ML20207K255
| ML20207K255 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 12/31/1986 |
| From: | Rice P GEORGIA POWER CO. |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-86 GN-1260, NUDOCS 8701090369 | |
| Download: ML20207K255 (4) | |
Text
Ceorg a Power Company fAl Post 0%ce Bm 282 Waynesboro. Georg a 30633 bephore 404 554 9961, b T/C
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404 724 8114 Ee M60 4
N P. D. Rice
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Vr@e Project December 31, 1986 United States Nuclear Regulatory Commission Region II, Suite 2900 File:
X7BG03-M135 101 Marietta Street, Northwest Log: GN-1260 Atlanta, Georgia 30323
Reference:
Vogtle Electric Generating Plant-Units 1 & 2; 50-424, 50-425; ASME Buried Piping Attention: Mr. J. Nelson Grace On December 5, 1986, Mr. R. E. Folker, Vogtle Project Quality Assurance Engineer, informed Mr.
M.
V.
Sinkule of the USNRC Region II of a potentially reportable condition associated with some embedded ASME piping at the soil to building interface.
This conditic^ was initially identified for the diesel generator fuel oil transfer lines during the preparation of documentation for ANSI B31.1 buried piping analysis.
Georgia Power Company has completed its evaluation and determined that a reportable condition as defined by the reporting criteria of Part 10CFR50.55(e) and Part 10CFR21 does exist.
Based upon NRC guidance in NUREG-0302, Revision 1, and other NRC correspondence, Georgia Power Company is reporting this condition pursuant to the reporting requirements of Part 10CFR50.55(e). A summary of our evaluation is attached.
This response contains no proprietary information and may be placed in the USNRC Public Document Room.
Yours truly,
/
P. D. Rice CWH/PDR/jl xc:
U. S. Nuclear Regulatory Comission Document Control Desk Washington, D. C. 20555 H. G. Baker D. R. Altman L. T. Gucwa J. P. O'Reilly J. A. Bailey C. W. Hayes G. F. Head G.
Bockhold G. A. McCarley R. E. Conway J. F. D'Amico R. W. McManus R. H. Pinson W. D. Drinkard Sr. Resident (NCR)
B. M. Guthrie C. C. Garrett (OPC)
J. E. Joiner (TSLA)
R. A. Thomas D.
Feig(GANE)
NORMS h10gCK0500o424-69 861232 4
S PDR 3Q}
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EVALUATION OF A POTENTIALLY REPORTABLE CONDITION ASE BURIED PIPING
- Initial Report:
On December 5,
1986, Mr.
R.
E.
Folker, Vogtle Project Quality, Assurance Engineer, notified Mr.
M.
V.
Sinkule of the USNRC Region II of a potentially reportable condition associated with some embedded ASME piping at the soil to building interface.
This condition was initially identified for the diesel generator fuel oil transfer lines during the preparation of documentation for ANSI B31.1 buried piping analysis.
Background Information:
The diesel generator (DG) fuel oil system consists of two independent fuel. storage and transfer trains, i.e.,
one train per DG and two trains per unit.
Each train is provided with a fuel oil storage tank, two fuel oil transfer pumps, a day tank and associated fuel supply and return piping.
During the preparation of the documentation for ANSI B31.1 buried piping analysis, it was identified that portions of ASME section III, Class 3 fuel oil transfer lines were embedded in the basemat of the diesel generator building (DGB) without pipe sleeves at the interface between the DGB and the soil.
The project design criteria requires that the subject piping be designed for the imposed loads on the piping system including differential building settlement and differential seismic motions between building and soil.
The piping isometric drawings for lines 1/2-2403-051, 053, 068, 066, 043 and 044 at DGB basemat to soil interface ' depicted these lines as " buried" in soil but these lines are actually embedded in the basemat concrete.
The stress analyst assumed that the piping was sleeved at this location.
As a result of the rigid connections, these lines could be subjected to stresses above ASME Code allowables due to the relative seismic anchor motion and building settlement loadings.
The following ASME section III diesel fuel oil lines are affected by this condition:
1.
Line numbers 1/2-2403-051 and 053:
These lines transfer fuel oil from the diesel - fuel oil storage tank to the day tank for trains A and B respectively.
2.
Line numbers 1/2-2403-068 and 066:
These lines provide everflow paths between the diesel fuel oil day tank and the diesel fuel oil storage tank for trains A and B respectively.
j 3.
Line numbers 1/2-2403-043 and 044:
These lines provide alternate paths for supplying diesel fuel oil to the day tank from the truck fill for trains A and B respectively.
L
Evaluation of a Potentially Reportable Condition ASME Buried Piping Page 2 Additional safety related buried lines have been identified at other building to soil interfaces.
Engineering verification of these additional buried lines concluded that the lines pass through pipe sleeves / penetrations and that pipe stresses are within ASME Code allowables.
It was also found-that portions of ASME buried lines were inadvertently omitted from the completion of the stress reconciliation notice (SRN) prior to the sign-off of the ASME N-5 data report.
Engineering Evaluation:
To address the broadness issue, Engineering conducted reviews of buried piping (both ASME and B31.1) and analytical scoping packages and, based on this review, determined that no other similar situations existed in safety related piping.
Therefore, it has been determined that the ASME piping overstress condition is limited to the identified six diesel fuel oil lines for each unit.
The diesel generator fuel oil storage system is designed to permit the operation of the emergency diesel generator for a period of seven days.
The stress analysis of the subject lines showed that with the lines buried in the basemat, the calculated stresses exceed the ASME Code allowables.
Failure of the diesel fuel oil lines may result in an inability to deliver fuel oil to the day tank for the diesel and loss of the diesels could adversely impact plant safety.
Evaluation of Quality Assurance Program Breakdown:
The buried portions of the subject lines were scoped into analytical packages as part of the final design verification program.
SRNs were issued for the analytical packages but did not specifically identify that the buried portion of the line was not considered.
To preclude this problem, separate analytical packages should have been scoped for the buried portion of the line and assigned specifically within the scope of analysis.
A quality assurance review has concluded that this condition of buried piping is an isolated event and does not represent a significant breakdown in the Bechtel quality assurance program.
==
Conclusion:==
Based on the above evaluation. Georgia Power Company has concluded that a reportable condition as defined by the reporting criteria of Part 10CFR50.55(e) and 10CFR21 does exist since the plant safety could have been adversely impacted had this condition l
gone uncorrected.
Based on guidance in NUREG-0302, Revision 1,
concerning duplicate reporting of an event, Georgia Powar Company is reparting this event per the criteria of Part 10CFR50.55(e).
i Evaluation of a Potentially Reportable Condition ASME Buried Piping Page 3 Corrective Action:
1.
The installation of a guard pipe around lines 1-2403-051, 053, 068, 066, 043 and 044 and the as-built stress calculations for Unit 1 train A and train B have been completed.
The guard pipe provides adequate flexibility to maintain stresses within ASME Code allowables.
Stress reconciliation notices have been issued for the portions of buried lines that were inadvertently omitted.
2.
Corrective actions for Unit 2 are tracked under program for completion work (PCW) item number 281591 and will be completed comensurate with Unit 2 construction schedules.
.