05000389/LER-2009-002, Ingress of Algae Results in Manual Trip
| ML091600364 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 06/01/2009 |
| From: | Johnston G Florida Power & Light Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-2009-120 LER 09-002-00 | |
| Download: ML091600364 (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 |
| 3892009002R00 - NRC Website | |
text
0 FPL Florida Power & Light Company, 6501 S. Ocean Drive, Jensen Beach, FL 34957 June 1,2009 L-2009-120 10 CFR 50.73 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 Re:
St. Lucie Unit 2 Docket No. 50-389 Reportable Event: 2009-002 Date of Event: April 1, 2009 Ingress of Algae Results in Manual Trip of St. Lucie Unit 2 The attached Licensee Event Report 2009-002 is being submitted pursuant to the requirements of 10 CFR 50.73 to provide notification of the subject event.
Respe tfully, G4rt
.J on Site Vice Pre dent St. Lucie Pla t GLJ/dlc Attachment AJ~
an FPL Group company
ir,,
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 08/31/201(
(9-2007)
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 LICENSEE EVENT REPORT (LER)
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.
- 13. PAGE St. Lucie Unit 2 05000389 1 of 4
- 4. TITLE Ingress of Algae Results in Manual Trip of St. Lucie Unit 2
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR SEQUENTIAL REV MONTH DAY YEAR NUMBER NO.I FACILITY NAME DOCKET NUMBER 04 01 2009 2009 -
002 00 06 01 2009
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply)
El 20.2201(b)
El 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C)
El 50.73(a)(2)(vii)
El 20.2201(d)
El 20.2203(a)(3)(ii)
El 50.73(a)(2)(ii)(A)
El 50.73(a)(2)(viii)(A)
El 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)
[E 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL t] 20.2203(a)(2)(ii)
El 50.36(c)(1)(ii)(A)
[
50.73(a)(2)(iv)(A)
[E 50.73(a)(2)(x)
El 20.2203(a)(2)(iii)
[I 50.36(c)(2)
El 50.73(a)(2)(v)(A)
El 73.71(a)(4)
[] 20.2203(a)(2)(iv)
[I 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B)
[j 73.71(a)(5) 92%
El 20.2203(a)(2)(v)
El 50.73(a)(2)(i)(A)
[j 50.73(a)(2)(v)(C)
E] 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 Unit 2 manual plant trip on April 1, 2009 is an outlier to this trend.
Analysis of the Event
This event is reportable under the requirements of 10 CFR 50.72(b)
(2)
(iv)
(A) due to manual reactor protection system (RPS) actuation, and under 10 CFR 50.72(b)
(3)
(iv)
(A) due to PWR auxiliary feedwater system actuation (AFSA).
The plant response to the reactor trip resulted in all control rods being fully inserted, no power operated relief valves (PORVs) opened, the reactor coolant system (RCS) heat removal was maintained with main feedwater and steam bypass control
- systems, and the auxiliary feedwater actuation system (AFAS) was automatically initiated on low steam generator level.
All systems functioned normally, and the plant was stabilized at normal operating temperature and pressure.
Prior to the trip, reactor power had been reduced to 94% in order to secure the 2AI CWP.
It was then identified that 2A2 circulating water debris filter differential pressure was above administrative limits of 200 inches water.
While the station was preparing to reduce circulating water flow on the 2A2 circulating water pump, the unit began losing condenser vacuum and the reactor was manually tripped at 92% power.
All systems functioned normally, and the plant was stabilized at normal operating temperature and pressure.
In previous site evaluations and in St. Lucie's original response to SOER 07-2, "Intake Cooling Water Blockage",
it had been determined that most sea grass and jelly fish events at the St. Lucie Plant occurred during the mid to late summer season.
Marine life macro-fouling across the southeastern Florida coast is expected to increase due to higher nutrient solutions being discharged from various sources across the coast.
Analysis of Safety Significance All safety related systems functioned as designed. The event was bounded by the analysis described in Section 15.2.3,"Loss of Condenser Vacuum".
The actual plant response was more conservative than that described in the analysis given the reactor and turbine were tripped manually before reaching automatic set points, the plant was not at full power when the events occurred and a complete loss of condenser cooling did not occur, thus the steam bypass control system was able to remove heat from the steam generators.
Given the response of the plant and actions taken, the health and safety of the public was not affected by this event.
Corrective Actions
Corrective actions taken include a daily Staff Biologists' analysis of biota entering the intake canal with reports provided to the Shift Manager and actions to review weir design, preventive maintenance pit cleaning and maintenance practices, and,
development of a procedure for Intake Intrusion Mitigation for monitoring, measuring!
and combating of intake intrusion events.
Similar Events
St. Lucie has experienced similar plant events as a result of intake sea grass and jelly fish intrusion and/or related equipment failures.
In previous site evaluations and in PSL's original response to SOER 07-2, "Intake Cooling Water Blockage",
it had been determined that most sea grass and jelly fish events at the station occurred during the mid to late summer season.
Additionally, the type and amount of sea grass experienced during this event had different characteristics which created additional cleaning challenges not previous experienced.
A review of nuclear industry events also identified several similar failures associated with traveling water screens and intake system blockage/intrusion resulting from algae and intake debris.
Failed Components NA