05000458/LER-2011-001, Regarding Unplanned Actuation of Standby Service Water System Due to Procedure Inadequacy
| ML110870915 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 03/21/2011 |
| From: | Lorfing D Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RBG-47131 LER 11-001-00 | |
| Download: ML110870915 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 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 |
| 4582011001R00 - NRC Website | |
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SEntergy Entergy Operations, Inc.
River Bend Station 5485 U.S. Highway 61N St. Francisville, LA 70775 Tel 225381 4157 Fax 225 635 5068 dlorfin@entergy.com David N. Lorfing Manager-Licensing RBG-47131 March 21, 2011 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555
Subject:
File No.
Licensee Event Report 50-458 / 11-001-00 River Bend Station - Unit 1 Docket No. 50-458 License No. NPF-47 G9.5 RBF1 0056
Dear Sir or Madam:
In accordance with 1 OCFR50.73, enclosed is the subject Licensee Event Report.
This document contains no commitments. If you have any questions, please contact me at 225-381-4157.
Sincerely, David N. Lorfing Manager - Licensing Enclosure
Licensee Event Report 50-458 / 11-001-00 March 21, 2011 RBG-47131 RBF1-11-0056 Page 2 of 2 cc:
U. S. Nuclear Regulatory Commission Region IV 612 East Lamar Blvd., Suite 400 Arlington, TX 76011-4125 NRC Sr. Resident Inspector P. O. Box 1050 St. Francisville, LA 70775 INPO Records Center E-Mail (MS Word format)
Mr. Jim Calloway Public Utility Commission of Texas 1701 N. Congress Ave.
Austin, TX 78711-3326 Mr. Jeffrey P. Meyers Louisiana Department of Environmental Quality Attn: OEC-ERSD P.O. Box 4312 Baton Rouge, LA 70821-4312
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2013 (10-2010) digits/characters for each block) the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE River Bend Station - Unit 1 05000-458 1 OF 3
- 4. TITLE Unplanned Actuation of Standby Service Water System Due to Procedure Inadequacy
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED SEQUENTIAL REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBER NO.
05000 FACILITY NAME DOCKET NUMBER 01 20 2011 2011-001-00 03 21 2011 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
[: 20.2201(b)
[I 20.2203(a)(3)(i)
[]
50.73(a)(2)(i)(C)
El 50.73(a)(2)(vii) 5 El 20.2201(d)
El 20.2203(a)(3)(ii)
El 50.73(a)(2)(ii)(A)
El 50.73(a)(2)(viii)(A)
E] 20.2203(a)(1)
El 20.2203(a)(4)
El 50.73(a)(2)(ii)(B)
El 50.73(a)(2)(viii)(B)
El 20.2203(a)(2)(i)
[E 50.36(c)(1)(i)(A)
El 50.73(a)(2)(iii)
El 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL E] 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)
[I 20.2203(a)(2)(iii)
El 50.36(c)(2)
El 50.73(a)(2)(v)(A)
E] 73.71 (a)(4) 0 [1 20.2203(a)(2)(iv)
El 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B)
El 73.71 (a)(5)
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)
El 50.73(a)(2)(v)(D)
Specify in Abstract below or in NRC Form 366A
- 12. LICENSEE CONTACT FOR THIS LER FACILITY NAME TELEPHONE NUMBER (Include Area Code)
David N. Lorfing, Manager - Licensing 225-381-4157MANU-REPORTABLE
CAUSE
SYSTEM COMPONENT MANU-REPORTABLE
CAUSE
SYSTEM COMPONENT FACTURER TO EPIX FACTURER TO EPIX n/a
- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED MONTH DAY YEAR SUBMISSION
[: YES (If yes, complete 15. EXPECTED SUBMISSION DATE) Z NO DATE ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)
At 2:34 p.m. CST on January 20, 2011, while the plant was in a refueling outage, standby service water (SSW) pump "C" started automatically during system realignment. The Division 1 SSW subsystem (pumps "A" and "C") was being started to facilitate maintenance on the normal service water system.
