ML20133J767
| ML20133J767 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 10/16/1985 |
| From: | Williams N CYGNA ENERGY SERVICES |
| To: | Council W TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| References | |
| 84056.090, NUDOCS 8510210076 | |
| Download: ML20133J767 (7) | |
Text
{,'
M s
.o, 101 Canfornia Street. Suite 1000. San Francisco, CA 94111-5894 415 397-6600 9g October 16, 1985 84056.090 4
f O'gi Mr. W.G. Council Executive Vice President Texas Utilities Generating Company Skyway Tower 400 North Olive Street, L.B. 81 Dallas, TX 75201
Subject:
Electrical Systems Review Questions Comanche Peak Steam Electric Station Independent Assessment Program - Phase 4 Job No. 84056 fl
Dear Mr. Council:
G Attached please find a list of the Phase 4 electrical questions and open items.
If you have any questions or require clarification prior to prepar ing a response don't hesitate to call.
Very truly.yours, N.H. Williams Project Manager Attachment cc: Mr. V. Noonan (USNRC) w/ attachment Mr. S. Burwell (USNRC) w/ attachment Mr. S. Treby (USNRC) w/ attachment Mr. W. Horin (Bishop, Liberman, et al.) w/ attachment Ms. J. van Amerongen (TUGC0/EBASCO) w/ attachment Mrs. J. Ellis (CASE) w/ attachment Mr. D. Pigott (Orrick, Herrington & Sutcliffe) w/ attachment Mr. F. Dougherty (TENERA) w/ attachment Mr. R. Ballard (Gibbs & Hill) w/ attachment Mr. J. Beck (TUGCO) w/ attachment (3
Mr. J. Redding (TUGCO) w/ attachment h-
[fj/),
pl tV) e510210076 851016 r
POR ADOCK 05000445 r
A PDR g
g San Francisco Boston Chicago Richland l
Mr. W.G. Council 0ctober 16, 1985 (mJage 2 v
ATTACHMENT A Electrical Data Requested In Letter 84056.081
Subject:
Cable Impedances Based Upon 75'C for Short-Circuit Studies R:;ferences:
Electrical RIL #5 Information Needs:
Provide justification and assurance that cable temperatures will always be at least 75'C.
Subject:
Subtransient Reactance Assumed for all 480V Motors is 25%
References:
Electrical RIL #5 Information Needs:
Provide justification that assumption is conservative for the 480V short-circuit calculation.
Subject:
System Model for the 480V Short-Circuit Calculation eferences:
Electrical RIL #5 Information Needs:
The 480V short-circuit calculation modelled 6.9KV and upstream system as a single impedance based upon a max. momentary symetrical short-circuit current of 36,000A. The G&H calculation indicates that the max. value is above 38,000A. Provide justification for the usage of 36,000A.
Subject:
Medium Voltage System Short-Circuit Calculation R;ferences:
Electrical RIL #5 Information Needs:
The short-cir uit calculations were based upon grid capacities dstermined in 1974.
Provide assuraace that the values used are still valid.
Subject:
Diesel Generator Short-Circuit Contribution
References:
Electrical RIL #5 Information Needs:
The diesel generator's short-circuit contribution during breaker interrupting is usually determined using a short-circuit decrement curve.
The curve, supplied by the vendor, provides S.C.
values during various fault and pre-fault conditions.
The curve takes into account time constants and regulator action.
l Demonstrate that the diesel generator's time constants are such that the method used pby Gibbs and Hill for determining the generator's short-circuit contribution is valid.
N]
Mr. W.G. Council October' 16, 1985 Page 3 O-ATTACHMENT A Electrical Data Requested In Letter 84056.081
Subject:
Medium Voltage System Voltage Regulation Study
References:
Electrical RIL #6 Information Needs:, Voltage regulation study for the medium voltage system states that adequacy of voltages during DBA conditions is not in Gibbs and Hill's scope.
As a result, cases of undervoltage conditions appear to remain uncorrected.
Demonstrate that the undervoltage conditions are acceptable or that they have been corrected.
Subject:
480V System Voltage Regulation Study
References:
Electrical RIL #6 Information Needs:
The 480V system regulation study did not study DBA conditions i
concurrent with normal offsite grid voltage variation. The Gibbs and Hill calculation shows some 480V buses experiencing transient dips below acceptable values and overvoltage conditions.
480V motor starting was not studied.
o Justify not studying DBA conditions concurrently with normal offsite grid voltage variations.
Provide calculations to demonstrate that system voltages will not dip below dcceptable levels during 480V motor starting.
o Demonstrate that the undervoltage and overvoltage conditions are acceptable or that they have been corrected.
Subject:
Offsite Grid Voltage Variations
[
i
References:
Electrical RIL #6 f
i Information Needs:
The source of data for offsite grid voltage variations is not identified.
Identify the source of data and provide a copy of that document.
Subject:
Overcurrent Protective Device Settings
References:
Electrical RIL #7 i
Information Needs:
The setting of overcurrent relays should be such that equipment protection is provided.
The setting of overcurrent relays for motors and transformers i
did not consider the thermal limits of the equipment.
