05000282/LER-2007-004, Regarding Technical Specification Required Shutdown Due to Both Emergency Diesel Generators Being Inoperable

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Regarding Technical Specification Required Shutdown Due to Both Emergency Diesel Generators Being Inoperable
ML080440106
Person / Time
Site: Prairie Island 
Issue date: 02/12/2008
From: Wadley M
Nuclear Management Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
Event 43859, L-PI-08-007 LER 07-004-00
Download: ML080440106 (5)
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LER-2007-004, Regarding Technical Specification Required Shutdown Due to Both Emergency Diesel Generators Being Inoperable
Event date:
Report date:
Reporting criterion: 10 CFR 50.73(a)(2)(v), Loss of Safety Function
2822007004R00 - NRC Website
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text

Prairie lsland Nuclear Generating Plant Operated by Nuclear Management Company, LLC February 12,2008 L-PI-08-007 10 CFR 50.73 U S Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Prairie Island Nuclear Generating Plant Unit 1 Docket 50-282 License No. DPR-42 LER 1-07-04, Technical Specification Required Shutdown Due to Both Emerqencv Diesel Generators Being Inoperable Nuclear Management Company, LLC (NMC) herewith encloses Licensee Event Report (LER) 1-07-04. The LER describes the events surrounding completion of a Technical Specification required shutdown of Unit 1. Nuclear Management Company, LLC (NMC) reported the initiation of the Technical Specification required shutdown per 10 CFR 50.72 on December 21,2007 (Refer to Event Number 43859).

Summarv of Commitments This letter contains one new commitment and no changes to existing commitments:

NMC will supplement this L ER upon completion of the root cause evaluation for this event.

I Nuclear Management Company, LLC Enclosure cc:

Administrator, Region Ill, USNRC Project Manager, Prairie Island, USNRC Resident Inspector, Prairie Island, USNRC Department of Commerce, State of Minnesota 171 7 Wakonade Drive East Welch, Minnesota 55089-9642 Telephone: 651.388.1 121

ENCLOSURE LICENSEE EVENT REPORT 1-07-04 3 Pages Follow

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (9 2007)

LICENSEE EVENT REPORT (LER)

(See reverse for requ~red number of d~g~tslcharacters for each block)

I.

FACILITY NAME Pra~r~e Island Nuclear Generat~ng Plant Unit 1 APPROVED BY OMB NO 3150-0104 EXPIRES 08/3112010 Estimated burden per response to comply with thls mandatory collect~on 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 llcenslng process and fed back to Industry Send comments regarding burden estlmate to the Records and FOlAlPr~vacy Sewlce Branch (T-5 F52), U S Nuclear Regulatory Comm~sslon Washlngton DC 20555-0001, or by Internet e-mall to ~nfocollects@nrc gov, and to the Desk Offlcer, Office of lnformatlon and Regulatory Affalrs, NEOB-10202, (3150-0066). Office of Management and Budget Washington DC 20503 If a means used to lmpose an ~nformat~on collect~on does not dlsplay a currently valld OMB control number, the NRC may not conduct or sponsor, and a person IS not requlred to respond to, the lnformatlon collectlon

2. DOCKET NUMBER 05000282 4 TITLE Techn~cal Spec~f~cat~on Requlred Shutdown Due to Both Emergency Dlesel Generators Being Inoperable
3. PAGE 1 of 3 5 EVENT DATE MONTH 12
6. LER NUMBER NAME Jeff KIVI
11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)

[7 20 2201(b) 20 2203(a)(3)(1) 50 73(a)(2)(1)(C) 50 73(a)(z)(vll)

[7 20 2201(d)

[7 20 2203(a)(3)(11)

[7 50 73(a)(2)(11)(A) 50 73(a)(2)(v111)(A)

[7 20 2203(a)(1) 20 2203(a)(4)

[7 50 73(a)(2)(11)(B) 50 73(a)(2)(v111)(B) 20 2203(a)(2)(1)

[7 50 36(c)(l)(l)(A)

[7 50 73(a)(2)(111) 50 73(a)(Z)(lx)(A) 20 2203(a)(2)(11)

[7 50 36(c)(l)(11)(A) 50 73(a)(2)(1v)(A)

[7 50 73(a)(2)(x) 20 2203(a)(2)(111)

[7 50 36(c)(2)

[7 50 73(a)(Z)(v)(A) 7 3 71 (a)(4) 20 2203(a)(2)(1v) 50 46(a)(3)(11) 50 73(a)(2)(v)(B) 73 71(a)(5) 20 2203(a)(2)(v) 5 0 73(4(2)(1)(A)

[7 50 73(a)(2)(v)(C)

OTHER 20 2203(a)(2)(v1)

[7 50 73(a)(2)(1)(B) 50 73(a)(2)(v)(D)

