ML20076K321

Discusses Evaluation of Conservative Pressure/Temp Domain During Normal Plant Operation,W/O Exceeding Peak Calculated Drywell Pressure for Design Basis Loca.Meeting Proposed to Address Tech Spec 3/4.6.1.6

ML20076K321
Person / Time
Site:	Shoreham File:Long Island Lighting Company icon.png
Issue date:	06/30/1983
From:	James Smith LONG ISLAND LIGHTING CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
SNRC-930, NUDOCS 8307080398
Download: ML20076K321 (6)

Text

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[ LONG ISLAND LIGHTING COMPANY j ,,m,f, 7 SHOREHAM NUCLEAR POWER STATION

b. - m e , ,,,, P.O. DOX 618, NORTH COUNTRY ROAD

• WADING RIVER N.Y.11792 Direct Dial Number June 30, 1983 SNRC-930 '

Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulator '

U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Technical Specifications Shoreham Nuclear Power Station - Unit 1 '

Docket No. 50-322

(

Dear Sir:

L Technical Specification 3/4.6.1.6 addresses Drvwell and Suppression Chamber Internal Pressure. For Shoreham Nuclear Power Station (SNPS), it is our intention to satisfy this specification with a curve to define acceptable operating pressures for Operational Condition 1. This curve will allow greater operational fle'ibility x at higher containment temperatures than would a single value design-ed to encompass all temperatures.

s The calculated peak containment pressure reflected in FSAR Chapter

> G is 41.9 psig. As indicated in the Design Assessment Report (DAR)

Revision 5, Appendix M, capping of six downcomers has increased this pressure by 1.9 psig. Additionally, a revised LOCA analysis based on the below listed parameters resulted in a pressure increase of 2.2 psig, giving a final calculated peak containment pressure of 46.0 psig.

Nominal initial pressure of 2 psig Minimal relative humidity of 20 percent o Relatively low drywell temperature of 110 F.

This set of initial conditions provides significant operating flexi-bility based upon normal operating conditions for primary contain-ment of a BWR plant.

This revision was necessary due to the restricted acceptable operat-ing margin which was available for drywell pressure and temperature.

This margin is expanded by the methodology discussed here.

'2he peak drywell pressure during a design basis loss of coolant acci-dent is a function of the initial mass of noncondensibles in the drywell at the time of the accident. Noncondensibles in the drywell

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June 30, 1983 SNRC-930 Page 2 are transferred to the wetwell.early in the accident. Moisture initially in the drywell condenses in the suppression pool, and does not affect the peak pressure. The initial mass of noncon-densibles in the drywell is inversely related to the relative humidity. If the mass of noncondensibles is maximized (i.e.

relative humidity minimized), then the peak pressure will also be maximized. To maintain the same LOCA peak pressure,for vary-ing relative humidities, assuming constant temperature, higher relative humidity would allow higher operating pressures without exceeding the specified LOCA peak pressure. During normal opera-tion, the drywell relative humidity is expected to be between 40 and 50 percent. For a conservative estimate, 20 percent was used in the DBA analysis.

An extensive analysis has been performed to evaluate a conservative pressure / temperature domain for Shoreham during normal operation, without exceeding peak calculated drywell pressure for the case of a design basis LOCA. The initial conditions used for this analysis are the same as these applied to the new FSAR-LOCA analysis except for the pressure and temperature which were varied in order to evaluate the operating domain. Figure 1 and Table 1 show the results of this limiting analysis for a normal operating temperature range.

For each initial drywell bulk average temperature, a series of DBA analyses were made with different values for initial pressure until the peak calculated pressure equaled that of the FSAR analysis of 46.0 psig. The corresponding initial condition was then used as the maximum permissible limits. This indicates that should a design basis LOCA occur when the drywell condition is below the curve in 4 Figure 1, the peak calculated pressure given in the FSAR would not be exceeded.

The. upper bound drywell pressure for operation is established from the GE analytical limit and peak LOCA containment pressure limit parameters. These two parameters intersect at about 110F . The operating domain is conservatively defined for temperatures greater ghan 110 F by the scram setpoint, and for temperatures less than 110 F by maintaining a margin of 0.4 psig below the peak LOCA prensure limit.

For operational conditions 2 and 3, a conservative analysis was made using the same methodology as discussed above, for an initial power of 20 percent of rated. This power level is well above the reactor protection system setpoint for these operational modes.

For these conditions, the GE analytical limit is more limiting 2' at all temperatures and therefore a constant value of 1.69 psig is ,

used as the operating limit.

