ML20049H208
| ML20049H208 | |
| Person / Time | |
|---|---|
| Site: | 05000000, 05000465 |
| Issue date: | 11/13/1981 |
| From: | Lafleur J NRC OFFICE OF INTERNATIONAL PROGRAMS (OIP) |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20049H209 | List: |
| References | |
| FOIA-82-167 NUDOCS 8112070012 | |
| Download: ML20049H208 (1) | |
Text
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]l.dr) l.3 e (4ff MEMORANDUM FOR: Harold R. Denton, Director Office of Nuclear Reactor Regulation FROM:
Joseph D. Lafleur Jr., Deputy Director Office of International Programs
SUBJECT:
TUBE FAILURE OF PREHEATER-TYPE STEAM GENERATOR Lars Larsson, Head of Inspection of the Swedish Nuclear Inspectorate (SKI), called Hovember 12 to give me an updating on the problems being experienced in Sweden with the Ringhals 3 reactor and to ask again for any information we can give him about our experience.
In sumary, he reports that there is significant tube failure in all,
three of the Ringhals 3 steam generators due to wearing down of tube walls from vibrational rubbing against baffle plates in the preheater sections of these (West-inghouse)steamgenerators. The SKI investigations indicate that some of the tubes have been worn down by as much as 90 percent of their wall thickness.
The two enclosures sumarize infonnation available in earlier comunications from SKI. SKI is interested in wiiether any US PWR's have this same kind of steam generator.
Apparently these steam generators contain a "preheater" section at the bottom of the secondary side, wherein feedwater flows around baffle plates and becomes preheated i
prior to entering the boiler section.
It is the vibrational rubbing of these baffle plates in the steam generator tubes which is apparently causing the wearing of the tubes. SKI has not been able to identify any US PWR's containing these preheater-l type steam generators, which in the Ringhals 3 case are identified as model "D-3."
Tests so far have found about 100 tubes in each steam generator with ultrasonic r
" indications" of wear. SKI has noted that the McGuire reactor is of about the same vintage as Ringhals 3 and, therefore, might have the same steam generator design.
I hope tne above information is useful to you.
I would appreciate it if you would let me know on an urgent basis (1) whether we have any such experience to offer to the.
Swedes, (2) which US PWR's, if any, have preheater-type steam generators. (3) does McGuire 1 have a preheater-type steam generatori (4) if so, what action is NRC taking)
(5) has Westinghouse notified NRC of problems in Ringhals or other steam generators of this type?
Joseph D. Lafleur, Jr.
Deputy Director Office of International Programs
Enclosures:
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