ML20148F292

Forwards Request for Analyses & Info Needed to Determine Potential for Occurrence & Consequences of Secondary Sys Fluid Flow Instability (Water Hammer) in Pwrs.Info Requested within 60 Days & Schedule for Submittal within 10 Days

ML20148F292
Person / Time
Site:	Yankee Rowe
Issue date:	05/13/1975
From:	Purple R Office of Nuclear Reactor Regulation
To:	Andognini G YANKEE ATOMIC ELECTRIC CO.
References
NUDOCS 8011040744
Download: ML20148F292 (5)

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rocket ::o . 50-29 MAY 131975 Yankee Atomic Electric Corrany ATT!i: Mr. C. Carl Andopnini, Assistant THIS DOCUMENT CONTAINS to the Vice President POOR QUAUTY PAGES 20 Turnpike tout Uestboro, I!assachusetts 015d1 i I Centlemen:

The Nuclear Regulatory Commission staf f's continuing review of reactor power plant safety indicates that the potential for occurrence and the potential consequences of secondary system fluid flow inst ability in P'nEs (characterized as " water hammer") need to be adequately analyzed by licensees an. the result s evaluated by the staf f. It has been found that events that caused damage to the feedwater system piping at the Indian Point 2 facility (1) and other operating plants can occur as a consequence of uncovering the feedwater sparger or the feeduater inlet nozzles in the steam generator. Subsequent events, including the operation of the Auxiliary Feedwater System, can result in the genera-tion of an instability or pressure wave that is propagated through the piping that can result in failure of the piping and/or its supports.

Structures, systens, and components important to safety should be { s designed and constructed so that destructive type fluid flow instability \

will not occur during normal, upset, or accident conditions. L'esed on i information presently available to us, the feedwater and/or auxiliary \ ',

feedwater systems in your plant may be susceptible to flow instabilities.

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We request that you provide us with analyses and other relevant infor- \k cation needed to determine the potential for occurrence end the potential  ;

consequences of such en event in your plant using the guidance provided '

in the enclosure. Since piping layouts and system designs ara substan-tially dif ferent from plant to plant , you should determine and indicate in your response the applicability to your plant of each of the items 3 0 11 04 o 7t'y O l ' feldUater Line Incident Eeport - Indien Point I! nit lio. 2", dated e January 14, 1974, as supplemented by submittal dated January 16, 1974. Recult s of test progran are shown in submit tals dated 7 7 #

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!! arch 12,1974, and August 30, 1974.

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. . MAY 13 r975 Yankee Atoalc Electric Company i

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in the enclosure. If the results of your analyses indicate that changes in the design or operation of st ructures , systems, or cor.ponents are necessary to prevent the water bacner event or assure syster integrity, ,

you should provide in for-ct ion on your plans to ecke tnese changes in l your facility. Any desien nodifications proposed should include appro- '

priate consideration of the ;;uidelines cnd requests for in f orrat ion in the enclosure. Within 10 days af ter receipt of this letter, notify us that you vill provide all the in fornation requested withir 60 days or explain why you (. a n n ot neet this schedule and provide the schedule that l you vill meet.

j This recuest for reneric in f orma t ion was approved by GeC under a blenket

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cleerence number L-150225 (R0072); this elecrance expires July 31, 1977. >

Sincerely, I

Original signed by:

Robert A. Purple

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Robert A. Purple, Chief l Operating Reactors Branch #1 f Division of Feactor Licensins; h I

Enclosure * '

Information pequired cc w/ enclosure:

See ner.t page DISTRIBUTION N Docket File i; NRC PDR [

Local PDR I ORB #1 Reading L JRBuchanan b TBAbernathy .

KRGoller [

TJCarter j OELD 0 .

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RAPurple i ABurger SMaheppard ACRS (14)

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4 out, S/12/7S 5//)/75 Form AEC.318 (Rev. 9 53) AECM 0240 c u s cov e nN n.f 47 PRINTING CFFeCE 1973 - 439 293

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. Yankee Atomic Elecl 'c Company 3' 6

, May 13,' 1975 cc:. Mr. Donald G. Allen, President Yankee Atomic Electric Company .

20 Turnpike Road E-

• Westboro, Massachusetts 01581 Greenfield Public Library r= 402 Main St' rect Greenficid, Massachusetts . 01581 -

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IECESTIOli REOUIFED

1. Describe all operating occurrences that could cause the level of the water /staan interf ace in the steen generator to drop below the feec-water sparger or inlet nozzles, and allow steam to enter the sparger and/or the feedwater piping.

2. Describe and show by iscretric diagrams, the routing of the main and auxiliary feedwater piping froa the steari generotors outwards throuth containrer.t up to the outer containment isolation valve and rest raint .

!'ote all valves and provide the elevations of the spar: er and/or inlet nozzles and all pipin? runs needed to perforr an in de pende n t analysis of drainaea characteristics.

3. Describe any "uater hatzer" experiences that have occurred in the feedwater system and the means by which the problen was pernanently corrected.

4. rescribe all analyses of the feedwater and auxiliary feedwater piping systems for which dynamic forcing functions were assumed. Also, pro-vide the results of any test programs that were carried out to verify that either uncovering of the feedwater lines could not occur at your facility, or if it did occur, that " water hammer" would not occur.

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a. If forcing functions were assumed in analyses, provide the technical bases that were used to assure that an appropriate

- choice was made and that adequate conservatisms were included in the analytical codel,

b. If a test progree was followed, provide the basis for assuring that the program adequately tracked and predicted the flow instability event that occurred , and further , th a t the test results contained adequate conservatises and an acceptable factor of safety, e.g., range of paraceters covered all con-ceivable modes of operation.

c. If neither a. or b. have been performed, present your basis for not requiring either and your plans to investigate this potential transient occurrence, omcE> _... .__....__._.. . . _ _ _ _ _ _ _ _ _ _ _ _ _ . ....______...___ .__ ......__ .__. .________....____. .____._______.

SURNAME > , , , , , , , , , , , , , , , , , , , ,,,,,,,,,,,,,,,,,

DATES __.____._________________.______...______ .___. ___ ._______________._.._________.___ ..___________...

' Form AEC.318 (Rev. 9 53) AtcM 0240 '  : u s' 'cova nbrW c'amdo~ orries Mn- osau ~

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fjg 5. Discuss the possibility of a sparger or nozzle uncovering and the ,

consequent pressure 'vave ef tects . that could occur in tne piping HE following a design basis loss-of-coolant accident, assuming con-current turbine trip .and loss of of fsite . power. 3

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== 6. If plant system design changes have been or are planned to be made to preclude ' the occurrence of flow instabilities , describe 4 these changes or modifications, and discuss the reasono that made

d. this alternative superior'to other alternatives that cight have  ;

been applied. Discuss the quality assurance prorrc- that pas or

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.will be followed to assure that the planned system :-odifications ,

vill have been correctly accomplished at the facility. If chen;es are indicated to be necessary for your plant , consider and discuss the ef fects of reduced euxiliary feedvater flow as a possible means of reducing the magnitude of induced pressure waves , including pos it ive ceans (e.g . , interlochs) to assure suf ficiently low flow rates and still meet the mininum requirement s for the systec safety ,

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SURNAME) , , _ , _ , , , , , , _ , _ _ ,,__,_,_,_,_, , _ , , , , , , , , , , ,,,,,,,,,,,,,, ,,,, ,,,,_,__,_, ,_ , ,

DATE)

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['- ~ f orm AEC 318 (Rev. 9-53) AECM 0240 f. u s novenuwsur enemine orries. isn--4ee ass