ML19312D208

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Forwards Addl Info for Containment Purge & Venting Sys in Response to NRC 800109 Request.All Instrumentation Needed to Initiate Engineered Safety Features Is Designated as safety- Related Equipment
ML19312D208
Person / Time
Site: Zion  File:ZionSolutions icon.png
Issue date: 03/17/1980
From: Naughton W
COMMONWEALTH EDISON CO.
To: Harold Denton
Office of Nuclear Reactor Regulation
References
NUDOCS 8003210505
Download: ML19312D208 (4)
v • d • e


Text

..

--m Commonwealth Edison

-one First National Ptan. Chicago, tigno.s 43dreHRepiy~to Post ffde Box 767 O

Chicago, libnois 60690 March 17, 1980 Mr. Harold R. Dentori, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

Zion Station Units 1 and 2 Adultional Information for Containment Purge and Venting Systems NRC Docket Nos. 50-295 and 50-304 References (a): January 9, 1980 letter from A. Schwencer to 0. L. Peoples (b): December 14, 1980 letter from D. L. Peoples to H. R. Denton

Dear Mr. Denton:

Reference (a) requested Commonwealth Edison Company to provide additional information for containment purge and venting systems for Zion Units 1 and 2.

Commonwealth Edison's response to this request is contained in the Attachment to this letter.

A copy of the requested drawings has been transmitted to Mr. E. A. Reeves of your Staff under separate cover.

Please address any additional questions that you might have concerning this matter to this office.

One (1) signed original and thirty-nine (39) copies of this letter are provided for your use.

Very truly yours, William F. Naughto Nuclear Licensing Administrator Pressurized Water Reactors

' Attachment 2

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ATTACHMENT Additional Information For Containment Purge System and Containment 2nting System for

. Zion Un2ts'l & 2 Docket 1Nos. 50-295/304 A.-

NRC Request for Additional Information' F

1.

The docketed information as to the design of Engineered Safety Features (ESF) such as the Containment Ventilation Isolation-(CVI) systems does not adequately address the following areas.

Please discuss how your design conforms with each:

1

.The overriding

  • of one type of safety actuation signal (e.g., radiation) should not cause the blocking of any other type of safety actuation signal (e.g., pressure) to'the isolation valves.

2-- Sufficient physical features (e.g., key lock switches) should be provided to facilitate adequate administrative controls.

3 - The system-level annunciation of the overridden

-status should be provided for every safety system impacted wnen an-override is active.

4 - Diverse signals should be provided to initiate isolation of the containment ventilation system.

Specifically, containment high radiation, safety injection actuation, and containment'high pressure should automatically initiate Containment Ventilation Isolation (CVI).

5 -.The instrumentation and control systems provided to initiate.ESF should be designed and qualified as safety-grade equipment. The overriding or resetting ** of the. isolation actuation signal'should not cause the automatic

. motion of.;any ESF valve.

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The following definitions are given for clarity of use in this 0verridel-Sthe signal is,still present, and it is N

issue:. - *

. blocked inJorder to perform a function contrary to the signal;

    • Reset:-JThe signal has come and gone, and the circuit is

.being cleared to; return to the normal' condition.,

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2.... Provide,the: process;and instrumentation (P&IO) and

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schematic, drawings ~ of your.' containment purge and vent

~6ystem:and control room; heating,-. ventilation-and air

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conditioning (CRHVAC) system.

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iB. ? Common' wealth Edison ~ Response M

1.12 - As. stated.in Reference'(b),.the. radiation overir'de

'(key' lock); switches have been disconnected ~from-the-

" control.circui.try for the; containment purge and. vent a

isolation valves, until the cicuft can be modified so that the' radiation override-does not' interfere with thefs'afety(injection:. signals for closure ~of the valves.~

No other override exists.. The circuit

' change:will'putJthe radiation override in series with the contacts for safeguards ~ actuation of the valves instead of in parallel.

There:still will be key I

switches to facilitate the' procedural controls.that now exist.

The~ change will also retain the

, i annunication that indicates the. override ls in use.

2 - See Item 1.1 above..

3 - See. Item 1.1 above.

4 - Conta'inment Ventilation Isolation is' initiated by R-11 and:R-12, the containment air monitors, and the variousfsafetyDinjection actuation signals including i

containment high. pressure.

5'- Alliinstrumentation!and contro11 systems'needed to initiate ESF is designated as1 safety-related

' equipment.

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, Switches,Einclu'ing'an auto position, have'been d

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installed on all containment isolation valves.

These

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iswitchesiwill keep the-valves closed.after an

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1solationis'ignalfresets until the control; switch is' manuallyi closed.. = The: motor operated " safeguards

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. valves,have1 spring. return to.normalLswitches.

These iswitches have'open' contacts through the control-switch.except;while-the1 switches are being manually

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moved.. (Therelare three' valves.actuatedLby. safeguards.

w that would closefautomatically;on'a reset.1.These are (the:three containment; spray header:isolationfvalves gi :.

'andiwouldLonly;close'lf'they)were closed prior;to "s

actuation. 'However, they are normally?(procedurally)

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key-lockedjopen..

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'The following P&ID'and' representative schematic drawings for the Zion purge and vent system as well as the'CRHVAC have been transmitted separately:

a)

Representative Drawings.for containment ventilation (HVAC)

Drawing No.

Page No.

M-53/

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22E-1-4840-RV49 s

22E-1-4840 RV50 22E-1-4840 RV95 22E-1-4840 RV98'

~22E-1-4920 b) Representative Drawings for Control Room HVAC.

Drawing No.

Page No.

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22E-0-4840 PVO 22E-0-4840 PV1

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22E-0-4840-Pv2-122E-0-4840 PV3 22E-0-4840 PV4 22E-0-4840 PV5

22E-0-4840 PV6

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PV7 22E-0-4840-PV8 22E-0-4840-PV9 22E-0-4840-PV10

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'22E-Ol4840L

'PV11-

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222E-0-4840

'PV12 22E-0-4840 PV13 22E-0-4840.

PV14 22Ea0-4840-

.PV15 22E-0-'4840 PV16

'22E-0-4840' PV99

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PV100 g:

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