ML19329B772

Deficiency Rept Re Potential of Auxiliary Feed Pump Governor to Bind.Caused by Misalignment Forces Applied to Governor T-bar.Procedure Mod Underway to Shut Turbine W/Governor Servometer in Low Speed Stop Position

ML19329B772
Person / Time
Site:	Davis Besse
Issue date:	10/05/1977
From:	Roe L TOLEDO EDISON CO.
To:
Shared Package
ML19329B768	List: ML19329B767 ML19329B772
References
REF-PT21-77-006-000 389, NUDOCS 8002060799
Download: ML19329B772 (2)

Text

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bW0 c r :2.4 rouco D 2 h.$ 1. d O M October 5, 1977 LOWELL E. ROE v... em...,.

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Scrisl No. 389 Docket No. 50-346 Mr. Je=es C. Keppler D

0 Regional Director, Region III Office of Inspection & Inforcement OO U.S. Nuclear Regu12 tory Corcission o1

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Dear Mr. Keppler:

In acccrdanca with 10 CFR ? art 21.21(b), this is a report of a defect in a cecpenent installed in the Davis-Easse Nuclear Power Station, Unit No. 1.

The cecponent involved is the governor on the auxiliary feed Punps.

The auxiliary.f aed pe=ps were supplied by Bylga Jackson Pump Division.

The str.am drivea pt. p t:::bine vas suppliad by Tarry. Corporation, to Byren Jackson. In turn, the tt:bine gevarnor was supplied to Terry Cc.rporation by Woodward Governor C,.cpany.

The turbine governor is identified cs a type FG-?L, which has a servemotor control e= ploying a 3odine Electric Company motor.

The defect involves a potential for the governor to bind under certain conditions and preventing the turbine from cc=ing up to design speed.

The operating procedures for this equipeent called for the gevernor to be placed in the high speed stop position prior to shutting down the

' turbine.

Investigation has shavn that with :he 3odine servocator driving against the high speed stop, a nisalignment force is cpplied to the T-bar of the governer linkage.

1his oisalign ant force craates a potential fer the go'rernor to bind at a speed position less than design speed upou a turbine startup. This misalign=ent force does not alvsys csuse the gov-ernor to bind and this =1salign=ent force can be renoved by driving the Bodine servosocor away from the high speed stop.

. The safety hazard which could be created is the potential for both auxiliary feed pu=ps to fail to co=a up to design speed upon startup.

This could result in-x.aubstantial loss of auxiliary feedvater flow to the steam gen.arators an:n such flow was required. This in turn could cauce significant reactor coolant systen pressure / temperature transients, i

and significant boillr-in the reactor coolant syste= if substantial decay heat were present in the reactor core.

OCT 11 N THE 70L"JO EOt3CN COMPANY EDSMPLAZA 300 MACrSON AVENUE

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Mr. J;mes G. APPlcr Paga 2 Octobar 3, 1977 Serial No. 389 The evalut. tion end identification of this defect was provided to La on September 30, 1977, rnd was discussed with Mr. T. Harpster of your office on Septefar 30, 1977.

There are two identical s,uxiliary. feed pumps with tha turbine governors, described above, inst 411ad in the' Davis-Besse Nuclear Power Station, Unit No. 1.

- The corrective action being taken is a procedure modification to require that the tur'aine be shut doun with the governor cervon:otor in the lov speed stop position (inste:d of the previously used procedure of shutting down t!.e governor at the high speed stop position). This vill elininate the possibility of any nian11gn= ant forces being cpplied to the governor T-bar nud, as a result, el W ate any potential for the governor to bind.

Confituatory testing of tio governors has choun that the turbines will cc:se up to design speed prior to the time required for the Bodine servo-motor to drive frem the 107 speed stop to the high speed stop position.

In addition to tha.prccedure codificatien, alarns are being providad in the control racm to c.ov the operators that the governor is at ochar than lov speed ctop positien when the turbine is shut down. We expect to couplete the above ch.utges prior to going to Mode 2 during the next unit startup.

Yours very truly,

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Lovell I. Ree Vice President Tscilities Development LER.r f

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