ML20141E481
| ML20141E481 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 12/19/1985 |
| From: | Foster D GEORGIA POWER CO. |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-85, REF-PT21-86-010-000 GN-760, PT21-86-010-000, PT21-86-10, NUDOCS 8601070710 | |
| Download: ML20141E481 (6) | |
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Georgia Power Company 1
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Post Office Box 282 s
Waynesboro, Georgia 30830 Telephone 404 554 9961. Ext. 3360 404 724-8114. Ext 3360 D. O. Foster Vice President and Pronct tm neem entnc system General Manager i
Vogtle Project December 19, 1985 6
i e
United States Nuclear Regulatory Commission Region II File:
XfpG03-M88 Suite 3100 Log:
GW760 101 Marietta Street, Northwest
..o Atlanta, Georgia 30323 o
VogtleElectricGeneratingPlant-Units 1and2;50-h,50-425;
Reference:
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Longitudinal Pipe Break Evaluations; also GN-740, dated 11/8/85 Attention: Mr. J. Nelson Grace On' October 11, 1985, Mr.
R.
E.
Folker, Vogtle Project Quality Assurance Engineer, informed Mr.
M.
Sinkule of the USNRC - Region II of a potentially reportable condition concerning the failure to postulate longitudinal pipe breaks at intermediate break locations in ASME III, Class 2 and 3 piping outside containment in accordance with Branch Technical Position MEB 3-1.
-In subsequent correspondence (see GN-740 dated November 8, 1985), Georgia Power Company indicated that the NRC would be informed of the results of the evaluation by December 20, 1985.
Georgia Power Company has concluded its evaluation of this condition and determined that a reportable condition per the criteria of Part 10 CFR 21 and 10 CFR 50.55(e) does exist.
In accordance with regulatory guidelines in NUREG-0302 and other NRC documents, Georgia Power Company is reporting this condition per the reporting requirements of Part 10 i
CFR 50.55(e). Enclosed is a summary of our evaluation.
I This response contains no proprietary information and may be placed in the NRC Public Document Room.
Very ruly yo s
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D. O. Foster i
REF/D0F/tdm i
Enclosure i
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U. S. Nuclear Regulatory Commission Document Control Desk Washington, D.C.
20555 R. J. Kelly
- 0. Batum D. L. Kinnsch G. F. Head G..Bockhold F. B. Marsh (BPC)
J. T. Beckham C. E. Belflower C. S. McCall (0PC)
D. O. Foster
' H:.: H. Gregory J. L. Vota'(W)
R. H. Pinson
\\EP D. Groover E. L. Blake, Jr.
ll; T. Gucwa (Shaw, et. al.)
P. D. Rice B. M. Guthrie
'Cl:W. Hayes J. E. Joiner D. E. Dutton G. A.'McCarley (Troutman, et. al. )
R. A. Thomas R. W. McManus D. C. Teper (GANE)
D. R. Altman W. T. Nickerson L. Fowler (LEAF)
.J. A. Bailey D. S. Read T. Johnson (ECPG)
NRC Sr. Resident 4
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S EVALUATI0N OF A POTENTIALLY REPORTABLE CONDITION LONGITUDINAL PIPE BREAK EVALUATION Initial Report - On October 11, 1985, Mr. R. E. Folker Vogtle Project Quality Assurance Engineer informed Mr. M. Sinkule of NRC-Region II of a potentially reportable condition concerning the failure to postulate longitudinal pipe breaks at intermediate break locations in ASME III, class 2 and 3 piping outside containment in accordance with Branch Technical Position MEB 3-1.
A total of four (4) break locations have been identified where longitudinal break locations outside containment had not been postulated as required by MEB 3-1.
In subsequent correspondence (see-GN-740 dated November 8,
1985), Georgia Power Company indicated that the NRC was expected to be informed of the results of the evaluation by December 20, 1985.
Background
Branch Technical Position MEB-3-1 addresses Postulated Rupture Locations in Fluid System Piping Inside and Outside Containment.
Paragraph B.1.3.b Longitudinal Pipe Breaks states:
The following longitudinal breaks should be postulated in high-energy fluid system piping at the locations of the' circumferential breaks specified in B.3.s:
(1) Longitudinal breaks in fluid system piping and branch runs should be postulated in nominal pipe sizes 4-inch and larger, except where the maximum stress range 3,4 exceeds the limits specified in B.I.c(1) and B.1.c(2) but the axial stress range is at least 1.5 times the circumferential stress range.
(2) Longitudinal breaks need not be postulated at:
(a) Terminal ends.
