ML20073E181
| ML20073E181 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 02/14/1978 |
| From: | Tedesco R Office of Nuclear Reactor Regulation |
| To: | Vassallo D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20071F735 | List: |
| References | |
| FOIA-93-375 NUDOCS 9409280287 | |
| Download: ML20073E181 (3) | |
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UNITED STATES E
NUCLEAR REGULATORY cOMMissl0N W ASHINGT ON, D. C. 20555
^ j FEB 14 39p Docket Nos.:
50-500 50-501 MEMORANDUM FOR:
D. B. Vassallo, Assistant Director for Light Water Reactors.
Division of Project Management FROM:
R. L. Tedesco, Assistant Director for Plant Systems, Division of Systems Safety
SUBJECT:
DAVIS-BESSE, UNIT NOS. 2 AND 3 - PROTECTION AGAINST MAIN STEAM LINE BREAK In PSAR Revisions 16 through 19, the Applicant submitted revised design bases and criteria for protection against the consequences of a high energy main steam and main feed line breaks.
The system layout shows main steam lines routed in close proximity to the control room and the main feed lines in close proximity to the spent fuel pool and cable t
spreading room.
We have reviewed the revised protection criteria and find them unacceptable since they fail to meet either Branch Technical Position APCSB 3-1 or Position C.2 of Regulatory Guide 1.29. This situation is like the Erie plant wherein we have required design changes to ensure adequate protec-tion. The applicant should modify the design. Our position is stated in 3
the enclosure.
h'h5c.A c
Robert L. Tedesco, Assistant Director for Plant Systems Division of Sytems Safety
Enclosure:
As stated cc:
S. Hanauer R. Mattson R. Boyd R. Hartfield s
L R. Bosnak J. Knight V. Benaroya P. Matthews D. Fischer H. Brammer B. Benedict i
J. Glynn
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1 ENCLOSURE ASB POSITION ON PROTECTION FOR HIGH ENERGY LINE BREAK OUTSIDE CONTAINMENT DAVIS-BESSE, UNIT N05. 2 AND 3 DOCKET NUMBERS 50-500/501 In order to meet the guidelines of Branch Technical Position APCSB 3-1, it is our position that the steam and feed system medt the following protection criteria:
1.
Steam and feedwater piping from the containment penetration to the first pipe restraint beyond the main steam isolation valve (MSIV) or main feed isolation valve (MFIV).
(a)
Fiping, restraints, and valves should be seismic-Catagory I and Quality Group B.
(b)
Piping should meet the low stress limits of B.l.b of Branch Technical Position MEB 3-1.
However, for safety considerations, the MISV and MFIV room and pipe tunnel structure should be designed to withstand the environmental effects of a non-mechanistic pipe br:-k, i.e., a break equivalent to the flow area of a single ended pipe rupture without pipe whip or jet forces.
In addition, we require any equipment, including isolation valves, in the valve room or pipe tunnel required for safe shutdown to be capable of operating in the resulting environment or flooding condi tions.
2 i j 2.
Steam and feedwater piping from first restraint beyond the MSIV or MFIV to the restraint beyond the control room or cable spreading room wall adjacent to the turbine building.
(a)
Piping should meet Position C.2 of Regulatory Guide 1.29 (b) Assume a double ended pipe break anywhere, including pipe whip and jet forces. Any structure affecting j
safety systems, including the pipe tunnel, control room, l
cable spreading room, and spent fuel pool structures should be protected against pipe whip and jet forces and should also be designed to withstand environmental effects of a double-ended pipe break in these areas.
In addition, any equipment in the pipe tunnel required for safe shutdown should be capable of operating in the resulting environment or flooding conditions.
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