Specify in Abstract below or In

12. LICENSEE CONTACT FOR THlS LER
9. OPERATING MODE 3
10. POWER LEVEL 0

DAY 21 TELEPHONE NUMBER (Include Area Code) 651.388.1121 YEAR 2007 REV NO YEAR

7. REPORT DATE 2007 0
8. OTHER FACILITIES INVOLVED SEQUENTIAL NUMBER MONTH 02 FACILITY NAME FACILITY NAME DOCKET NUMBER DOCKET NUMBER DAY 12 REPORTABLE TO EPlX YEAR 2008 YEAR 2008 ABSTRACT (Llrnlt to 1400 spaces, I e, approxrmately 15 slngle-spaced typewrrtten Ilnes)

On December 21, 2007, with the Unit 1 Train B emergency diesel generator (D2) out of service for planned ma~ntenance, Nuclear Management Company, LLC (NMC) staff were conducting a required surveillance test on the Unit 1 Train A 4kV Bus (Bus 15) load sequencer. The load sequencer failed the surveillance and the Unit 1 Train A emergency diesel generator (Dl) was declared inoperable as a result. With both D l and D2 Inoperable, Technical Specifications requires the affected Unit to be shutdown. Shutdown to Mode 3 was completed at approximately 0700 on December 21, 2007. Thus, this event is being reported in accordance wlth 10 CFR 50 73(a)(2)(i)(A) as a Technical Specification required shutdown.

Unlt 1 resumed Mode 1 power operation at approximately 1600 on December 24, 2007, after the Bus 15 load sequencer (and D l ) and D2 were returned to service.

NRC FORM 366 (9-2007)

CAUSE

COMPONENT MANU FA CTURER

14. SUPPLEMENTAL REPORT EXPECTED O YES (If yes, complete 15. EXPECTED SUBMISSION DATE).

0 NO SYSTEM MANU FACTURER COMPONENT

15. EXPECTED SUBMISSION DATE REPORTABLE TO EPlX MONTH 03 DAY 28

CAUSE

SYSTEM

EVENT DESCRIPTION LlC E NS EE EVENT RE PORT (LE R)

U.S. NUCLEAR REGULATORY COMMISSION (9-2007)

CONTINUATION SHEET On December 21, 2007, with the Unit 1 Train B emergency diesel generator' (D2) out of service for planned maintenance, Nuclear Management Company, LLC (NMC) staff were conducting a required surveillance test on the Unit 1 Train A 4kv2 BUS^ (BUS 15) load sequencer. The load sequencer failed the surveillance and the Unit 1 Train A emergency diesel generator (Dl) was declared inoperable as a result. With both D l and D2 inoperable, Technical Specifications requires the affected Unit to be shutdown. Shutdown to Mode 3 was completed at approximately 0700 on December 21, 2007.

I.

FACILITY NAME Prairie Island Nuclear Generating Plant Unit 1

EVENT ANALYSIS

The event resulted in Unit 1 being brought to Mode 3, thus, this event is being reported in accordance with 10 CFR 50.73(a)(Z)(i)(A) as a Technical Specification required shutdown.

2. DOCKET 05000282 Impact on Safety System Functional Failure Performance Indicator No actual loss of function occurred as a result of this event. The Unit 1 emergency AC buses remained energized at all times and D l (although inoperable) was available for powering Bus 15 using manual operator actions under an approved procedure. Consequently, this event is not reportable per 1 OCFR 50.73(a)(2)(v).
6. LER NUMBER SEQUENTIAL REV YEAR NUMBER NO 2007 -

04

- 0

SAFETY SIGNIFICANCE

3. PAGE 2 of 3 Unit 1 emergency AC buses remained energized throughout the event. D l was available for powering Bus 15 using manual operator actions had offsite sources to the Unit 1 emergency AC buses been lost during the event. Additionally, the cross-ties between Unit 1 and Unit 2 emergency AC buses were available to repower Unit 1 emergency AC buses from the Unit 2 emergency diesel generators. Thus, this event did not affect the health and safety of the public and the safety significance of this event is considered minimal.

CAUSE

The cause of the Bus 15 sequencer failure is under investigation. After completion of the root cause evaluation, NMC will supplement this LER.

1 Ells System Identifier: EK; Ells Component Identifier: DG 2 Ells System Identifier: EB 3 Ells Component Identifier: BU

CORRECTIVE ACTION LICENSEE EVENT REPORT (LER)

U.S. NUCLEAR REGULATORY COMMISSION (9-2007)

CONTINUATION SHEET NMC staff conducted troubleshooting and replaced an inputloutput card on the Bus 15 load sequencer, after which the Bus 15 load sequencer successfully passed the surveillance. As a result, the Bus 15 load sequencer and D l were returned to operable status. D2 was returned to operable status after completion of the planned maintenance.

I. FACILITY NAME Prairie Island Nuclear Generating Plant Unit 1 Further Corrective Actions will be identified by the root cause evaluation. After completion of the root cause evaluation, NMC will supplement this LER.

PREVIOUS SIMILAR EVENTS

2. DOCKET NUMBER 05000282 Review of Licensee Event Reports for Unit 1 and Unit 2 since 2005 found three previous Technical Specification required shutdowns. However, none of these were the result of a failed bus sequencer (two were for Unit 2 emergency diesel generator issues and one was for containment fan coil unit leakage.)
6. LER NUMBER YEAR SEQUENTIAL REV NUMBER NO 2007 -

04

- 0
3. PAGE 3 of 3

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