ML19350C388
| ML19350C388 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 03/30/1981 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Linder F DAIRYLAND POWER COOPERATIVE |
| References | |
| TASK-08-04, TASK-8-4, TASK-RR LSO5-81-03-074, LSO5-81-3-74, NUDOCS 8104010290 | |
| Download: ML19350C388 (13) | |
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Docket No. 50-409 LS05-81-03-074 D
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Mr. Frank Linder General Manager
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0 Dairyland Power Cooperative
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'wi Lacrosse, Wisconsin 54601
Dear Mr. Linder:
SUBJECT:
SEP TOPIC VIII-4 ELECTRICAL PENETRATIONS OF REACTOR CONTAINMENT (LACROSSE)
Enclosed is a copy of our revised safety assessment of SEP Topic VIII-4, Electrical Penetrations of Reactor Centainment. This assessment compares your facility, as described in Docket No. 50-409, with the criteria currently used by the regulatory staff for licensing new facilities. This report has been revised to reflect the factual coments provided by your October 8,1980 letter and a subsequent telephone conference.
This evaluation will be a basic input to the integrated safety assessment for your facili,ty. As previously stated, this assessment may be revised in the future if your facility design is changed or if NRC criteria relating to this subject are modified before the integrated assessment is completed.
Sincerely, Dennis M. Crutchfielo, 6.'.ef Operating Reactors Bran.?. No. 5 Division of Licensing
Enclosure:
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UNITED STATES i
NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555
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MAR 3 01981 l
Docket No. 50-409 LS05-81-03-074 1
Mr. Frank Linder General Manager I
Dairyland Power Cooperative l
2615 East Avenue South Lacrosse, Wisconsin 54601
Dear Mr. Linder:
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SUBJECT:
SEP TOPIC VIII-4, ELECTRICAL PENETRATIONS OF REACTOR CONTAINMENT (LACROSSE)
Enclosed is a copy of our revised safety assessment of SEP Topic VIII-4, Electrical Penetrations of Reactor Containment. This assessment compares your facility, as described in Docket No. 50-409, with the criteria currently used by the regulatory staff for licensing new facilities. This report has been revised to reflect the factual comments provided by your October 8,1980 letter and a subsequent telephone conference.
This evaluation will be a basic input to the integrated safety assessment for your facility. As previously stated, this assessment may be revised in the future if your facility design is changed or if NRC criteria relating to this subject are modified before the integrated assessment is completed.
Sincerely, i
M Dennis M. Crutchfield, Chi Operating Reactors Branch No. 5 Division of Licensing
Enclosure:
As stated cc w/ enclosure:
See next page
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Mr. Frank Linder l
CC Fritz Schubert, Esq,: ire Director, Standards and Criteria Staff Attorney Division Dairyland Power Cooperctive Office of Radiation Programs 2615 East Avenue South (ANR-460)
La Crosse, Wisconsin 54601 U. S. Environmental Protection Agency
- 0. S. Heistand, Jr., Esquire Washington, D. C.
20460 Morgan, Lewis a Bockius 1800 M Street, N. W.
Washington, D. C.
20036 U. S. Environmental Protection Agency Mr. R. E. Shimshak Federal Activities Branch La Crosse Boiling Water Reactor Region V Office Dairyland Power Cooperative ATTN: EIS C0ORDINATOR P. O. Box 135 230 South Dearborn Street Genoa, Wisconsin 54632 Chicago, Illinois 60604 Ms. Anne K. Morse Charles Bechhoefer, Esq., Chairman Coulee Region Energy Coalition Atomic Safety and Licensing Board P. O. Box 1583 U. S. Nuclear Regulatory Comission La Crosse, Wisconsin 54601 Washington, D. C.
20555 La Crosse Public Library Dr. George C. Anderson 800 Main Street Department of Oceanography La Crosse, Wisconsin 54601 University of Washington Seattle, Washington 98195 U. S. Nuclear Regulatory Commission Resident Inspectors Office Mr. Ralph S. Decker Rural Route #1, Box 225 Route 4. Box 190D Genoa, Wisconsin 54632 Cambridge, Maryland 21613 Town Chairman Dr. Lawrence R. Quarles Town of Genoa Kendal at Longwood, Apt. 51 Route 1 Kenneth Square, Pennsylvania 1934B Genoa, Wisconsin 54632 Thomas S. Moore Chairman, Public Service Comission Atomic Safety and Licensing Appeal Boart of Wisconsin U. S. Nuclear Regulatory Comission Hill Farms State Office Building -
Washington, D. C.
