05000370/LER-2005-001, Automatic Actuation of Motor Driven Auxiliary Feedwater Pumps During Outage
| ML051250289 | |
| Person / Time | |
|---|---|
| Site: | Mcguire |
| Issue date: | 04/25/2005 |
| From: | Gordon Peterson Duke Power Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LER 05-001-00 | |
| Download: ML051250289 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| 3702005001R00 - NRC Website | |
text
X P Duke LJPowere A Duke Energy Company GARYR. PETERSON Vice President McGuire Nuclear Station Duke Power MGO1VP / 12700 Hagers Ferry Road Huntersville, NC 28078-9340 704 875 5333 704 875 4809 fax grpeters@duke-energy.com April 25, 2005 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C.
20555
Subject:
McGuire Nuclear Station, Units 2 Docket No. 50-370 Licensee Event Report 370/2005-01, Revision 0 Problem Investigation Process (PIP) M-05-00847 Pursuant to 10 CFR 50.73, Sections (a)(l) and (d), attached is Licensee Event Report (LER) 370/2005-01, Revision 0, concerning an automatic actuation of the motor driven Auxiliary Feedwater Pumps on McGuire Unit 2.
This report is being submitted in accordance with 10 CFR 50.73 (a) (2) (iv) (A).
Probabilistic risk assessment has determined this event to be of no significance to the health and safety of the public.
There are no regulatory commitments contained in the LER.
G. R. Peterson Attachment www.duke-energy. corn
U. S. Nuclear Regulatory Commission April 25, 2005 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. J. Shea (Addressee Only)
NRC Project Manager (McGuire)
U. S. Nuclear Regulatory Commission Mail Stop 0-7 D11 Washington, DC 20555-0001 J. B. Brady Senior Resident Inspector U. S. Nuclear Regulatory Commission McGuire Nuclear Site Beverly 0. Hall, Section Chief Radiation Protection Section 1645 Mail Service Center Raleigh, NC 27699-1645
Abstract
Unit Status:
At the time of the event, Unit 1 was in Mode 1 (Power Operation) at 100 percent power and Unit 2 was in Mode 3 (Hot Standby) at 0 percent power.
Event Description
On March 2, 2005, McGuire Unit 2 experienced an automatic actuation of the 2A and 2B Motor Driven Auxiliary Feedwater (MDCA) pumps.
The 2A Main Feedwater (CF) pump was in recirculation mode and, as per procedure, the 2B CF pump was in a tripped condition and out of service. While performing system evolutions, Unit 2 CF system pressure unexpectedly dropped to a level that caused initiation of a low CF pump suction pressure signal which tripped the 2A CF pump.
Since the 2B CF pump had previously been placed in a tripped condition, the logic for automatic start of the 2A and 2B MDCA pumps was satisfied and these pumps started as designed.
Since the 2A and 2B MDCA pumps started in response to actual plant conditions or parameters satisfying the requirements for initiation of the Auxiliary Feedwater (CA) System safety function, this represented a valid actuation of the CA system. This event was not significant with respect to the health and safety of the public.
Event Cause
The cause of this event is attributed to a procedural deficiency.
PT/2/B/4250/024, "Feed Water Heater Tube Integrity Test" did not prohibit the restoration portion of the procedure from being performed prior to blocking the CA autostart signal, a procedurally driven task performed upon entry into Mode 4.
Corrective Action
Procedure PT/1(2)/B/4250/024 will be revised to ensure blocking of the CA autostart signal (in accordance with the Technical Specifications) has been completed orior to nerformina the restoration section of the test.
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)
- 2. The CA pumps were shutdown and system realignments completed.
Subsequent:
- 1. Procedures PT/1(2)B/4250/024 were placed on technical hold.
Planned:
- 1. Procedure PT/1(2)/B/4250/024 will be revised to ensure blocking of the CA autostart signal (in accordance with the Technical Specifications) has been completed prior to performing the restoration section of the test.
SAFETY ANALYSIS
The loss of both Main Feedwater pumps initiated an automatic start of the MDCA pumps as designed. All steam generators levels were maintained at adequate levels to ensure an adequate heat sink for the reactor coolant system.
The risk significance of this event was evaluated using the current version of the McGuire PRA.
The conditional core damage probability and conditional large early release probability have been estimated to be approximately 4E-07 and 2E-08 respectively.
Based on this analysis, this event is not considered to be significant.
At no time were the health and safety of the public or plant personnel affected as result of this event.
ADDITIONAL INFORMATION
A three year search of the McGuire corrective action database (PIP) and LER database revealed no other automatic starts of the MDCA pumps during testing; therefore, this event is not recurring.