05000482/LER-2008-005, Re Unanalyzed Condition Discovered Due to Improperly Installed Fuse in Class 1 E Electrical Equipment Room Cooler

Re Unanalyzed Condition Discovered Due to Improperly Installed Fuse in Class 1 E Electrical Equipment Room Cooler

ML081840110
Person / Time
Site:	Wolf Creek
Issue date:	06/23/2008
From:	Matthew Sunseri Wolf Creek
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
WO 08-0015 LER 08-005-00
Download: ML081840110 (5)

LER-2008-005, Re Unanalyzed Condition Discovered Due to Improperly Installed Fuse in Class 1 E Electrical Equipment Room Cooler

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
4822008005R00 - NRC Website

text

W#,ý.LF CREEK NUCLEAR OPERATING CORPORATION Matthew W. Sunseri Vice President Operations and Plant Manager June 23, 2008 WO 08-0015 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555

Subject:

Docket No. 50-482:

Licensee Event Report 2008-005-00, Unanalyzed Condition Discovered Due To Improperly Installed Fuse In Class 1 E Electrical Equipment Room Cooler Gentlemen, The enclosed Licensee Event Report (LER) 2008-005-00 is being submitted pursuant to 10 CFR 50.73(a)(2)(ii)(B) regarding an unanalyzed condition that could potentially affect postfire safe shutdown equipment availability at Wolf Creek Generating Station.

Commitments made by Wolf Creek Nuclear Operating Corporation in the enclosed LER are identified in the Attachment to this letter.

If you have any questions concerning this matter, please contact me at (620) 364-4008, or Mr.

Richard D. Flannigan, Manager Regulatory Affairs at (620) 364-4117.

Sincerely, Matthew W. Sunseri MWS/rlt Attachment Enclosure cc:

E. E. Collins (NRC), w/a, w/e V. G. Gaddy (NRC), w/a, w/e B. K. Singal (NRC), w/a, w/e Senior Resident Inspector (NRC), w/a, w/e P.O. Box 411 / Burlington, KS 66839 Phone: (620) 364-8831 An Equal Opportunity Employer M/F/HC/VET

'r

Attachment to WO-08-0015 Page 1 of 1 LIST OF COMMITMENTS The following table identifies those actions committed to by Wolf Creek Nuclear Operating Corporation in this document. Any other statements in this letter are provided for information purposes and are not considered regulatory commitments. Please direct questions regarding these commitments to Mr.

Richard Flannigan, Manager Regulatory Affairs at Wolf Creek Generating Station, (620) 364-4117.

REGULATORY COMMITMENT DUE DATE The remaining twenty circuits in the plant with redundant post Prior to plant startup fire safe shutdown fusing will be examined to verify that the following Refueling fuses are wired correctly.

Outage 17.

Procedure AP 16E-002, 'Post Maintence Testing December 19, 2008 Development,' will be revised to ensure equipment with redundant fusing are properly wired.

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 06/30/2007 (6-2004)

, the NRC may (See reverse for required number of not conduct or sponsor, and a person is not required to respond to, the digits/characters for each block) information collection.

3. PAGE WOLF CREEK GENERATING STATION 05000 482 1 OF 3

4. TITLE Unanalyzed Condition Discovered Due To Improperly Installed Fuse In Class 1 E Electrical Equipment Room Cooler

5. EVENT DATE

6. LER NUMBER

7. REPORT DATE

8. OTHER FACILITIES INVOLVED SEQUENTIAL REV YEAR FACILITY NAME DOCKET NUMBER NUMBER NO.

05000 FACILITY NAME DOCKET NUMBER 04 26 2008 2008 005 -

00 06 23 2008 05000

9. OPERATING MODF

11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check al/ that apply) 6

] 20.2201(b)

[J 20.2203(a)(3)(i)

[]

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

[]

50.73(a)(2)(vii)

El 20.2201(d)

El 20.2203(a)(3)(ii)

E] 50.73(a)(2)(ii)(A)

E] 50.73(a)(2)(viii)(A)

[1 20.2203(a)(1)

El 20.2203(a)(4)

[]

50.73(a)(2)(ii)(B)

[

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

[] 20.2203(a)(2)(i)

E] 50.36(c)(1)(i)(A)

E] 50.73(a)(2)(iii)

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

10. POWER LEVEL [J 20.2203(a)(2)(ii) 5 50.36(c)(1)(ii)(A) fl 50.73(a)(2)(iv)(A)

E] 50.73(a)(2)(x)

[J 20.2203(a)(2)(iii)

El 50.36(c)(2)

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

El 73.71(a)(4) 000 20.2203(a)(2)(iv)

E] 50.46(a)(3)(ii)

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

El 73.71(a)(5)

E] 20.2203(a)(2)(v) 5 50.73(a)(2)(i)(A)

E] 50.73(a)(2)(v)(C)

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

[J 50.73(a)(2)(i)(B)

E] 50.73(a)(2)(v)(D)

Specify in Abstract below or in (If more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A)

BASIS FOR REPORTABILITY:

10CFR50 Appendix R Section III.L.7 requires "The safe shutdown equipment and systems for each fire area shall be known to be isolated from associated non-safety circuits in the fire area such that hot shorts, open circuits, or shorts to ground in the associated circuits will not prevent operation of the safe shutdown equipment." Based on this information, WCNOC made an eight hour Emergency Notification System call in accordance with 10 CFR 50.72(b)(3)

(ii)(B).

This condition is also reportable pursuant to 10 CFR 50.73(a)(2)(ii)(B) for any event or condition that resulted in the nuclear power plant being in an unanalyzed condition that significantly degraded plant safety.

ROOT CAUSE:

The 'B' train Class 1 E electrical equipment room cooler, power and control cabinets, were replaced in the fall of 2003.

The vendor incorrectly wired the line side of the dedicated post fire safe shutdown control power transformer isolation fuse to the load side of the control room supply fuse. This placed both the isolate and remote power supply fuses of the control power transformer in series instead of the required parallel configuration. The termination error rendered the post fire safe shutdown redundant isolation fuse incapable of performing its intended design function to supply independent isolated control power to the circuit in the event of a control circuit fault due to a fire in the control room.

Normaltesting of the circuit did not catch the error.

CORRECTIVE ACTIONS

The wiring for the fuses was corrected to place them in parallel prior to entering Mode 4.

Over the 23 years of plant operation no other redundant fuse incorrect wiring issues are known to have been found.

As a precaution, the additional twenty circuits in the plant with redundant post fire safe shutdown fusing will be examined to verify that the fuses are wired correctly. This will be accomplished prior to plant startup following Refuel Outage 17.

Procedure AP 16E-002, 'Post Maintence Testing Development,' will be revised by December 19, 2008, to ensure equipment with redundant fusing are properly wired.

SAFETY SIGNIFICANCE

This issue is of low safety significance. Loss of the Class 1 E electrical equipment room cooler units does not automatically cause inoperability of the associated Class 1 E electrical equipment. There is reasonable assurance that safe shutdown would be achieved if a fire occurred in the control room that resulted in a loss of Class 1 E electrical equipment room cooling.

OPERATING EXPERIENCE/PREVIOUS EVENTS:

None.