ML20207F330

Forwards Comments in Response to D Katze Questions Posed in 860715 Telcon.Util Will Administratively Ensure That Valves 2C11 D001-103 & 2C11 D001-1056 Closed During Fine Motion Crd.W/One Oversize Encl

ML20207F330
Person / Time
Site:	LaSalle
Issue date:	07/18/1986
From:	Allen C COMMONWEALTH EDISON CO.
To:	Bournia A NRC
Shared Package
ML20207F335	List: ML20207F330 ML20266F076
References
1856K, NUDOCS 8607220518
Download: ML20207F330 (3)

Text

.\ Commonwmith Edison

_ _ _ . . 72 Wrst Ad'.ms Street, Chicago, Illinois

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Address Reply to: Post Office Box 767 ONcago, il:inois 60690- 0767 July 18, 1986 gyd - 3 M Dr. A. Bournia, Project Manager U.S. Nuclear Regulatory Commission 7920 Norfolk Avenue Bethesda, MD 20014

Dear Dr. Bournia:

Attached are the written comments provided by General Electric concerning the questions posed by your reviewer D. Katze in our telecon July 15, 1986. Also as stated in that call, Commonwealth Edison will administra-tively insure that the 2C11 D001-103 and 2C11 D001-1056 valves are closed during the FMCRD test.

If you have any additional questions concerning this matter, please contact me through this office.

Sincerely C. M. Allen Nuclear Licensing Administrator im Attachment 1856K 8607220518 860718 4 dq DR ADOCK 0500 i

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o GE Response to FMCRD In-Plant Demonstration Concerns As Expressed By the U.S. NRC During 7/15/86 Telecon Reference 1. Licensing Topical Report, "La Salle Unit 2 Fine Motion Control Rod Drive - Demonstration Test Description" NED0-31130, December, 1985.

Reference 2. FMCRD Hydraulic Unit Piping Interconnection Diagram (796E704)

1. NRC Concern (Referring to the above References 1 and 2 assuming leakage through LPHC'J 02-43 isolation valve V-105 (CRD water exhaust line) and operation of CRD insert directional control valves V121 and V123 by control room operator, what is effect on LaSalle-2 plant operation?

GE Response There would be no impact on LaSalle-2 plant operation, since vessel pressure would be present on both up-stream and down-stream sides of V105 resulting in zero differential pressure and/or flow.

2. NRC Concern Same as noted above excepting as applied to V103 (CRD drive water header isolation valve).

GE Response Here again, there would be no effect on LaSalle-2 plant operation. V123 is an electro-hydraulic speed control valve, manually adjusted to regulate LPCRD drive velocity to 3 inch /second. To accomplish this, the drive water header pressure of reactor pressure plus 250 psi (PR+250) supplied to V123 via V103 is reduced tg 85 psid (PR+85) which is then applied to the LPCRD piston under area of 4.1 in at a rate of 4.2 gpm, resulting in the desired 3.0 inch /second insert drive velocity.

For the above conditions, assuming the full 250 P drop through this valve results in a maximum flow of approximately 5 GPM. 5GPM would then be the maximum flow available to FMCRD assuming a full-open failed V-103 valve.

Testing conducted at the GE engineering test facility while employing FMCRD, has shown that supplying FMCRD with 10 GPM flow results in 22 psid (PR+22) maximum hydraulic pressure being applied to the FMCRD piston under area. Additionally, it has been demonstrated that a minimum of 65 psid is required to be applied to the FMCRD piston under area in order to result in FMCRD involuntary drift into the reactor core.

The net effect of this postulated concern would be to supply FMCRD with additional purge water flow, with no attendant La-Salle plant operational impact.

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3. NRC Concern (Referring to the above References 1 and 2)

What effect will leakage through V126 [LPHCU 02-43 inlet scram valve (mechanically adjusted to the full-closed position)] have on LaSalle-2 plant operation, with FMCRD installed.

GE Response There would be no impact on LaSalle-2 plant operation prior to or during scram.

A. Prior to Scram -- Scram accumulator charge water supplied via LPHCU 02-43 V113 (charging water isolation valve) through check valve V115 would act as additional purge water being supplied to FMCRD. As long as the charging water header pressure was maintained above reactor pressure, FMCRD booster hydraulic pump operation would be unaffected.

Assuming gross V126 leakage, in excess of 15 GPM, resulting in application of FMCRD piston under pressure of 65 psid (PR+65) or more, FMCRD would drift into the core (inherently safe); however, in so doing, the FMCRD Operation Panel SEPARATION indicator would alarm, alerting control room personnel to the problem. Also, FMHCU V115A check valve would prevent loss of FMHCU scram accumulator charge should the V126 postulated leakage total less than that required to result in FMCRD drift-in, thereby maintaining FMCRD in a scram ready state.

B. During Scram -- Reverse leakage through V126 during FMCRD scram would have no adverse system impact, since the LPHCU 02-43 V115 check valve would prevent reverse flow of scram water into the charging water header. Also, the LPHCU 02-43 scram accumulator piston will be bottomed on the N 2 side of the accumulator, while FMCRD is installed, and filled with water. Since water is essentially non-compressible, here again, reverse flow during scram will not occur.

In summary, GE feels that good engineering practice dictates isolation of unused-portions of LPHCU 02-43 from the remainder of the CRD hydraulic system while FMCRD is installed at LaSalle-2 plant.

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