05000237/LER-2009-006, Regarding Failure of Main Control Room Ventilation Due to Breaker Malfunction

Regarding Failure of Main Control Room Ventilation Due to Breaker Malfunction

ML100200206
Person / Time
Site:	Dresden
Issue date:	01/11/2010
From:	Hanley T Exelon Generation Co, Exelon Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
SVPLTR # 10-0002 LER 09-006-00
Download: ML100200206 (4)

LER-2009-006, Regarding Failure of Main Control Room Ventilation Due to Breaker Malfunction

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(v), Loss of Safety Function 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)(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)(i)(B), Prohibited by Technical Specifications
2372009006R00 - NRC Website

text

Exelokn Exelon Generation www.exeloncorp.com Dresden Generating Station Nucear 6500 North Dresden Road Morris, I L 60450-9765 10 CFR 50.73 SVPLTR # 10-0002 January 11,2010 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Dresden Nuclear Power Station, Unit 2 Renewed Facility Operating License No. DPR-19 NRC Docket No. 50-237

Subject:

Licensee Event Report 237/2009-006-00, "Failure of Main Control Room Ventilation Due to Breaker Malfunction" Enclosed is Licensee Event Report 237/2009-006-00, "Failure of Main Control Room Ventilation Due to Breaker Malfunction," for Dresden Nuclear Power Station. This event is being reported in accordance with 10 CFR 50.73(a)(2)(v)(D) "Any event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident."

The final analysis of the breaker malfunction has not been completed at this time. Therefore a supplemental Licensee Event Report will be submitted upon completion of the analysis.

There are no regulatory commitments contained in this submittal.

Should you have any questions concerning this letter, please contact Ms. Marri Marchionda at (815) 416-2800.

Respectfully, Tim Hanley6 Site Vice President Dresden Nuclear Power Station Enclosure cc:

Regional Administrator - NRC Region III NRC Senior Resident Inspector - Dresden Nuclear Power Station

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 08/31/2010 (9-2007)

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 Records and FOIA/Privacy Service Branch (T-5 F52), U.S. Nuclear Regulatory Commission, LICENSEE EVENT REPORT (LER)

Washington, DC 20555-0001, or by internet e-mail to infocollects@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. Ifa means used to impose an information collection does not display a currently valid OMB control (See reverse for required number of number, the NRC may not conduct or sponsor, and a person is not required to respond digits/characters for each block) to, the information collection.

13. PAGE Dresden Nuclear Power Station, Unit 2 05000237 1 OF 3

4. TITLE Failure of Main Control Room Ventilation Due to Breaker Malfunction

5. EVENT DATE

6. LER NUMBER

7. REPORT DATE

8. OTHER FACILITIES INVOLVED FACILITY NAME DOCKET NUMBER MONTH DAY YEAR Y

SEQUENTIAL REV MONTH DAY YEAR N/A M

MA YEAR NUMBER NO. IN/A FACILITY NAME DOCKET NUMBER 11 12 2009 2009 006 -

00 01 08 2010 N/A N/A

9. OPERATING MODE

11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)

[1 20.2201(b)

[I 20.2203(a)(3)(i)

El 50.73(a)(2)(i)(C)

[E 50.73(a)(2)(vii) 5 [1 20.2201(d)

[I 20.2203(a)(3)(ii) 0l 50.73(a)(2)(ii)(A)

[I 50.73(a)(2)(viii)(A)

E] 20.2203(a)(1)

El 20.2203(a)(4) 0l 50.73(a)(2)(ii)(B)

El 50.73(a)(2)(viii)(B)

[I 20.2203(a)(2)(i)

[1 50.36(c)(1)(i)(A) 0l 50.73(a)(2)(iii)

El 50.73(a)(2)(ix)(A)

10. POWER LEVEL

[: 20.2203(a)(2)(ii)

El 50.36(c)(1)(ii)(A)

[1 50.73(a)(2)(iv)(A)

[I 50.73(a)(2)(x)

El 20.2203(a)(2)(iii)

[1 50.36(c)(2)

El 50.73(a)(2)(v)(A)

[E 73.71 (a)(4) 000 E] 20.2203(a)(2)(iv)

El 50.46(a)(3)(ii)

El 50.73(a)(2)(v)(B)

El 73.71 (a)(5)

E] 20.2203(a)(2)(v)

[E 50.73(a)(2)(i)(A)

El 50.73(a)(2)(v)(C)

El OTHER E] 20.2203(a)(2)(vi)

[E 50.73(a)(2)(i)(B) 5 50.73(a)(2)(v)(D)

Specify in Abstract below or in C.

Cause of Event

Troubleshooting was initiated following the breaker malfunction. At this time, no conclusive evidence has been identified which indicates the cause of the breaker failure. The failed breaker was quarantined and subsequently sent to a vendor for failure analysis. Once the failure analysis is completed a supplemental report will be submitted.

D.

Safety Analysis

The health and safety of the public was not compromised as a result of this condition due to the availability of safety systems needed to mitigate offsite releases and remove residual heat.

Therefore, the safety significance of this event is minimal. Additionally, the capability to shut the plant down and maintain it in a safe condition was not compromised during this condition. Offsite power was available during the course of this event. The function was restored well within the required completion time of the plant's technical specifications.

E.

Corrective Actions

Troubleshooting was performed. However, no cause was identified. Upon completion of the failure analysis, corrective actions will be developed and a supplemental report will be issued.

F.

Previous Occurrences

A review of DNPS Licensee Event Reports (LERs) was performed and no control room emergency ventilation failures due to breaker failure events were identified.

G.

Component Failure Data

Component Failure information will be provided in a supplemental report following completion of the failure analysis.PRINTED ON RECYCLED PAPER NRIC FORM 366A (9-2007)

PRINTED ON RECYCLED PAPER