ML20114E941
| ML20114E941 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 08/27/1968 |
| From: | Porse L, Stello V US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Boyd R US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML093631134 | List:
|
| References | |
| NUDOCS 9210120316 | |
| Download: ML20114E941 (4) | |
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August 27, 1968 Roger S. Boyd, Assistant Director for Feector Projects, DRL fg THRU: Robert L. Tedesco, Chief, RPB-2, DRL 6
MINUTES OF THE AUGUST 8,1968 OYSTER CREEK PRESSURE VESSEL MEETING DOCKET NO. 50 219 The purpose of the meeting was to discuss the bases and technique of the proposed repair program for the Oyster Creek Unit No. I reactor vessel. Interested parties, including representatis is of Jersey Central. Niagara Mohawk, General Electric, ACES, RDT. DRL, DRS and Consultants were in attendance. A complete list cf attendees is attached.
1 Much of the material discussed ut the meeting ses m sed on information provided in previous amendments to the Oyste - C
< application. GE also presented an outlint 7f "
informa+ ' au tua t is to be provided in a subsequent amendment. inis Amendment, No. LO, vill contain nnalyses to support the proposed repairs for the shroud support ring and nozzle safe ends. Experience with sensitized staintens steel in the Nine Mile Point and Tarapur reactor vessels was also discussed.
The major items discussed at the meeting are outlir.c i below.
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- 1. GE his concluded that EDTA and TSP (cleaning agents) are not the decisive corrodenta. The cause of intergrannular attack is believed to be related to more than one contaminant and/or accelerators. However, it is felt that chlorides are now the most likely conteminant, and that some synergistic effect other than the cleaning solutions is responsible for the failure.
The etaff suggested that the synergtst may be simply hieh reeldual fabricating stress.
2, It was disclosed that. cladding overlay will be applied to the Oyster Creek and Tarapur vessels but not to the Nine Mile Point vessel, When asked why NMP stub tubes and other vessel members did not need to be clad, GE replied that exemPations to date en the NMD sensitized stainless steel canponenou did not reveal any intergranular attack. GE sta ted that because the sensitiztd stainless steel did not show signs e t ta ck,
the clad overlay or other repaire were not required. We did not ecknowledge any response to this conclusion.
GE also stated that for those components which were found to be subjected to intergranular attack the repairs (overlay and auxiliary suppurts) were initiated because it was not clear
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vhat effect the intergranular attack v uld have on the material during opera tion.
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9210120316 920520 PDR ORG NRCHIST PDR
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i-Roger S. Boyd
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Au gus t' 27, 1968 3
The staff inquired about a potenti~1 influence of chloride accumulation in crud during normal operation which can attract 3
and hold the' contaminant byLa factor of 10 or more above the i
coolant concentration. GE stated that the crud attracted.
chlorides do not act to accelerate attack on the stainless steel st this area.-
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GE mentioned that further review of the shroud-support ring for OC had disclosed that the ring dimensions had been " built
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up" by veld deposition end.that;most of the DP' indications were i-
'in -the velded area which, of course, does not resemble the -
material' properties of the ser.sitized ring forging. Many of the DP indicatione-found in the shroud' support ring could be related to velding and slag inclusions.. However, intergranular i
attack'vas found in the shroud support ring. Of special interest was the repair planning for the shroud support ring for the three plants: For OC a redundant structure vill be j
supplied, -for Tarapur the ring forgings will be clad-similar to the tub tubes, and for NMP no cladding vill be.provided l
for stub tubes and r.o cladding or redundant support structure i
'ta planned for the ring forging.
5 It was not clear that-the redundant structure proposed for the shroud support ring was designed for accident conditions.
GE~ stated that the purpose: of the auxiliary structure was to 4-permit. continued operation even if the shroud support ring failed; consequently,'it is obvious that any auxiliary support j
structure must be designed for accident loads. GELintends to
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clarify this point in Amendment No. 40.
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Repair of the nozzle safe ends vas ' atarted.' It was noted that both supply lines to the emergency' condensers were cut in order to repair the nozzle safe ends. We noted that we are atill reviewing the emergency condenser isolation valve arrangement end that isolation valves may have to be installed in these lines.
.All nozzle safe ends made of sensitized stain-lese steel except those in the-top head 411 be removed or provided j
vith a clad everley.
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A discussion evolved about t7e significance and/or potential importance of fabrication strain and residual stress. GE's stress summation is based on tt.s operational mode and not on i
fabricating technique.
It was shova that the residual stress after fabrication vill be changed
..u differ from the reeidual local stress after the first opert.tional cycle. GE stated that l
they are not concerned with stress during fabrication and that J
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I Boger S. Boyd August 27, 1968 f
the fabrication and/or operational stress is not important when. the " diseased" stub tube' material has been_ clad.
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8.. For the Tarapur plant, problems have been encounteced with the steam generators. At this time it has been estabiished that the-stainless steel tubes have ersched in the vicinity i
of the tube sheets. When.the tubes-have been lemoved the.
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full extent of the damage will be ascertained. It is planned 1
to completely retube the steam generators. Preliminary-investigations have disclosed a very coarse grain size of_.
2-3 for the tube material, a condition that makes the material more prone to' ettack by corrodant.
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. Stel o,'Jr.
Reactor Project Branch 2 l>
Division of Beactor Licensing L. Forse Division of React :r Licensing
Attachment:
List of Attendees
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i Distribution:
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DRL Reading j
RPB-2 Sending P. A. Morris i
F. Schroeder S. Levine Branch Chie24 RP Brar.ch Chiefs, RT V. Stello l-L.-Porse CO (2) 4 Attendees 1
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LIST OF ATTENDEES I
MIETING WITH AEC/GE/JC/NMP AUGUST 7, 1968 AEC - DRL GE-APE _D P. A. Morris W. L. Walker F. Schroeder I. R. Kobsa R. Boyd S. W. Ta Ea r t i
S. Levine S. Naymerk R. Tedesco GE J{ B. Graham e oung V. Stello R. T. Pennington L. Forse H. I Powell M. A. McCoy J. F. Ca ge GE - R&DC, Schy.
D. C. Fis h r M. Wetterhahn W. Love
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AEC - DRS D. K. Willett R. L. Ferguson J. Bernard B. Blumenthal 1
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- E AEC - RDT D. E. Erb W. H. Lees R. W.
Berber General Public' Utilities J. R. Hunter L. H. Roddis, Jr.
AEC - CO ACRS G. W. Reinmuth J. G. Keppler H. Etherington R. H. Engelken M. C. Gaske M
- 3. Hildreth W. B. Stratton l
L. Kornblith J. W. Freeman S. Bush AEC - DR l
M. M. Mann Jerney Central Power & Light ORNL G. H. Ritter E. C. Miller G. F. Trowbridge MPR Associates D. R. Rees Wm. R. Schmidt Niagare Mohawk Power Co.
Picka r d, Love & Associates D. L. Pracht F. Schvoerer P. A. Burt 1
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