ML20128D890

Understands That Util Proposing Prompt Relief Trip Circuit for Plant Bwr,As Well as Mod to Relief/Safety Valve Sys. Listed Items Should Be Considered

ML20128D890
Person / Time
Site:	Monticello
Issue date:	02/19/1974
From:	Stello V US ATOMIC ENERGY COMMISSION (AEC)
To:	Skovholt D US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 9212070414
Download: ML20128D890 (2)

Text

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I p*) d, 3 l i FEB 19 N M ,

j Donald J. Skovholt. Assistant Director for 0:>erating Reactors. L i

! Pit 0MPT RELIEF TRIP-j j We unders tand in Reactor Safety:TR that tiurthern States Power is proposing a prompt reliaf trin (R9T) circuit for its Monticello BWR, as well:as l

nodifications to its relief / safety valve system. AltSouqh we have not i j as yet been requested tn assist you in this matter, by means of a TAR.

j 4 oc believa the followino itets should be considered, as whatever action j ,

is taken on Monticello will form sone precedent for subsequent actions, j 1. The RPT circuits should be reviewed by El&CSB for confor-mance with applicable standards.

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2. The transient analysis technique as describo,i in !!EDO-13S32 has not Daen revitNed by: RS(indeednoTARhasbeenissued.

l ye t) . Ih have included it as part of our overall ATW5 review, but this effort will. not be accomplished for about-

l j .- i six months, i

i l 3. Tne transient analysis used for relief / safety valve sizing

! I may be adversely effected, if andwhen the' recirculation

i nump trip required to control an ATWS is incorporated.

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4. _ The assuqed reactor physics paraecters -(including integral

rod worta inserted, reactivity coefficients) may be in a

changing situation. GE has said, at other times, that

1' they intend to go to less conservative-values. Only a

careful check of each submittal will determine whether i changes nave been made.

l l 5. . Gar review of GETAl is not complete. Presumably..some of the

!_  ! events, such as turbine trip without bypass. have been ---

l . analyzed on ?Ionticello' with GETAB, and in fact are limiting.

The number of relief valves and the functioning (or lack 1  !

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of it) of the RPT affect'the course of transient, and _ .

; tnereby the GETAS results. We will not be finished with -

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GETAB for several months.

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I EB 191914 D. J. Skovholt - 2-i in strrary, we wish to point out that a complete technical solution to the adequacy of PRT is intertwined with ATWS and GETAB reviews and will take several months. "ny action on plants such as Monticello which i

r=1st tale place sooner should nnt be considered as precedent-sattino

, ed should incorporate suinble conservatism to compensato for lack

of fully reviewed events.

Orleinal Slgual tig

• Yletor Stello Victor Stello, Jr. , Assist 1at Director for Reactor Saf ty Directorate of Liccasinc DISTRIBUTION:

J. M. Hendrie, DDTR A. Giambusso DDRP R. Boyd,L:RP J. Gallo, 0GC l V. Stello, L:RS D. Ziemann, L:0RB-2 D. Ross, L:CPB T. Ippolito, L:EICSB J. Shea, L:0RB-2 R. Bevin, EP-4 l R. Diggs, L:RP l- G. Williams, EP-4 PDR(3) l L Reading File l RS Reading File 1

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