20555' Madison, Wisconsin 53702 Mr. John M. Buck Alan S. Rosenthal, Esq., CPairman Atomic Safety and Licensing Appeal Boart Atomic Safety and Licensins Appeal Board U. S. Nuclear Acgulatory Comission U. S. Nuclear Regulatory Cemission Washington, D. C. 20555 Washington, D. C.
20555 U. S. Nuclear Regulatory Comission Mr. Frederick Milton Olsen, III Resident Inspectors Office 609 North lith Street Rural Route #1, Box 225 Lacrosse, Wisconsin Genoa, Wisconsin 54632 4
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SEP TECHNICAL EVALUATION TOPIC VIII-4 ELECTRICAL PENEIRATIONS OF REACTOR CONTAINMENT FINAL DRAFT LA CROSSE 3 OILING ~4ATER REACTOR Docket No. 50 '09 Novemoer 1980 11-6-80 J
't CONTENTS
1.0 INTRODUCTION
1 2.0 CRITERIA..
2
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3.0 DISCUSSION AND E7ALUAT10N 3
3.1 Typical Low Voltage (0-1000 VAC) Penetration 4
3.1.1 Low Voltage Penetration Evaluation.
4 3.2 Typical Medium Voltage (>1000 VAC) Penetration 4
3.2.1 Medium Voltage Penetration Evaluation 4
3.3 Typical Direct Current Penetration 5
3.3.1 Direct Current Penetration Evaluation 5
4.
SUMMARY
5 5.
REFERENCES.
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ELECTRICAL PENETRATIONS OF REACTOR CONTAINMENT LACROSSE BOILING WATER REACTOR 4
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1.0 INTRODUCTION
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This review is part of the Systematic Evaluation Program (SEP), Topic 1
VIII-4.
Dairyland Power Cooperative (DPC) has provided information describing typical penetrations, typical in-containment loads, and fault currents. Reference 1 did not provide an analysis of the suitability of the penetrations and circuit protection devices. Reference 2 is a previous NRC analysis of the suitability of the penetrations and their circuit pro-tactive devices. Additiona*. penetration design information was obtained 3
from a DPC letter of October 8, 1980 and telephone calls of November 5 and 6, 1980.' The objective of this review is to determine the capability of the overcurrent devices to prevent exceeding the design rating of the electrical penetrations through the reactor contaimment upon short circuit conditions at LOCA temperatures.
General Design Criterion 50, " Containment Design Basis" of Appendix A,
" General Design Criteria for Nuclear' Power Plants" to 10 0FR Part 50 requires that penetrations be desi red so that the containment structure can, without exceeding cne design leakage rate, accommodate the calculated pressure, temperature, and other environmental conditions resulting from any loss-of-coolant accident (LOCA).
IEEE Standard 317, " Electric Penetration Assemblies in Containment Structures for Nuclear Power Generating Stations", as augmented by Regula-tory Guide 1.63, provides a basis of electrical penetrations acceptable to the staff.
Specifically, this review will examine the protection of typical elec-trical penetrations in the containment structure to determine the ability l
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of the protective devices to clear the circuit during a short circuit con-dicion prior to exceeding the containment electrical penetration test or l
design ratings at an initial LOCA temperature.
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2.0 CRITERIA I
I IEEE Standard 317, " Electric Penetration Assemblies in Containment l
Structures for Nuct>Gr Power Generating Stations" as supplemented by Nuclear Regulatory Commission Regulatory Guide 1.63, " Electric Penetration Assem-blies in Containment Structures for Light-Water-cooled Nuclear Power Plants" provide s the basis acceptable to the NRC staff. The following criteria are used in this report to determine compliance with current licensing requirements:
1.
lEEE Standard 317, Paragraph 4.2.4- "The rated short circuit current and duration shall be the max 0zum short circuit current in amperes that the conductors of a circuit can carry for a specified duration (based on the operating time of the primary overcurrent protective device or apparatus of the circuit) following continuous operation at rated continuous current without the temper-at re of the conductors exceeding their short-circuit design limit with all other conductors in the assembly carrying their rated continuous current under the speci-fied normal environmental conditions."
