ML19323B339
| ML19323B339 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 04/11/1980 |
| From: | Caruso R Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| TASK-03-04.B, TASK-3-4.B, TASK-RR NUDOCS 8005120257 | |
| Download: ML19323B339 (2) | |
Text
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- April 11, 1980 Docket No. 50-213 LICL:.:aEE: Connecticut Yankee Atomic Power Company (CYAPC0)
FACILITY: Haddam Neck Plant
SUBJECT:
SUMMARY
OF MARCH 28, 1980 MEETING REGARDING P0TENTIAL CRACKS IN HADDAM NECK LOW PRESSURE TURBINE DISCS AND BASES FOR CONTINUED OPERATION On March 28, 1980, a meeting was held to discuss various bases for continued operation of the Haddam Neck Plant in light of recent discoveries of cracks in several Westinghouse turbines and the results of an analysis of the Haddam Neck turbine which indicate that postulated crack sizes in low pressure discs could exceed limiting values under certain overspeed conditions. A telephone meeting was held between the NRC staff and CYAPC0 on March 21, 1980, but the issue could not be resolved at that time so the licensee proposed a meeting in Bethesda for March 28, 1980. A list of attendees is attached.
The licensee presented three arguments in favor of continued operation.
1.
Low moisture content of steam in the area of interest.
Measurements of co.1ditions in the area of the LP turbine first stage disc indicated that hub temperatures are. greater than saturation temperature for the steam flowing through the stage. The licensee measured actual steam quality and found.only 0.5% moisture in the interstage region. He therefore concluded that favorable conditions did not exist for the promotion of stress corrosion cracking and that he should not have cause to fear excessive cracking.
The staff position is that we do not know the causes of the cracking phenomena at this time, but the licensee should continue attempts to correlate known instances of cracking and known cases of turbines with no cracks with different environmental conditions in the turbine.
If he can show conclusively that turbines similar to his, with similar operating environments, have experienced.
no cracking, ther this would be a very strong argument for continued operation.
l The licensee intends to pursue this case with Westinghouse.
2.
Low bore stresses.
The licensee recalculated bore stresses and found slightly lower values, but these would not have a significant effect on the calculatad crack sizes.
. 3.
Conservative calculations of critical crack size.
The licensee proposed to do more detailed and sophisticated analyses of critical crack size to show that the postulated crack size is less than-critical crack size. The NRC staff position is that further analysis of this type is not useful or conclusive, because preliminary indications do not indicate that a significant reduction in critical crack size will be developed.
The NRC staff indicated to the licensee that he should also consider proposals to limit the maximum overspeed which would occur if a turbine generator loss-of-load accident were to occur. The 128% overspeed condition produced the maximum stress in the turbine disc, and preliminary calculations indicate that if the overspeed transient could be limited to 120%, then the plant might be able to continue operation. The licensee agreed to study this option.
The licensee was reminded that our current position would allow him to operate for only one more week before requiring a turbine disc inspection and that he should submit the additional information and proposals quickly, l
Ral Caruso Operating Reactors Branch #2 Division of Operating Reactors
Attachment:
List of Attendees cc w/ attachment:
See next page j
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- tc w/ attachment:
Day, Berry & Howard U. S. Environmental Protection Counselors at Law Agency One Constitution Plaza Region I Office Hartford, Connecti.ut 06103 ATTN:
EIS COORDINATOR JFK Federal Building Superintencent Boston, Massachusetts 02203 Haddam Neck Plant RFD el Post Office Box 127E East Hampton, Connecticut 06424 Mr. James R. Himmelwright Northeast Utilities Service Company P. O. Box 270 Hartford, Connecticut 06101 Russell Library 119 Broad Street Middletown, Connecticut 06457 Board of Selectmen Town Hall Haddam, Connecticut 06103 Connecticut Energy Agency ATTN:
Assistant Director Research and Policy Development Department of Planning and Energy Policy 20 Grand Street Hartford, Connecticut 06106 Director, Technical Assessment Division Office of Radiation Programs (AW-459) i U. S. Environmental Protection Agency Crystal Mall e2 Arlington, Virginia 20460
i ATTACHMENT 4
LIST OF ATTENDEES NRC CYAPC0 M. Chiramal T. Murray H. Balukjian P. Austin R. Giardina G. Drechsler
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W. Hazelton' J. Levine C. Sellers R. Klecker Westinghouse R. Caruso W. Ross J. Schmerling D. Crutchfield K. Conrad i
T. Wambach l
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.. g o DISTRIBUTION FOR MEETING SUMMARIES Docket 50-213 9 00 PDR 50-213 I ocal PDR 50-213 H. Smith
~ TERA SEPB Reading NRR Reading H. Denton E. Case L. Shao i
D. Eisenhut R. Vollmer W. Russell i
B. Grimes T. Carter T. Ippolito R. Reid G. Knighton V. Noonan A. Schwencer D. Ziemann D. Crutchfield G. Lainas J. Scinto, OELD
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ACRS (16) i Licensee - Mr. W. G. Cour.sil NRC Participants D. Knuth'fstall, KMC KMC R. Schaf R. Silver T. Wambach M. Chiramal H. Balukjian R. Giardina W. Hazelton C. Sellers i
R. Klecker R. Caruso W. Ross T..Murray, CYAPC0 P. Austin, CYAPC0 G. Drechsler, CYAPC0 J. Levine, CYAPC0 J. Schmerling, ~W K. Conrad, W M*