ML20235A617
| ML20235A617 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 01/07/1988 |
| From: | Beck J TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| CP-84-12, TXX-88043, NUDOCS 8801120361 | |
| Download: ML20235A617 (2) | |
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EE Log # TXX-88043 Z
Fi1e # 10110 r
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U. S. Nuclear Regulatory Commission Attn: Document Control Desk l
Washington, D. C.
20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET N05. 50-445 AND 50-446 IMPACT OF HELB TEMPERATURES ON QUAllFlED EQUIPMENT OUTSIDE CONTAINMENT SDAR:
CP-84-12 (FINAL REPORT)
Gentlemen:
On June 4, 1984, we verbally notified your Mr. D. Hunnicutt of a deficiency involving the environmental qualification of equipment outside containment for high energy line breaks (HELB). Our latest interim report, logged TXX-7016, was submitted on November 30, 1987.
Based upon the mass and energy release data provided by Westinghouse, blowdown from a ruptured main steam line will become superheated when the steam generator tube bundle becomes uncovered.
Per FSAR criteria, a non-mechanistic crack with a flow area of one square foot must be postulated for determining the environmental qualification of safety related equipment and for subcompartment analyses.
To produce the limiting environment, cracks are postulated in the 32 inch main steam line (greatest mass and energy release due to superheated steam effects) in the Safeguards Building.
No single active failure has been assumed since piping failure need not normally be postulated in the Break Exclusion Area as defined in MEB 3-1.
Since the crack is non-mechanistic, it is assumed that jets are not generated and that the non-seismic fire protection system will be available.
For conservatism, the most severe MSLB superheated steam mass and energy releases and the minimum sprinkler mass and energy releases were used.
Essential components for this event were identified by the Systems Interaction Program for mitigation of HELBs outside containment.
An EQ review of the components and cables located in the affected compartments was conducted.
The results of this review demonstrated that all CPSES equipmont and cables, which are required to function to mitigate the consequences of a MSLB with a superheated steam release outside containment and to provide subsequent safe shutdown capability, are qualified with adequate margin to function during the event.
Sufficient information is available to control room operators for event mitigation as well as confirmation of essential safety functions.
Therefore, we have concluded, in the event this issue had remained uncorrected, no condition adverse to safety would have existed.
This issue is not reportable under the provisions of 10CFR50.55(e).
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TXX-88043 January 7, 1988 Page 2 of 2 i
Records supporting this conclusion are available for your inspectors to review at the CPSES site.
Very truly yours, W. G. Counsil By:
Mb Joy W. Be t-Vice Presi! nt, Nuclear Engineering BSD/ min c - Mr. R. D. Martin, Region IV-Resident Inspectors, CPSES (3) i l
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