| 07-19-2007 | On May 21, 2007, a review of industry operating experience ( OE) related to emergency diesel generators ( DG) found a condition which is not consistent with the assumptions of the River Bend Station ( RBS) post-fire safe shutdown analysis. That analysis assumes that the high temperature trips on the Division 1 DG would remain active following a start signal resulting from a loss of offsite power ( LOP). This OE review found that when the DG starts following a LOP, non-critical trips (such as high temperature) are bypassed. With the non-critical trips bypassed, the DG will continue to run without sufficient cooling, likely resulting in damage to the engine. It appears that, during past revisions of the safe-shutdown analyses, reviewers did not adequately assess all potential failure modes resulting from multiple spurious actuations. This is being reported in accordance with 10CFR50.73(a)(2)(ii)(B) as a condition resulting in the plant being in an unanalyzed condition that significantly degrades plant safety.
This condition does not cause the Division 1 DG to be inoperable with respect to its function required in the accident analysis and Technical Specifications. A pre-existing Standing Order that prohibits welding and grinding in the main control room during Modes 1, 2, and 3 was revised to specifically address this condition. |
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LER-2007-003, Entergy Operations, Inc.
River Bend Station
5485 U.S. Highway 61N
St. Francisville, LA 70775
Tel 225 381 4157Enter*v
Fax 225 635 5068
dlorfin@entergy.com
David N. Lorfing
Manager-Licensing
July 19, 2007
U. S. Nuclear Regulatory Commission
ATTN: Document Control Desk
Washington, DC 20555
Subject:G Licensee Event Report 50-458 / 07-003-00
River Bend Station — Unit 1
Docket No. 50-458
License No. NPF-47
File Nos.G G9.5, G9.25.1.3
RBG-46713
RBF1-07-0117
Ladies and Gentlemen:
In accordance with 10CFR50.73, enclosed is the subject Licensee Event Report.
This document contains no commitments.
Sincerely,
David N. Lorfing
Manager — Licensin
DNL/dhw
Enclosure
Licensee Event Report 50-458 / 07-003-00
July 19, 2007
RBG-46713
RBF1-07-0117
Page 2 of 2
cc:UU. S. Nuclear Regulatory Commission
Region IV
611 Ryan Plaza Drive, Suite 400
Arlington, TX 76011
NRC Sr. Resident Inspector
P. 0. Box 1050
St. Francisville, LA 70775
INPO Records Center
E-Mail
Mr. Jim Calloway
Public Utility Commission of Texas
1701 N. Congress Ave.
Austin, TX 78711-3326
Mr. Jeff Meyers
Louisiana Department of Environmental Quality
Office of Environmental Compliance
P.O. Box 4312
Baton Rouge, LA 70821-4312
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 06/30/2007
(6-2004)
LICENSEE EVENT REPORT (LER)
(See reverse for required number of
digits/characters for each block)
1. FACILITY NAME
River Bend Station - Unit 1
4. TITLE
Estimated burden per response to comply with this mandatory collection
request: 50 hours. 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, 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. If a means used to impose an information
collection does not display a currently valid OMB control number, the NRC may
not conduct or sponsor, and a person is not required to respond to, the
information collection.
2. DOCKET NUMBER 3. PAGE
05000-458 1 of 4
Unanalyzed Condition of Emergency Diesel Generator in Post-Fire Safe Shutdown Scenario| River Bend Station - Unit 1 |
| Event date: |
05-21-2007 |
|---|
| Report date: |
07-19-2007 |
|---|
| Reporting criterion: |
10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition |
|---|
| 4582007003R00 - NRC Website |
|
full load without cooling water and reconcile with the time to establish control at the local and remote shutdown panels." The response to this item took credit for the high temperature trips being active following a LOP event. This erroneous assumption appears to have been based solely on previous revisions of the safe shutdown analysis.
IMMEDIATE ACTIONS
This condition does not cause the Division 1 DG to be inoperable with respect to its safety function specified in the accident analysis and Technical Specifications. A pre-existing Standing Order that prohibits welding and grinding in the main control room during Modes 1, 2, and 3 was revised to specifically address this condition.
CORRECTIVE ACTION
Various options for correcting this condition are being evaluated, including:
- re-assessing the design and licensing requirements related to DGs in the safe shutdown scenario,
- validating the operator's response time for restoring cooling water to the DG following a main control room fire / LOP event, and,
- modifying the DG to retain the function of the high temperature trip after starting in response to a LOP.
Actions for addressing this condition are being tracked in the station's corrective action program.
SAFETY SIGNIFICANCE
This condition is unique to the Division 1 DG. The Division 3 DG, which also has remote shutdown transfer switching in its design, retains all its trips active in the LOP event, bypassing them only in a LOCA response. The Division 2 DG has no remote shutdown transfer switching capability, and is considered by the safe shutdown analysis to be damaged in the fire. This condition does not cause the Division 1 DG to be inoperable with respect to its function required in the accident analysis and Technical Specifications.