This paragraph is augmented by Regulatory Guide 1.63, Paragraph C "The electric penetration assembly should be designed to withstand, without loss of mechanical l
1;.:. city, the maximum possible fault current versus time conditions that could occur given single random failures of circuit overload protection devices."
2.
IEEE Standard 317, Paragraph 4.2.5 "The rated maximum duration of rated short circuit current shall be the maximum time that the conductors of a ctreuit can carry l
rated short circuit current based on the operating time l
of the backup protective device or ap.aratus, during which the electrical integrity may be lost, but for which the penetration assembly shall maintain contain-ment integrity."
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l 3.0 DISCUSSION AND EVALUATION In this eval 2ation, the results of typical containment penetrations l
being in a LOCA concurrent with a random failure of the circuit protective devices ~will be analyzed.
DPC aas provided information '
and the NRC has prior information on typical penetrations. All wer; manufactured by General Cable Company.
f No short circuit test data was made available by DPC for these penetrations.
Under ae:ident conditions, a peak containment temperature of 280 F (138 C) has been calculated.
P In supplying the value of the maximum short circuit current available (Isc), DPC supplied values for a three phase (on a three phase system) bolted f ault; this type being able to supply the most heat into the pene-tration. DPC did not specify if the I, value includes, in t he symmetri-cal AC component, contributions by other connected induction tsocors.
The following formula was used to determine the time allowed for a short circuit before the penetration temperature would exceed its limiting value.
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(Formula 1) t=
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Short circuit current -- amperes I
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Maximum operating temperature (138 C, LOCA T
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y condition, to account for current in other penetration conductors)
Maximum short circuit temperature (limiting T
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2 factor for a given penetration).
This is based upon the heating effect of the short circuit current on
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the conductors. Credit for any time lag for the seal materials in reaching elevated temperatures is not given in this review.
It should be noted that the short circuit temperature-time limits of the conductors in this report vary from the values calculated by u/C.
This report uses the DPC supplied fault current magnitude and a a..sumed smaller temperature rise to calculate the maximum time allowed to clear a fault condition. Also in this report, a prefault penetration conductor temperature equal to the peak LOCA containment atmosphere temperature is assigned, thus simplifying, while accounting for, an elevated conductor temperature caused by a preexisting current flow and an above normal ambient temperature.
3.1 Typical Low Voltage (0-1000 VAC) Penetration. DPC has provided information on a pens; ration for the Seal Injection Pump 1A as typical of a 480-V AC circuit. Tnis penetration has a multi-conductor #4 mineral insul-ated copper sheathed cable with a brass packing gland' at each end.
Assuming the entire cable and packing gland assembly to be isothermal at any given time results in a limiting temperature of 1710 F (932 C) for the penetration, which is dependent on Oe brass packing gland. The maximum i
I available at this penetration is approxiantely 17,000 ras amperes se synetrical.
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.It is calculated that, with the 932 C temperature limit of the seal i
material, this short circuit current can be carried by the penetration for 0.089 second before the penetration conductors exceed 932 C, with an
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initial temperature of 138 C (peak LCCA in-containment temperature).
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o l;I Bath the primary circuit breaker and the backup fuse will clear this fault or faults of less magnitude in less time than is required to heat the penetration seat sufficiently to breach contaiw ent.
3.1.1 Low Voltage penetration Evaluation. With an initial pene-tration temperature of 138 C (the LOCA containment temperature), the containment electrical penetration design for this low voltage penetration
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is in conformance with the criteria described in Section 2.0 of this report i
for all levels of fault current. The DPC also supplied curves showing that, above the rated current of the penetration (90 amperes), no protec-tion is afforded until 120 amperes (primary) and 350 amperes (backup).
However, at these current levels, the time required to overheat the pene-I tration is sufficiently long (heat transfer to the containment liner would increase this time) that the feeder cables would melt before penetration damage would occur.
3.2 Typical Medium Voltage (>1000 VAC) Penetration. DPC has provided information on a penetrations used to power the forced circulation pump 1A as typical of medium voltage penetrations. Each penetration censists of multi-conductor #4/0 mineral insulated, copper sheathed cable. Again, the temperature limiting element of the hermetic seal of the penetration is the brass packing gland (932 C).
The maximum I, available at the penetra-tion is approximately 22,000 ras synetrical amperes. DPC did not supply the asynetrical fault current.
It is calculated that 1.363 second elapse after a fault occurs at a penetration temperature of 138 C (LOCA containment temperature) before the conductors exceed the temperature limit of 932 C.
