ML19323D613
| ML19323D613 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 05/09/1980 |
| From: | Ippolito T Office of Nuclear Reactor Regulation |
| To: | Parris H TENNESSEE VALLEY AUTHORITY |
| References | |
| NUDOCS 8005220022 | |
| Download: ML19323D613 (5) | |
Text
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UNITED STATES 8'
]s NUCLEAR REGULATORY COMMISSION E
WASHINGTCN, D. C. 205$5 e.
/
MAY 9 1980 Docket Nos.
50-259 50-260 and 50-296 m
THIS DOCUMENT C0iiTA!ils l
Mr. Hugh G. Parris Manager of Power Tennessee Valley Authority 500 A Chestnut Street, Tower II Chattanooga, Tennessee 37401
Dear Mr. Parris:
Reference is made to my letter of April 8,1980 forwarding a request for information regarding the adequacies of station electric distribution system voltages for the Browns Ferry Nuclear Planc.
From discussions with your staff, we understand that you expect to submit the design of the proposed long-tem modifications within the next month and will address the coments in my April 8,1980 letter as part of the submittal on the long-term improve-ments. Our continuing review has identified additional coments and ques-tions, particularly on your submittal of September 4,1979.
It is re Jsted that you also respond to these questions and coments in your submittai on the long-tem improvements.
Sincerely, A -
Thomas
. Ippolito, Chief Operating Reactors Branch #2 Division of Licensing
Enclosure:
Questions on Adequacy of Station Electric Distribution System Voltages cc w/ enclosure:
See next page
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6 0 05 220GRd
d' Mr. Hugh G. Parris RAY 9 1983 cc:
.s H. S. Sanger, Jr., Esquire General Counsel Tennessee Valley Authority 400 Commerce Avenue E llB 33 C Knoxville, Tennessee 37902 Mr. Ron Rogers Tennessee Valley Authority 400 Chestnut Street, Tower II Chattanooga, Tennessee 37401 Mr. H. N. Culver 249A HBD 400 Commerce Avenue Tennessee Valley Authority Knoxville, Tennessee 37902 Robert F. Sullivan U. S. Nuclear Regulatory Commission P. O. Box 1863 Decatur, Alabama 35602 Athens Public Library South and Forrest Athens, Alabama 35611 t
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BRO *JNS FERRY UNITS 1, 2, AND 3 (Docket Nos. 50-239, 50-260, anc 50-296)
QUESTIONS ON ADEQUACT OF STATION ELECTRIC DISTRI3CTION SYSTEM VOLTAGES References a.
TVA letter, J. E. Gilleland, to Idso: G. Oase, Office of Nuclear Reac-tor Regulation, KRC, Docket Nos. 50 ~59, 50-260, and 50-296, May 2, 1978.
b.
TVA letter,.J. I. Gilleland to Direc:or :f "u: lear Reactor Regulation, NRC, Docket Nos. 50-259, 50-260, and 50 ~is, "ay 12, 1978.
c.
TVA letter, R. H. Davidson to Edsca G. Casa, Office of Nuclear Reactor Regulation, NRC, Docket Nos. 50-259, 50 ~50, and 50-296, May.17,1978.
ThA letter, H. S. Fox, to Janes ?. O' Reil'.7, Office aof Inspection and d.
En f orcement, Region II, NRC, Decke: No.53-239, January 23, 1979.
NRC generic letter to all Power Reactor Lic=nsees, " Adequacy of Station e.
Electric Distribution Syste= Vol: age." ds:ed August 8,1979.
f.
TVA letter, L. M. Mills to Director cf N :'. ear Reactor Regulation, NRC, Docket Nos. 50-259, 50-260, and 30-195, September 4, 1979.
QU2stions "donfirm the acceptability of the vo'.:a;e ::niitions on the station electric distribution syste=s with regard :: i::h (1) potential overloading due to transfers of either safety or n:n-ssf e:y loads, and (2) potential starting transient proble=s in addi:ica to :he cenerns e:cpressed in our June 2, 1977 correspondence with resard ta de;rided voltage conditicas due c
- o condicions originating on the grid.",.
Specifically:
1.
Figure l shows :ha t ene shutdown bus (3osed) can have power supplied from a s'econd shutd:vn bus.
I'f nothin pr:hibits such a connection, h
- - +
g g
gay
0 it sh uld b2 analyzed for cil thr:e uni:s es BC guid line 1
+
requires.
2.
With the addition of generatcr low-side bres*4ers and (automatic 7) d tap-changin; station service transf.sers (1:e=s 4, 5 ), another possible power source to :he class IE buses is established. Per NRC guideline 1*, this should be analyzed for all :hree units.
w 3.
Supply the calculated voltages for all lev-voltage AC (480 V and less),
class IE buses (including alternate ' source connections) for each anal-yzed case. Do these system supply any instru ents and control circuits as required by GDC 137 If so, is all epi; men: rated to operate with th analy:ed voltages without blovits fuses, :verheatin5, etc.
and without affecting the equipments' abili:y :o perform the required fune: ion?
4.
The ENGINEERED SAFETY FEATURE ACTUATION SYSTE.M INSTRUl!ENTATION TRIP VALUESD table shows that a i 5% tolerance is allowed on 3920V b
(95% of 4160V) set point (figure I ).
Positive 5% tolerance will cause spurious trip of off-site power (NRC Guidelline 12e) whereas the negative 5% tolerance vill cause unacceptable 8
voltages on equipment on 480V and below (NRC guideline 10 ).
Justify the proposed tolerance band or provide new values.
5.
The TVA references do not define the =iniec= and maxi =us anticipated grid volta;es. Guideline 6* allous three rathods of determining the value of the de; aded grid voltage, whichever provides the worse case.
TVA should describe how thei: ; rid v:1:1;c !cve'.s are de: ermined (one method say produce the low voltage whi'.e a;.sther nethcd =sy preiuce the hign voltage) and sta:e what these vaines are.
I i
6.
Per NRC guidelines 3 and 9*, cenpare :1.e effe:: of starting cnd running a 8000-HF reac:o recire.11.; s e- :. C.1 class II buses and c
loads with :he required voltage range fs,norn:1 operation of these class 12 loads (starters, conta:: ors. ::::: ::.-ings, et:. ). What are the bcs a..d load voltages when startin; the lar;est I.S0 V class 1E 9
load when all class 1E buses are o:herwise fu~.~.y loaded?
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7.
I RC cuidelina 11", which asks fo: a dcter=*naticn of the maximum voltage expected at each safety load (and starting circuit), has not been supplied b)* any of the TVA referen:es.
.T'.*A should supply this analysis; they should identify and ccr ect any overvoltage conditions.
S.
The TVA references have r.ot provided 1 separate analysis for each Browns Ferry unit as required by NRC guideline 2*.
TVA should supply the analysis of the mini =us grid conditica and the " largest load demand situation" for each unit, and include the documentation required by NRC guideline 7*.
9.
The NIC requires (page 2, paragraph 3*) verification of the analysis method and parameters. The TVA should subsit (a) "a description of the =ethod for performing this verification, and (b) the test results,"'
as the referenced sub=ittals did not cover this =aterial.
10.
The :iRC requested (page 2, paragraph '*) that the TVA review the Browns Terry electric power syste=s to dater =ine if' potential viola-tions of CDC 17 existed. The TVA references did not contain the requested review. The TVA should supply the requested review.
11.
The last paragraph, page 2', indicates that the ::RC is to approve a p cpssed icng-ter: =odification. The 7:Oposal as to be submitted prior to February 1980. This proposal has not becn received for raview or its impact on this current revicv.
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