ML20247M541
| ML20247M541 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 05/25/1989 |
| From: | William Cahill TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| CP-88-33, TXX-89272, NUDOCS 8906050064 | |
| Download: ML20247M541 (1) | |
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"""ll Log # TXX-89272 File # 10110 908.3 R # '*C'R***"(*'
TUELECTRIC Milliam J. Cahill. Jr.
Executive Vice President U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C.
20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NOS. 50-445 AND 50-446 EDG VOLTAGE OUTPUT SDAR: CP-88-33 (FINAL REPORT)
Gentlemen:
On August 30, 1988 TU Electric verbally notified the NRC of a reportable deficiency under the provisions of 10CFR50.55(e) involving the Emergency Diesel Generator (EDG) static exciter voltage regulation (SEVR) circuitry.
The last report on this issue, logged TXX-89232, was submitted May 8,1989.
This report is to inform you of the final corrective action for this issue.
As previously discussed in TXX-88656, dated August 31, 1988, the CPSES EDG's are designed to operate at 450 rpm.
Upon initiation of EDG shutdown, the SEVR is tripped and does not reset until the engine speed decreases to 425 rpm.
If an emergency start signal is received during the coastdown prior to reaching 425 rpm, the engine would accelerate to its synchronous speed of 450 rpm but there would be no generator output, since the exciter would not be energized.
This is a momentary condition occurring during shutdown of an EDG.
To prevent occurrence of this postulated event, the Unit I system operating procedure has been revised to require that during EDG shutdown, an operator will be present at the EDG local control panel. The operator's function is to
'nanually activate the exciter reset pushbutton if the EDG starting light comes on during the shutdown, before the SEVR circuit is automatically reset.
The start light on the panel indicates emergency demand for an EDG start.
The procedure revision described above completes the required corrective action for this issue for Unit 1.
The corrective action for Unit 2 will be completed by Unit 2 fuel load.
Sincerely, r
g6050064890525 g
ADOCK 05000445 2"
William J.f/
PNV Tahill, Jr.
WJH/vid c - Mr. R. D. Hartin, Region IV
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Resident Inspectors, CPSES (3) 400 North Olive Street LB 81 Dallas. Texas 75201
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