ML19351E740

Forwards Revised FSAR Chapter 15.4 Pages Re Control Room Doses Following Loca.Revision Completes Control Room Ventilation Sys Mods to Provide Positive Pressure During Normal & Emergency Conditions

ML19351E740
Person / Time
Site:	Summer
Issue date:	12/15/1980
From:	Nichols T SOUTH CAROLINA ELECTRIC & GAS CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
NUDOCS 8012190140
Download: ML19351E740 (5)

Text

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SOUTH CAROLINA ELECTRIC a GAS COMPANY POST C F hC E 801 764 CotuMeiA, Souin CAROLINA 292tB T. C. NicwoLs, J R.

WE P.tsc*t .*0 Gh* Dic#wt December 15, 1980 u u . . c. ....< ,

Mr. liarold R. Denton, Director Of fir.e of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C. 20555

Subject:

Virgil C. Summer Nuclear Station Docket No. 50/395 Control Room Ventilation System

Dear Mr. Denton:

South Carolina Electric and Gas Conpany, acting for itself and agent to South Carolina Public Service Authority, provides forty-five (45) copies of revised FSAR Chapter 15.4 pages regarding control room doses follouing a LCCA.

This material completes documentation of the charges in the FSAR for the modifications made to the control room ventilation system to provide a positive pressure in the control room during both normal and emergency conditions. This material will be incorporated into the next FSAR amendnent, but should provide you with sufficient material to complete your review.

If you have any questions, please let us know.

Very truly yours, s / j'

, , p&s /$, f T. C. Nichols, Jr.

RBC:TCN:glb

Enclosures:

cc: V. C. Summer w/o enclosures G . 11. Fischer w/o enclosures T. C. Nichols, Jr. w/o enclosures E. 11. Crews , J r.

O. W. Dixon, J r.

D. A. Nauman O. S. Bradham W. A. Williams, Jr. _, , l} .,

A. A. Smith i d '*

A. R. Koon ' SO p

R. B. Clary .

J. B. Knotts, Jr. - j: i 5 fd J. L. Skolds - d r, [,W B. A. Bursey [

11. E. Yocum Q d C

B. Seith p d NPCF/Whitaker File S

, 8012390 go

{Ch I

4 The direct dose to operators in the control room from the contain-cent was calculated using a point source =odel and centainment accident source strengths 'generated with the IAEC computer code.(22] Credit was taken for a minimum of 6.75 feet of concrete (

shiciding provided by the following:

a. Reactor building, 4 feet.

b. Control building, 2 feet. (

c. Control room ceiling, 0.75 feet.

In addition, credit was taken for deso reduction due to a distance of 131 feet, the minimum distance between the reactor building and the control building.

5. Atmospheric dif fusion factors for the control room are as follows and are based upon metheds presented in Reference (23] for a diffuse source-point receptor model: -

Time After Accident X/0 (sec/m )

0-8 hours I' O.4d5 x 10-3 8-24 hours 2*kg4x10-3

• -4

• d -'

1-4 days 4.f;5 x 10 4-30 days avec x 10

-4 <- --

6* Design of the control room venttlatica system is described in Section 9.4.1. By operatien of either one of two supply air syste=s and the ,

centrol of the appropriate dampers, controlled amounts of cutside air are admitted to the control room. .

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t5,r._yg :Q1NDt1NT 2f' E t W 19SO w,-e wa,,.

p.Sof f

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t)Mb During the normal and emergency modes of operation, the a=ount of outside air admitted to the control room to maintain a positive cen- .

' 400 trol roes air ;re.ssure is limited to a maximum flow of aft efa by a --

manual damper located downstream of the isolation dampers. During the -

nor=al mode of operation, the control room recirculation air flow wili be bypassed around the Control Room E=crgency Filter Plenum. For the.

\ cmergency mode of operation, the control room recirculation air flow will be routed through the Control Room E=ergency Filter plehus.

In the purge mode of operation, the system will supply IC1 percent

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The manual derpers downstream of the outside air to the control rocm.

isolation dampers will be manually positioned to the full open posi-tica to allow an outside air flow of 20,000 cfm into the control rocm. The recirculation flow will be ter=inated for the duration of the purge mode.

Each control roca air intake is provided with two isolation dampers in~

series and a mar.ual damper that restricts the outside air flew to a 4c0 a$facfm flow for both normal and emergency modes. Upon receipt of an -<- .

[ s engineered safety features actuation signal, the control roca ventila-tica system switches to the emergency mode.

\

i 15.4-24a x1E: tMENT 21 CCT03ER, 1980

.- y. + of s~

TABLE 15.4-17 Q (_ 26b PARAMETERS USED IN ANALYSIS OF CONTROL ROOM DOSE FOLLO*4ING A LOSS OF COOLANT ACCIDENT Paraneters Control Rocs Free Volume 226,040 ft 3 l 19 Filtered Recirculation Flow 20,000 efs Recirculation Filter Efficiencies 95% for all species of iodine 440 p Control Roca Filtered Air Infiltration Rate, MO cfm Control Room Unfiltered Air Infiltration Rate 10 efs -

21 AfA Control Room Outleakage Equal to total inleakage (.yf efe) _.g___

s d.4 e Meteorology 0-8 hrs: ni ?_

x 10-3 ,,cjm3

a. 7 ?- -

• 8 "4 hrs: M t .x 10-3 sec/m#

r[ %

1-4 days:

/<aN~ x 10' -

sec/m 3

3

+

4 30 days: i-M x 10 sec/m 21

. . 0 - 24 hrs 100%

Percent of Time Operator Is in

~

1. I' Centrol Roce Following Accident 4 - 30 days 40%

Duration of Accident' 30 days Breathing Rate of Operators in 3

Control Roco 3.47 x 10 m /sec Activity Release Assunpticas Table 15.4-15 Method of Dose Calculation Appendix ISA 15.4-117 .OtENDENT 21 OCTO5ER, 1980

.. j. S'o f f A

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TABLE 15.4-18 CONTROL RO3M DOSES FOLLO' JING A LOCA

[ Deses (Eem)

Thyroid Gn=a Eeta Skin

~

L 3,13 ~ /, 4 f .

Realistic Analysis 1.6K x 10 1 L&? x 10' .idt x 10"

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4* S 7 /. 4 7 21 Conservative Analysis 1.6f x 10 1 -3r29 x 10 -2 1.6's x 10 -1 2*[5 y 4.67 2 /4 Ultra-Conservative Analysis h?2 x 10 Src0 x 10 -2re9 x 10 s..

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15.4-118 toiE: CME::I 21 OCTOBER, 1980