NRC-95-0135, Forwards Info to Supplement RAI Re Relief Request PR-7-R1 for IST of RHR Svc Water Pumps

Forwards Info to Supplement RAI Re Relief Request PR-7-R1 for IST of RHR Svc Water Pumps

ML20095J368
Person / Time
Site:	Fermi
Issue date:	12/18/1995
From:	Mckeon R DETROIT EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
CON-NRC-95-0135, CON-NRC-95-135 NUDOCS 9512270073
Download: ML20095J368 (7)

Text

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" Robert McKeon.

Anistant Vc3 President

,and Manager, operations

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00 North Dixie Hwy Edison lm"A"ar""'"

W are.s December 18,1995 NRC-95-0135 U. S. Nuclear Regulatory Commission Attn: Document Control Desk t

Washington, D. C. 20555

References:

1)

Fermi 2 NRC Docket No. 50-341 NRC License No. NPF-43 i

2)

Detroit Edison letter to NRC, " Response to Inspection Follow-up Items 95002-01 and 95002-02," NRC-95-0034, dated 4

April 7,1995 3)

Detroit Edison letter to NRC, " Relief Requests for Inservice Testing Program for Pumps and Valves," NRC-95-0077, dated July 14,1995

Subject:

Information Related to Relief Request PR-7-R1 for Inservice Testing i

of the Residual Heat Removal Service Water Pumps This letter confirms the telephone conversation between our Ms. Lynne Goodman, et al and Mr. Timothy G. Colbum of your staff on December 6,1995, and provides the information requested to supplement Relief Request PR-7-R1 (Reference 3). Detroit Edison submits the following:

1. Fnclosure 1: Throttling Capabilities of the RHR Service Water Flow Control Valves F068 A&B, El1-51, EF2-62,910 memorandum dated March 15,1983.

2. Fnclosure 2: El150F068A Broken Stem History.

3. Fnclosure 3: Purpose of Seal-in Feature on Control Valve F068 A&B.

In addition, Detroit Edison is planning to perform testing of the Residual Heat Removal Service Water (RHRSW) single pump operation. This testing may result in n w n p,

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.g USNRC December 18,1995 l

NRC-95-0135 Page 2 -

the need for a revised relief request. If this occurs, the relief request will be submitted to the NRC as required for review and approval.

If you have any questions on this matter, please contact Mr. Ilari O. Arora at (313) 586-4213.

Sincerely, N'

Enclosures (3) cc: T. G. Colburn M. J. Jordan

11. J. Miller A. Vegel 1

p Enc.losure 1 to f(RC,9 5 -013 5 Detroit Edison ENRICO FERMI UNIT 2 PROJECT ENGINEERING March 15, 1983 EF2-62,910 s,

To:

C.R. Gelletly Supervising Engineer-SUEA From:

J.H. Casiglia Supervising Engi,near-EG44 References :

1. FAST F2582-4673

2. Startup Field Report #793

Subject:

Throttling Capabilities of the RER Service Water Flow Control Valves F068A, B E11-51 Per Reference 1 FAST, a detailed hydraulic analysis was performed on the RER Service Water System to determine the throttling re-quirements of the system's flow control valve, F068. However, no data as to the actual throttling capabilities of 7068 was available from the valve vendor (William Powell) and since the system could not be run without extreme cavitation occurring at F068, the valve's throttling capabilities could not be determined by field testing.

l This being the case, EG-44 installed a restricting orifice on the discharge side of F068 in order to reduce she pressure drop require-ments at the valve. The orifice was sized to limit the flow to 9000 l

GPM (2 pump operation) through the tube side of the RER heat exchanger l

with F068100% open.

Soon after the orifice was installed, on 1-18-83 EG-44 in cooperation j

with SUEA and Startup conducted a field test on the system to determine the throttling capabilities of F068 with the restricting orifice in-stalled. F068 successfully throttled the flow with both one and two l

pumps operating for the conditions listed below:

1 Flow Mode Pumo F068A Conditions I

RHRSW Discharge Flow

• Discharge X

Inlet

&P

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Div. I Flow (GPM)

Pressure Open Press.

