ML17193A026

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Forwards Evaluation of SEP Topic VIII-3.B, DC Power Sys Bus Voltage Monitoring & Annunciation. Requests Notification If as-built Facility Differs from Licensing Basis Assumed in Assessment
ML17193A026
Person / Time
Site: Dresden Constellation icon.png
Issue date: 08/12/1980
From: Crutchfield D
Office of Nuclear Reactor Regulation
To: Peoples D
COMMONWEALTH EDISON CO.
References
TASK-08-03.B, TASK-8-3.B, TASK-RR NUDOCS 8009120281
Download: ML17193A026 (6)
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Docket -No. 50-237

  • **. AUGUST.

1 2 1980..

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ORB #5 Reading SEP Fi le'.

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.*_.. *.*SEP, PF M~.-. o. :Louis Peoples -: *

  • .Director of Nucle~r Licensing_*--*.

. *. Commo*nwea.lth Edi son.GQmpan,Y : * -

.: P-ost Off1 ce -Box 767

' Chicago, I ll1 no1 s. *606~fo.

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Dear Mr. *P-eoples:

RE*=

SEP *roPic viII~3~B DC POWER *svsi'EM :aus VOLTAGE MONiTORING AND

. **.. ANNlJNCI!\\TIOt{" -(DRESDE_N UN*lT 2)

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Enclosed.is. ac *~o-py of our.e-valuation of*.Sys-tematic Evaluation. Program Topic YIII-3.* B., "DC.Power System Bus Vo1tage*Mon1tor1ng and Annunciation.

This assessment compares your facility, as-descr1bed.1n Docket No. 50'!"237,

. with the criteria currently used by 'the regulatory staff for licensing

  • new facil it 1es. __.Please 1 nform us 1f your-as-built filci Hty differs fr.om
  • the licensing basis assumed in our.as$e$*sment within 30days of receipt
  • of this letter:\\

This evaluation.wil1 be *a basic. input to_ the,fnt_egrated safety assessment*

for.your :facility unless you.1dent1fy changes needed to reflect the as-built conditions at,your. fac111ty.

  • This. topic assessment may be rev1 sed in the
  • future-i.f your facility design* is *changed.or if NRC criteria relating to

~- this.topic are mod1fied_'before the integr~ated as_sess~nt is co~leted.

Enclosure:

Completed SEP. *'

i Topic VIII-3.B.

'cc -w/enclosure:

See next page sincerely,. b.

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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 Docket No. 50-237 Mr~ o. Louis Peoples

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Director of Nuclear Licensing Co1T1110nwealth Edison Co~any Post Office Box 767 Chicago, Illinois 60690

Dear Mr. Peoples:

August 12, 1980 RE:

SEP TOPIC VIII-3.B *Dc POWER SYSTEM BUS VOLTAGE MONITORING AND ANNUNCIATION" (DRESDEN UNIT 2}

Enclosed is a copy of our evaluation of Systematic Evaluation Program Topic VIII-3.B, "DC Power System Bus Voltage Monitoring and Annunciation.

This assessment co~ares your facility, as described in Docket No. 50-237, with the criteria currently used by the regulatory staff for licensing new facilities. Please inform us if your as-built facility differs from the licensing basis assumed in our assessment within 30 days of receipt of this letter.

.This evaluation will be a basic input to the integrated safety assessment for your facility unless you identify changes needed to reflect the as-built conditions at your facility. This topic assessment may be revised in the future if your facility design is changed or if NRC criteria relating to this topic are modified before the integrated assessment is COl!l>leted.

Enclosure:

Co~leted SEP Topic VIII-3.B cc w/enclosure:

See next page Sincerely,

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~Dennis M. Crutchfield, Chief

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Operating Reactors Branch 15 Division of Operating Reactors

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Mr. D. Louis Peoples cc w/enclosure:

Isham, Lincoln & Beale Counselors at Law One First National Plaza, 42nd Floor Chicago, Illinois 60603 Mr. B. B. Stephenson Plant Superintendent Dresden Nuclear Power Station Rura 1 Route #1 Morris, Illinois 60450 Natural Resources Defense Council 917 15th Street, N. W.

Washington, D. C.

