ML20027A619
| ML20027A619 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 10/10/1980 |
| From: | Brown S VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | Harold Denton, Parr O Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20027A620 | List: |
| References | |
| 823, NUDOCS 8010160580 | |
| Download: ML20027A619 (3) | |
Text
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l onoin accinic ano no.ca cou 4sv. anc,uono. vincini, 2iasi October 10, 1980 Mr. Harold R. Denton, Director Serial No.
S23 Office of Nuclear Reactor Regulation PSE&C/KSB: val: wang Attn: Mr. O. D. Parr, Chief Light Water Reactors Branch No. 3 Docket Noq. 50-339 Division of Project Management V
U. S. Nuclear Regulatory Commission Washington, D.C.
20555
Dear Mr. Denton:
PRIMARY AND SECCNDARY ELECTRICAL PROTECTION OF CONTAINNENT PENETRATION 5 FOR NORTH ANNA PO't!ER STATION -UNIT 2 J
In compliance with your letters of August 3,1979 and November 30, 1979 on electrical penetration protection for North Anna 2, we hereby submit the primary and secondary (independent back-up) electrical penetration protection for the power, control, and instrumentation electrical circuits. Enclosed are twenty copies each of " Electrical Penetration Protectien ocwer Circuits (Primary and Secondary)," " Electrical Penetraticn Protection-Control Circuits (Primary and Secondary)," and " Electrical Penetration Protection-Instrumentation Circuits."
Each of these Occuments incluces the following information for their respective circuit classification:
I 1.
Identification of each electrical circuit that cenetrate's the containment.
2.
Identification of each penetration type and conductor size.
3.
Description of the primary and secondary orotective devices.
4 Time-current characteristic curves showing the fault current-vs-time i
regime fcr the primary and secondary protective devices, the fault current-vs-time regine for the penetrations, and the coordination i
between the two. An analysis was nade to ensure that the maximum temcaratura when ccmbining the cenetration temperature rise due to tne maxinum fault with the pea!: LOCA temcerature did not exceso the maxirun temperature for which the penetraticn is cualified. This analysis assumec no neat generated by fault current passing through the penetration was lost from the censtratien.
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i The following clarifications apply to the instrumentation circuits:
1.
Time-current characteristic curves are not shown for the majority of penetrations because the maximum fault current is less than the penetration continuous rating in those cases.
Secondary protection is not recuired for these cases, i
i 2.
For the penetrations of the following circuits, a maximum fault current has not yet been obtained from the equipment 2
manufacturers. To ensure protection of the penetration, primary and secondary protection are applied to these circuits.
Time-current characteristic curves have not been included because of the small size of the primary and secondary protective fuses with respect to the penetrations' continuous ratings. The curves will be provided upon request.
4 A.
Drive assemblies A, B, C, D, E B.
Drive assemblies A-2, B-2, C-2, 0-2, E-2 1
2 C.
Five path transfer devices for drive assemblies A, B, C, D, E
1 D.
Evacuation horn i
j The following clarifications apply to the control circuits:
1 1.
For curves IB-1, IB-2A,18-29,18-3,18 4, 18-5, IB-6, IB-7, IB-8, IB-9, and 18-10 a continuous rating of 25 amps has been 4
used instead of 12 amps. The 12 amo rating applies with 12 amps i
in each of the 140 conductors. Since this is not a feasible l
case for control circuits of this nature, we have applied a more realistic case: a shared load of 20 amps in 138 conductors.
This current equals a minimum of twice the full load expected and is applied simultanecusly to the conductors while the actual i
loads occur intermittantly. Under this condition, any 2 of the 140 conductors are cacable of carrying 25 amps continuously.
This rating has been oerived by test.
2.
The protection scheme is designed arcund the highest possible fault current available. The current shcwn on the curves is the current calculated using only line impedance from the circuit's source. No credit has been taken for power supply or Centroller r
Imoedances. In additicn, internal protection devices located in power suoplies or centrollers are not incorporated into the analysis, even thcugh these factors Cecrease available fault current and offer additional steps of protection.
l 3.
For those AC and DC circuits which are ungrounded and have a fuse in each leg of the circuit, these fuses serve as primary and secondary protecticn for the penetraticn.
4 The fault current for Curve 19-9 will be no greater than SCO anos.
I E
.o 5.
For those circuits which do not have a full load current specified, the full load current will not materially affect the penetration analysis.
6.
The penetration in curve IB-2B is a #1a feed thru with single and dcuole seal integrity characteristics shown.
The following clarification soplies to the power circuits:
1.
Eight circuits associated with non-class lE loads that do not need to be energized when containment integrity must be maintained do not have secondary protection. When containment integrity is required, the circuit breakers providing the power feeds to these circuits will be open.
This submittal completes the requirements set forth in paragraph 2-C-10 on Page 6 of the Facility Operating License NPF-7 issued en August 21, 1980. The secondary protection will be instelled and operational prior to resuming power cperation follcwing the first refueling outage for Unit 2.
If further information is required, please contact this office.
Ver truly,yo 's, l
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6.
SenicrVicePresident[,
Power Station Engineerin and Construction cc:
Mr. Victor Stello, Director Office of Inspection & Enforcement Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulaticn