ML20128D897

Summarizes 740220-21 Meetings W/Util & GE Re Proposed Prompt Relief Trip Sys Intended to Enhance Scram Reactivity Insertion Rate

ML20128D897
Person / Time
Site:	Monticello
Issue date:	02/26/1974
From:	Basdekas D US ATOMIC ENERGY COMMISSION (AEC)
To:	Ippolito T US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 9212070417
Download: ML20128D897 (2)

Text

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FEB 2 61974 I

f- Docket No. 50-263 / +

i-j Thomas A. Ippolito, Chief, Electrical, instrumentation & Control 4

l Systems Branch, L

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, GENERAL ELECTRIC PROPOSED PROMPT RELIEF TRIP (PRT)- STETEM'FOR j  !!ONTICELLO 1

}' On February 20 and 21, 1974,- a meeting chaired by J. J. Shea, j ORB-2, eas held'with General Electric and Northern States Power

; Company to discuss the proposed Prompt Relief Trip System I i intended to enhance the scram reactivity insertion rate which 1 i was found by G.E. to be deficient toward the end of the fuel

]- cycle for BWRs in general'.

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! A brief sunanary of an earlier G.E. presentation on the ' subject

! j was given as reported =in my memo to you of' october 18, 1973.

i Additional information was presented on'the details of the PRT 1mplementation in Monticello largely contained in the applicant's

submission of January 23, 1974.

i- l F i The PRT, as proposed during this meeting, is intended to satisfy j

t the requirements of IEEE 279.

l Our review of the electrical and instrumentation aspects of the-

, proposed PPT has not been performed, and questions such as single failure proofness, interaction with the ADS, reliability with

regard to function performance on demand. testability and inadvertent j- actuation cranot be answered at this time.

The applicant is aining at getting our approval for installing a

PRT but not "outrating" it until our: review is- couplete.and our approval final.

r Technical aspects of keeping the PRT de-activated after installation-j i are not unworkable.

During the discussion with the applicant and G.E. the following I

items came up that are of interest in making a determination of the-safety metits 'of the PRT as proposed'in the Monticello caset

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4 The PRT function, without any other desi8u changes considered._ i will be required only for something like 20% of the operating 3 life of the plant, toward the and of the fuel cycle, yet it will be challenged throughout the finel cycle.

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i Not all viable alternatives and combinations thereof have 1 i

been considered and/or analyzed with specific reference to the present Monticello design. A notable case in point is 1

j i that it has not been analyzed with reference to the recirculation ptasp trip as implemented for the ATWS fix.

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. 3. The present Monticello design has a reactor scram initiated j

by low condonser vacuum before a turbine trip setpoint is

' reached. The presently available and/o1 enhanced. turbine 4 bypass capability with possibic changes in the bypass system-have not been analyzed. "

4. The question of inadvertent and/or unnecessary actuations in conjunction with the bad history of the relief valvos sticking open remains at best, a cute one.

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t Demetrios L. Basdekas Electrical, Instrumentation &

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-Control Systems Branch 3,

Directorate of Licensing y, i

cci V. Stello

D. Ross-T. Novak ,r C. Bailey W. Minners p EI&CSB Hembers 4

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