05000369/LER-2005-006, Automatic Reactor Trip and Auxiliary Feedwater System Actuation Due to Steam Generator Hi--Hi Water Level
| ML060540438 | |
| Person / Time | |
|---|---|
| Site: | McGuire  |
| Issue date: | 02/13/2006 |
| From: | Gordon Peterson Duke Power Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LER 05-006-00 | |
| Download: ML060540438 (9) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| 3692005006R00 - NRC Website | |
text
P Duke
- arPower, A Duke Energy Company GARY R. PETERSON Vice President McGuire Nuclear Station Duke Power MG01 VP / 12700 Hagers Ferry Road Huntersville, NC 28078-9340 704 875 5333 704 875 4809 fax grpeters@duke-energy.com February 13, 2006 U.S. Nuclear Regulatory Commission ATTENTION: Document Control Desk Washington, DC 20555
Subject:
McGuire Nuclear Station, Unit 1 Docket No. 50-369 Licensee Event Report 369/2005-06, Revision 0 Problem Investigation Process (PIP) M-05-05989 Pursuant to 10 CFR 50.73, Sections (a)(1) and (d), attached is Licensee Event Report (LER) 369/05-06, Revision 0, concerning an automatic trip of the McGuire Nuclear Station Unit 1 reactor and automatic actuation of the Unit 1 Auxiliary Feedwater (CA)
System.
This LER is being submitted as per the requirements of 10 CFR 50.73 (a)(2)(iv)(A).
This event is considered to be of no significance to the health and safety of the public.
There are no regulatory commitments contained in this LER.
Very truly yours, And'r
/w,4V Gary Et. Peterson Attachment 11-C-P
"
www. duke-energy. corn
U.S. Nuclear Regulatory Commission February 13, 2006 Page 2 of 2 cc:
W. D. Travers U. S. Nuclear Regulatory Commission Regional Administrator, Region II Atlanta Federal Center 61 Forsyth St., SW, Suite 23T85 Atlanta, GA 30303 J. F. Stang, Jr. (Addressee Only)
NRC Project Manager (McGu:ire)
U. S. Nuclear Regulatory Commission Mail Stop 8 H4A Washington, DC 20555-0001 J. B. Brady Senior Resident Inspector U. S. Nuclear Regulatory Commission McGuire Nuclear Site B1. 0. Hall, Section Chief Radiation Protection Section 1.645 Mail Service Center Raleigh, NC 27699-1645
bxc: Gary R. Peterson (MG01VP)
Thomas P. Harrall Jr. (MG01VP)
Scott W. Brown (MGOlVP)
Scotty L. Bradshaw (MGOlOP)
Scott B. Thomas (EC08G)
Steve Snider (MG05EE)
Jeff Nolin (MG05SE)
Ken Evans (MGOlIE)
Michael S. Kitlan (EC08I)
Dayna J. Herrick (EC08H)
Robert P. Boyer (EC08H)
Kay L. Crane (MG0lRC)
Berry G. Davenport (ON03RC)
Randall D. Hart (CN0lRC)
Lisa F. Vaughn (ECliX)
Robert L. Gill (EC05P)
(NSRB Support Staff) (EC05N)
INPO Paper Distribution:
'[aster File (3.3.7)
ELL (ECQ50)
EGC File
Abstract
(Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)
Unit Status: At the time of the event:, both Unit 1 and Unit 2 were in Mode 1 (Power Operation) at 100 percent power.
Event Description
On December 17, 2005, the 1A Steam Generator experienced High-High water level when its controlling channel for main feedwater flow failed low.
A main feedwater isolation occurred along with a turbine trip, trip of both CF pumps, automatic start of the motor driven CA pumps, and reactor trip.
All safety systems needed to respond to this event operated as designed.
This event is considered 1:o be of no significance to the health and safety of the public.
Event Cause
The cause of this event was intermittent degraded voltage to transmitter 1A SG Channel 1 flow loop (lCFFT5000).
Corrective Action
Selected components were replaced.
Lessons learned from this event will be incorporated in appropriate training to further strengthen operator response time to steam generator level deviations.
NRC FORM 366 (6-2004)
(If more space is required, use additional copies of NRC' (If mors space is required, use additional copies of NRC Forn 366A)
Reactor Protection [JC](IPE) System:
The function of the RPS System circuits associated with turbine trip is to minimize the pressure/temperature transient on the reactor.
A turbine trip from a power level below the P-8 setpoint, approximately 48% power, will not actuate a reactor trip.
Above the P-8 setpoint, a turbine trip will cause a reactor trip to minimize the transient on the reactor.
EVENT DESCRIPTION
On December 17, 2005, with Unit 1 at 100% power, the 1A SG experienced Hi-Hi water level when its controlling channel (Channel 1) for CF flow failed low.
This caused the associated CF control valve 1CF-32 to open and SG level to increase.
In response, 1CF-32 was placed in manual control per Abnormal Procedure AP-06, SG Feedwater Malfunction, to reduce 1A SG water level.
Notwithstanding, 1A SG water level reached the Hi-Hi level and'a P-14 signal was actuated.
A main feedwater isolation occurred along with a turbine trip, trip of both CF pumps, automatic start of the motor driven CA pumps, and reactor trip.
The relevant sequence of events is as follows (all times approximate):
03:10:28 03:10:34 03:10:37 03:10:40 03:10:58 03:11:26 03:11:29 03:11:29 03 : 11: 30 1A SG Channel 1 CF flow started trending down.
IA SG Channel 1 CF flow failed low.
1A SG Channel 2 CF flow was spiking up.
1CF-32 position indicated full open.
CF pump speed and flow were increasing.
CF pump flow to B, C And D SG's were increasing.
1CF-32 position indicated intermediate (not full open) due to manual operator actions.
1A SG Narrow Range Level II indicated Hi-Hi.
1A SG Narrow Range Level II and Level IV indicated Hi-Hi.
1A SG Hi-Hi Level Turbine Trip and Reactor Trip occurred.
Both CF pumps tripped and both motor driven CA pumps automatically started as designed.
(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)
ADDITIONAL INFORMATION
A review of previous events at McGu.ire for the past three years did not identify arty previous events with the same underlying concern or reason for reporting.
However, one event was identified that involved failure of CF FCV and increasing SG level con unit 2 which did not result in a turbine or reactor trip.
On May 13, 2005, with unit 2 at 100% power, SG 2A Channel 1 feed flow failed low causing SG level to increase. The operator's manual control of 2CF-32 restored normal flow and level conditions just below turbine trip setpoint.
The cause of this event was failure in the associated 7300 PCS isolator card.
The failed component was replaced.