ML020790552
| ML020790552 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 03/04/2002 |
| From: | Hopkins L Constellation Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NMP1L 1648 | |
| Download: ML020790552 (2) | |
Text
P.O. Box 63 Lycorning, New York 13093 Constellation Nuclear March 4, 2002 Nine Mile Point N
L14 Nuclear Station March 48 A Member of the Constellation Energy Group U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 RE:
Nine Mile Point Unit 1 Docket No. 50-220 DPR-63
Subject:
Special Report, Channel #12 Suppression Chamber Water Level Indicator Inoperable Gentlemen:
In accordance with Action Statement 4.a of Nine Mile Point Unit 1 Technical Specification Table 3.6.11-2, Accident Monitoring Instrumentation Action Statements, Nine Mile Point Nuclear Station, LLC (NMPNS) is submitting the following Special Report concerning the inoperability of Channel #12 Suppression Chamber Water Level indicator.
Description of Event On February 16, 2002, at approximately 0205 hours0.00237 days <br />0.0569 hours <br />3.38955e-4 weeks <br />7.80025e-5 months <br />, Channel #12 Suppression Chamber Water Level indicator LI-58-05A was declared inoperable when it drifted outside its loop accuracy of +/- 0.2 feet.
Previously, on January 25, 2002, Channel #12 Suppression Chamber Water Level indication was declared inoperable when it exhibited erratic behavior. The investigation determined that the cause was ripple voltage on the power supply.
This condition was discussed in NMPNS Special Report, letter NMIP1L 1641, dated February 8, 2002, with the corrective action being the repair of the power supply.
On February 13, 2002, the power supply was repaired and Channel #12 Suppression Chamber Water Level indication restored to an operable condition. A review to determine if a relationship exists between the indication performance on January 25th and February 16th will be part of the cause determination.
Redundant Suppression Chamber Water Level indication Channel #11 is operable.
Samba'
Page 2 NMP1L 1648 Cause of Event The cause of the Channel #12 Suppression Chamber Water Level indication malfunction has not been determined. The malfunctioning Channel #12 Suppression Chamber Water Level indication uses a Rosemount Model 11 53DA-5 transmitter. After discussions with Rosemount, and an evaluation of the level indication response, NMPNS concluded that the most probable cause of the Channel #12 Suppression Chamber Water Level indication malfunction is due to failure of the transmitter or its capillary sensing line.
Corrective Actions
- 1.
The malfunctioning Rosemount Model 1153DA-5 transmitter will be replaced with a more reliable transmitter by April 5, 2002.
- 2.
A failure analysis of the malfunctioning transmitter will be performed.
- 3.
The cause evaluation of the malfunction of the Channel #12 Suppression Chamber Water Level indication will be completed.
Very truly yours, LA L-L Lawrence A. Hopkins Unit 1 Plant General Manager LAH/KLE/jm cc:
Mr. H. J. Miller, NRC Regional Administrator, Region I Mr. G. K. Hunegs, NRC Senior Resident Inspector Records Management