ML20033A208
| ML20033A208 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 11/05/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20033A205 | List: |
| References | |
| NUDOCS 8111240913 | |
| Download: ML20033A208 (5) | |
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SAFETY EVALUATION LACROSSE BOILING WATER REACTOR DOCKET NO. 50-409 ADEQdACY OF STATION ELECTRIC DISTRI'BUTION SY' STEM V0LTAGES INTRODUCTION AND
SUMMARY
Dairyland Power Cooperative (DPC) was requested by NRC letter dated August l8,.
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1979, to review the electric power system of Lacrosse Boiling Water Reactor.
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The review Mas to consist ofi
~(*) Deterniin'ing analytical'ly'the capacit'y and capability of the offsite'
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power system and the onsite distribution system to start automatically.
and to operate-all re'quir'ed'sa'fety 1oads within their required voltiage
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s ratings in th'e event'~of'(T) an a~nsicipated transient.or (2) an accident, such' as LOCI,' without nian >al' shedding of any electric loads.
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(b) Determining 'if there are any events or conditions which could result in the simultaneous or consequential loss of both required circuits
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frca the of# site net..cek to tne ons' e electric distributi n sys, tem, N'
tnus violating the requirements of GDC 17.
7ne August 3, 1979 ietter indicated staff guidelines for performing the recuired
'c': age :nalys's.
urtneracre, ne licensee was 'scuired to cerform tests.:o r
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verify tha validity of the analytical results.
3PC responded with letters cateo Marca 13, 1980; May 12, 1980 (wnicn containec the required electric system analysis); September 17, 1981; and June 22, 1981. A detailed review and technical evaluation of the submittal was performed by EG&G under centract to the NRC and with general supervision by the NRC staff. This work was reported
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in EG&G's Technical Evaluation Report, "Adecuacy of Station Electric Distribution a
System Voltages, Lacrosse Soiling Nater Reactor datec August 1981" which is attached.
We have reviewed this report and concur in-the conclusion that upon r
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PDP ADOCK 05000409.
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resetting the taps of the reserve auxiliary transformer, ~the offsite power system and onsite distribution system will be capable of providing acceptable voltages at the terminals of the Class lE equipment for the worst case station electric load and grid voltages. DPC changed the tap settings on,Jan. 7, 1981.
-These voltag,es are based on having open bus ties between auxiliary busses l A.and
-1B.and between Class lE busses.lA and lB..The licensee states that.these bus ties are never closed except during cold shutdown, although.there.are no. technical specifications or limiting conditions of operation preventing the use of the bus-ties at other times.
Also, it should be noted that this small nuclear facility was constructed w
prior to the promulgation of GDC-17, and has only a single circuit connection from the off-site grid to the on-site distribution system. Furthermore, an analysis of postulated bus-tie failures a's a cause of simultaneous loss cf two off-site sources is a moot issue, since there is only one off-site source to cegin with.
These non-conforming items will be adcrassec in ne ':RC Systematic Evaluation
?-ogram's integrated assessment of the Lacrosse Boiling Water Reactor.
EVALUATION CRITERIA-The criteria used by_ EG&G in this technical evaluation of the analysis includes GDC 5 (" Sharing of Structures, Systems, and Components"), GDC 13 ("Instrumenta-tion and Control"), and GDC 17 (" Electric Power _ Systems") of Appendix A to -
10 CFR 50; IEEE Standard 308-1974 (' Class lE Power systems for Nuclear Power mas a
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_ Generating Stations"); ANSI C84.1-1977 (" Voltage Ratings for Electric Power-
. Systems and Equipment - 60 HZ"); andLthe staff positions ar? guidelines in.the NRC letter to OPC dated August 8,-1979.
ANALYSIS AND TEST FEATURES DPC 'has determined by previous steady state voltage measurements that the p
maximum expected offsite grid voltage is 73.2KV and the minimum is.70.8KV.
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3, DPC has analyzed.the.offsite scurce'.to'tne'onsite distribution. system under:
extremes of load and offsite voltage conditions to determine the' terminal voltages.at the class lE ' quipment. The worst case _ class lE equipment.
e terminal voltages occur under the following conditions:-
- 1..The worst loading condition occurs when all loads that operate for-cower operation and the class lE LOCA loads are carried by tne reserv auxiliary transformer.
2.
The worst transient voltage occurs on' the class 'lE system urider? the:
above condition ccabined with starting a 1500 hp feedwater pumo on a 2400V bus.
