ML20056A082
| ML20056A082 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 07/27/1990 |
| From: | William Cahill TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TXX-90273, NUDOCS 9008030199 | |
| Download: ML20056A082 (3) | |
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Log # TXX-90273 me lllllllll '"llllll" File # 10013 F-10125 g
Ref. # 10CFR50.72(a)(i) nlELECTRIC July 27, 1990
% tiliam J. ( shill, Jr.
lar<uren ikr ivru. lens U. S. Nuclear Regulatory Commission Attn: Document control Desk Washington, D.C.
20555
SUBJECT:
COMANCllE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NO StHt6 fo d4S TRANSMITTAL Of REPORT FOLLOWING A NOTiflCATION Of UNUSUAL EVENT (NUREG 0654)
Gentlemen:
As specified in the CPSES Emergency Plan. TV Electric hereby transmits the attached report which summarizes the incident which occurred on July 26, 1990.
As stated in the corrective action, an ovaluation is in process and a Licensee Event Report (LER) will be submitted in accordance with 10CfR50.73 by August 27, 1990.
Sincerely, O-William J. Cahill, Jr.
JRW/daj c - Mr. R. D. Martin, Region IV Mr. J.11. Wilson, NRR Resident Inspectors, CPMS (3)
Mr. Robert Lansford, Division of Emergency Management l
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I Er'iclo20re TXX-90273 Page 1 of 2 TU Electric Comanche Peak Steam Electric Station, Unit 1 Docket No. 50-445 Notification of an Unusual Event as a Result of Safety injection Actuation Renort Reautrement This report is being submitted as recommended by NU. REG-0654, " Criteria for Preparation and Evaluation of Radiological Emergency Response Plans and Preparedness in Support of Nuclear Power Plants" and in accordance with Comanche Peak Steam Electric Station (CPSES) Emergency Plan Procedures. The CPSES Emergency Plan procedures require that a written summary be submitted within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of the closcout of the Notification of an Unusual Event (NOUE).
Event Desetiption On July 26,1990 at 1416 CDT with the plant in llot Standby and the Reactor Coolant System (RCS) temperature at 557 degrees F and pressure at 2235 psig, an Engineered Safety Features Actuation Signal (ESFAS) occurred which resulted in the initiation of a Safety Injection (SI). The plant staff response to the transient was in accordance with Emergency Operating Procedures (EOPs). Activation of the Emergency Plan with the Notification of an Unusual Event occurred at 1420. Notification of the Nuclear-Regulatory Commission and the appropriate offsite agencies was accomplished in accordance with the applicable regulatory and procedural requirements, injection flow was terminated in accordance with the EOPs, and the plant was restored to a stable condition with RCS temperature at 559 degrees F and pressure at 2235 psig. The NOUE was terminated at 1740. The initial review conducted subsequent to the event indicates that all components and systems functioned as designed following the Si actuation. At no time was there a threat to the health and safety of the public as a result of the event.
Immediate Cause At the time of the event, the secondary side of the plant was being isolated in preparation for maintenance activities on various valves and components.
As part of the clearance process, fuses were pulled to de energize the solenoid air control valves associated with the Main Steam Isolation Valves (MSIVs). Because the air supply had not yet been isolated from MSIVs 2 and 4, the solenoid operated air supply valve to the hydraulle pump and the solenoid operated valve controlling the hydraulic dump system positioned to allow hydraulle fluid to drive open MSIVs 2 and 4. The resultant rate compensated low main steamline pressure initiated a Safety Injection.
Ericlosure TXX-90273 Page 2 of 2 Corrective Actions immediate correcuve actions were focused on restorir.g the plant to a stable condition. Actions to prevent recurrence will be determined based on the results of the Evaluation Team findings associated with the Plant incident investigation of this event. The details of the event and the subsequent recovery, including root cause determination and recommendations for corrective actions, will be included in the Licensee Event Report to be submitted to the Commission in accordance with 10CFR50.73.
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