ML20024B370

Lists Procedures for All Operating Plants to Follow When High Pressure Injection Has Actuated Because of Low Pressure Condition,Following 790328 Accident

ML20024B370
Person / Time
Site:	Crane
Issue date:	04/04/1979
From:	Fairburn G BABCOCK & WILCOX CO.
To:	Geoffrey Miller METROPOLITAN EDISON CO.
References
TASK-*, TASK-02, TASK-2, TASK-GB GPU-2466, TMI-79-47, NUDOCS 8307080564
Download: ML20024B370 (3)

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P.o. Box 1260. Lynen::u. g va. 245s5 Te!e:hene:(804) s34 5111 April '4,1979 TMI-79-47 Mr. G. P. Miller Station Superintendent Metropolitan Edison Company P.O. Box 480 Middletown, PA 17057

Subject:

Three Mile Island Auclear Generating Station - Unit 1 TMI-2 Loss of Feedwater Transient

Dear Mr. Miller:

Although details of the causes and course of events of the incident at Metropolitan Edisen's TMI-2 plant on March 28, 1979 are still being

' developed, it appears that the incident was initiated by a loss-of-cain feedwater flow (LOFW) and that a distinguishing characteristic of this transient ccmpared to other previous LOFW transients was the securing of the High Pressure Injecti,on (HPI) system.

Consequently, all operating plants are advised to implement the following in::,ediately:

If the HPI system has actuated because of low pressure condition, it must remain in operation until either:

f. Both LPI pu=::s are in operation and flowing at a rate in excess of 1000 GPM each and the situation has been stable for 20 minutes.

OR

' 2.

TheHPIsystemhasbeeninoperationfor30minutesandallhot and cold leg temperatures are at least 50 below the saturation temperature for the existing RCS pressure.

If 500 subcooling can-not be maintained, the HPI shall be reactivated.

If. the HPI system has been activated and if RC pu=ps are in operation, at least one RCP pump per loop should be maintained.

This information supplements that previously transmitted.

If you liave any questions regarding this advisory, please advise.

Yery truly yours, J J,81 "If)

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PDR ADOCK 050002G9 G. T. Fairburn P

HOL Service Manager GTP/hh cc: RM Klingaman bec: JD Phinney T1.1020 JF Hilbish RL Pittman

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LL Lawyer TM Dixens JL Seelinger GM Olds CR Montgomery HA Bailey LC Rogers Record Ctr. NSS-5 T1.2 SL Smith The Babcock & Wacox Company / Er

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1 P.c., Box 1260. Lynchturg. va. 2y505 Te!e;hene: (So4) 384-5111 April 18, 1979 TMI.-79-55 Mr. G. P. Miller Station Superintendent Metropolitan Edison Cc pany P.O. Box 480 Middleto.:n, PA 17057

Subject:

Three Mile Island Nuclear Generating Station - Unit 1 HPI - Operating Instructions Referen:e: Letter., GT Fairburn to GP Miller, TMI.-79--}7, dated 4/,4/79 s.

Dear Mr. Miller:

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The operating instructions, given in the above reference, for operator-action to everride the' engineering safety features actuation system and terminate HPI have been revised. This rev.ision (attached) allcws-the operator an alternative to the 20' minute operability pericd, under certain conditiens, to preclude the pressurizer from going solid.

This info.matien supplements that previcusly transmitted..If you have any questions regarding this advisory, please advise.

i Very truly yours, J:

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G. T. Fairburn Service Manager' GTF/hh

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cc: w/ attachment Rii Klingaman

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JF Hilbish LL Lawyer JL Seelincer L-CR Montsch.ery LC Rogers SL Smith 1:

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T11021 The Babcock & witcom Company / Established 1867

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S LEMENTAL OPEPATING I;;STRUCTIO FOR HPI SYSTEll CPERATION REY. 01 - 4/17/79 Although details of the causes and course of events of the incident at Metropolitan Edison's TMI-2 plant on March 28, 1979 are still being developed, it appears that the incident was initiated by a loss-of-main feedwater flow (LOFW) and that'a distinguishing characteristic of this transient compared to other previous LOFW transients was the securing of the high pressure injection (HPI) system.

Consequently, all operating plants are advised to implement the following immediately:

If the HPI system has actuated because of low pressure condition, it

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must remain in operation until one of th e following criteria is satis-fied:

1.

Both LPI pumps are in operation and flowing at a rate in excess of 1000 gpa each and the situation has been stable for 20

-... minutes.

i' oR.

,2..

The HPI system has been in operation for 30 minutes and all het and cold leg temperatures are at least 50 belowghesaturatien

-.. temperature for the existing RCS pressure.

If 50 subcooling

,cannot be maintained, the HPI shall be reactivated.

7 OR 3.

All hot and cold leg temperatures are at least 50 below the saturation temperature for the existing RCS pressure, at least one RC pump in each loop is running, and the action is necessary to prevent tge indicated pressurizer level from going off-scale

- -- high.

If 50 subcooling cannot be maintained, the HPI shall be

. n-reactivated.

If the HPI system has been activated and if RC pumps are in operation, at least one RC pump per loop should be maintained.

.. :-H T11022 P

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