Docket No. 50-440, License No. NPF-58 Licensee Event Report Submittal Enclosed is Licensee Event Report (LER) 2011-001, "Fire Protection Design Vulnerability Results in an Unanalyzed Condition." There are no regulatory commitments contained in this submittal.
If there are any questions or if additional information is required, please contact Mr. Robert Coad, Manager - Regulatory Compliance, at (440) 280-5328.
Sincerely, Mark B. Bezilla
Enclosure:
LER 2011-001 cc:
NRC Project Manager NRC Resident Inspector NRC Region III
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 EXPIRES 10/31/2013 (10-2010)
, the NRC may digits/characters fnot conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE Perry Nuclear Power Plant, Unit 1 05000440 1 OF 4
- 4. TITLE Fire Protection Design Vulnerability Results in an Unanalyzed Condition
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED SEQUENTIAL REV MYEAR F
MONTH DAY YEAR YEAR NUMBER NO.
MONTH AY 07 5 211 011 00
- - oI 8 1 31211FACILITY NAME DOCKET NUMBER 07 052 011~
2011 -
001
- - 00 08 3 201
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
El 20.2201(b)
El 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C)
E] 50.73(a)(2)(vii)
[] 20.2201(d)
[
20.2203(a)(3)(ii)
E] 50.73(a)(2)(ii)(A)
E] 50.73(a)(2)(viii)(A)
E] 20.2203(a)(1)
LI 20.2203(a)(4)
E 50.73(a)(2)(ii)(B)
[] 50.73(a)(2)(viii)(B)
E] 20.2203(a)(2)(i)
[j 50;36(c)(1)(i)(A)
LI 50.73(a)(2)(iii)
El 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL Ej 20.2203(a)(2)(ii)
[
50.36(c)(1)(ii)(A)
LI 50.73(a)(2)(iv)(A)
[] 50.73(a)(2)(x)
[] 20.2203(a)(2)(iii)
LI 50.36(c)(2)
E] 50.73(a)(2)(v)(A)
El 73.71(a)(4) 100 0
20.2203(a)(2)(iv)
E] 50.46(a)(3)(ii)
[
50.73(a)(2)(v)(B)
[- 73.71 (a)(5)
E] 20.2203(a)(2)(v)
E] 50.73(a)(2)(i)(A)
LI 50.73(a)(2)(v)(C)
Z OTHER 20.2203(a)(2)(vi)
E]50.73(a)(2)(i)(B) 5073(a)(2)(V)(D)
Specify in Abstract below 2
a 5.a)
B 5or in
EVENT ANALYSIS
The wiring deficiency is an original design condition involving two control room ammeter circuits. Some of the major components in the circuits include sensing current transformers [XCT], overcurrent protective relays [51] and a control room ammeter [11]. In the unlikely event of a postulated control room fire, the potential exists for a hot short to occur in the wiring associated with the control room ammeters, which could actuate the protective relays and trip the component breaker [52]. The actuation of the protective relays could result in either one or both breakers tripping to the open position. The breakers supply power to equipment that is analyzed to ensure the plant can safely shutdown in the unlikely event of a control room fire, which includes the ESW A pump and the CCCW Chiller A. These systems are required support systems for various safety-related systems that are required to safely shutdown the plant.
The site Safe Shutdown Capability Report credits the Division 1 train to safely shutdown and maintain the plant in a safe condition during a postulated control room fire. The design deficiency resulted in the plant not being able to meet a requirement of 10 CFR 50 Appendix R, in particular Section III.G. 1, which states that "Fire protection features shall be provided for structures, systems, and components important to safe shutdown. These features shall be capable of limiting fire damage so that one train of systems necessary to achieve and maintain hot shutdown conditions from either the control room or emergency control station(s) is free of fire damage." Implementation of the temporary modifications on July 8, 2011, restored compliance with 10 CFR 50 Appendix R Section III.G.1.
A probabilistic risk assessment was performed to quantify the change in core damage frequency (CDF) associated with the identified condition. A postulated fire impacting the Division 1 components in the Control Room would result in a change in CDF of 2.88E-08. If it was postulated that a fire affected both Division 1 and Division 2 components, a change in CDF of 2.55E-07 was calculated. As the Large Early Release Frequency (LERF) is on an order of magnitude lower than the CDF, LERF would be on the order of 1.OE-08.
Configurations with changes in CDF of less than 1.0E-06 and a change in LERF of less than 1.OE-07 are not considered to be significant risk events. Based on the probabilistic risk assessment results, this condition is considered to be of low safety significance.
CORRECTIVE ACTIONS
An extent of condition review was completed on other similar power circuits in Division 1, with no other deficiencies noted.
Interim corrective actions were performed to isolate the affected circuits via two temporary modifications. The modifications lifted leads and installed jumpers that removed the control room ammeters from the circuits, thereby eliminating the potential of a control room fire creating a hot short adversely affecting Division 1.
Planned corrective actions include:
- 1) Design and implement a solution to isolate the ammeter circuits in the unlikely event of a control room fire.
- 2) Communicate the lessons learned from this LER to Engineering personnel with an emphasis that indication circuits can impact safe shutdown.
- 3) A sample of circuits not considered to impact safe shutdown in the site Safe Shutdown Report will be reviewed to ensure that categorization is correct.
PREVIOUS SIMILAR EVENTS
A search of License Event Reports and the corrective action program documents for the last three years at the Perry Nuclear Power Plant found that one similar event had been reported.
LER 2009-002 (Diesel Generator CO2 Fire Suppression Control Panel Miswiring Results in an Unanalyzed Condition) reported an unanalyzed condition involving a modification to the Fire Protection system. During the installation of a modification on the diesel generator carbon dioxide (CO2) fire protection system, a wiring error occurred which would have resulted in the Division 2 diesel generator ventilation supply fans isolating during a Division 3 diesel generator CO2 actuation. Additionally, in the event of a Division 2 diesel generator CO2 actuation, the Division 3 diesel generator ventilation supply fans would have isolated. The root cause of this event was determined to be an inadequate post modification test, with a contributing cause of less than adequate cable tag/wire mark configuration control process.
The corrective actions for this event were focused on correcting the root and contributing causes and would not have been reasonably expected to have prevented the condition documented in LER 2011-001.
COMMITMENTS
There are no regulatory commitments contained in this report. Actions described in this document represent intended or planned actions, are described for the NRC's information, and are not regulatory commitments.