ML20246D936
| ML20246D936 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 07/07/1989 |
| From: | William Cahill TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| RTR-REGGD-01.075, RTR-REGGD-1.075 CP-87-136, TXX-89428, NUDOCS 8907120040 | |
| Download: ML20246D936 (2) | |
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,7 mumsmemme EM Log # TXX-89428 F """
File # 10110 1
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C Ref. # 10CFR50.55(e) 1UELECTRIC July 7,1989 wmi m s, cahm,Jr.
Executive Vicel*resulent U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C.
20555
SUBJECT:
COMANCilE PEAK STEAM ELECTRIC STATION (CPSES) u0CKET NOS. 50-445 AND 50-446 MOTOR CONTROL CENTER SPACE HEATERS SDAR: CP-87-136 (SUPPLEMENTAL REPORT)
Gentlemen:
On January 11, 1988, TU Electric notified the NRC by final report logged TXX-88065 of an electrical separation deficiency involving the space heaters for Class IE motor control centers (MCC's). The last letter submitted on this issue was TXX-89393, dated June 12, 1989. This supplemental report is submitted to partially revise the corrective action for this issue and update the completion schedule.
The identified deficiency involved unqualified space heaters for the Class IE MCC's connected to Class IE power sources in the MCC's. Additionally, Class IE shunt trips for the non-Class IE MCC's at the service water intake structure are connected as part of the space heater circuit. These conditions do not meet the isolation criteria described in the CPSES FSAR.
'TXX-88065, dated January 11, 1988, described the following corrective actions to resolve these deficiencies:
1)
The two fuses in each non-Class IE space heater circuit for all Class IE MCC's will be removed.
2)
When the Class IE MCC's are de-energized, temporary power will be connected to the space heater circuits.
3)
The shunt trip circuits will be rewired to accommodate a direct power supply from the Class IE source.
In lieu of corrective action items 1 and 2 described above for the MCC space heaters, the design will be changed to trip the space heater supply breakers on receipt of a Safety Injection Signal. This will properly isolate the Class IE MCC's frem the space heaters and meets the requirements of Regulatory Guide 1.75.
s907120040 890707 l
AcocK0500g5 DR M North Olive Street LBB1 Dallas, Texas 73201
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TXX-89428 July 7, 1989 Page 2 of 2 The corrective action described in item 3 for the shunt trip circuits remains unchanged.
To preclude recurrence of this condition, the isolation criteria as described in the CPSES FSAR have been included in the applicable Design Basis Document (DBD).
In lieu of performing the previously specified field verification method FVM-EE/ME/IC/CS-088, "PCHV Program for Engineering Reverification of Electric Separation", to confirm that adequate isolating devices exist where Class IE to non-Class IE isolation is required by Regulatory Guide 1.75, a review has been completed which validated the electrical one line drawings against '.he updated DBD.
Corrective action associated with this issue will be completed for Unit 1 prior to Unit I fuel load and for Unit 2 prior to Unit 2 fuel load.
Sincerely,
~
William J. Cahill, Jr WJH/vid c - Mr. R. D. Martin, Region IV Resident inspectors, CPSES (3) i