ML20235A377
| ML20235A377 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 01/06/1988 |
| From: | Counsil W, John Marshall TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| CP-87-128, TXX-88032, NUDOCS 8801120221 | |
| Download: ML20235A377 (2) | |
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"""" 9 907.6 Ref. # 10CFR50.55(e)
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TUELECTRIC January 6,1988 Willam G. Coumil Executive Vke Pressdent.
V. 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 LOSS OF CONTROL POWER INDICATION SDAR: CP-87-128 (INTERIM REPORT)-
Gentlemen:
'On. December 7,1987,: we verbally notified your Mr. H. S. Phillips of a deficiency involving the Emergency Diesel Generator Auto Start Circuitry for i
loss of control power.
After further evaluation we have determined that this
-deficiency is reportable pursuant to 10CFR50.55(e).
The required information follows.
Description During design validation of the 118V ac Static Uninterruptable Power Supply (UPS) elementary diagrams for the diesel generator auto-start circuits, it was disclosed'that there was no available means to monitor for loss of control power as required by IEEE 308.
The auxiliary relay racks are provided with internal blown fuse indicators; however, the indicators are not visually available to the operators for monitoring purposes.
The cause of the. described deficiency appears to be an oversight during design whereby the requirement to monitor for loss of control power was overlooked.
Safety Implications The circuits, as desi energized to operate)gned, do not fail safe (i.e., auxiliary relays must be and a loss of control pwer, blown fuse, etc. r uld prevent the circuit from performing its safety function. Without setveillance provisions, a loss of control power would not be detectable and could prevent auto-starting of the diesel generator and the shedding of nonessential loads on a safety injection signal. This condition represents a significant i
deficiency in final design as approved and r eleased for construction.
Had the condition remained uncorrected, it could have prevented proper operation of the diesel generator, thus adversely affecting the safety of operations during an accident.
>A 8801120221 880106 PDR ADOCK 050 S
8
,4 400 North Olive Street LBof Dallas Texas 75201
K TXX-88032 January 6, 1988 Page 2 of 2 Corrective Action
.The corrective action for this deficiency is the modification of the auxiliary relay racks to provide a visual means for thd operator to monitor the blown fuse indication for routine surveillance of indicator status.
After a review of other safety-related 120Vac and 125Vdc circuits, similar deficiencies have been identified.
The corrective action described above or the addition of loss of control power monitoring lights will be implemented on all Class 1E ac and de control circuits that are not in compliance with IEEE-308.
This corrective action will also require operator routine surveillance of indicator light status.
The schedule for the completion of corrective actions will be provided in a supplemental letter, which we will submit no later than March 31, 1988.
Very truly yours, d). 6 Co n so C W. G. Counsil By:
J. S. Marshall l
Supervisor, Generic Licensing VIP /grr c - Mr. R. D. Martin, Region IV Resident Inspectors, CPSES (3)
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