The settings may not be adequate or may be too conservative leading to nuisance tripping.
Demonstrate that equipment protection is provided and that the likelihood of nuisance tripping is kept at a minimum.
O
Mr'. W.G. Council October 16, 1985 r 7 age 4 ATTACHMENT A Electrical Data Requested In Letter 84056.081
Subject:
Coordinate of Protective Devices
References:
Electrical RIL #7 Ir. formation Needs:
The setting of instantaneous tripping devices should be such that
- faulted circuits are quickly isolated.
The setting of the protective devices on the 6.9KV system did not consider the situation where the DG is the only power source.
Demonstrate that the DG has sufficient S.C. capability to operate the instantaneous tripping devices.
Subject:
The Protection of RCP Penetrators Does Not Appear to Meet the Single-Failure Criterion of R.G.1.63
References:
Electrical RIL #7 Information Needs:
Primary protection is via three current transformers into three overcurrent relays tripping the RCP feeder breaker.
Back-up protection is via two of he same three current transformers into two overcurrent relays tripping the main witchgear feeder breaker.
Demonstrate that the DC control power to the RCP feeder reaker and the main switchgear breaker are from diverse sources and that sharing of current transformers meets the single failure criterion.
Subject:
The Gibbs and Hill Cable Sizing Calculation has Derated Caoles Inside Containment for a Maximum Ambient Temperature of 50 C.
l
References:
Electrical RIL #8 Information Needs:
The FSAR shows the long-term post-accident temperature inside containment as 65.6*C.
Demonstrate that cables inside containment are still adequately sized given the higher ambients.
l
Subject:
The CCW Motor Vendor has Sized the Motor and Determined Acceleration l
Time Based Upon a Start Against a Closed Discharge Valve.
The CCW Pump j
is Actually Stc-ted Against an Open Discharge Valve.
1 i
References:
Mechanical RIL #8 Irformation Needs:
Demonstrate that the motor can still accelerate the pump and that j
the acceleration time is still within five seconds.
,y a
Mr. W.G. Council 2 7 October 16, 1985
\\,,/'ge 5
?
ATTACHMENT A Electrical Data Requested In Letter 84056.081 Additional Data Requests
Subject:
The Ra'nge of FT-4536B Does Not Appear to be Consistent with FI-4536B.
References:
Transcript of Cygna-NRC Meeting Dated 5/21/85 Information Needs:
The flow transmitter will provide a 4.7VDC output on a AP of 43.3 psig.
43.3 psig corresponds to a flow of approximately 7,000 gpm.
The flow indicator cill indicate a flow of approximately 6,700 gpm on an input of 4.7VDC.
Demonstrate that this discrepancy has been corrected and identi fy the mechanism (procedure, drawing, etc.) that insures other instrument.and indicator ranges are compatible.
Subject:
Instrument Tubing Installation
References:
Communications Report Dated 6/7/85 (B. Phillips of TUGC0 and P. Costello of Cygna) nformation Needs:
Provide instrument tubing isometric diagrams for the subject nstrument tubing runs and documentation showing that the problem has been corrected.
Subject:
The Instrument Data Sheet in the Purchase Specification is not Consistent with the Information on the Calibration Card.
R;ferences:
Transcript of Cygna-NRC Meeting Dated 5/21/85 Information Needs:
The purchase specification shows the range of LT-4500 as 4-20MA for 0-120"W.C.
The calibration card shows the range as 20-4MA for 7.8-79.8"W.C.
Provide documentation resolving this discrepancy.
Subject:
Voltage Drop Calculations Were Not Done for AC or DC Control Circuits or Medium Voltage Power Circuits.
References:
Transcript of Cygna-NRC Meeting Dated 5/21/85 Information Needs:
Demonstrate that adequate voltage will exist at the end device for the subject circuits.
I b
l
\\~ J
Mr. W.G. Council October 16, 1985 ge 6 ATTACHMENT A Electrical Data Requested In Letter 84056.081
Subject:
Raceway Fill for Maintained Space Cable Trays is Tracked by Percent Fill
References:
Transcript of Cygna-NRC Meeting Dated 5/21/85 Information Needs:
Demonstrate that this method will assure that adequate spacing exists in the design.
Subject:
Cable Ampacity Calculations Performed per TUGC0 Procedure CP-EI-4.0-42
References:
Transcript of Cygna-NRC Meeting Dated 5/21/85 Information Needs:
The procedure did not co.isider tray covers and used an incorrect d: rating factor.
The procedure also indicates that derating factors are not cumulative.
Verify that these methods will not result in load currents being in excess of the derated cable ampacity.
^^'bject:
The Instrument Calibration Cards Do Not Agree With the Setpoint
)
Calculation R ferences:
Transcript of Cygna-NRC Meeting Dated 5/21/85 Information Needs:
The setpoint of LB-4500A, LB-4500B, PS-4250, and PS-4518 do not agree with the setpoint calculation.
Demonstrate the overall system operation is not impacted and identify the applicable project procedure (s) for instrument setpoints.
f) l
._.