(PSID)

Pumps Fath (PSIG)

(PSIC)

A&C Cooling 9000 81 25%

47 13 Towers C

Cooling 5250 69 15%

48 40 Towers C

Cold Weather 5600 60 15%

31 27 Bypass

Memo to:

March 15, 1983 C.R. Gelletly Page 2 EF2-62,910

• The flow was calculated using the pump discharge gauge pressure as read on the permanent plant instrumentation in conjunction with the certified pump curve for these pumps. A reservoir water ele-i vation of 583'-0" was measured and a water temperature of 45,F was estimated.

Two Pump Operation As seen in the first flow mode above, F068 successfully throttled 9000 GPM (design flow) with two pumps operating. Absolutely no cavi-tation occurred at or near F068.

j One Pump Operation It was the concern of Systems Engineering, if in the emergency situa-j tion where one pump in a division is inoperable, can F068 successfully j

throttle the flow of the other pump running by itself in that same di-vision. In the second two flow modes above, F968 successfully throt-tied the flow of pump C running by itself to 5250 GPM while discharging to the cooling towers and to 5600 GPM while di9 charging through the cold weather bypass. Again, no cavitation cecurred at F068.

Note that for these flows of 5250 and 5600 GPM, this is the corresponding maximum pressure drop that F068 can handle (40 and 27 PSID). If attempts are made to throttle the flow below 5250 and 5600 with F068, extreme cavi-tation will occur at the valve. In this situation, requiring more pres-sure drop with F068, the pressure within the valve drops below the vapor j

pressure of the water, thus causing flashing and cavitation.

i Flows greater than 5250 and 5600 GPM can be throttled using F068 with one pump operating. However, it is advisable not to exceed 6500 GPM. This keeps the flow within the safe operating range of the pump.

l Therefore, since the RHR Service Water system is fully capable of provid-i ing the following flows to the tube side of the RHR heat exchangers l

1.

9000 GPM (design flow) with two pumps operating.

l 2.

5250-6500 GPM with one pump running discharging to the cooling towers in an emergency situation.

i 3.

.5600-6500 GPM with one pump running discharging to the cold weather bypass in an emergency situation.

EC-44, in concurrence with Systems Engineering believe that no further engineering action regarding the throttling capabilities of F068 is.re-quirad.

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Memo to:

March 15, 1983 C.R. Gelletly Page 3 EF2-62,910 If you have a y s ons, please contact the writer at 649-7262.

J

)l3 Noted by: Y T.G. Wallace Task Leader Approved:

M-3'N' hh J.W. N5aley Director-Project Design Written by: D.G. Jax g j lP3 h &'

VfU cc:

R.J. Adler T.A. Alessi R.C. Anderson R.W. Barr E.R. Bosetti J.R. Fenton E.P. Griffing G. Hookerjee l

,S.H. Noetzel 7.D. Ozdarski 1

David Spiers R.A. Vance Records Center f

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. to NRC-95-0135 Page1 a

E1150F068A BROKEN STEM HISTORY 12/27/83. NCR-83-1289.10CFR50.55(e) #109

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Description:==

Valve stem and dise (below seat) guide pin failure.

Cause:

Fatigue failure caused by throttling vibration.

Corrective Action:

Replaced damaged components and examined El150F068B for similar problems.

Corrective Action Orifice has been installed.

To Prevent Recurrence System Operating Procedures (SOP) revised to limit (CATPR) throttling outside optimum range.

7/6/85. DER NP-85-0343

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Description:==

Valve stem and guide pin failure.

Cause:

Fatigue failure caused by throttling vibration accelerated by improper heat treatment. The stem lacked adequate toughness and failed in a brittle mode once the fatigue crack propagated to critical size.

Corrective Action:

Replaced damaged components and examined El150F068B for similar problems.

CATPR:

SOP revised to reduce throttling operation Valve replacement investigated (PDC-3506) but no modification made.

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- to NRC-95-0135 Page1 PURPOSE OF SEAL-IN FEATURE ON CONTROL VALVE F068A/B 4

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The seal-in feature is for operational convenience, and is only active in the closing i

direction. Momentarily depressing the CLOSE pushbutton seals in the close signal, until the valve reaches a minimum position block or until the OPEN pushbutton is i

l momentarily depressed by the operator. As a result, the operator does not have to remain at the control switch while the valve closes. As designed, the control valve can be stopped at any position in the opening mode by releasing the OPEN pushbutton, or in the closing mode by momentary contact of the OPEN pushbutton l

as the valve is closing.

The seal-in feature could be disabled by a design change to the switch; however, i

such a change is not considered to be an enhancement to the design or operation of j

the system.

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