05000348/LER-2009-002, Turbine Driven AFW Pump Inoperable Due to Internal Flooding Concerns
| ML091460777 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 05/26/2009 |
| From: | Jerrica Johnson Southern Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NL-09-0772 LER 09-002-00 | |
| Download: ML091460777 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 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)(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 |
| 3482009002R00 - NRC Website | |
text
J. R. Johnson Southern Nuclear Vice President - Farley Operating Company, Inc.
Post Office Drawer 470 Ashford, Alabama 36312-0470 Tel 334.814.4511 Fax 334.814.4728 May 26, 2009 Docket Nos.: 50-348 NL-09-0772 50-364 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Joseph M. Farley Nuclear Plant - Units 1 and 2 Licensee Event Report 2009-002-00 Turbine Driven AFW Pump Inoperable Due to Internal Flooding Concerns Ladies and Gentlemen:
In accordance with the requirements of 10 CFR 50.73(a)(2)(i)(B), 10 CFR 50.73(a)(2)(ii)(B), and 10 CFR 50.73(a)(2)(v)(D), Southern Nuclear Operating Company (SNC) is submitting the enclosed Licensee Event Report.
This letter contains no NRC commitments. If you have any questions, please advise.
Sincerely, J. R. Johnson Vice President - Farley JRJ/CHM Enclosure: Units 1 and 2 Licensee Event Report 2009-002-00
U. S. Nuclear Regulatory Commission NL-09-0772 Page 2 cc:
Southern Nuclear Operating Company Mr. J. T. Gasser, Executive Vice President Mr. J. R. Johnson, Vice President - Farley Mr. P. M. Marino, Vice President - Engineering RTYPE: CFA04.054 U. S. Nuclear Regulatory Commission Mr. L. A. Reyes, Regional Administrator Mr. R. E. Martin, NRR Project Manager - Farley Mr. E. L. Crowe, Senior Resident Inspector - Farley
Joseph M. Farley Nuclear Plant - Units 1 and 2 Licensee Event Report 2009-002-00 Turbine Driven AFW Pump Inoperable Due to Internal Flooding Concerns Enclosure Units 1 and 2 Licensee Event Report 2009-002-00
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (9-2007)
LICENSEE EVENT REPORT (LER)
APPROVED BY OMB: NO. 3150-0104 EXPIRES: 08/31/2010
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 1. FACILITY NAME Joseph M. Farley Nuclear Plant - Unit 1
- 2. DOCKET NUMBER 05000 348
- 3. PAGE 1 of 3
- 4. TITLE Turbine Driven AFW Pump Inoperable Due to Internal Flooding Concerns
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL NUMBER REV NO.
MONTH DAY YEAR FACILITY NAME Farley Nuclear Plant Unit 2 DOCKET NUMBER 05000 364 03 27 2009 2009 - 002 - 00 05 26 2009 FACILITY NAME DOCKET NUMBER 05000
- 9. OPERATING MODE 1
- 10. POWER LEVEL 96
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply) 20.2201(b) 20.2203(a)(3)(i) 50.73(a)(2)(i)(C) 50.73(a)(2)(vii) 20.2201(d) 20.2203(a)(3)(ii) 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A) 20.2203(a)(1) 20.2203(a)(4) 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B) 20.2203(a)(2)(i) 50.36(c)(1)(i)(A) 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A) 20.2203(a)(2)(ii) 50.36(c)(1)(ii)(A) 50.73(a)(2)(iv)(A) 50.73(a)(2)(x) 20.2203(a)(2)(iii) 50.36(c)(2) 50.73(a)(2)(v)(A) 73.71(a)(4) 20.2203(a)(2)(iv) 50.46(a)(3)(ii) 50.73(a)(2)(v)(B) 73.71(a)(5) 20.2203(a)(2)(v) 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(C)
OTHER 20.2203(a)(2)(vi) 50.73(a)(2)(i)(B) 50.73(a)(2)(v)(D)
Specify in Abstract below or in (If more space is required, use additional copies of NRC Form 366A) (17) PRINTED ON RECYCLED PAPER)
The AFW System consists of two motor driven AFW Pumps and one steam turbine driven pump configured into three trains. Each motor driven AFW Pump is powered from an independent Class 1E power supply and feeds all steam generators through a common header. The steam turbine driven AFW pump receives steam from two main steam lines upstream of the main steam isolation valves. The turbine driven AFW pump supplies a common header capable of feeding all steam generators. Thus, the requirement for diversity in motive power sources for the AFW System is met.
The limiting Design Basis Accidents (DBAs) and transients for the AFW System are Feedwater Line Break (FWLB), Main Steam Line Break (MSLB), and Loss of Main Feedwater. A FWLB in the MSVR requires two of the three AFW pumps to meet the AFW flow demands. This is also the DBA that puts the most water in the MSVR.
With the drain from the MSVR to the Lower Equipment Room affecting the TDAFW Pump and assuming a single active failure (failure of a motor-driven AFW Pump), the AFW system could have challenged the required AFW flow for a FWLB event. This condition has been present since original design and construction of both Farley Units. In the past for both Units 1 and 2, equipment outages have occurred where a motor-driven AFW Pump was out of service. During these equipment outages, if a FWLB had occurred, FNP could have challenged the design requirements for AFW system. The event was evaluated using the FNP Probabilistic Risk Assessment (PRA) model and shown to be of very low safety significance. In the operating history of FNP, neither unit has experienced a FWLB. Therefore, the safety and health of the public was not adversely affected by the failure to isolate the drain path from the MSVR to the Lower Equipment Room.
Corrective Action
SNC installed a Thaxton plug in each floor drain thus returning both Units to the design configuration consistent with the internal flooding calculation.
Plant procedures have been revised to show that the affected drains are required to be plugged.
A further review of the plant internal flooding calculation is being performed to ensure that the calculation properly reflects the floor drains as they are configured per plant procedures. Any problems identified during this review will be tracked and corrected under the site corrective action program.
Additional Information
Previous Similar Events LER 2008-002-00 Unit 1 TS 3.0.3 Entry Due to Inoperability of Residual Heat Removal System