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June 30, 1983 i SNRC-930 Page 3 The lower bound of the operating pressure domain is controlled by two parameters; containment negative pressure design limit and peak LOCA temperature. Negative containment pressure differential is discussed in detail in Section 6.2.1.3.2 of the Shoreham FSAR.

A lower bound of -0.7 psig leaves sufficient margin for both phenomena; therefore, -0.7 psig will be used for the lower operating bound, for operational conditions 1,'2 and 3.

We will be pleased to meet with your staff to further describe this proposed method of addressing the subject Technical Specifica-tion, should you desire. Please address all correspondence regard-ing this matter to this office.

Very truly yours,

. 'I./

J. L. Smith Manager,'Special Projects Shoreham Nuclear Power Station

. RCW:bc Attachment cc: R. Caruso

, J. Higgins All Parties Listed in Attachment 1 i

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ATTACHMENT 1 .

Lawrence Brenner, Esq. Herbert H. Brown, Esq.

Administrative Judge Lawrence Coe Lanpher, Esq.

Atomic Safety and Licensing Karla J. Letsche, Esq.

Board Panel Kirkpatrick, Lockhart, Hill U.S. Nuclear Regulatory Commission Christoper & Phillips Washington, D.C. 20555 8th Floor 1900 M Street, N.W.

Washington, D.C. 20036 Dr. Peter A. Morris Administrative Judge .

Atomic Safety and Licensing Mr. Marc W. Goldsmith Board Panel Energy Research Group U.S. Nuclear Regulatory Commission 4001 Totten Pond Road Washington, D.C. 20555 . Waltham, Massachusetts 02154

~

Dr. James H. Carpenter MHB Technical Associates Administrative Judge 1723 Hamilton Avenue Atomic Safety and Licensing Suite K Board Panel . San Jose, California 95125 U.S. Nuclear Regulatory Commission Washington, D.C. 20555 " '

, Stephen B. Latham, Esq. -

Twomey, Latham & Shea Daniel F. Brown, Esq. 33 West Second Street Attorney P.O. Box 398 Atomic Safety and Licensing Riverhead, New York 11901 Board Panel -

U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Ralph Shapiro, Esq.

Cammer and Shapiro, P.C.

9 East 40th Street Bernard M. Bordenick, Esq. New York, New York 10016 David A. Repka, Esq.

. U.S. Nuclear Regulatory Commission ,

Washington, D.C. 20555 ~

, , ' Matthew J. Kelly, Esq.

State of New York Department of Public Service James Dougherty Three Empire State Plaza 3045 Porter Street Albany, New York 12223 Washington, D.C. 20008 9

0 8

_. ._ . 1 4

'E'#

Drywell (1)} Drywell (2) Drywell j peak LOCA(2)g

• Temp., F ' Dewpoint, F press., psig l press.,psig l i  : i I

l l 130  ; 76.0 j 2.5 ,

46.07 l r  ; 2.8 46.59 i i  !

120  ; 68.0 2.2 45.93  ?

I.

! 2.3 46.10 i

110 . 60.0 2.0 45.96 i

! l

. t {_

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105 55.8 1.6 , 45.30 1.9 j 45.96 103 53.4 1.85 45.95 Table 1 Sensitivity of peak LOCA pressure due to initial conditions.

Notes: (1) The LOCA contr,lled pressure curve (Fig. 2) is conservatively extrapolated for temperatures less than 110'F. This is necessary due to com-puter code limitations at low dew points.

(21 This is based en a minimum relative humidity of 20 percent.

(31 Based on new LOCA analysis with peak drywell pressure of 46.0 psig (Design limit 48 psig).

c 1

+3.0 .

+2.5 -

PEAK LOCA PRESSURE LIMIT [

GE ANALYTICisL LI? LIT

+2.0 - =--------------------------------- -----------------------------

+1.69 TECil SPEC SCRAM SETPOINT - /

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+1.5 .

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0 +1.0 H - ..'

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c. OPERATING LIMIT

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0 0.5.

W x

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$ ATMOSPIIERIC PRESSURE

[E 0,0 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -----------------------------

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-0.5

-0.7

-1.0 a a a i e s .

60 70 80 90 100 110 120 130 140 145 DRYWELL BULK AVERAGE TEMPERATURE, F FIGURE 1 Crywell Pressure for Normal Operation

_ _ . . _ . - _ . _ _ _ ,_. __ . __