05000247/LER-2005-004, Automatic Start of Both Motor Driven Auxiliary Feedwater Pumps Due to 22 Steam Generator High-High Level Signal Caused by Overfeeding Due to Personnel Error
| ML060580169 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 02/14/2006 |
| From: | Dacimo F Entergy Nuclear Indian Point 2 |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NL-06-019 LER 05-004-00 | |
| Download: ML060580169 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(iv)(B), System Actuation |
| 2472005004R00 - NRC Website | |
text
A Entergy Indian Point Energy Center 450 Broadway, GSB P.O. Box 249 Buchanan, N.Y. 10511-0249 Tel (914) 734-6700 Fred Dacimo Site Vice PResident Administraton February 14, 2006 Indian Point Unit No. 2 Docket No. 50-247 NL-06-019 Document Control Desk U.S. Nuclear Regulatory Commission Mail Stop O-Pl-17 Washington, DC 20555-0001
Subject:
Licensee Event Report # 2005-004-00, "Automatic Start of Both Motor Driven Auxiliary Feedwater Pumps Due to 22 Steam Generator High-High Level Signal Caused by Personnel Error."
Dear Sir:
The attached Licensee Event Report (LER) 2005-004-00 is the follow-up written report submitted in accordance with 10 CFR 50.73. This event is of the type defined in 10 CFR 50.73(a)(2)(iv)(A) for an event recorded in the Entergy corrective action process as Condition Report CR-IP2-2005-05252.
There are no commitments contained in this letter. Should you or your staff halve any questions regarding this matter, please contact Mr. Patric W. Conroy, Manager, Licensing, Indian Point Energy Center at (914) 734-6668.
Sincerely, I. _V(
Indian Point Energy Center a.C;~
Docket No. 50-247 NL-06-019 Page 2 of 2 Attachment: LER-2005-004-00 cc:
Mr. Samuel J. Collins Regional Administrator - Region I U.S. Nuclear Regulatory Commission U.S. Nuclear Regulatory Commission Resident Inspector's Office Resident Inspector Indian Point Unit 2 Mr. Paul Eddy State of New York Public Service Commission INPO Record Center
Abstract
On December 22, 2005, while offline for maintenance, at approximately 0550 hours0.00637 days <br />0.153 hours <br />9.093915e-4 weeks <br />2.09275e-4 months <br />, both motor driven Auxiliary Feedwater pumps (AFWPs) received an automatic actuation signal to start.
Both AFWPs were in service at the! time feeding the SGs with the 22 Main Boiler Feedwater Pump (MBFP) on turning gear and the 21 MBFP isolated and in recirculation. A 22 SG High-High Level signal resulted in tripping the 21 MBFP which by design initiates start of the AFWPs.
The Reactor Operator (RO) assigned to feed water control failed to adequately monitor SG level and overfed the 22 SG.
The RO had decreased AFW flow instead of stopping AFW flow as intended.
The RO failed to adequately monitor SG levels, check his actions or request a peer check.
Operators restored the 22 SG level to normal.
The apparent cause was personnel error due to failure to perform self checking, and failure to monitor alternate SG level indications to ensure appropriate SG levels. Corrective actions include, administrative removal of the RO from licensed duties, simulator testing and evaluation and return to duty, coaching the RO on use of human performance tools, issuing a Station Clock Reset/Red Memo for this event as well as others for the shutdown to advise personnel of the event and lessons learned and convey management's expectations on use of human performance tools.
The event had no effect on public health and safety.
NRC FORM 366 (6-2004)
(If more space is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A) (1 7)
EVENT ANALYSIS
The event is reportable under 10CFRE0.73(a)(2)(iv)(A).
The licensee shall report any event or condition that resulted in manual or automatic actuation of any of the systems listed under 10CFR50.73(a)(2)(iv)(B).
Systems to which the requirements of 10CFR50.73(a)(2)(iv)(A) apply for this event include the AFWS.
Th-s event meets the reporting criteria because a start signal was initiated for the AFWS in accordance with design as a result of the 22 SG High-High level signal.
PAST SIMILAR EVENTS A review of the past two years of Licensee Event Reports (LERs) for events that involved an AFWS actuation as a result of high SG level identified one LER.
LER-2004-001 reported a High-High level signal due to overfeeding the 22 SG as a result of a failure of Main Feedwater Regulating valve (FCV-427) to fully close.
The AFWPs had already been started due to a low SG level signal as a result of a manual reactor trip.
The event reported in LER-2004-001 did not have the same cause (stuck valve) as this event (operator error), therefore the corrective actions for the event reported in LE:R-2004-001 would not have prevented this event
SAFETY SIGNIFICANCE
This event had no effect on the health and safety of the public.
There were no actual safety consequences for the event because there were no transients or accidents during the time of the event.
Both AFWPs were operating and providing adequate FW flow to the SGs.
Operators had alarms/indications alerting them to high SG level and procedures to direct proper actions.
Operators during this event recognized the 22 SG overfeed condition and took actions in accordance with plant procedures.
There were no significant potential safety consequences of this event under reasonable and credible alternative conditions.
Excess FW addition at full power would cause a greater load demand on the reactor coolant system (RCS) due to increased subcooling in the SGs.
A failure of operators to recognize the AFW pump operation could result in excess FW flow.
The addition of co-d FW would cause a decrease in RCS temperature and a consequential positive reactivity insertion due to the effects of negative moderator coefficient of reactivity.
Continuous excessive FW addition would be terminated by an automatic FW isolation actuated upon receipt of a SG High-High level water signal.
The SG high-high water level signal also results in a turbine trip and subsequent reactor trip.
Excessive FW addition transients at power are attenuated by the thermal capacity of the secondary plant and of the RCS.
The reactor protection system overpower and overtemperature delta temperature trips and the high neutron flux trip prevent any power increase that could lead to a departure from nucleate boiling ratio (DNBR) less than the applicable DNBR limit.
This event was bounded by the analyzed event described in FSAR Section 14.1.10, Excessive heat removal due to a FW system malfunction. The plant performed as expected and the event was bounded by the FSAR analysis.
For this event the AFWS actuated as designed and operators were alerted to the high Sc; condition to perform corrective action in accordance with plant procedures.