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)

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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.

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

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is taken on Monticello will form sone precedent for subsequent actions, j

1.

The RPT circuits should be reviewed by El&CSB for confor-

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mance with applicable standards.

j 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 l

review, but this effort will. not be accomplished for about-j.-

i six months, i

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

careful check of each submittal will determine whether i

changes nave been made.

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5.. Gar review of GETAl is not complete. Presumably..some of the events, such as turbine trip without bypass. have been ---

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

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

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

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

0 GETAB for several months.

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9212070414-740219 PDR-ADOCK 05000263 P

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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 "ny action on plants such as Monticello which take several months.

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 V. Stello, L:RS l

D. Ziemann, L:0RB-2 D. Ross, L:CPB T. Ippolito, L:EICSB J. Shea, L:0RB-2 R. Bevin, EP-4 R. Diggs, L:RP l

l-G. Williams, EP-4 PDR(3) l L Reading File l

RS Reading File 1

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Form AEC.318 (Rev. 913) AECM 0240 peo can to e s.e s.s s a o~ s e4