05000369/LER-2005-002, Regarding Main Steam Isolation Valve Inoperable Due to Internal Binding
| ML051790165 | |
| Person / Time | |
|---|---|
| Site: | McGuire  |
| Issue date: | 06/16/2005 |
| From: | Gordon Peterson Duke Power Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LER 05-002-00 | |
| Download: ML051790165 (9) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3692005002R00 - NRC Website | |
text
Duke GARY R.
PETERSON rWPowere Vice President McGuire Nuclear Station A Duke Energy Company Duke Power MGOO VP / 12700 Hagers Ferry Rd.
Huntersville, NC 28078-9340 704 875 5333 704 875 4809 fax grpeters@duke -energy. corn June 16, 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 369/2005-02, Revision 0 Pursuant to 10 CFR 50.73, Sections (a)(1) and (d), attached is Licensee Event Report (LER) 369/2005-02, Revision 0.
On April 28, 2005, McGuire Nuclear Station concluded that Unit 1 Main Steam Isolation Valve (MSIV), 1SM-1, was likely inoperable in the past for a period longer than permitted by plant Technical Specifications.
Therefore, as per the requirements of 10 CFR 50.73 (a)(2)(i)(B), this condition is being reported as an operation prohibited by Technical Specifications.
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.
Peterson Attachment www. dukepower. corn
U. S. Nuclear Regulatory Commission June 16, 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 S. E. Peters (Addressee Only)
NRC Project Manager (McGuire)
U. S. Nuclear Regulatory Commission Mail Stop 0-8 G9 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
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Abstract
Unit Status:
At the time of the event, Unit 1 was in MODE 4 (Hot Shutdown) at 0 percent power.
Event Description
In April 2004, stroking of ISM-1 ("D" Steam Generator Main Steam Isolation Valve) introduced valve stem scoring.
This scoring was indicative of conditions which probably prevented the valve from fully closing.
The inability to close renders ISM-1 inoperable.
Since the applicable Technical Specification required actions and completion times were not satisfied, this represented a Technical Specification prohibited operation reportable as per the requirements of 10 CFR 50.73 (a)(2)(i)(B). This event was not significant with respect to the health and safety of the public.
Event Cause
The most probable cause was a pre-existing out of specification internal guide rib combined with flow induced vibration and normal stroking wear of the guide rib and main valve poppet guide pad.
This caused the main valve poppet to tip and subsequently bind, preventing ISM-1 from fully closing.
Corrective Action
The guide ribs for 1SM-1 were repaired and returned to specifications.
A new valve main poppet was installed along with an anti-vibration kit and a stem guiding system.
The clearance between the valve stem and cover bushing was increased.
NRC FORM 366 (6-2004)
t4RC (If more space Is required, use additional copies of NFC (If more space is required, use additional copies of NRC For 366A)
McGuire Technical Specification (TS) 3.6.3 -
Containment Isolation Valves:
The TS 3.6.3 LCO specifies that each containment isolation valve shall be operable in Modes 1, 2, 3, and 4.
TSSR 3.6.3.5 and associated test acceptance criteria indicate that an MSIV is operable when it is capable of closing in less than or equal to 8 seconds upon receipt of an isolation signal.
As per TS 3.6.3, Condition C, if one or more MSIVs are inoperable, each affected penetration flow path shall be isolated by the use of at least one closed and de-activated automatic valve, closed manual valve, or blind flange within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> and each affected penetration flow path shall be verified to be isolated once per 31 days.
If the required action and associated completion time of Condition C are not met, then TS 3.6.3, Condition F, states that the respective Unit must be in MODE 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in MODE 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.
EVENT DESCRIPTION
Note: All events are shown in the approximate sequence in which they occurred.
All times are approximate.
April 2004:
On April 4, 2004, during startup from the Unit 1 EOC16 refueling outage and with Unit 1 in MODE 3, lSM-l
("D" SG MSIV) was hot stroke tested.
No abnormalities were identified in this test.
However, MSIV 1SM-7 failed to fully close during stroke testing of that valve.
On April 6, 2004 at 1216, Unit 1 entered MODE 4 to make repairs to 1SM-7 following a failed stroke test of that valve.
At 1626, Unit 1 entered MODE 5.
On April 9 and 10, 2004, during startup following repair of 1SM-7, ISM-1 was cold stroked with no abnormalities identified.
Unit 1 entered MODE 4 at 0356 on April 10, 2004.
Unit 1 entered MODE 3 at 1156.
On April 27, 2004, scoring was discovered on the valve stem for 1SM-1.
Subsequent investigation concluded that the scoring was most likely introduced during the stroking of 1SM-1 on April 9, 2004 or April 10, 2004.
An operability assessment determined that the scoring did not render ISM-1 inoperable.
(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) vibration and normal stroking wear of the guide rib and main valve poppet guide pad.
Therefore, the event described in this LER is not considered a recurring event.
Applicable Energy Industry Identification (EIIS) system and component codes are enclosed within brackets.
McGuire unique system and component identifiers are contained within parentheses.