ML20036C002
| ML20036C002 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 06/02/1993 |
| From: | Stolz J Office of Nuclear Reactor Regulation |
| To: | Opeka J CONNECTICUT YANKEE ATOMIC POWER CO., NORTHEAST NUCLEAR ENERGY CO. |
| Shared Package | |
| ML20036C003 | List: |
| References | |
| IEB-88-002, IEB-88-2, TAC-M67309, NUDOCS 9306080264 | |
| Download: ML20036C002 (4) | |
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WASHINGTON. D.C. 205$5-0001 June 2, 1993 Docket No. 50-213-.
Mr. John F. Opeka Executive Vice President, Nuclear Nuclear Engineering and Operations Connecticut Yankee Atomic Power Company Northeast Nuclear Energy Company Post Office Box 270 Hartford, Connecticut 06141-0270
Dear Mr. Opeka:
SUBJECT:
RESPONSE TO NRC BULLETIN N0. 88-02, " RAPIDLY PROPAGATING CRACKS IN STEAM GENERATOR TUBES" FOR HADDAM NECK PLANT (TAC NO. M67309)
A steam generator (SG) tube ruptured at North Anna Unit 1 in July.1987. The cause of the tube rupture was determined to be high-cycle fatigue due to flow-induced vibration.
It was shown that of the possible flow-induced vibration mechanisms, fluidelastic instability was the most-likely cause.
On February 5, 1988, the NRC issued Bulletin 88-02, " Rapidly Propagating Fatigue Cracks in Steam Generator Tubes," requesting licensees with Westinghouse SGs to assess the potential of such tube failures in its plants.
By letters dated March 24, 1988, May 25, 1989, August 1, 1991, and May 27, 1993, Connecticut Yankee Atomic Power Company (CYAPC0) responded to NRC Bulletin No. 88-02.
Your response dated March 24, 1988, responded with the results of the short-term actions and committed to a long term analysis in response to Item C.2.a in the bulletin.
By letter dated May 25, 1989, you stated this analysis was completed and available for staff review at your corporate office.
In addition, CYAPC0 noted that it will maintain the enhanced leak monitoring 3
program, even though it is not required in order to preclude h North Anna i
Unit 1 1987 type event.
CYAPC0 and its consultants performed a fluidelastic instability analysis in response to Bulletin 88-02, for the Westinghouse Model 27 SGs at Haddam Neck, and determined that no corrective action was required at that plant.
We reviewed this analysis, as provided in JAYCOR Report J5439-89-00R1,
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"Fluidelastic Instability Analysis of the U-Bend Region of a Westinghouse Model.27 Steam Generator" and issued a request for additional information (RAl) concerning this analysis on July 19, 1990.
By letter dated August 1, 1991, CYAPC0 provided JAYCOR Report J1681-90-00RO, " Response to NRC Request For Additional Information - Haddam Neck," in response to our RAI.
In its response, CYAPC0 qualified its earlier analytical model.by means of a similar i
evaluation of fluidelastic instability for the known failed SG _ tube at North Anna Unit 1.
CYAPC0 also responded to other staff concerns regarding establishment of a quantitative measure for.the onset of instability and justification for the selection of damping ratios employed in the fluidelastic instability analyses.
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l Mr. John F. Opeka Based on its review of the fluidelastic instability analysis for Model 27 SGs -
at Haddam Neck, the staff concludes that CYAPC0 has generally adopted a conservative approach, and fluidelastic instability is not likely to occur at these SGs. Therefore, corrective actions such as downcomer flow restriction, or tube plugging are not considered necessary for the Haddam Neck SGs.
The staff has determined that your response meets the requirements set forth in Bulletin No. 88 c'.
NRC's review of your response is considered complete and TAC No. 67309 has been closed. A copy of the Safety Evaluation is enclosed.
If you have any comments or questions regarding the Safety Evaluation contact Alan Wang at (301)504-1445.
Sincerely, Original siged by:
John F. Stolz, Director Project Directorate I-4 Division of Reactor Projects - 1/II Office of Nuclear Reactor Regulation
Enclosure:
Safety Evaluation cc w/ enclosure:
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4 June 2, 1993 Mr. John F. Opeka Based on its r'ev'iew of the fluidelastic instability analysis for Model 27 SGs at Haddam Neck, the staff concludes that CYAPC0 has generally adopted a conservative approach, and fluidelastic instability is not likely to occur at these SGs. Therefore, corrective actions such as downcomer flow restriction, or tube plugging are'not considered necessary for the Haddam Neck SGs.
The staff has determined that your response meets the requirements set forth in Bulletin No. 88-02. NRC's review of your response is considered complete and TAC No. 67309 has been closed. A copy of the Safety Evaluation is enclosed.
If.you have any comments or questions regarding the Safety Evaluation contact Alan Wang at (301)504-1445.
Sincerely, n F. Stolz, Direc P oject Directorate
-4 ivision of Reactor Projects - I/II Office of Nuclear Reactor Regulation
Enclosure:
Safety Evaluation cc w/ enclosure:
See next page i
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_ -. J Mr. John F. Opeka Haddam Neck Plant Northeast Nuclear Energy Company cc:
Gerald Garfield, Esquire R. M. Kacich, Director Day, Berry and Howard Nuclear Licensing Counselors at Law Northeast Utilities Service Company City Place Post Office Box 270 Hartford, Connecticut 06103-3499 Hartford, Connecticut 06141-0270 W. D. Romberg, Vice President S. E. Scace, V' ice President Nuclear Operations Services Hillstone Nuclear Power Station Northeast Utilities Service Company Northeast Nuclear Energy Company Post Office Box 270 Post Office Box 120 Hartford, Connecticut 06141-0270 Waterford, Connecticut 06385 Kevin McCarthy, Director Regional Administrator Radiation Control Unit Region I Department of Environmental Protection U.S. Nuclear Regulatory Commission State Office Building 475 Allendale Road Hartford, Connecticut 06106 King of Prussia', Pennsylvania 19406 Allan Johanson, Assistant Director Board of Selectmen Office of Policy and Management Town Office Building Policy Development and Planning Division Haddam, Connecticut 06438 80 Washington Street Hartford, Connecticut 06106 Resident Inspector Haddam Neck Plant J. P. Stetz, Vice President c/o U.S. Nuclear Regulatory Commission Haddam Neck Plant 361 Injun Hollow Road Connecticut Yankee Atomic Power Company East Hampton, Connecticut 06424-3099 362 Injun Hollow Road East Hampton, Connecticut 06424-3099 Nicholas S. Reynolds Winston & Strawn D. J. Ray 1400 L Street, NW Haddam Neck Unit Director Washington, DC 20005-3502 Connecticut Yankee Atomic Power Company 362 Injun Hollow Road East Hampton, Connecticut 06424-3099 G. H. Bouchard, Director Nuclear Quality Services Northeast Utilities Service Company Post Office Box 270 Hartford, Connecticut 06141-0270
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