3.
The hicnest steacy state voltage was determined : occur if no icads were ocerating.
The analysis shows that, with one exception, all class lE loads a're capable-of starting and. continuously operating under.all' conditions..The one exception -is the 480 volt diesel plant battery charger. However, this -device :
shuts down wnen the input voltage is below its' minimum rating land; automatically
. resumes. operation wnen input voltage is. restored above this limit.
The-licensee has stated that this will not damage the charger.
Loss.of-the charger outout current will~ annunciate, cause' the batteries to carry the-DCzloads.
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_4 and initiate a limiting condition of operation (LCO). The LCO requires that if the battery charger is not made operable within two hours, then a hot shutdown must be initiated. The licen:ee has stated that the battery bank:
being charged by this charger can carry its rated load for eight hours.-
The voltage analysis was verified by measuring the grid voltage, the bus voltage,-the actual load on the busses, and the actual load on the MCCs while using Ehe reserve. auxiliary trans'ormer to supply power. Comparing the measured lE bus voltage to the calculated voltage shows that the calcu-lated values are up to.l.0", higher than-the measured voltage.
This ; difference must be accounted for in evaluating the voltages supplied to the lE equipment;
.however, the close correlation does verify the adequacy ~of the analysis' submitted.
- MCLUSIONS We have reviewed the EG&G Technical Evaluation Report. Our conclusions are is follows:
1.
With the tao c.nange cf the reserve auxiliary transformer, voli. ages 1re new :aitnic the operating linits of the class iE etuipment under
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worst case conoitions of piant load arc offsite power grid conditions.
2.
The ceasurements taken to -verify the analysis shows that the calculated values are accurate representations of the worst case conditions analyzed.
3.
The analysis did not include the c;.se of one 2400 to 480 volt auxiliary.
transformer supplying both 440 volt busses via existing bus-ties. The license.e stated that the bus-ties are only used during cold shutdown.
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Whether or r.ot the use of the bus ties should become part of the Technical Specifications or impose limiting conditions of operation should be in-cluded in the Systematic Evaluation Program for tnis facility.
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The Lacrosse station, having been built before the advent of GDC-17,.
does not~have a second source of off-site power. This situation will-be "considereo in the NRC Systematic Evaluation Program's. integrated:
assessment of.he LaCross station.
EG&G Idaho,'Inc. is performing a _ separate review of the undervoltage relay protection at the L' Crosse. station,. This will evaluate _the relay ~setpoints-and a
1 time delays to determine that spurious tripping of the class.lE buses will not occur with normal o#fsite source voltages.
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FORu EG&G 398 e ii m INTERIM REPORT C~
Accession No.
Report No. EGG-EA-5304 Ccntract Program or Project
Title:
Selected Operating Reactor Issues Program (III)
Subject of this Document'.
Adequacy of Station Electric Distribution System Voltages, La Crosse, oiling r
Water Reactor, Docket No. 50-409, TAC No. 12763 Type of Document:
Informal Report Author (s):
A. C. Udy Dit] of Document:
August 1981
( csp nsible NRC Individual and NRC Office or Division Paul Shemanski, Division of Licensing This document was prepared primatily for preliminary orinternaluse. it has not received full review and approval. Since there may be substantive changes,this document should not be considered final.
EG&G Idaho, Inc.
l Prepared for the U.S. Nuclear Regulatory Commission l
Washington, D.C.
Under DOE Contract No. DE-AC07-761D01570 NRC FIN No. A6429 l (
INTERIM REPORT D il% 8 5959 2 2 4 2 $ 9
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ADEQUACY OF STATION ELECTRIC DISTRIBUTION -SYSTEM VOLTAGES LA CROSSE BOILING WATER REACTOR Docket No."50-409
' Augusti 1981 i
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.I A.'C. Udy'
-l Reliability and Statistics Branch-
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Engineering Analysis Division
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EG&G Idaho, Inc.
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- k' ABSTRACT The Nuclear Regulatory Commission has required all licensees'to' analyze the electric power system at each nuclear' station.
This' review is to deter-mine~if the'onsite distribution system in conjunction with the offsite power. sources has sufficient capacity and ' capability to automatically start and operate all required safety loads-within-the equipment voltage ratings.
This Technical Evaluation Report reviews the submittals for the La Crosse Boiling Water Reactor.
