05000369/LER-2005-004, Ice Condenser Lower Inlet Door Failed Surveillance Testing
| ML053410422 | |
| Person / Time | |
|---|---|
| Site: | McGuire  |
| Issue date: | 11/14/2005 |
| From: | Gordon Peterson Duke Power Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| M-05-4227 LER 05-004-00 | |
| Download: ML053410422 (7) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3692005004R00 - NRC Website | |
text
_Duke GARY R.
PETERSON 00t Vice President McGuire Nuclear Station I
A Duke Energy Company Duke Power MGO1 VP / 12 700 Hagers Ferry Road Huntersville, NC 28078-9340 704 875 5333 704 875 4809 fax grpeters@duke-energy. corn November 14, 2005 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C.
20555 Subject: McGuire Nuclear Station, Unit 1 Docket No. 50-369 Licensee Event Report 369/2005-04, Revision 0 Problem Investigation Process (PIP) M-05-4227 Pursuant to 10 CFR 50.73, Sections (a)(1) and (d), attached is Licensee Event Report (LER) 369/2005-04, Revision 0.
This report is being submitted in accordance with 10 CFR 50.73 (a)(2)(i)(B) due to the McGuire Unit 1 Ice Condenser lower inlet door failed surveillance testing.
This event was determined to be of no significance to the health and safety of the public.
There are no regulatory commitments contained in this LER.
G. R. Peterson Attachment www. duke-energy. com
U.S. Nuclear Regulatory Commission November 14, 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. F. Stang, Jr. (Addressee Only)
NRC Project Manager (McGuire)
U. S. Nuclear Regulatory Commission Mail Stop 08H4A 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
A i
Abstract
approximately 15 single-spaced typewritten lines)
Unit Status: At the time of the event, Unit 1 was in Mode 5 (Cold Shutdown) at 0 percent power.
Event Description
On September 17, 2005, testing of the forty-eight Ice Condenser Lower Inlet Doors (LIDs) was performed in accordance with Technical Specification (TS) Surveillance Requirement (SR) 3.6.13.6. The "as-found" testing was performed in Mode 5 during the unit shutdown as a first time evolution.
This SR ensures all LIDs' open uniformly by quantifying resistance in the door hinges and springs through a series of force tests. Two of the forty-eight LIDs failed to meet a portion of the SR test acceptance criteria (TAC).
McGuire subsequently determined that these two LIDs could have been previously inoperable in Modes 1-4 for a period longer than allowed by TS.
Event Cause
The failure of the two doors has been attributed to excessive spring tensioning caused by corrosion of the rod end/clevis brackets.
Inadequate preventive maintenance resulted in excessive force being required to open the two LIDs.
Corrective Action
All rod end/clevis brackets on the forty-eight LIDs have been cleaned, lubricated and satisfactorily retested in accordance with SR 3.6.13.6.
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 (If more space is required, use additional copies of NRC Form 366A) would have opened as designed following the potential bounding LOCA.
Analyses have been performed using the GOTHIC computer code to determine what fraction, if any, of the LIDs can be completely blocked closed with containment pressure remaining below the calculated peak containment internal pressure (Pa=14.8 psig) during the blow-down period of the limiting size Large Break LOCA.
These analyses demonstrated that approximately 1/3 of the forty-eight doors can be completely blocked shut (i.e., will not open at all) during the design basis events and containment pressure will remain below 14.8 psig.
The LIDs at McGuire were not blocked shut.
The doors would have opened as designed during a limiting Large Break LOCA.
For the small break LOCA event, the doors also would have opened as designed, but two of the doors might not have exhibited the expected flow proportioning capabilities as described in UFSAR 6.2.2.8.1.
In conclusion, the GOTHIC results demonstrate that for a large break LOCA, all of the Ice Condenser Lower Inlet Doors would have performed their design basis function.
Adequate operating doors would mitigate the small break LOCA.
The slight increase in the required opening/closing torque on the two LIDs would not be expected to have a measured effect on the containment response following any design basis accident.
ADDITIONAL INFORMATION
A three year review of the McGuire corrective action database identified one previous reportable occurrence of the LIDs failing to meet the torque test.
This was reported in LER 370/2005-02. The Unit lEOC17 refueling outage was the first opportunity to implement the preventive maintenance procedure enhancements documented in Planned Corrective Action #1 of this LER.