05000440/LER-2002-001, For Perry Unplanned Automatic Scram During Main Turbine Mechanical Trip Weekly Testing
| ML023330342 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 11/18/2002 |
| From: | Kanda W FirstEnergy Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| PY-CEI/NRR-2671L LER 02-001-00 | |
| Download: ML023330342 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv), System Actuation 10 CFR 50.73(a)(2)(iv)(B)(1) |
| 4402002001R00 - NRC Website | |
text
FENOC FirstEnergy Nuclear Operating Company Perry Nuclear Power Plant 10 Center Road Perry Ohio 44081 440-280-5579 William R. Kanda Fax 440-280-8029 Vice President - Nucolear Fx-402082 November 18, 2002 PY-CEI/NRR-2671 L United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 Perry Nuclear Power Plant Docket No. 50-440 LER 2002-001-00 Ladies and Gentlemen:
Enclosed is Licensee Event Report (LER) 2002-001, "Unplanned Automatic SCRAM During Main Turbine Overspeed Testing". Any actions discussed within this LER are described for, information only and are not regulatory commitments.
If you have questions or require additional information, please contact Mr. Vernon K. Higaki, Manager - Regulatory Affairs, at (440) 280-5294.
Very truly yours, I--,
Attachment cc: NRC Project Manager NRC Resident Inspector NRC Region IlIl
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Abstract
On September 22, 2002, at 0146 hours0.00169 days <br />0.0406 hours <br />2.414021e-4 weeks <br />5.5553e-5 months <br />, when the Perry Nuclear Power Plant was operating in Mode I at 90 percent reactor power, a turbine trip occurred which resulted in a turbine control valve fast closure reactor scram. Investigation determined that the turbine trip occurred due to the failure of the turbine trip latch assembly to properly reset following weekly testing. While attempting to reset the scram following the event, it was identified that a Scram Discharge Volume (SDV) drain valve stem coupling had failed. The valve repositioned to its required closed position during the scram, however, it would not reopen when the scram was reset. Additionally, increased seal leakage from Reactor Recirculation Pump A was noted. The turbine trip was caused by a malfunction of the turbine trip latch assembly which failed to reset following testing of the mechanical trip device.
The failure to relatch was determined to be caused by latch travel limitations as a result of two missing setscrews. The missing set screws were replaced, the linkage was adjusted and the assembly was retested. The SDV drain valve failure to close was due to failure of the stem coupling. All four SDV vent and drain valve stem couplings were replaced with a coupling of an improved design. The reactor recirculation pump seal leakage was due to a dislodged guide bushing in the seal assembly. The seal was replaced with a rebuilt spare seal. This event was reviewed and determined to be within design evaluation limits, and therefore was determined to be not safety significant. This event was reported via the Emergency Notification System in accordance with I OCFR50.72(b)(2)(iv)(B), as an event that resulted in an actuation of the Reactor Protection System when the reactor is critical.
This report is being submitted in accordance with 10CFR50.73(a)(2)(iv), any event or condition that resulted in manual or automatic actuation of the system specified in IOCFR50.73(a)(2)(iv)(B)(1), which is the Reactor Protection System.
NRC FORM 366 (7-2001)
I (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) (17)
V. Corrective Actions
The missing set screws for the turbine trip latch assembly were replaced. The vender did not recommend any additional means of securing the setscrews. Additional components in the assembly were replaced as necessary due to wear. The linkage was adjusted and tested to ensure proper tripping and resetting. Periodic inspections of the linkage are being incorporated into maintenance procedures.
Couplings of an improved design were fabricated and installed in all four SDV vent and drain valves and torqued to the appropriate value.
The seal for Reactor Recirculation pump A was removed and replaced with a reconditioned spare.
The above events and corrective actions have been entered in the Plant Corrective Action Program.
VI. Previous Similar Events
The most recent turbine trip induced scram, LER 98-002, resulted from a failed optical isolation card that caused an initiation of the Reactor Core Isolation Cooling (RCIC) System. The RCIC initiation caused trips of the main turbine and the feedwater turbines.
The cause of this event is not similar to this event which was the result of missing fasteners that are part of the turbine-reset mechanism. Therefore, this event is not a recurring event.
Energy Industry Identification System (EIIS) codes are identified in the text in the format [xx].
NRC FORM 386A (1-2001)