This condition results in a noncompliance with the requirements of 10CFR50 Appendix R, for a specific scenario that has a low likelihood of occurrence. Plant equipment remains
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| | | Reporting criterion |
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| 05000458/LER-2007-003 | Entergy Operations, Inc.
River Bend Station
5485 U.S. Highway 61N
St. Francisville, LA 70775
Tel 225 381 4157Enter*v
Fax 225 635 5068
dlorfin@entergy.com
David N. Lorfing
Manager-Licensing
July 19, 2007
U. S. Nuclear Regulatory Commission
ATTN: Document Control Desk
Washington, DC 20555
Subject:G Licensee Event Report 50-458 / 07-003-00
River Bend Station — Unit 1
Docket No. 50-458
License No. NPF-47
File Nos.G G9.5, G9.25.1.3
RBG-46713
RBF1-07-0117
Ladies and Gentlemen:
In accordance with 10CFR50.73, enclosed is the subject Licensee Event Report.
This document contains no commitments.
Sincerely,
David N. Lorfing
Manager — Licensin
DNL/dhw
Enclosure
Licensee Event Report 50-458 / 07-003-00
July 19, 2007
RBG-46713
RBF1-07-0117
Page 2 of 2
cc:UU. S. Nuclear Regulatory Commission
Region IV
611 Ryan Plaza Drive, Suite 400
Arlington, TX 76011
NRC Sr. Resident Inspector
P. 0. Box 1050
St. Francisville, LA 70775
INPO Records Center
E-Mail
Mr. Jim Calloway
Public Utility Commission of Texas
1701 N. Congress Ave.
Austin, TX 78711-3326
Mr. Jeff Meyers
Louisiana Department of Environmental Quality
Office of Environmental Compliance
P.O. Box 4312
Baton Rouge, LA 70821-4312
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 06/30/2007
(6-2004)
LICENSEE EVENT REPORT (LER)
(See reverse for required number of
digits/characters for each block)
1. FACILITY NAME
River Bend Station - Unit 1
4. TITLE
Estimated burden per response to comply with this mandatory collection
request: 50 hours. 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, 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. If a means used to impose an information
collection does not display a currently valid OMB control number, the NRC may
not conduct or sponsor, and a person is not required to respond to, the
information collection.
2. DOCKET NUMBER 3. PAGE
05000-458 1 of 4
Unanalyzed Condition of Emergency Diesel Generator in Post-Fire Safe Shutdown Scenario | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition | | 05000458/LER-2007-005 | River Bend Station
5485 U.S. Highway 61N
St. Francisville, LA 70775
Tel 225 381 4157Entergy Fax 225 635 5068
dlonin@entergy.com
David N. Lorfing
Manager-Licensing
November 14, 2007
U. S. Nuclear Regulatory Commission
ATTN: Document Control Desk
Washington, DC 20555
Subject:G Licensee Event Report 50-458 / 07-005-00
River Bend Station — Unit 1
Docket No. 50-458
License No. NPF-47
File Nos.G G9.5, G9.25.1.3
RBG-46760
RBF1-07-0208
Ladies and Gentlemen:
In accordance with 10CFR50.73, enclosed is the subject Licensee Event Report.
This document contains no commitments.
Sincerely,
David N. Lorfing
Manager — Licensing
DNL/dhw
Enclosure
Licensee Event Report 50-458 / 07-005-00
November 14, 2007
RBG-46760
RBF1-07-0208
Page 2 of 2
cc:UU. S. Nuclear Regulatory Commission
Region IV
611 Ryan Plaza Drive, Suite 400
Arlington, TX 76011
NRC Sr. Resident Inspector
P. 0. Box 1050
St. Francisville, LA 70775
INPO Records Center
E-Mail
Mr. Jim Calloway
Public Utility Commission of Texas
1701 N. Congress Ave.
Austin, TX 78711-3326
Mr. Jeff Meyers
Louisiana Department of Environmental Quality
Office of Environmental Compliance
P.O. Box 4312
Baton Rouge, LA 70821-4312
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION
(9-2007)
LICENSEE EVENT REPORT (LER)
(See reverse for required number of
digits/characters for each block)
1. FACILITY NAME
River Bend Station - Unit 1
4. TITLE
APPROVED BY OMB: NO. 3150-0104 EXPIRES: 08/31/2010
Estimated burden per response to comply with this mandatory collection
request: 50 hours. 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, 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. If a means used to impose an information
collection does not display a currently valid OMB control number, the NRC may
not conduct or sponsor, and a person is not required to respond to, the
information collection.
2. DOCKET NUMBER 3. PAGE
05000-458 1 of 4
Unplanned Reactor Scram During Surveillance Testing Due to Damaged Terminal Board | 10 CFR 50.73(a)(2)(iv), System Actuation |
|