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~ The offsite power. sources,.in conjunction'with the onsite distribution-system, h' ave been shown to have sufficient capacity and capability to auto-
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matically start, as well as continuously operate, all required safetyL related loads within the equipment rated voltage limits in the event of either an anticipated transient or an accident condition.
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' FOREWORD
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t This report is supplied as part of.the'" Selected Operating Reactor C'
Issues Program-(III)" being conducted for the U.S. Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation, Division of Licensing, by.
EG&G Idaho, Inc., Reliability and Statistics Branch. -
The U.S. Nuclear. Regulatory Commission funded the work. under-the auth-orization B&R 20 19 01 06, FIN No. A6429.'
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CONTENTS 1.0 IS TR O D UC T I O N......................................................
1 2.0 DESIGN BASIS CRITERIA.............................................
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'3.0 SYSTEM DESCRIPTION................................................
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4.0 ANALYSIS DESCRIPTION..............................................
2 4.1 Design Changes...............................................
2-4.2 Analysis Conditions..........................................
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'4.3 Analysis Results.............................................
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'4.4 Analysis Verification........................................
S' 5.0 EVALUATION........................................................
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6.0 CONCLUSION
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7.0 REFERENCES
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'. FIGURE.
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La Crosse electrical single-line diagram..........................
3 TABLE l.
Clas.s lE Equipment Voltage Ratings and (9
-Analyzed Worst Case Load Terminal' Voltages........................
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ADEQUACY OF STATION ELECTRIC DISTRIBUTION SYSTEM V0LTAGES
. LA CROSSE BOILING WATER REACTOR
1.0 INTRODUCTION
1 An. event.at the Arkansas Nuclear One station on September 16,-1978 is described in NRC IE Information Notice No.-79-04.
As a result of this event, station conformance to General Design Criteria (GDC) 17 is being questioned at all nuclear power stations. The NRC,.in the generic letter ofAugugt8,1979,"AdequacyofStationElectricDistribution-SystemsVolt-ages,"
required each licensee to confirm, by analysis, the adequacy of the voltage at the class 1E' loads.
This-letter included 13 specific guide-lines to be followed in Aetermining if the load. terminal voltage:is adequate to star.t and continuously operate the class lE loaas.
Dairyland Power Cooperative '(DPC)l responded to the NRC letterl:with.
letters of March 13,.1980,2 and May 12, 1980.3 The Safeguards-Report -
(SR) and the DPC re ponse to concerns about the earlier submittals, dated September 17, 61960, a telephone call in November-1980 5 a letter of J.une 22, 1981, and a telephone call on July 31,1981,I complete the.
information reviewed for this-report.
Based on the information supplied by DPC, this report addresses the capacity and capability of the onsite distribution' system of'the La Crosse Boiling Water Reactor, in conjunction with the offsite power system, to maintain the voltage for the reggired class 1E equipment within acceptable
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limits for the worst-case starting and load conditions.
2.0 DESIGN BASIS CRITERIA Tne positions applied in determining the acceptability of Ihe offsite voltage conditions in supplying power to the class lE equipment are derived from the following:
1.
General Design Criterion 17 (GDC 17), " Electrical Power Systems," of Appendix A, " General Design Criteria for Nuclear Power Plants," of 10 CFR 50.
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General Design Criterion 5 (GDC 5), " Snaring of Struc-I tures, Systems, and Components," of Appendix A, " General l
Design Criteria for Nuclear Power Plants," of 10 CFR 50.
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General Design Criterion 13 (GDC 13), " Instrumentation and Control," of Appendix A, " General Design Criteria for Nuclear Power Plants," of 10 CFR 50.
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IEEE Standard 308-1974, " Class lE Power Systems for Nuclear Power Generating Stations."
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Staff positions as detailed in a letter sent to the licensee, dated August 8, 1979.I 1
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NOTE:
Breakers.are shown aligned for the preferred source of.offsite power.
l 69KV SWITCHYARD'
'VIA MAIN 69KV TRANSFORMER SWITCHYARD A
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TRANSFORMER TRANSFORMER mm
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[C]:
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EC]
240dV 2400V
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BUS 1A
-BUS 1B C
[e T
i 480V 480V BUS 1A
. BUS la ECJ
[C]
[C]
[0]
[0]
[C]
480V 480V
'l CLASS 1E CLASS lE BUS 1A
[0]
' [C]
[0]
[C]
[C] BUS 1B 480V 480V 66 06 l
Turb. Bldg.
