05000251/LER-2008-001, Manual Reactor Trip Due to High Level in the 4A Steam Generator
| ML081270234 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 04/25/2008 |
| From: | Jefferson W Florida Power & Light Co, Florida Power & Light Group |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-2008-097 LER 08-001-00 | |
| Download: ML081270234 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), 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)(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 |
| 2512008001R00 - NRC Website | |
text
FPL APR 2 5 2008 10 CFR § 50.73 L-2008-097 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555-00001 Re:
Turkey Point Unit 4 Docket No. 50-251 Reportable Event: 2008-001-00 Date of Event: February 29, 2008 Manual Reactor Trip due to Hiqh Level in 4A Steam Generator The attached Licensee Event Report 05000251/2008-001 -00 is being submitted pursuant to the requirements of 10 CFR 50.73(a)(2)(iv)(A) to provide notification of the subject event.
If there are any questions, please call Ms. Olga Hanek at 305-246-6607.
Very truly yours, William)*,fersIM, Jr.
Vice Prf'sident Turkey Point Nuclear Plant Attachment cc:
Regional Administrator, USNRC, Region II Senior Resident Inspector, USNRC, Turkey Point Nuclear Plant an FPL Group company
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 08/31/201C 19"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 reqluired to respond to, the information collection.
Turkey Point Unit 4 05000251 I
1 of 4
- 4. TITLE Manual Reactor Trip due to High Level in the 4A Steam Generator
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE J
- 8. OTHER FACILITIES INVOLVED SSEQUENTIAL REV FACILITY NAME DOCKET NUMBER
- NUMBER, MONTH DAY YEAR A
IFACILITY NAME DOCKET NUMBER 2
29 2008 2008 = 001
- 00.
4 25 20081
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§' (Check all that apply)
[1 20.2201(b)
[I 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C)
El 50.73(a)(2)(vii)
[] 20.2201(d)
El 20.2203(a)(3)(ii)
E] 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)
El 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)
[I 50.73(a)(2)(x)
El 20.2203(a)(2)(iii)
E] 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) 10 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 D.
EVENT ANALYSIS
The event was evaluated to determine the root cause and contributing casual factors.
The procedure used for this evolution, 4-GOP-301, Hot Standby to Power Operation, does not provide guidelines for the rate of initial loading of the main generator. The operating crew determines the loading rate based on their training and plant conditions. During this event, an abnormally fast generator loading was implemented, which exacerbated steam generator level fluctuations and resulted in the loss of the 4A steam generator level control.
The operator at the reactor controls (RCO) did not attend the just-in-time-training (JITT), due to operations personnel demands resulting from the dual unit trip, and therefore, did not benefit from the crew's training and practice session.
This changed crew dynamics for returning Unit 4 to power from the way they practiced in the plant's simulator.
Having a different crew makeup than during the JITT contributed to the crew's fast generator loading and failure to include the feedwater operator in all load change communications.
The abnormally fast generator loading implemented by the operating crew focused the unit supervisor on peer checking the RCO as recommended in the Nuclear Administrative Procedure, NAP-402, Conduct of Operations.
The requirement for frequent peer checks of the RCO weakened the unit supervisor's overall oversight role during the evolution of power escalation.
The turbine operator and senior reactor operator continued to increase turbine load while the steam generator level continued to increase after the Main Feed Regulating Bypass Valves were closed. The operator at the feedwater controls did not stabilize SG levels and did not communicate his concerns about the SG level control.
E.
ROOT CAUSE The root cause of the event is insufficient guidance for the initial loading of the main generator and for stabilizing power while preparing to transfer to automatic feed regulating valve control. Other factors which contributed to the root cause are: (1) not all the operating crew members attended the same JITT to practice this evolution, (2) the abnormally fast loading of the main generator shifted the Unit Supervisor's focus from overall oversight to peer checking a large number of reactivity changes, (3) a weakness in understanding the SG "shrink" and "swell" concept and, (4) failure to communicate the SG levels and trends to the rest of the operating crew members.
F.
CORRECTIVE ACTIONS
Turkey Point is in the process of implementing procedural changes to provide guidance for ramp rates during turbine initial loading and appropriate hold points to ensure proper control of plant parameters.
Corrective actions to address the event's contributing factors have been entered in the Turkey Point Corrective Action program.
G.
SAFETY ASSESSMENT
This event resulted in a manual reactor trip due to the excessive feedwater level in the 4A SG. The reactor power was at 10% at the time of the trip. There was no challenge to the integrity of the primary or secondary plant. The plant response during this event is bounded by an event assuming an increase of 200% feedwater flow analyzed in Turkey Point's Updated Final Safety Analysis Report. This event is not a safety significant event, and had no adverse effect on the health and safety of the public.
H.
ADDITIONAL INFORMATION
The condition report that includes the post trip report and the root cause evaluation is CR 2008-7157.
EIIS codes are shown in the format [EIIS SYSTEM: IEEE Component function identifier, second component function identifier (if applicable)]
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