ML20149D322
| ML20149D322 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 02/05/1988 |
| From: | Beck J TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| CP-87-131, TXX-88177, NUDOCS 8802090451 | |
| Download: ML20149D322 (2) | |
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EE Log # TXX-88177
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File # 10110
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118 ELECTRIC February 5,1988 w au-c. co a Enuweve int hesident U. S. Nuclear Regulatory Comission Attn: Document Control Desk Washington, D.C.
20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION DOCKET N05. 50-445 AND 50-446 DEFICIENCIES IN STEAM GENERATOR CUBICLE STEEL PLATFORM FRAMING AND PRESSURIZER SUPPORT SLAB SDAR:
CP-87-131 (FINAL REPORT)
Gentlemen:
On December 15, 1987, we verbally notified your Mr. H. S. Phillips of a possible deficiency involving unacceptable subcompartment pressurization effects resulting from a postulated pressurizer surge line break.
We are reporting this issue under the provisions of 10CFR50.55(e).
The required information follows.
Description During design validation of the steam generator cubicle structural steel platforms and the reinforced concrete pressurizer support slab it was determined that the calculated stresses resulting from the pressurization effects due to a postulated pressurizer surge line break would exceed the specified design allowables (the members are overstressed).
This is a deficiency in final design as approved and released for construction such that the design does not conform to the criteria and bases stated in the FSAR.
The cause of this deficiency was the failure of the original calculations to adequately address the pressurizer surge line break loads.
All postulated high energy line break loads have been reviewed as part of the Corrective Action Program.
This review has resulted in our conclusion that this deficiency is isolated.
Safety implication llad this deficiency remained uncorrected, the resulting overstressed structural elements during a postulated pressurizer surge line break could have adversely affected the safety of plant operations.
!k Db O f
400 krsh Otm Street iB si Dallas. Texas 13.'01
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February 5, 1988 Page 2 of 2 l
Corrective Action Design criteria for the consideration of loadings resulting from high energy line breaks have been documented in the Design Basis Documents which are used as the basis for design validation, (DBD-CS-073, -074, -081, -083, -084 and
-085).
Future plant modifications will be controlled by these design documents.
An analysis of the pressurizer surge line is being performed to eliminate the 1
need to consider the dynamic effects associated with the postulated break, l
This analysis is being performed in accordance with the recently modified General Design Criterion (GDC) 4, using leak-before-break methodology.
Completion of the corrective actions indicated above are expected to resolve this issue.
The leak-before-break analysis of the Unit 1 pressurizer surge line is scheduled for completion by March 21, 1988.
The analysis for Unit 2 will be completed prior to Unit 2 Hot functional Test.
Very truly yours, W. G. Counsil By: h M./ b EtM W. Beck Vice President, Nuclear Engineering BSD/grr.
c-Mr.-R. D. Martin, Region IV Residentinspectors,CPSES(3)
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