ML20011E091
| ML20011E091 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 01/30/1990 |
| From: | Bevan R Office of Nuclear Reactor Regulation |
| To: | Cockfield D PORTLAND GENERAL ELECTRIC CO. |
| References | |
| IEB-88-002, IEB-88-2, TAC-67328, NUDOCS 9002070301 | |
| Download: ML20011E091 (4) | |
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- Mr; David W. Cockfield EJordan.
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Dear Mr. Cockfield:
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SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION, NRC BULLETIN 88-02 RESPONSE (TACNO.-67328),
The NRC-staff has reviewed the PGE submittal of December'23, 1988, WCAP 12024 for Trojan. 'This PGE submittal was in response to NRC'Bulletin 88-02,
" Rapidly Propagating. Fatigue; Crocks in Steam Generation Tubes".
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In:our review of WCAP 12024, we find that additional information is needed to complete our review and closeout the Bulletin 88-02 issue for. Trojan. Please provide the information' requested in the. enclosure to this letter within
- 45 days of receipt of this letter.
l Sincerely, original signed by Roby Bevan Roby.Bevan,PfojectManager e
Project Directorate'V.
t Division of Reactor Projects --III, l:
IV, V and Special Projects p
Office of Nuclear Reactor Regulation l
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Enclosure:
I As stated Lcc w/ enclosure:
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' January 30 J1990
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Docket No. 50-344
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.p Mr. David W. Cockfield-i
.Vice President, Nuclear i
. Portland General-Electric Company 121 S.W. Salmon Street
' Portland,. Oregon-97204-
Dear Mr. Cockfield:
SUBJECT:
-REQUEST FOR ADDITIONAL INFORMATION.NRC-BULLETIN 88-02 RESPONSE l
The NRC staff has reviewed the PGE submittal of December 23, 1988 WCAP 12024 for Trojan. This PGE submittal was:in response to NRC Bulletin 88-02, g
" Rapidly Propagating Fatigue Crocks-in Steam Generation Tubes".
.In our review'of WCAP 12024, we find that additional information is needed to complete our-review and closeout the Bulletin 88-02 issue for Trojan.
Please' 4
' provide the.information requested in the enclosure to this letter within 45 days; of receipt of this letter.
Sincerely, c% f Roby Bevan, Project Manager Project Directorate V Division of Reactor Projects - III, IV, V and Special Projects Office of Nuclear Reactor Regulation Enclosure-As' stated.
cc w/ enclosure:
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W.~ David W. Cockfield Trojan Nuclear Plant j
Portland General Electric Company s
CC:
Senior-Resident Inspector U.S. Nuclear Reilulatory Comission Trojan Nuclet" ?lant Post Office Box 0 Rainier, Oregon 97048 Mr. Mchael J. Sykes, Chairman Board of County Comissioners Columbia County St. Helens, Oregon 97501 Mr. David Stewart-Smith c
Oregon Department of Energy Salem ~, Oregon 97310 Regional Administrator, Region V ll.S. Nuclear Regulatory Comission 1450 Maria Lane, Suite 210
' Walnut Creek, California 94596 j'
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j REQUEST FOR ADDITIONAL INFORMATION PORTLAND GENERAL ELECTRIC COMPANY i
TROJAN UNIT 1 i
IMPLEMENTATION OF BULLETIN 88-02 t
i By letter dated December 23, 1988, the licensee submitted WCAp-12024 for Trojan Unit 1.
This report details analyses for steam generator tube vibration fatigue which were performed in response to NRC Bulletin 88-02.
l The staff has reviewed this report and has the following coments concerning estimates of flow peaking factors for certain tubes. The staff requests that infornation be provided as necessary to resolve these coments and to demon-strate that the subject tubes are acceptable for continued service. Alterne-i tively, the tubes should be plugged at the next scheduled steam generator inspection.
1.
Tube R9C35. SG-A In WCAP-12024 Table 8-7, this tube has been assigned a flow peaking factor of 1.37. This flow peaking factor appears to correspond to ioealized AVB configu-ration 4f as pictured in Figure 8-7.
The staff notes, however, that idealized AYB configuration 4f differs from the actual AVB configuration associated with tube R9C36 in one possibly significant manner. Namely, the centerline of the AVB between columns 36 and 37 penetrates the gaa between R7C36 and R7C37, thus restricting flow between these tubes.
Note tiat the centerline of the subject AVB projects to the 7.2 position, and the bottom surface of the AVB is close to the 7.0 position.
l In view of the significant flow restriction between R7C36 and R7C37, the staff believes that idealized AVB configuration 4f is potentially non-conservative for tube RSC35 and that the actual flow peaking factor for this tube may substan-tially exceed 1.37. A peaking factor significantly in excess of 1.37 coulo cause the fatigue usage f actor for the subject tube to exceed 1.0.
2.
Tube RSC25. SG A WCAP-12024. Table 8-7, has assigned a flow peaking factor of 1.16 to this tube.
This appears to correspond to idealized AVB configuration 4a. This appears to be a reasoM ble assumption provided that one or more of the AYBs between columns 22 and 23, 23 and 24, 26 and 27, and 27 and 28 do not penetrate far enouph into the bundle to restrict flow between row 7 tubes.
[TheAVBprojectionvaue where there may begin to be some flow restriction around row 7 tubes is about 7.4.) Unfortunately, Figure 6-2 of WCAP-12024 does not show how far down these AVBs project. The staff notes that if some of these AV8s do in fact project to row 7, the flow peaking factor could approach or even exceed 1.58, potentially leading to a significant fatigue usage factor.
3.
Tube R8C64. SG B Similar comment as item 2 above 4.
Tube R8C60. SG D Similar comment as item 2 above a