Diesel Bldg.
lA MCC 1A 1B
.MCC.
480V LA CROSSE MC UNIT ONE LINE. DIAGRAM FIGURE'l J
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4 voltage is below the minimum r'at isreturnedtoabove.thislimit.gd,andresumesoperationwhenthevoltage1 DPC indiates that the battery charger
. will not-be: damaged fn the interim whils'the battery' supplies power to the
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DC ' loads.
Loss of the DC output current of the' charger (float curren') is-
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. annunciated,andthiswouldthenimpose'atechnjcalspecificationlimiting_
condition of operation (4.2.3.2.3) on the unit.
- The battery has the capacity to carry the load for this length of time and any. subsequent load that should be required for'.an accident condition.7 4.4 Analysis Verification.
The computer analysis was verified,4 3
by measuring tne gria ano ous voltages, and thE actual load of the buses-and MCCs while using the reserve. auxiliary transformer to supply power..
The currentiin the feeder to each bus and MCC was equal to or greater than
-72 ampere.
An analysis was done using the measured offsite source voltage and measured. loads, and the results compared with the measured bus voltages.
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The comparison shows that-the class lE bus calculated voltages are up)
.to 1.09% higher than the measured bus voltages.-
Tnis verifies the adequacy of the submitted analysis; however,'this differenc5'must b'e aEcounted for in evaluating the voltage' supplied to the class lE equipment..
5.0 EVALUATION lines {ixreviewpositionshavebeenestablishedfromtheNRC'analysisguide-and the: documents listed in Section 2.0 of;t.his report.. Each review position is stated below followed by an evaluation of the licensee submittals. The evaluations are oaIsed on completion of change descriDed in Section 4.1.
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Position 1--With the minimum expe'cted offsite grid voltage and maximum load condition, each offsite source and distribution system connection combination must be capable of starting and of continuously operating 'all class lE equipment within the equipment voltage ratings.
DPC has shown, by analysis, that the La Crosse Boiling Water Reactor.
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has sufficient capability and capacity for starting and continuously operating the class IE loads within the equipment voltage ratings (Taule i and Section 4.3).
Position 2--With the maximum expected offsite grid voltage and minimum load condition, each offsite source and distribution system connection combination must be capable of continuously operating'the required class lE-equipment without exceeding the equipment voltage ratings.
DPC has shown, by analysis, tnat the voltage ratings of the class -lE equipment will not be exceeded.
Position 3--Loss of. offsite power to either of the redundant class ~ lE distribution systems due to operation of voltage protection relays, must not occur when the offsite power source is within expected voltage limits.
EG&G' Idaho, Inc., will verify, in a separate report, that the require-ments of this position are satisfied (TAC N0. 10031).
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s 7.0- REFERENCES l..
NBC letter, William Gammill, to All Power Reactor Licensees (Except
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.liumboldt Bay), " Adequacy of Station Electric Distribution Systems Voltage," August 8, 1979.
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DPC-letter,LFrank Linder,'to U.S. Nuclear. Regulatory Commission,' "Ade-quacy of Station Electric Distribution System Voltage for the'La Crosse Boiling Water Reactor," March 13, 1980, LAC-6822..
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DPC' letter, Frank Linder, to U.S. Nuclear Regulatory Commission, "Ade -
quacy of Station Electric Distribution System ','oltage for the La Crosse Boiling Water Reactor," May 12, 1980, LAC-6912..
.4.
DPC letter, Frank;Linder, to Director of Nuclear Reactor. Regulation,.
NRC, '.' Adequacy of Station Electric Distribution System Voltages:for the La Crosse Boiling Water Reactor," September. 17, 1980, LAC-7160.
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'Telecon; J. Shea,_ NRC; A. Udy, EG&G Idaho; Inc.; R. Shimshak and.
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W; Nowicki, DPC; November 5 and 6,1980.
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D?Cletter,FrankLindertoDirectorofNuclearReactorRegu'laEion, NRC, " Adequacy of Station-Electrical Distribution System Voltages (SEP
. Topic VIII-1. A)," June-22, 1981, LAC-7619.
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Telecon,- A. Udy, EG&G Idaho,.-Inc., J. ~Lazevnick,' R. Caruso,' NRC,.
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R. Shimshak, W. Nowicki, L. Kelly, DPC,-July 31,.1981.
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