ML20197G436
| ML20197G436 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 05/09/1986 |
| From: | Conway R GEORGIA POWER CO. |
| To: | Youngblood B Office of Nuclear Reactor Regulation |
| References | |
| GN-902, NUDOCS 8605160216 | |
| Download: ML20197G436 (4) | |
Text
Georgia Power Company 333 Piedmont Avenue A!!ar: a. Georgia 30308 Telepnone 404 526-6724 Mading Address-Post Once Box 4545 Atanta. Georg>a 30302 R.E.ConwaY the southem electnc system Senor Vce Pres. dent May 9, 1986 Director of Nuclear Reactor Regulation File:
X6BB06 Attention: Mr. B. J. Youngblood Log:
GN-902 PWR Project Directorate #4 Division of PWR Licensing A United States Nuclear Regulatory Commission Washington, D. C.
20555 NRC DOCKET NUMBERS 50-424 and 50-425 CONSTRUCTION PERMIT NUMBERS CPPR-108 and CPPR-109 V0GTLE ELECTRIC GENERATING PLANT - UNITS 1 and 2 ARBITRARY INTERMEDIATE PIPE BREAKS Referer.ces: '(1) Letter from D. O. Foster (GPC) to H. R. Denton (NRC) dated April 26, 1984 (Log: GN-352)
(2) Letter from D. O. Foster (GPC) to H. R. Denton (NRC) dated November 11,1985(Log: GN-281)
Dear Sir:
In reference (1), Georgia Power Company (GPC) provided additional technical information to justify the alimination of the need to postulate arbitrary intermediate pipe breaks for Vogtle Electrical Generating Plant (VEGP).
As part of the technical information provided, GPC stated that a review was performed of all arbitrary intermediate break locations (AIBL) to be eliminated and determined that in no case were welded attachments located closer than five piping diameters (SD) from the postulated break locations (Attachment "e" of the reference letter 1).
Since that time, GPC has performed various reviews to verify if welded attachments were located within SD of an eliminated AIBL.
These reviews were based on the following:
1.
The design stress isometrics were used for the evaluation.
2.
The high stress points from the latest stress analyses were used rather than the early AIBL's defined in reference 2.
3.
As-built information or the construction tolerances that could result in changes in the -1 stance between the high stress point and welded attachment wert not considered.
4.
The definition used for the SD length dimension was five times the nominal pipe diameter, and the location of the welded attachment was considered to be the center line of the support.
N A
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File: X6BB06, Log: GN-902 May 9, 1986 Page two The summary of these reviews has identified _ six high stress points i
that were within. SD distance from the center line of _the supports with welded attachments.
Attachment (1) illustrates these six 1ccations.
Two of these locations (1054C and 1055C) were overlooked during the initial review which was documented in reference (1).
Please refer to illustrations 5 and 6 for these locations.
The other four high stress points moved to within 5D of a welded attachment due to the resolution of _ field changes on piping systems during l
installation.
Please refer to illustrations 1 through 4 for these locations.
Two other cases have been reviewed and are not included in Attachment (1).
This review has identified AIBL 1064C as being SD of a welded attachmcat.
The high stress point for this case is at i
the middle of the elbow and is outside the 5D guideline and, therefore, is not included in Attachment (1).
However, the AIBL is selected i
at the edge of the elbow which is marginally. inside SD guideline.
The other AIBL, P-1119-C, that was within SD of' a welded attachment and was overlooked during the April 1984 review - has been evaluated and established that the high stress point is now located outside the SD guideline.
The reason AIBL 1054C and 1055C were overlooked during the early review cannot be established.
However, in reviewing the installation details it should be noted that break location 1054C is approximately-seven feet away from welded attachment 147 and approximately twelve feet away from attachment 148.
It should also be noted that it is separated from welded attachment 147 by a tee and from welded attachment 148 'by a reducer and a tee.
The AIBL 1055C was postulated to occur at any of the three ends of the tee as shown in illustration (6).
The high stress point is located at the reducer (data point 68).
The tee connections were chosen as the AIBL over the reducer because it was judged that this would maximize the dynamic effects and the effects of the break on equipment located in the vicinity.
Attachment (1) also shows the listing of stress evaluation results.
4 The local stresses at the welded attachment and at the arbitrary break locations (high stress points) are shown in the table.
It should be noted that in no case does the stress exceed the 0.8 (1.2 Sh + Sa) limit used as criteria for postulation of breaks.
e 4
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. o File: X6BB06, Log: GN-902 May 9, 1986 Page three Georgia Power Company requests a meeting with your staff in the near future to discuss the application of the SD criteria, in detail, for current and future VEGP piping system designs.
Prior to this meeting, GPC will conduct another review based on available up-to-date as-built information and on the SD distance measured from the welded attachment to the high stress point.
The results of this review will also be presented during this meeting.
Until after this meeting no action is being taken on these identified issuas.
Should you have any questions, please inquire.
R. E. Conway N Attachment xc:
J. Nelson Grace R. A. Thomas J. A. Bailey J. E. Joiner, Esq.
B. W. Churchill, Esq.
M. A. Miller, 2 copies enclosure B. Jones, w/o enclosure G. Bockhold, Jr.
D. C. Teper, w/o enclosure W. C. Ramsey L. T. Gucwa Vogtle Project Files 1
n
ATTACHMENT 1
SUMMARY
OF WELDED ATTACHMENTS WITHIN 5 PIPE DIAMETERS
?
OF ARBITRARY BREAK LOCATIONS (1986 REVIEW)
STRESS EQ. 9 + 10 + LOCAL STRESSI2I I
- ARBlT, AT SUPPOR T WITHIN g"
E OUATION ITEM ISOME TRIC CALC-BREAK
- ARBIT, 5 PIPE DlA. Or (NC 3652)III MITHOD M T OD 9 + 10
.8 (1.2Sh + San NOTES X4CP-
^SE 0, P, BH AK ARBIT BRE AK D. P.
- 1) GENERAL PIPE STRESS AT WELCED ATTACH MENT LOCATION 1
IK3-1208 066 01 7001A 26A 8,363 V1 1208 066 H006 26A 8,363 32,752 18,963 30,941
- 2) LOCAL STRESS AT WELDED ATTACH-MENT LOCATION.
2 IK31314 084 03 7063A 800 21,974 V1 1314 084 H013 160 4.187 32,400 14,787 11,921 INCL D D IN TOTALS WE RE CON.
SE R VATIVE LY 3
1K4-1208 00542 7092 88 23.301 V1 1208 005 H006 90 8,806 32,126 19,406 28,498(3)
CALCUL ATE D IN MANY OF THE CASES
- 3) E NVELOPED BY 4
1K41208 005 02 7092 156 24,297 VI-1208-255 H001 155 8,997 32,126 19.597 28,498 VI.1208-255-H001 4)
D. P. ME ANS DAT A 5
1K5-130100141 7073/74 68 33,541 V1-1301-008 H052 148 10,487 37,800 22,577 37,193 6
1KS-1331-001-01 7073/74 75 24.646 V 1-1301-008-H055 147 14.326 37,800 25.076 35.441 l
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