20005

u. s. Nuclear Regulatory Conmission Resident Inspectors Office Dresden Station RR #1 Morris, Illinois 60450 Susan N. Sekuler Assistant Attorney General Environmental Control Division 188 w. Randolph Street Suite 2315 Chicago, Illinois 60601 Morris Public Library 604 Liberty Street Morris, Illinois 60451 Chai nnan Board of Supervisors of Grundy County Grundy County Courthouse Morris, Illinois 60450 August 12, 1980 Department of Public Health ATTN:

Chief, Division of Nuclear Safety 535 West Jefferson Springfield, Illinois 62761 Director, Technical Assessment Division Office of Radiation Programs (AW-459}

u. s. Environmental Protection Agency Crystal Mall #2 Arlington, Virginia 20460
u. s. Environmental Protection Agency Federal Activities Branch Region V Office ATTN:

EIS COORDINATOR 230 South Dearborn Street Chicago, Illinois 60604 Resident Inspector Dresden Nuclear Power Station c/o U. S. NRC Rura 1 Route #1 Morris, Illinois 60450

1.0 INTRODUCTION

SEP TECHNICAL EVALUATION TOPIC VIII-3.B DC POWER SYSTEM BUS VOLTAGE MONITORING AND ANNUNCL~TION

. DRESDEN UNIT 2 The objective of this review is to determine if the DC power sys-tem bus voltage monitoring and *annunciation are in compliance with current licensing criteria for Class IE DC power systems.

The specific requirements for DC power system ~onitoring derive from the general requirements embodied in Sections 5.3.2(4), 5.3.3(5),

and 5.3.4(5) of IEEE Standard 308-19741, and in Regulatory Guide 1.472*

In summary, these general requirements simply state that the DC system (batteries, distribution systems, and chargers) shall be monitored to the extent that it is shown to be ready to perform its intended function.

2. 0 CRITERIA As a minimum, the following indications and alarms of the Class IE 3*

DC power system(s) status shall be provided in the control room:

Battery current (acmeter-charge/discharge)

Battery charger output current (ammeter) o DC bus voltage (voltmet~r)

Battery charger output voltage (voltmeter)

Battery high discharge rate alarm DC bus undervoltage and overvoltage alarm e

DC bus ground alarm (for ungrounded system)

~attery breaker(s) or fuse(s) open alarm l

-~

  • Battery charger output breaker(s) or fuse(s) open alann Battery charger trouble alarm (one alarc for a number of abnormal conditions which are usually indicated locally).

3.0 DISCUSSION AND EVALUATION 3.1 Discussion.

Dresden Unit 2 has three levels of Class IE DC power systems:

250 V DC; 125 V DC; and 48/24 V DC. 4 3.1.1 250 V DC Power.

The 250 V DC poYer system is com-prised of No batteries (shared with Unit 3), two battery chargers (one shared), and t~o buses.

Unit 2 control room indication consists of charger trip alar~s (t~o), bus feed ACB alarms (t~o), and a battery ground alarm for one battery.

Local (charger roo~) indication consists of voltmeters and ammeters on each charger and a ground detection alarm.

3.1.2 125 V DC Power.

Within the context of this SEP Topic, the 125 V DC power system is substantially identical to the 250 V DC power system.

3~1.3 48/24 V DC Power.

The 48/24 V DC power system is comprised of two center-tapped 48 V batteries (2A-and 2B), four 24 V battery chargers (two per battery), and* two three-'Wire buses*

Control roo~ indication consists of charger AC/DC circuit fail~re alarms (two) and bus under/overvoltage alarms (two).

Local (charger room) indica-tion consists of voltmeters on each of the battery chargers.

3.2 Evaluation.

The Dresden U~it 2 control room has no indica-tion of battery current, cha=ger output current, DC bus voltage battery charger output voltage, battery high discharge rate, or charger under/

overvoltage for either the 250 or the 125 V DC power systems.

Neither does it have any indication battery current, charger output current, battery high discharge rate, or battery breakers open for the 48/24 V DC po~er syste~. Therefore, the Dresden Unit 2 DC power systems monl-toring is not in compliance with current licensing criteri~.

2

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SUMMARY

Of 11 parameters currently required to be indicated or alarmed in the control room, only two are alarmed for each of the three DC popwer systems at Dresden 2.

Therefore., the Dresden Unit 2 DC power systems are not monitored in compliance with current licensing criteria.

5.0 REFRENCES

1.

IEEE Standard 308-1974, "Standard Criteria for Class IE Pover Systems for Nuclear Power Generating Stations."

2.

Regulatory Guide 1. 7 4, "Bypassed and Inoperable Status Indication for Nuclear Power Plant Safety Systems."

3*.

NRC Memora::idum, PSB (Rosa) to SEPB (Crutchfi~ ld), "DC System Monitoring and Annunciation," dated October 16, 1979.

4.

Letter, Cot:::llonwealth Edison (Janecek) to DOR (Ziemann),

"Dresden Units 1 and 2, Systematic Evaluation Prograt:i, Topic VIII-3.B," dated July 25, 1979.

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