ML20065H984
| ML20065H984 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 09/29/1982 |
| From: | Oprea G HOUSTON LIGHTING & POWER CO. |
| To: | Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, ST-HL-AE-887, NUDOCS 8210050329 | |
| Download: ML20065H984 (4) | |
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The Light C G Itt P u y iie s'e"iin 'i"x &ie <<
n i o.iie i7oo ii" s'e". Tex s77"oi<7>3)228-o2ii September 29, 1982 ST-HL-AE-887 File Number: G12.130 SFN: V-0530 Mpg f
Mr. John T. Collins Regional Administrator, Region IV r
Nuclear Regulatory Commission S@30W i
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611 Ryan Plaza Dr., Suite 1000 l'
i Arlington, Texas 76012 L;
/
Dear Mr. Collins:
South Texas Project Units 1 & 2 Docket Nos. STN 50-498, STN 50-499 Final Report Concerning Design Loadings for the Isolation Valve Cubicle Walls On September 1,1982, pursuant to 10CFR50.55(e), Houston Lighting &
Power Company (HL&P) notified your office of an item concerning the design pressure loading for the Isolation Valve Cubicle (IVC) walls. Attached is the Final Report which provides the results of the evaluation that has been l
performed.
1 1
If you should have any questions concerning this item, please contact Mr. Michael E. Powell at (713)877-3281.
Very truly yours,
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Q' rea w
Execu ive Vice President MEP/mg Attachment
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I 8210050329 820929 PDR ADOCK 05000498 8
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September 29, 1982 J. H. Goldberg ST-HL-AE-887 J. G. Dewease File Number: G12.130 J. D. Parsons Page 2 D. G. Barker C. G. Robertson R. A. Frazar J. W. Williams R. J. Maroni J. E. Geiger H. A. Walker S. M. Dew J. T. 2111ns (NRC D. E. Sells NRC W. M. Hill, Jr.
NRC M. D. Schwarz Baker &Botts)
R. Gordon Gooch Baker & Botts)
J. R. Newman Lowenstein, Newman, Reis, & Axelrad)
STP RMS Director, Office of Inspection & Enforcement Nuclear Regulatory Commission Washington, D. C. 20555
- 6. W. Muench/R. L. Range C'narles Bechhoefer, Esquire Central Power & Light Company Chairman,' Atomic Safety & Licensing Board P. G. Box 2121 U. S. Nuclear Regulatory Commission Corpus Christi, Texas 78403 Washington, D. C.
20555 H. L. Peterson/G. Pokorny Dr. James C. Lamb, III City of Austin 313 Woodhaven Road P. O. Box 1088 Chapel Hill, North Carolina 27514 Austin, Texas 78767 J. B. Poston/A. vonRnsenberg Mr. Ernest E. Hill City Public Service Board Lawrence Livermore Laboratory P. 0. Box 1771 University of California San Antonio, Texas 78296 P. O. Box 808, L-46 Livermore, California 94550 Brian E. Berwick, Esquire William S. Jordan, III Assistant Attorney General Harmon & Weiss for the State of Texas 1725 I Street, N. W.
P. O. Box 12548 Suite 506 Capitol Station Washington, D. C.
20006 Austin, Texas 78711 Lanny Sinkin Citizens for Equitable Utilities, Inc.
Citizens Concerned About Nuclear Power c/o Ms. Peggy Buchorn 5106 Casa Oro Route 1, Box 1684 San Antonio, Texas 78233 Brazoria, Texas 77422 Jay Gutierrez, Esquire llearing Attorney Office of the Executive Legal Director U. S. Nuclear Regulatory Commission Washington, D. C.
20555 Revision Date 08-23-82
Attachment Final Report Concerning the Design Loadings for the Isolation Valve _ Cubicle Walls _
I.
Summary The design pressure Icading of the Isolation Valve Cubicle (IVC)
Auxiliary Feedwater (AFW) pump compartment walls could be exceeded in the event of a feedwater bypass line break.
Failure of the AFW pump compartment walls may lead to unacceptable safety hazards in cubicles adjacent to the break compartment. A detailed failure analysis of the walls and the resulting effects was not performed because the building will be redesigned to accomodate the loadings resulting from a feedwater bypass line break.
II.
Description of the Inciden,t On September 1, 1982, pursuant to 10CFR50.55(e), Houston Lighting a Pcwer Company (HL&P) notified your office of an item concerning the design pressure loading for the IVC AFW pump compartment walls. The design pressure loading of the IVC AFW pump compartment walls could be exceeded in the event of a feedwater bypass line break. A calculation performed by NUS shows the pressure calculated to result from a feedwater bypass line break to be 35.24 psid (not including additional loading factors), while the subject walls are designed for 19.1 psid based upon a 10.6 psid applied load plus additional loading factors. This condition is assumed to compromise the integrity of the walls.
III.
Corrective Action The design of the IVC is being reviewed and revised. The design of AFW pump cubicles is included in this review. More realistic calculational models, structural design changes and system design changes are being considered in finding an acceptable solution.
In any case, sufficient venting will be available to maintain the AFW pump cubicle integrity. A final pressure /temperatore analysis will be performed based on the revised design to confirm its adequacy.
The redesign and restart of construction as currently scheduled is shown on the Milestone Sumary Schedules (line number 10) provided under separate cover on September 20, 1982. Once the design is finalized FSAR Section 3.8.4 will be updated.
IV.
Recurrence Control Bechtel includes conservatisrh in its structural design criteria to compensate for the uncertainty due to the preliminary nature of postulated loads.
In the earlier stages of structural design, greater margins are included to account for possible changes which may occur as a result of design evolution. Final analysis is performed to confirm the loads after the design has progressed to a more completed stage. This process provides adequate assurance that major structural redesign will not be required.
Attachment Page 2 V.
Safety Analysis Analysis of the pressure / temperature conditions following a postulated feedwater bypass line break has confirmed that without redesign the applied loads due to pressurization of the AFW pump cubicle exceed the structural allowance. The IVC structure will be redesigned and no further detailed failure analysis is planned.
We have concluded that a condition exists which could have adversely affectedthesafetyofoperationoftheSouthTexasProject(STP). This condition will be corrected as outlined in Section III.
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