When the "A" pump was manually started, the pressure transient caused by the realignment of the motor-operated valves in the system caused a momentary low system pressure, actuating SSW pump "C" automatically. This event resulted from a weakness in the operating procedure, in that the intended system configuration for this operation exceeded the flow capacity for one pump. Actions are being taken to strengthen this and other similar procedures to prevent recurrence. This event is being reported in accordance with 10CFR50.73(a)(2)(iv)(A) as a condition that resulted in the automatic actuation of the "C" SSW pump.
NRC FORM 366 (10-2010)LICENSEE EVENT REPORT (LER)
U.S. NUCLEAR REGULATORY COMMISSION (10-2010)
CONTINUATION SHEET
- 1. FACILITY NAME
- 2. DOCKET
- 6. LER NUMBER
- 3. PAGE River Bend Station - Unit 1 YEAR SEQUENTIAL REV.
05000-458 2 OF 3 2011 -- 001 -- 00 REPORTED CONDITION At 2:34 p.m. CST on January 20, 2011, while the plant was in a refueling outage, standby service water (SSW) (BS) pump (**P**) "C" started automatically during system realignment.
The Division 1 SSW subsystem (pumps "A" and "C") was being started to supply necessary cooling loads during the outage. When the "A" pump was manually started, the pressure transient caused by the realignment of the motor-operated valves in the system caused a momentary low system pressure, actuating SSW pump "C" automatically.
This event is being reported in accordance with 10CFR50.73(a)(2)(iv)(A) as a condition that resulted in the automatic actuation of the "C" SSW pump. The pump actuated as designed in response to a momentary low pressure signal in the non-safety related normal service water system.
CAUSAL ANALYSIS As part of the refueling outage that was in progress at the time of the event, the Division 1 SSW subsystem was being started to facilitate maintenance on the normal service water system.
Operators were executing the system operating procedure for a manual start. The procedure contains a chart for estimating the system flow demands for various loads and configurations.
However, the chart provided no information concerning the flow required for the residual heat removal or spent fuel pool cooling systems. No notes or warnings were included in the procedure prior to the performance of a step that has the potential to cause the actuation of a standby pump.
The intended system configuration for this operation exceeded the flow capacity for one pump.
During the valve alignment, a momentary low system pressure actuated SSW pump "C" automatically.
PREVIOUS OCCURRENCE EVALUATION Two actuations of SSW that occurred during system configuration changes were reported by River Bend Station in 2006 (LERs 050-458/2006-03-00 and 050-458/2006-05-00). The investigation of this event found that the corrective actions for those events did not address potential procedural vulnerabilities to inadvertent SSW actuations similar to the reported event.
Weaknesses in the affected procedures will be addressed by the corrective action plan for this event.(10-2010)
LICENSEE EVENT REPORT (LER)
U.S. NUCLEAR REGULATORY COMMISSION CONTINUATION SHEET
- 1. FACILITY NAME River Bend Station - Unit 1 1
- 2. DOCKET
- 6. LER NUMBER
- 3. PAGE SEQUENTIAL NUMBER REV.
NO.
3 OF 3 2011 -- 001 -- 00 CORRECTIVE ACTION TO PREVENT RECURRENCE The following actions have been incorporated into the station's corrective action program:
- 1) An engineering evaluation has been performed to determine the system configurations that can be supported by the capacity of one SSW pump.
- 2) The results of the engineering evaluation will be incorporated into a new revision of the system operating procedure, as well as other procedures that present a vulnerability to unplanned actuations of SSW.
SAFETY SIGNIFICANCE
The "C" SSW pump responded as designed to a valid low pressure signal. Therefore, this event was of minimal significance with regard to the health and safety of the public.
(NOTE: Energy Industry Component Identification codes are annotated as (**XX**).)