ML19319E039
| ML19319E039 | |
| Person / Time | |
|---|---|
| Site: | Indian Point, Rancho Seco  |
| Issue date: | 05/13/1975 |
| From: | Purple R Office of Nuclear Reactor Regulation |
| To: | Davis E SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| References | |
| NUDOCS 8003310506 | |
| Download: ML19319E039 (5) | |
Text
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I pocket ro. 50-312 MAY l51975 Eccrarento Municit.ai Utility District D
E ATTM:
Er. E. L Davis General 1:scaper OO 6201 S Street n'
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3 Jentlemen:
The !!uclear Fevulatory Concission staf f's continuing review of reactor pover plant safety indicates that the potential for occurrence and the potential consequences of secondcry systett fluid flow instability in PWRs (chcracterized as water ha=rer") need to be adequately analyzed by licensees cud the results evaluated by the statf.
It has been found that events that caused nage to the feedvater systen piping et the Indian Point 2 fccility and other operating plcnts can occur cs a consecuence of uncoverine the feedvater spcrger or the feeductor inlet nozrles in the stear renerator.
Subsequent everts, including the operation of the Auxilicry Feeovater Systen:, can result in the genere-tion of an instability or pressure wave that is proparcted through the
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piping that can result in f ailure of the piping cnd/or its supports.
N Etructures, systecs, and cocronents ieportant to safety should be desigreed and constructed so that destructive type fluid flow instability X
4 will not occur durine norircl, upset, or accident cond i t ior,s.
pesed on infoructioc presently availabic to us, the feedwater and/or auxiliary feeds.cLer syrtens in your plant may te susceptible to flov instabilit ies.
Ie reccest that you provide es vith enslyses cod other relevant infor-retion needed to deterrice the potentici for occurrence end the potentici censect.ences of nuch en event in your plent ueinp the guidance provided in the ecciosure.
Since piping layouts and system desiens are substen-ticily dif ferent from plant to plcnt, you should deterriine cnd indicate in your response the aptlicchility to your plant of ecch ot the itens (i) ~'iiTeNatcr 'i.ine Incident T.erert - Indian Ioint Unit 1:o.
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January 14, 1974, cs supplenented by subittal dated Janucry 16, 1974.
Fesult s of test prorrar era shovr in subt it tels dated 4
onrcn 12, 197t., and August 30, 1974.
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If the results of your analyses indicate that changes in the design or operation of structures, systems, or components are necessary to prevent the water hanser event or assure systera integrity, you should provide information on your plans to =ake these changes in your facility.
Any desire r:odifications proposed should include appro-priate consideration of the guidelines and requests for information in the enclosure.
Vithin 10 days af ter receipt of this letter, notify us that you will provide all the information requested within 60 days or explain why you cannot :neet this schedule and provide the schedule that you will meet.
This request for peneric information was approved by CAO under a blanket clearance number E-180225 (r0072); this clearance expires July 31, 1977.
Sincerely, Original signed by:
Robert A. Pucp!a Eobert A. Turple, Chief Operating I:eactors branch 61 Livision of Feactor Licensing
Enclosure:
Infornation Eequired I
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SURNAMED D^"> _____/____________4_________________._________.__________________________________________a___.__________
Form AEC-318 (Rev. 9-53) AECM 0240
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May 13, 1975 Sacramento Manicipal Utility District David S. Kaplan, Secretary and cc:
Cencral Counsel 6201 S Street Post Office Box 15S30 Sacramento, California 95513 Business and >!unicipal Department Sacramento City-County Library 828 I Street Sacramento, California 95S14 r-,
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+iii-could cause the level of the Lescribe all operating occurrences that water / steam interfsce in the steam generator to drop below the feed-1.
water sparger or inlet nozzles, and allou stenn to enter the sparger and/or the feedvater piping.
the routing of the ccin cnd Describe and show by iso:,etric diagrams, auniliary feeducter piping from the steac generators outwards through 2.
isolction valve and restraint.
centainment up to the outer contcinrentthe elevations of the sparger and/or i;cte all valves and provide independent nozzles and all piping runs needed to perfore an inlet analysis of drainage characteristics.
in the Pescribe any " water hcm ar" experiences that have occurred feeds: ster system and the means by which the problec was percenently 3.
corrected.
feedwater and auxiliary feedwater piping 4.
rescribe all analyses of the syste=s for which dyncnic forcing functions vere assured.
Also, pro-prograno that vere carried out to verify vide the results of any test occur at your either uncovering of the feedvater lines could not that "uater haemer" s<ould not occur.
f acility, or if it did occur, that If forcing functions were assu:ned in analyses, provide the technical bases thet vere used to assure that en appropriate a.
choice was rade and that adequate conservatisus vere included in the cnclytical rodel.
progree ess follot:ed, provide the basis for cssurine b.
If a test program adequately tracked and predicted the flow that the instability event that occurred, and further, that the test results contained cdecuate conservatistus and cn acceptable fcetor of safety, e.g., rance of parsmeters covered all con-iieivsble redes of operation.
If neither a. or b. have been perforced, present your basis recuiring either and your plans to investicate this c.
for not potential transient occurrence.
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Discuss the possibility of a sparger or nozzle uncovering and the consecuent pressure wave cf f acts that could occur in the piping followine a design basis loss-of-coolant accident, assuning con-current turbine trip and loss of of f site power.
6.
If plant sys te:3 design changes have been or are planned to be made to preclude the occurrence of flow instabilities, describe these chances or r,odifications, and discuss the reasons that mcde this alternative superior to other alternatives that night have been applied.
Discuss the quclity assurance prograra that was or will be followed to assure thct the planned systere nodifiestions till have been correctly accorplished at the facility.
If changes are indicated to be necessary for your plant, consider and discuss the ef fects of reduced auxiliary feeducter flow cs a possible means of reducing the carnitude of induced pressure vaves, including
=s positive reans (e.g.,
interiocks) to assure suf ficiently low flow rates cnd still meet the mininun requirecents for the system safety function.
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5:* i: E' 314 (Res. 9-53) ACCP/ 0243
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