ML18227D433

01/03/1978 Letter Response to Request for Information Re Design & Procedural Modifications to Preclude Water Hammer in PWR Feedwater Systems

ML18227D433
Person / Time
Site:	Turkey Point
Issue date:	01/03/1978
From:	Robert E. Uhrig Florida Power & Light Co
To:	Lear G Office of Nuclear Reactor Regulation
References
Download: ML18227D433 (5)

Text

DI IP'TION AFTER ISSUANCE OF OP NG LICENSE

)RC~aAM 195 U.S. NUC! EAR REGULATORV COMMISS OOCKET NUMBE Z-7BI E

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NRC DlSTRlBUTION FoR PART 50 DOCKET MATERlAL iOI FROM: FPL OATS OF OOCUMENT Mr. George Lear Miami~ Fl. 33101 01 03 78 Robert E. Uhrig OATE RECEIVEO 01 10 78

'QKTTKR QNOTORIZEO PROP INPUT FORM NUMBER OF COPIES RECEIVED gPRIGINAL l,(UNCLASSIFIED Qcopv e

)KSCRIPTION ENCLOSURE Response to NRC's ltr dt's 09/02/77.. ~ consisting of inf mation concerning design,and/or procedural modifications necessa at Units 3 & 4 to preclude water ha, er in the steam generator feedwater ys tern... ~

2p PLAh~ NAME. TURKEY POINT UNITS 3 & 4

. jcm 01/11/78 FOR ACTION/INFORMATION BRANCH CHIEF: 7 INTERNAL 0 RIBUTION EG '%.

.'O CG EXTERNAL DISTRIBUTION CO TROL NUMBER FDR:

TC NSIC 78011006

%CRS 16 CYS SENT CATE R

FLORIDA POWER 84 LIGHT COMPANY January 3,1978 L-78-6 Office of Nuclear Reactor Regulation Attention: Mr. George Lear, Chief-Operating Reactors Branch I3 Division of Operating Reactors EcE(ypg U. S. Nuclear Regulatory Commission ;inst'p'~(~ .,ai'a Washington, D. C. 20555

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Re: Turkey Point Units 3 s 4 Docket, Nos. 50-250 6 50-251 Water Hammer in PWR Pee'dwater S stems cgX +

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Dear Mr. Lear:

I01'y letter dated September 2, 1977, you forwarded a request for information concerning design and/or procedural modifications which might be necessary at Turkey Point Units 3 and 4 to preclude water hammer in the steam generator feedwater system.

The intent of the staff's request was to gain assurance that feedwater hammer will not occur under normal and transient operating conditions.

As was described in our letter of July 3, 1975 (L-75-246), FPL .

has already implemented design modifications at Turkey Point in an effort to eliminate the occurrence of feedwater hammer.

These modifications are consistent with vendor recommendations and include the following:

1) The lengths of the horizontal runs of feedwater piping entering the steam generator at the level of the feedwater inlet nozzle were decreased to within the guidelines of the vendor recommendations.

2) Auxiliary feed flow is manually controlled with the operator routinely limiting flow rate to the, minimum necessary to meet operating requirements.

Additionally, automatic initiation logic is provided for starting the auxiliary feedwater system upon a signal(s) indicating a loss of normal feedwater.

Since the modifications were implemented (1974), the operating experience of both units has demonstrated that the effects of water hammer have indeed been eliminated or at least reduced. <<CAVING This is evident from the fact that no indications of water hammer damage have been observed during the period from 1974 to 1977.

Therefore, we do not believe that further modifications are 780ii0060 PEOPLE

c,'pl Mz. George Lear, Chief U. S. Nuclear Regulatory Commission Page Two required to prevent equipment damage from feedwater hammer.

One conclusion of the report (NUREG-0291, An Evaluation of PWR Steam Generator Water Hammer, Final Technical Report, June 1, 1976-December 31, 1976), which was commissioned by the USNRC and was prepared by CREARE, Inc., is that "the most immediate means avail-able to reduce the frequency and severity of steam generator water hammer is for operating reactors to upgrade their system within the framework of the present PWR vendor recommendations." As was described above, FPL has been responsive to this conclusion with past action.'ery truly yours, Robert E. Uhrig Vice President WAK:dt cc: Mr James P. O'Reilly, Region II Robert Lowenstein, Esq.

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