ML20024C733

Submits Clarification Re Small Break LOCA Analysis N4M-2-14(AR),in Response to 790125 Ltr.Appropriate Explanation for Not Requiring Thermal Balance Requested by 790315

ML20024C733
Person / Time
Site:	Three Mile Island, Bellefonte
Issue date:	02/28/1979
From:	Patterson D TENNESSEE VALLEY AUTHORITY
To:	Mcfarland J BABCOCK & WILCOX CO.
References
TASK-06, TASK-07, TASK-6, TASK-7, TASK-GB GPU-0476, GPU-476, NUDOCS 8307130176
Download: ML20024C733 (2)

Text

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. KNOXVILLE.TENHCsOEE L7902 w ,

Co.merce Avenue W10C125. 400 .

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February 8,1979 g,gy E 3. Q78 m my.

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.c Babcock a'nd Wilcox f- Post Office Box 1260 24505 .

Lynchburg, Virginia 4 ,

Attention: Mr. James McFarland c

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Gent 1' amen:

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SELLEF0hT5 HUCLEAR PLANT UNITS 1 hMD 2 .

NUCLEAR STEAM SUPPLY SY5ilms C0tti?ACT 71C52-57.14-2 4

LETTER 60. K-2472 h N4M-2 14(AO-

% SPALL EREAX LOCA AM LYSI5 iME3 790125 555) and 3

_'de ackn:wledge receipt of yccr let er No. 3-;*02 .

@ hava the 1:liewin; cc= ants. ditional explahitienThe .

p$ r - TVA will require the followingl clarification i and referenceand folicwing statements:

letter.e.d Q f, ,\ , to ccmpleta its review of the sub.iect e will beana con-. ys sa g 1.

"After natural circulation ceases, thehsystem d threuch pressurThat trolled by a 'velume balance.'

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l Fj; balance at a point where the volume ted in of the fluid cere. disc arce

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the break equals the volume of steam being creak increase '

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. . . the volume relief system pressure.. . . .

out the brea decreases with

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"The volume of steam being generated in the core l$

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' 3. increasing pressure."

h the requirement given in W small break f

i~ 5tatements 2 and 3 appear to be inconsistent witY statement LOCA analysis 1. as a conservajive prediction of m n mappe Please breaks smaller than 0.05 ftWe assume that statement 2

)i l correct as written.

l1 clarify.

be in "thertial a

6 4 We were also wondering ifThat youis, considered the systemthe system pressure s

balance" balance atas a point well aswhere " volume the volume balance."

the h deca core and being of 7yeat fluid the heat created content h s the 3

j7 equals the volume of steam being creat

'( ' / .J 6 in the core.

volumetric steam flow ratio (final value/ n

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I 'Babecek and Wilcox .

February 8, 1979 .

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l value).

prepertienal to the enthalpy and density i flow withratios (

the range of interest, the net effect is a decrease inMcwever,. volumetr cTh increasina systen pressure. re. is proport o the mass [ volume X density) of fluid c:nverted to steam  :

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the enthalpy ratio only, which is increasing with in l r::2 :f 1::s of ry: tan inventory (massj.

l I It is this increasing inventory deplati:n ecupiedf:rwith T7A'sa decrea l r::a fr:a the HPI pump at elevated pressure that forms the basis One way 1:r 31H to alievia: this c:ncarn is t shew that a

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" thermal balance does not have to pertain; c:herwise, it w uld app ceptablayb:ending tha: the is.i small break L:CA analysis ety n:: he an aclier than C.05 ft'.

. predictor of minimum core level for breaks sma di" TVA with an appropriate explanation i eryfor not Such a reply should resolve mest of cur remaining questiens c small break LOCA behavior. . , ld be Of course, concepts such as " volume balance" i and l cases."ther:a i i les

( recognized as oversimplifications which maydapply only to a i

The rigorous solution must be based on mass and energy c phase changes applied to the entire system including all inputs, outputs, an within the system.

15, 1979. ,

l Please give us your written response. by March Very truly yours, TENNESSEE VALLEY AUTHORITY 1

l D. R. Patterson, Chief Mechanical Engineering Branch 6 In triplicate

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- cc: Mr. J. L. Atchison XO40185 f.

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! 1 184

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