(b) At intermediate locations where the criterion for a minimum number of break locations must be satisfied.
(3) Longitudinal breaks should be assumed to result in an axial split without i
pipe severance.
Splits should be oriented (but not concurrently) at two diametrically opposed points.on the piping circumference such that the jet reactions causes out-of-plane bending of the piping configuration.
Alternatively, a single split may be assumed at the section of highest tensile stress as detec.ined by detailed stress anslysis (e.g., finite element analysis).
1 (4) The dynamic force of the fluid jet discharge should be based on a circular or elliptical (20 x 1/2D) break area equal to the effective cross-sectional flow area of the pipe at the break location and on a calculated fluid pressure modified by an analytically or experimentally determined thrust coefficient as determined for a circumferential break at the same location.
Page 2 Line restrictions, flow limiters, positive pump-controlled flow, and the absence of energy reserviors may be taken into account, as applicable, in the reduction of jet discharge.
(5) Piping movement should be assumed to occur in the direction of the jet reaction unless limited by structural members, piping restraints, or piping stiffness as demonstrated by inelastic limit analysis.
In summary, branch technical position MEB 3-1 states that longitudinal breaks shall be postulated at high stress points in all Class 1, 2, and 3 lines 4" and larger.
Longitudinal. breaks were postulated where applicable in all Class 1 lines; however, no longitudinal breaks were postulated in Class 2 and 3 lines at Vogtle Electric Generating Plant.
Engineering Evaluation - The engineering evaluation identified the following four break locations (outside containment) where longitudinal breaks had not been postulated based on the high stress criteria.
ISOMETRIC NO.
LINE NO.
BREAK N0DE 1K2-1301-173-01 1301-173-4" 662 1K2-1301-010-02 1301-009-4" 5
1K2-1301-010-02 1301-009-4" 8
1K2-1301-013-01 1301-013-10" 10 Zone of Influence (ZOI) figures were prepared for each of these breaks and any affected safety system was identified.
One break had no affect on any system and therefore no adverse impact on plant safety (Iso.
No.
The remaining three breaks were evaluated for any affect on piping, instrumentation, electrical, and equipment.
The evaluation for break node 5 (break P-13G1-1083-L1) did not identify any impact on an essential piping system.
However, it did identify an impact on electrical systems.
Two power cables in cable tray 1BE425TMAA were impacted.
These cables supply power to valve HV-8105 (Charging Pump Reactor Coolant Isolation Valve) and valve HV-8801 (Boron Injection Tank Discharge Isolation Valve).
Additionally, two control cables in cable tray IBE425TRAA were also impacted. These control tables also connect to valves HV-8105 and HV-8801.
The evaluation for break node 8 (Break P-13G1-1803-L2) did not identify any impact to an essential piping system.
An impact was identified to the electrical systems.
This impact was the same as discussed for breck node 5.
The evaluation for break node 10 (Break B-13G1-1087-L) identified the same electrical impact as discussed in break node 5.
Additionally, three essential piping impacts were identifed in lines 1301-170-4";
1301-016-8",
and 1301-229-4".
In summary, four essential electrical cable impactees have been identified as requiring protection.
The longitudinal breaks which impinge on these cables are postulated in branch lines off of loop 1 of the main steam system.
The loss of these cables could result in the loss of both trains of the charging flow to the RCS and, therefore, is reportable.
i Page 3 Three essential piping impactees have been identified where protection may be required.
The failure of these impactees in loop 4 of the main steam system could result in the simultaneous blowdown from two steam generators.
This would be an unanalyzed condition and, therefore, is reportable.
Evaluation for a Quality Assurance Program Breakdown - A review of this concern identified that this omission of postulated longitudinal breaks was an isolated case and does not constitute a breakdown in the quality assurance program.
Conclusion - Georgia Power Company has concluded that this condition represents a reportable condition as defined by the reporting criteria of Parts 10CFR50.55(e) and Part 10CFR21.
In NUREG-0302 Rev. 1 and other NRC documents, licensees are instructed to avoid the duplicate reporting of an event.
Based upon this guidance, Georgia Power Company is reporting this condition per the reporting criteria of Part 10CFR50.55(e).
Corrective Action The four cables supplying power and control to valves 1-HV-8105 and 1-HV-8801B will be rerouted to ensure that they are not disabled for pipe break events requiring proper operation of the valves.
9 In addition, an analysis is being performed to determine if the three essential piping impactees will withstand the effects of jet impingement from these breaks.
This analysis will be completed by January 31, 1986.
Appropriate protection will be designed, if required, by February 28, 1986.
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