05000335/LER-2022-003, Manual Reactor Trip Due to Loss of Feedwater Pump
| ML22301A127 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 10/28/2022 |
| From: | Strand D Florida Power & Light Co |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| L-2022-179 LER 2022-003-00 | |
| Download: ML22301A127 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(i) 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) |
| 3352022003R00 - NRC Website | |
text
U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 Re:
St. Lucie Unit 1 Docket No. 50-335 Reportable Event: 2022-003-00 Date of Event: September 2, 2022 Manual Reactor Trip Due to Loss of Feedwater Pump October 28, 2022 L-2022-179 10 CFR 50.73 The attached Licensee Event Report 2022-003 is being submitted pursuant to the requirements of 10 CFR 50. 73 to provide notification of the subject event.
Respectfully, Dianne Strand General Manager, Regulatory Affairs Florida Power & Light Company Attachment cc:
St. Lucie NRC Senior Resident Inspector St. Lucie NRC Program Manager Florida Power & Light Company 6501 S. Ocean Drive, Jensen Beach, FL 34957
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 08/31/2023 (08-2020)
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3.Page St. Lucie Unit 1 05000335 1 of 3
- 4. Title Manual Reactor Trip Due to Loss of Feedwater Pump
- 5. Event Date
- 6. LER Number
- 7. Report Date
- 8. Other Facilities Involved Year I Sequential I Revision Facility Name Docket Number Month Day Year Number Number Month Day Year n/a 05000 Facility Name Docket Number 9
2 2022 2022 -
003 -
00 10 28 2022 n/a 05000
- 9. Operating Mode 110. Power Level 1
40%
11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 10 CFR Part 20 20.2203(a)(2)(vi) 50.36(c)(2)
~ 50.73(a)(2)(iv)(A)
- 50. 73(a)(2)(x) 20.2201(b) 20.2203(a)(3)(i) 50.46(a)(3)(ii)
- 50. 73(a)(2)(v)(A) 10 CFR Part 73 20.2201(d) 20.2203(a)(3)(ii) 50.69(9)
- 50. 73(a)(2)(v)(B) 73.71 (a)(4) 20.2203(a)(1) 20.2203(a)(4)
- 50. 73(a)(2)(i)(A) 50.73(a)(2)(v)(C) 73.71 (a)(5) 20.2203(a)(2)(i) 10 CFR Part 21 50.73(a)(2)(i)(B) 50.73(a)(2)(v)(D) 73.77(a)(1) 20.2203(a)(2)(ii) 21.2(c) 50.73(a)(2)(i)(C)
- 50. 73(a)(2)(vii)
- 73. 77(a)(2)(i) 20.2203(a)(2)(iii) 10 CFR Part 50
- 50. 73(a)(2)(ii)(A)
- 50. 73(a)(2)(viii)(A)
- 73. 77(a)(2)(ii) 20.2203(a)(2)(iv) 50.36(c)(1 )(i)(A) 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B) 20.2203(a)(2)(v) 50.36(c)(1 )(ii)(A) 50.73(a)(2)(iii)
- 50. 73(a)(2)(ix)(A)
OTHER (Specify here, in abstract or in NRC 366A)
- 12. Licensee Contact for this LER Licensee Contact I
319-851-7900 Bob Murrell, Licensing Engineer Cause System Component Manufacturer Reportable
Cause
System Component Manufacturer Reportable To IRIS To IRIS E
SD PMC y
- 14. Supplemental Report Expected
- 15. Expected Month Day Year D YES (If yes, complete 15. Expected Submission Date)
~NO Submission Date Abstract (Limit to 1560 spaces, i.e., approximately 15 single-spaced typewritten lines)
On September 2, 2022 with Unit 1 in Mode 1 at 40% power, during performance of a planned shutdown for refueling outage SL 1-31, the operating Main Feedwater Pump tripped resulting in lowering level in the steam generators. As a result, the unit was manually tripped. The cause of the Main Feedwater Pump trip was a loss of suction pressure due to Condensate Recirculation Valve FCV-12-1 fully opening when flow controller FIC-12-1 was taken to manual as part of the planned shutdown. The lowering steam generator water level led to an Auxiliary Feedwater system actuation.
The reactor trip was uncomplicated, and all safety systems responded as designed. Reactor shutdowns are analyzed events in the Updated Final Safety Analysis Report. Therefore, this event had no impact on the health and safety of the public. This event was reported under Event Notification 56087 in accordance with 10 CFR 50.72(b)(3)(iv)(A) and 50.72(b)(2)(iv)(B). This licensee event report is being submitted pursuant 1 O CFR 50. 73(a)(2)(iv)(A).
Description
- 2. Docket 05000335 Year 2022
- 6. LER Number I
Sequential Number 003 I
Rev No.
00 On September 2, 2022, St Lucie Unit 1 operators were performing a planned shutdown in accordance with unit procedures in preparation for refueling outage SL 1-31. At approximately 2220, the Unit 1 Reactor down power reached 44% power. Per procedures, operators proceeded to secure the 1 B Main Feedwater Pump, followed by securing the 1 B Condensate Pump. After securing the pumps, an operator was directed to control condensate flow for the operating 1 C Condensate Pump using the Condensate Recirculation Valve FCV-12-1 in accordance with procedures. The operator reported taking actions to place the condensate flow controller FIC-12-1 in manual as directed by procedure.
When the local flow control switch FIC-12-1 was placed to manual, the operator reported FCV-12-1 went full open. Attempts to adjust flow using the controller were not successful. At 2246, with the Unit 1 operating at approximately 40% power, the 1A Main Feedwater Pump tripped on low suction pressure.
Operators were alerted to the pump trip by plant annunciators and feedwater indications. Due to inability to maintain steam generator levels, a manual reactor trip was initiated at 2247 and Auxiliary Feedwater (AFW) was manually aligned to both steam generators. The Aux Feedwater Actuation System (AFAS) actuated for both steam generators due to low level prior to level recovery using AFW.
Cause of the Event
The direct cause of this event was an erroneous indication on condensate flow controller FIC-12-1.
Specifically, when the FIC was taken to manual it indicated the manual loader pressure adjustment was balanced with the automatic control output. Subsequent investigations show that this was the cause of FCV-12-1 to go full open. The root cause of this event was improper maintenance and pre-operational checks of FIC-12-1.
Analysis of the Event
This event was reported under Event Notification 56087 in accordance with 10 CFR
- 50. 72(b)(3)(iv)(A) and 50. 72(b)(2)(iv)(B). This licensee event report is being submitted pursuant 10 CFR 50.73(a)(2)(iv)(A).
Safety Significance
The reactor trip was uncomplicated, and all safety systems responded as designed. Reactor shutdowns are analyzed events in the Updated Final Safety Analysis Report. Therefore, this event had no impact on the health and safety of the public.
Corrective Actions
FIC-12-1 was rebuilt during SL 1-31.
Actions have been initiated to revise Unit 1 and Unit 2 maintenance procedures to include exercising FIC-12-1 to ensure reliability. The specific actions are related to calibrations checks, observations of controller function, and verifying proper indication of balance between the automatic and manual settings. In addition, actions have been initiated to update preventative maintenance requirements Unit 1 and 2 control loops F-12-1 components.
Similar Events
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