05000443/LER-2002-001-01, Reactor Trip Due to Digital Rod Position Indication Card Failure
| ML022190356 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 07/26/2002 |
| From: | Feigenbaum T North Atlantic Energy Service Corp |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NYN-02066 LER 02-001-01 | |
| Download: ML022190356 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| 4432002001R01 - NRC Website | |
text
North Atlantic Energy Service Corporation S T N
rh _P.O.
Box 300 Seabrook, NH 03874 Atlantic (603) 474-9521 The Northeast Utilities System July 26, 2002 Docket No. 50-443 NYN-02066 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Seabrook Station Licensee Event Report (LER) 02-001-00 for Reactor Trip Due to a Digital Rod Position Indication Card Failure Licensee Event Report (LER) 02-001-00 is provided in Enclosure 1. This LER reports an event that occurred at Seabrook Station on May 28, 2002. This event is being reported pursuant to 10 CFR 50.73(a)(2)(iv)(A).
Should you require further information regarding this matter, please contact Mr. James M.
Peschel, Manager - Regulatory Programs at (603) 773-7194.
Very truly yours, NORTH ATLANTIC ENERGY SERVICE CORP.
Ted C.FeiuM Execut' ice President and Chief Nuclear Officer cc:
H. J. Miller, NRC Region I Administrator R. D. Starkey, NRC Project Manager, Project Directorate 1-2 G. T. Dentel, NRC Senior Resident Inspector
/
ENCLOSURE 1 TO NYN-02066
Abstract
On May 28, 2002, at 2:31 AM, with the plant in Mode 4, the Control Room Operator initiated a manual reactor trip due to the loss of indication for control rod L5 during control rod surveillance testing.
At the time of the event, control bank A was at 72 steps withdrawn; the other shutdown and control banks were fully inserted into the core. During the withdrawal of control bank A, a Digital Rod Position Indication (DRPI) urgent alarm was received indicating that the rod position indication for Control Bank A was invalid. Pursuant to Technical Specification 3.1.3.3, the reactor trip breakers were manually opened using the reactor trip switch. All rods fully inserted. All systems functioned as required. At the time of the event, reactor coolant temperature was approximately 276 degrees Fahrenheit and reactor coolant pressure was approximately 552 psig.
An eight-hour event notification to the Nuclear Regulatory Commission (NRC) was made pursuant to the requirements of 10CFR50.72(b)(3)(iv)(A). The event notification was 38947.
It was determined that DRPI rod L5 position indication card had failed in service. The failed card was replaced and the surveillance was completed satisfactorily.
This License Event Report is being submitted pursuant to the requirements of 1 OCFR50.73(a)(2)(iv)(A).
NRC FORM 366 (7-2001)
(If more space is required, use additional copies of (if more space is required, use additional copies of NRC Form 366A) (17)A manual reactor trip due to a failed rod position indication is classified as a Category II, Fault of Moderate Frequency, plant operating condition. The UFSAR, section 15.4.3, "Rod Control Cluster Assembly Misoperation (System Malfunction or Operator Error) states that "If one or more rod position indicator channels should be out of service, detailed operating instructions shall be followed to assure the alignment of the nonindicated [Rod Cluster Control Assembly] RCCA (AA). The operator is also required to take action as outlined by the Technical Specifications." During this event, the Control Room Operator followed the direction contained within the action statement for TS 3.1.3.3, which states "With less than the above required position indicator(s) OPERABLE, immediately open the Reactor Trip System breakers."
The significance of this event is minimal due to the reactor plant being in Mode 4 with only one control bank partially withdrawn.
IV. Corrective Action
The faulty card was replaced and the new card was tested satisfactorily. The reactor trip breakers were closed and procedure OX1410.07 was repeated for control bank A satisfactorily. The surveillance was then completed satisfactorily.
V. Additional Information
An operating experience search was performed using the EPIX database. No examples of detector/encoder card failures were identified.
Similar Events
One previous control bank detector/encoder board failure has occurred at Seabrook Station on January 26,2001.
Plant Engineering routinely monitors printed circuit board failures. An adverse trend regarding printed circuit board failures has not been identified for the DRPI system.