05000285/LER-2011-010, Re Fire Causes a Circuit Breaker to Open Outside Design Assumptions

Re Fire Causes a Circuit Breaker to Open Outside Design Assumptions

ML12018A044
Person / Time
Site:	Fort Calhoun
Issue date:	01/16/2012
From:	Bannister D Omaha Public Power District
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
LIC-12-0003 LER 11-010-00
Download: ML12018A044 (6)

LER-2011-010, Re Fire Causes a Circuit Breaker to Open Outside Design Assumptions

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 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)(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
2852011010R00 - NRC Website

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Omaha Publlt: PDwrn IJIBIIfct 444 South 16th Street Mall Omaha, NE 68102-2247 LlC-12-0003 January 16, 2012 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001

Reference:

Docket No. 50-285

Subject:

Licensee Event Report 2011-010, Revision 0, for the Fort Calhoun Station Please find attached Licensee Event Report 2011-010, Revision 0, dated, January 16, 2012. This report is being submitted pursuant to 10 CFR 50.73(a)(2)(v)(A), (B), (C) and (D). If you should have any questions, please contact me.

Sincerely,

>>-~

D. J. Bannister Vice President and Chief Nuclear Officer Fort Calhoun Station DJB /epm Attachment c:

E. E. Collins, Jr., NRC Regional Administrator, Region IV L. E. Wilkins, NRC Project Manager J. C. Kirkland, NRC Senior Resident Inspector INPO Records Center Employment with Equal Opportunity

NRC FORM 366 (10-2010)

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (10-2010)

LICENSEE EVENT REPORT (LER)

(See reverse for required number of digits/characters for each block)

APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2013

, the NRC may not conduct or sp onsor, and a person is not required to respond to, th e

information collection.

1. FACILITY NAME Fort Calhoun Station

2. DOCKET NUMBER 05000285

3. PAGE 1 OF 3

4. TITLE Fire Causes a Circuit Breaker to Open Outside Design Assumptions

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 DOCKET NUMBER 05000 6

7 2011 2011 - 010 -

0 1

16 2012 FACILITY NAME DOCKET NUMBER 05000

9. OPERATING MODE 5

11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 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) 20.2203(a)(2)(ii) 50.36(c)(1)(ii)(A) 50.73(a)(2)(iv)(A) 50.73(a)(2)(x) 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 LICENSEE EVENT REPORT (LER)

CONTINUATION SHEET that bus should open to isolate the fault without tripping upstream circuit breakers. Load center circuit breakers should not open due to a fault or fire in the opposite train.

10 CFR 50, Appendix R design assumptions are that a fire in either the east or west switchgear room will result in the loss of switchgear in the affected room, but will not impact the operability of the switchgear in the opposite room. During the fire in 1B4A, the formation of fire residue (soot) on the non-segregated bus stabs within 1B4A switchgear bus tie circuit breaker cubicle created fault currents that were sensed by circuit breaker 1B3A. At the time of the event, circuit breaker BT-1B4A was open and circuit breaker BT-1B3A was closed supplying island bus 1B3A-4A.

An NRC Part 21 (2005-039) addressed spurious tripping of the Micrologic trip devices, and the supplier Nuclear Logistics Incorporated (NLI) added a filter capacitor to the trip module. Additionally, a subsequent industry spurious trip of NLI/Square D Masterpact circuit breakers in 2008 (OE 21873) resulted in a design change to the trip module. The NLI/Square D Masterpact circuit breakers replaced in 2009, contained the industry operating experience of the Micrologic trip units, and the vendor confirmed the FCS trip units contained the upgrades driven by the NRC Part 21 (2005-039).

CORRECTIVE ACTIONS

As documented in LER 2011-008 (Fire in Bus 1B4A) the following actions have been or are being taken:

The affected bus was de-energized and the Halon system extinguished the fire. The Halon system was recharged and restored to service.

FCS conducted inspections and testing of the unaffected 480 V buses, the supply circuit breakers to the 480 V buses, and the 480 V bus tie circuit breakers. The tested 480 V supply circuit breakers and bus tie circuit breakers passed their inspections and testing.

FCS is replacing the affected bus (1B4A), which contains two 480 V supply circuit breakers, 1B4A and BT-1B4A (supply circuit breaker to the associated island bus).

Additional corrective actions will be determined following completion of the root cause for this event.

SAFETY SIGNIFICANCE

The safety significance will be fully evaluated following completion of the root cause analysis for this event.

SAFETY SYSTEM FUNCTIONAL FAILURE This event does result in a safety system functional failure in accordance with NEI-99-02.

PREVIOUS EVENTS LER 2011-008 documents the fire associate with this event.

FORT CALHOUN STATION NOD-QP-9.2 QUALITY PROCEDURE FORM R0 LICENSING CORRESPONDENCE REVIEW FORM LIC-12-0003 Date Issued: 1/6/12 Requested Return Date:____1/11/12______

Review/Approval Information Dave Bannister Brad Blome John Herman Woody Goodell Steve Miller Tim Nellenbach Susan Baughn Chris Sterba Dave Digiacinto John Adams Fred Fork C. Cameron Mike Cooper Subject: ___ LER 2011-010 Fire Creates Fault Currents Outside Design Assumptions.

Please review and approve the attached draft correspondenc e (referenced above). In order to document your review for our records, please sign this form and return it to the Licensing Coordinator. If n o notification is received by the requested return date, your concurrence with no comment will be assumed.

E. Matzke 6855_

Technical Coordinator (Ext.) Licensing Coordinator (Ext.)

[ ] Approved with no comment. [ ] Approved pending resolution of comments as noted.

Comments:_______________________________________________________________________________

Reviewer's Signature Date

FORT CALHOUN STATION NOD-QP-9.2 QUALITY PROCEDURE FORM R0 LICENSING CORRESPONDENCE REVIEW FORM SUMMARY LIC-12-0003 Date Issued: 1/6/12 Requested Return Date: 1/11/12 Name Date Comments Received No Comments1 Comments - How Resolved2 Dave Bannister 1/7/*12 Corrected J. Herman none Woody Goodell none Tim Nellenbach none Susan Baughn 1/11/12 Corrected Mike Cooper 1/11/12 Corrected Steve Miller none Chris Sterba none Brad Blome 1/10/12 X

Dave Digiacinto none John Adams 1/9/12 Corrected Fred Fork none C. Cameron none Subject: ___ LER 2011-010 Fire Creates Fault Currents Outside Design Assumptions.

NOTE - This submittal does ____ does not __X__ include documents/files on CD-ROM.3 NL Comment Coordinator Signature E. Matzke Date 1/16/12 Responsible Dept. Manager (if required)

Date Review by Nuclear Licensing Supervisor Date 1/16/12 1 Attach only signed Licensing Correspondence Review Form.

2 Attach necessary documentation.

3 Ensure that the CD-ROM files are formatted properly for electronic information exchange (EIE) to the NRC. (Reference NL-17)