The fault clearing time of the primary and the identical secondary circuit breakers are approximately 0.5 second.I Both circuit breakers clear the fault before the conductor temperature exceeds 932 C for any level of fault current identified on the breaker characteristic curve.
i 3.2.1 Medium Voltage Penetraticn Evaluation. With an initial pcnetration temperature of 138 C (the LOCA containment temperature), the
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I containment penetration design for this medium voltage penetration is in conformance with the criteria described in Section 2.0 of this report for all levels of overcurrent. As the DPC supplied information shows, neither
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circuit breaker provides the penetration with protection between the rated continuous current (235 amperes) and approximately 2500 amperes, however, at these current levels, heat transfer from the penetration would extend il the allowable time under fault conditions and the smaller (#2/0) feeder cables would melt before penetration damage would occur.
I 3.3 Typical Direct Current Penetration. DPC has provided information for a typical 125-V DC penetration aed with DC magnetic clutches. The penetration construction is identical to that discussed in Section 3.1 except that a multiconductor f6 mineral insulated cable is used. The temperature limit is also 932 c.
The maximum I, availabl. at this penetration is approximately 5000 amperes.
It is calculated that the maximum I, can be carried by this pene-tration for 0.02 second before the cotluctor temperature reaches 932 C.
The primary circuit. breaker and the secondary fuse curves supplied by DPC show th:t both the primary circuit breaker and the secondary fuse will clear this fault in less than 0.406 second. At all current levels above the 70-ampere rating of the penetration, the clearing time is adequate to prevent damage to the penetration seal.
3.3.1 Direct Current Penetration Evaluation. With an initial penetration temperature of 138 C (the LOCA containment temperature), the containment electrical penetration design for this DC penetration is in conforemance with Section 2.0 of this report.
4.0
SUMMARY
This evaluation looks at the capability of the circuit protective devices to prevent exceeding tne design test ratings of the selected pene-trations to maintain containment atmosphere isolation in the event of (a) a i
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i LOCA evene, (b) a fault current through the penetration and si=ultaneously, (c) a random failure of the circuit protective devices to clear the fault.
The environmental qualification tests of the penetrations 's :he subject of g
SEP Topic III-12.
l This assessment neglects any heat transfer from the penetration to the I
containment liner. To account for rated current in the penetration con-l t
ductors, an initial penetration temperature equal to the peak LOCA in-contaicnent temperature was assigned.
With a LOCA environment inside containment, the protection of all the penetrati ons conform to the specified criteria, which assumes a short cir-cuit fau.t and a single random failure of the circuit protective devices.
5.0 RITERINCES 1.
DPC. letter LAC-6210, F. Linder, to D. L. Ziemann, NRC, " Systematic Evaluetion Program (SEP), Topic VIII-4", Docket No. 50-409, April 17, 1979.
2.
U.S. NRC letter, R. W. Reid, NRC, to Dairyland Power Cooperative, Docket No. 50-409-411, Augus t 12, 1976.
3.
DPC letter LAC-7177, F. Linder, to Director of Nuclear Reactor Regulation. U.S. NRC, " Systematic Evaluation Program, Topic VIII-4, Electrical Pentrations of Reactor Contai=nent," October 8,1980.
4.
Telecon; J. Shea, U.S. NRC; R. Shinshak, W. Norwick, DPC; A. Udy, EG&G Idaho, Inc., November 5 and 6,1980.
5.
Regulatory Guide 1.63, Revision 2, " Electrical Penetration Assemblies in Containment Structures for Light-Water-Cooled Nuclear Power Plants."
6.
General Design Criterion 16, " Containment Design" of Appendix A, " Gen-eral Design Criteria of Nuclear Power ?tants," 10 CFR Part 50, " Domestic Licensing of Production and Utilization Fa-ilities."
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Nucicar Regulatory Comisaion Standard Review Plan, Section 8.3.1, "AC Power Syste=s (Onsite)."
8.
IEEE Standard 317-1976, "IEEE Standard for Electric Penetration Assem-blies in Containment Structures for Nuclear Power Generating Stations."
l 9.
IPCEA Publication P-32-382, "Short Circuit Characteristics of Insulated l
Cable."
- 10. IEEE Standard 242-1975, "IEEE Recomended Practice for Protection and j
Coordination of Industrial and Comercial Power Systems."
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