ML20148G323
| ML20148G323 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 01/18/1988 |
| From: | Counsil W TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| CP-88-15, TXX-88115, NUDOCS 8801260469 | |
| Download: ML20148G323 (2) | |
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$$$h[E"fl, January 18, 1988 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C.
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SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION DOCKET NOS. 50-445 AND 50-446 CONTAINMENT MAXIMUM FLOOD LEVEL SDAR:
CP-88-15 (FINAL REPORT)
Gentlemen:
On January 11, 1988, we verbally notified your Mr. H. S. Phillips of a deficiency involving containment maximum flood level.
We are reporting this issue under the provisions of 10CFR50.55(e).
The required information follows.
DESCRIPTION During recent design validation efforts, the calculation which developed the containment maximum flood level was noted to contain an unconservative assumption concerning the position of the incore instrumentation door.
This assumption took credit for the reactor cavity volume during the maximum containment flooding event, even though this volume could be potentially l
isolated from other flooded volumes. Correction of this assumption in a new calculation resulted in an increase of 10 inches in the maximum containment flood level from elevation 817 ft. 6 in. to elevation 818 ft. 4 in.
A review of equipment located inside containment indicates some safety related equipment could be affected by the increased flood level.
The cause of this deficiency is an apparent failure to correctly determine the position of the incore instrunntation door when calculating the containment maximum flood level.
Although this deficiency was potentially applicable to l
assumptions made for other containment doors, a review of other doors has not resulted in the identification of additional errors.
SAFETY IMPLICATIONS l
Failure to correctly determine the containment maximum flood level could result in failure of qualified equipment inside containment during a LOCA.
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L TXX-88115 January 18,.1988 Page 2 of 2 This issue represents a significant deficiency in a design input utilized as the basis for establishing qualification of equipment inside containment, Extensive evaluation will be required to establish the adequacy of qualified components to perform intended safety functions when subjected to the increased flood level; CORRECTIVE ACTION Design criteria for containment maximum flood level has been established in Design Basis Document DBD-ME-008 "Containment Analysis" and Design Basis i
Document DBD-ME-076 "Posulated Environment for Equipment Qualification."
To correct the specific concern, the incore instrumentation door will be modified to allow water to flow into the adjoining area and a flood level calculation will be performed based on the modified door.
The revised flood level will be incorporated into the equipment qualification program.
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Records to support our evaluation will be available for your inspectors review af ter September 16, 1988, at which point our corrective actions will be l
complete.
Very truly yours, W. G. Counsil HAM /grr c-Mr. R. D. Martin, Region IV Resident inspectors CPSES (3)
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