05000369/LER-2008-003, Regarding Manual Reactor Trip Taken to Mitigate Control Rod Drop Caused by Shorted Control Rod Drive Mechanism (CRDM) Cable Connector
| ML090130447 | |
| Person / Time | |
|---|---|
| Site: | McGuire  |
| Issue date: | 12/30/2008 |
| From: | Brandi Hamilton Duke Energy Carolinas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LER 08-003-00 | |
| Download: ML090130447 (7) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| 3692008003R00 - NRC Website | |
text
Duke BRUCE H HAMILTON Vice President McGuire Nuclear Station Duke Energy Corporation MG01 VP / 12700 Hagers Ferry Road Huntersville, NC 28078 704-875-5333 704-875-4809 fax bhhamilton@duke-energy. com December 30, 2008 U.S. Nuclear Regulatory Commission ATTENTION: Document Control Desk Washington, D.C. 20555
Subject:
Duke Energy Carolinas, LLC McGuire Nuclear Station, Unit 1 Docket No. 50-369 Licensee Event Report 369/2008-03, Revision 0 Problem Investigation Process No.: M-08-07057 Pursuant to 10 CFR 50.73 Sections (a)(1) and (d), attached is Licensee Event Report (LER) 369/2008-03, Revision 0, regarding the Unit 1 Manual Reactor trip completed on October 31, 2008 due to K-2 Control Rod drop condition caused by shorted control rod drive mechanism (CRDM) cable connector.
This report is being submitted in accordance with 10 CFR 50.73 (a) (2) (iv) (A).
This event is considered to be of no significance with respect to the health and safety of the public. There are no regulatory commitments contained in this LER.
If questions arise regarding this LER, contact Rick E. Abbott at 704-875-4685.
Very truly yours, Bruce H. Hamilton Attachment www. duke-energy. com
U.S. Nuclear Regulatory Commission December 30, 2008 Page 2 cc:
L. A. Reyes, Regional Administrator U.S. Nuclear Regulatory Commission, Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW, Suite 23T85 Atlanta, GA 30303 J. F. Stang, Jr. (Addressee Only)
Senior Project Manager (McGuire)
U.S. Nuclear Regulatory Commission Mail Stop O-8G9A Washington, DC 20555 J. B. Brady Senior Resident Inspector U.S. Nuclear Regulatory Commission McGuire Nuclear Station B. 0. Hall, Section Chief Radiation Protection Section 1645 Mail Service Center Raleigh, NC 27699
Abstract
Event Description
On October 31,
- 2008, Unit 1 was in Mode 2 and performing Zero Power Physics Testing when operators received a "Rod Control Urgent Failure" annunciator. Abnormal procedure 14 was entered and subsequently re-entered when control rod K-2 dropped to the fully inserted position. The condition was terminated when the operators manually opened the Unit 1 Reactor Trip Breakers per operating procedure and completed subsequent emergency response procedure actions. This event is considered to be of no significance with respect to the health and safety of the public.
Event Cause
A root cause was completed following the'event and it was determined a CRDM power cable head connector failed causing the K-2 control rod to drop to. the fully inserted position.
It was concluded the CRDM power cable head connector design was inadequate for the application.
Corrective Actions
The Unit 1 CRDM connectors were removed and the cables were spliced and tested prior to returning Unit 1 to service.
NRC FORM 366 (7-2001)
(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 (If more space is required, use additional copies of NRC Form 366A)
Planned:
- 1. Eliminate or replace the Unit 2 CRDM Pyle National connectors at the reactor head.
The Planned corrective action is voluntary and does not constitute a
commitment
It may be modified as operating experience, judgment and evaluations dictate and will be documented in Duke's corrective action process.
SAFETY ANALYSIS
Duke Energy used a risk-informed approach to determine the risk significance associated with the reactor trip of October 31, 2008.
The Conditional Core Damage Probability (CCDP) and the Conditional Large Early Release Probability of this event was evaluated by considering the following:
- A reactor trip initiating event
- Actual plant configuration and maintenance activities at the time of the trip The CCDP associated with this event was evaluated to be less than 1.OE-
- 7.
The Conditional Large Early Release Probability (CLERP) associated with this event was evaluated to be less than 1.OE-8.
This event is considered to be of no significance to the health and safety of the public.
ADDITIONAL INFORMATION
A review of McGuire's corrective action database was performed and it was determined that this is NOT a recurring or similar event.
NRC FORM 366 (7-2001)