05000328/LER-2007-001, Plan Re Reactor Trip Following Closure of Main Feedwater Valve Due to Control Air Line Failure
| ML070860277 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 03/20/2007 |
| From: | Morris G Tennessee Valley Authority |
| To: | Document Control Desk, NRC/NRR/ADRO |
| References | |
| LER 07-001-00 | |
| Download: ML070860277 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv), System Actuation 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)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3282007001R00 - NRC Website | |
text
Tennessee Valley Authority, Post Office Box 2000, Soddy-Daisy, Tennessee 37384-2000 March 20, 2007 U.S. Nuclear Regulatory Commission 10 CFR 50.73 ATTN:
Document Control Desk Washington, D.C.
20555-0001 Gentlemen:
TENNESSEE VALLEY AUTHORITY -
SEQUOYAH NUCLEAR PLANT (SQN)
UNIT 2 -
DOCKET NO.
50-328 -
FACILITY OPERATING LICENSE DPR LICENSEE EVENT REPORT (LER) 50-328/2007-001-00 The enclosed LER provides details concerning an automatic reactor trip and engineered safety feature (ESF) actuation of auxiliary feedwater. The automatic trip occurred as a result of low-low steam generator level when a feedwater regulating valve closed as a result of a failed control air line.
This report is being submitted in accordance with 10 CFR 50.73(a) (2) (iv) as an event that resulted in the automatic actuation of engineered safety features, including the reactor protection system.
Sincerely, Glenn W. Morris
- Manager, Site Licensing and Industry Affairs Enclosure cc (Enclosure):
INPO Records Center Institute of Nuclear Power Operations 700 Galleria Parkway, SE, Suite 100 Atlanta, Georgia 30339-5957 Printed on recycled paper
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 06/30/2007 (6-2004)
Estimated burden per response to comply with this mandatory collection request: 50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-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),
LICENSEE EVENT REPORT (LER)
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, NEOBL10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to (See reverse for required number of impose an information collection does not display a currently valid OMB digits/characters for each block) control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE Sequoyah Nuclear Plant (SQN) Unit 2 05000328 1 OF 5
- 4. TITLE Reactor Trip Following Closure of Main Feedwater Valve Due To Control Air Line Failure
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE 1
- 8. OTHER FACILITIES INVOLVED SEQUENTIAL REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBER NO.
MONTH DAY YEAR 05000 FACILITY NAME DOCKET NUMBER 01 23 2007 2007 -
001 -
00 03 20 2007 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply) 0l 20.2201(b)
El 20.2203(a)(3)(i) 0l 50.73(a)(2)(i)(C) 0l 50.73(a)(2)(vii) 1 El 20.2201(d) 0l 20.2203(a)(3)(ii)
[I 50.73(a)(2)(ii)(A)
[I 50.73(a)(2)(viii)(A)
El 20.2203(a)(1)
El 20.2203(a)(4)
[I 50.73(a)(2)(ii)(B)
El 50.73(a)(2)(viii)(B)
El 20.2203(a)(2)(i) 0l 50.36(c)(1)(i)(A)
El 50.73(a)(2)(iii)
El 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL El 20.2203(a)(2)(ii)
El 50.36(c)(1)(ii)(A) 0 50.73(a)(2)(iv)(A)
El 50.73(a)(2)(x) 0l 20.2203(a)(2)(iii)
El 50.36(c)(2)
El 50.73(a)(2)(v)(A)
El 73.71(a)(4)
El 20.2203(a)(2)(iv)
El 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B)
El 73.71(a)(5) 100 El 20.2203(a)(2)(v)
El 50.73(a)(2)(i)(A)
El 50.73(a)(2)(v)(C)
El OTHER El 20.2203(a)(2)(vi)
El 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 (ff more space is required, use additional copies of (ff more space is required, use additional copies of NRC Form 366A)
B. Corrective Actions to Prevent Recurrence:
Corrective actions include revisions to the conduct of modifications procedures to strengthen the constructability walk down process and thermal growth considerations in piping specifications and installation instructions.
VII.
ADDITIONAL INFORMATION
A.
Failed Components:
Unit 2 Loop 2 feedwater regulating valve failed closed as a result of a control air tubing break.
B. Previous LERs on Similar Events:
A review of previous reportable events identified a similar event that resulted in a reactor trip that was initiated from a failed feedwater regulating valve control air line.
LER 50-327/95017 addressed the SQN Unit 1 event on December 8, 1995, which resulted from a lack of programmatic controls for maintenance activities that affect vibration through system configuration changes. The January 23, 2007, Unit 2 event is similar in that the thermal movement of the valve was not adequately considered during the planning and implementation of the control air line configuration changes on the Loop 2 feedwater regulating valve. The corrective actions to prevent recurrence from the previous Unit 1 event would not have prevented this air line/fitting failure.
C.
Additional Information
None.
D. Safety System Functional Failure:
This event did not result in a safety system functional failure in accordance with 10 CFR 50.73(a)(2)(v).
E.
Loss of Normal Heat Removal Consideration:
This condition did not result in a loss of normal heat removal.
VIII.
COMMITMENTS
None.