ML19262A381
| ML19262A381 | |
| Person / Time | |
|---|---|
| Site: | Indian Point, Crane  |
| Issue date: | 05/15/1975 |
| From: | Lear G Office of Nuclear Reactor Regulation |
| To: | Arnold R METROPOLITAN EDISON CO. |
| References | |
| NUDOCS 7910260700 | |
| Download: ML19262A381 (5) | |
Text
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DISTRIBUTION:
NRC PDR Local PDR N Y 1 5 i975 Docket rocket bo.
50-259 ORB 43 Rdg KRGoller TJCarter GLear DJaffe JWetmore SATeets Metropolitan Edison Co pany TBAbernathy ATTN:
Mr. R. C. Arnold SVarga Vice President - Generatton OELD P. O.
Box 542 OI6E (3)
Reading, Pennsylvania 19603 VBenaroya Gray file Gentlezen:
The Nuclear Regulatory Coensission Ataf f's coatinuing review of reactor power plant safety indicates that the potential for occurrence and the pormtial consequences of secondary system fluid flow instability in PWRs (characterized as " water harmer') need to be adequately analyzed by licensees and the results evaluated by the st af 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 spareer or the feedwater 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 propacated through the piping that can result in failure of the piping and/or its supports.
Structures, systems, and components important to safety should be designed and constructed so that destructive type fluid flow instability will not occur during normal, upset, or accident conditions.
Based on information presently available to us, the feedwater and/or auxiliary feedwater systems in your plant may be susceptible to flow instabilities.
We request that you provide us with analyses and other relevant infor-nation needed to deter:nine the potential for occurrence and the potential consequences of such an event in your plant using the guidance provided in the enclosure.
Since piping layouts and system designs are substan-t ially 'd i f f e rent from plant to plant, you should deter:nine and indicate in your response the applicability to your plant of each of the it ems 1485 257 i'l F "Feedwater Line Incident Report - Indian Point Unit No.
2", dated January 14, 1974, as supplernented by subciittal dated January 16, 1974.
Result s of test program are shown in sube'it tals dated March 12,1974, and August 30, 1974.
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- Forum AEc.318 (Rev. 9 53) AIcM 0240 W v. s. eovsRNMENT PmMTINe OFFICE 31974 326 564 7910260 N O 8
9 Metropolitan Edison Company MAY 1 5 1375 in the enclosure.
If the results of your analyses indicate that changes in the design or operation of structures, systens, or cceponents are necessary to prevent the water hacuer event or assure systent integrity, you should provide information on your plans to make these changes in your facility. Any design modifications proposed should include appro-priate consideration of the guidelines and requests for in format ion in the enclosure. Within 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 meet this schedule and provide the schedule that you will meet.
This request for generic information w:s approved by GAO under a blanket clearance number B-180225 (R0072); this clearance expires July 31, 1977.
Sincerely, George Lear, Chief Operating Reactors Branch #1 Division of Reactor Licensing
Enclosure:
Information Required cc w/ enclosure:
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- Metropolitan Edison Company cc:
G. F. Trowbridge, Esquire Shaw, Pittman, Potts, Trowbridge 6 Madden Barr Building 910 17th Street, N. N.
Washington, D. C.
20006 GPU Service Corporation Richard W. Heward, Project Manager Thomas M. Crimmins, Jr., Safety and Licensing ':anager 260 Cherry Hill load Parsippany, New Jersey 07054 Pennsylvania Electric Company Vice President, Technical 1001 Broad Street Johnstown, Pennsylvania 15907 Mr. Weldon B. Archart, Chairman Board of Supervisors of Londonberry Township 2148 Foxiana Road Middletown, Pennsylvania 17057 Miss Mary V. Southard, Chairman Citizens for a Safe Environment P. O. Box 405 Harrisburg, Pennsylvania 17108 Government Publications Section State Library of Pennsylvania Box 1601 (Education Building)
Harrisburg, Pennsylvania 17126 1_4 88 2j59.
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INFORMATION REOUIRED 1.
Describe all operating occurrences that could cause the level of the water / steam interface in the steam generator to drop below the feed-water sparger or inlet nozzles, and allow steam to enter the sparger an Uor the feedwater piping.
2.
Describe and show by iscmetric diagrams, the outing of the main and auxiliary feedwater piping from the steam generators outwards through containment up to the outer containment isciation valve and restraint.
Note all valves and provide the elevations of the sparger and/or inlet no::les and all piping runs needed to perform an independent analysis of drainage characteristics.
3.
Describe any " water ha=aer" experiences that have occurred in the feedwater system and the means by which the problem was permanently corrected.
4.
Describe all analyses of the feedwater and auxiliary feedwater piping systems for which dynamic forcing functions were assumed. 'Also, provide 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.
If forcing functions were assumed in analyses, provide the technical a.
bases that were used to assure that an appropriate choice was made and'that adequate conservatisms were, included in the analytical model.
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If a test program was followed, provide the basis for assuring that the program adequately tracked and predicted the flow instability event that occurred, utd further, that the test results contained adequate conservatisms and an acceptable factor of safety, e.g., range of parameters covered all conceivable modes of operation.
c.
If neither a. or b. have been perfor: 3d, present your basis for not requiring either and your plans to investigate this potential transient occurrence.
5.
Discuss the possibility of a sparger or no::le uncovering and the consequent pressure wave effects that could occur in the piping following a design basis loss-of-coolant accident., assuming concurrent turbine trip and loss of off-site power.
6.
If p.lant system design changes have been or are planned to be made to preclude the occurrence of flow instabilities, describe these changes or modifications, and discuss the reasons that made this alternative superior to other alternatives that might have been applied.
Discuss the quality assurance program that was or will be followed to assure that the planned system modifications will have been correctly accomplished at the facility.
If changes are indicated to be necessary for your plant, consider and discuss the effects of reduced auxiliary feedwater flow as a'possible means of reducing the magnitude of induced pressure waves, including positive means (e.g., interlocks) to assure sufficiently low flow rates and still meet the minimu= requirements for the system
. 4afety function.
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