ML20212L078
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Distribution 00cket Files D. Allison JUli14 y37I E. Hy1 tun LW l File DocketNo.60-27[
and 50-323 NEMORANDU!1 FOR:
I. Sihwell, Chief, Structural Engineering Branch R. Bosnak, Chief,!iechanical Engineering Branch FROH:
D. P. Allison, Project Manager, Light Water Reactors Branch No. 1
SUBJECT:
SEISMIC REEVALUATION OF DIABLO CANYON Following the discussion with D. Jeng," P. T. rsuo, A. Fratoni, R. Bosnak, E. Sullivan and P. Y. Chen on June 3,1977, I have telephoned the attached comments to PG&E concerning their proposed draft specifications for outdoor storage tanks, piping and mechanical and electrical equipment.
Some of the comments forwarded in a memo from Dave Jeng to ne dated May 24, 1977, have been revised or deleted. The significant changes are as follows:
1.
A(3) was deleted since their proposal concerning ductility and Newmark's spectra is in accordance with our position.
2.
A(4) Was deleted since (1) tornado wind loads need not be combined with WNJR!!!!
SSE loads and (2) we are only concerned here with the seismic'reeval-F uation. Other load conditions, such as those concerned with tornado -
analyses, are documented in the FSAR and have previously been reviewed.
PG&E has provided a specific load combination equation for the seismic reevaluation of tanks in the specification. SEB is requested to review I
this load combination equation to determine if it is acceptable (Item 5.a in the specification for oatdoor storage tanks).
3 A(5) was deleted. PG&E has proposed using ASME Section VIII to develop stress limits for structural steel.
In our discussions we did not identify any thing wrong with using Section VIII for this purpose.
Instead, it just doesn't happen to be what is employed in the latest branch positions for, tanks undergoing CP review. SEB is requested to review PG&E's proposal and determine if it is acceptable.
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Concents (2) and (6) on the mechanical and electrical equipment specifications were added asking for further details on actual material strengths and asking about torsion for systems other than the reactor coolant system.
6.
PG&E had proposed using TID 7024 for tanks. During our discussion a question was raised as to whether this would be conservative. SEB is requested to review this matter to determine whether the orocosal is acceptable.
Please conglete the above determination as soon as possible.
D.
. Allison, Project Manager Light Water P,eactors Granch No.1 Division of Project Management r
Enclosures Comments on Draft PGaE Specifications for Outdoor Storage Tanks and Mechanical and Electrical Equipment cc:
J. Stolz ggggg D. Jong P. T. Kuo A. Fratone P. Y. Chen i
E. Sullivan J. Knight i
D. Vassallo N. Newmark, University of j
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f ENCLOSURE Comments on PG&E Draft Specifications for Outdoor Storage Tanks and Mechanical and Electrical Equipment A.
Outdoor Storage Tanks (1)
Item 1.d indicates that ductility may be allowed in certain cases.
If ductility is used specify where and how much.
(2)
Item 1.f indicates that an equivalent method may be used in lieu of a vertical response analysis.
If equivalent methods are used, describe the methods and indicate where they are used.
B.
Piping Mechanical and Electrical Equipment (1)
Item a. on the first page indicates that preliminary soectra will be used in the evaluation. Compare these preliminary spectra to the final spectra and justify the adequacy of your approach.
(2)
Item c on the first page indicates that actual material properties may be used. Describe where actual material properties are used and provide appropriate details to justify the adequacy of this approach.
(3)
Item d. on the first page indicates that earthquake loads will l' n be combined with normal operating loads.
Items 1.a. 2.a and 3a k
also discuss load combinations. Provide specific load combination formulas similar to those normally provided in the Safety Analysis Report.
(4) The first page indicates that reanalysis may not be used in cases where simpler methods suffice. With regard to the simpler methods mentioned:
(a) How will the comparison between the increase in load to the available margin be performed? Some clarification of this item is needed.
(b) Define " acceptably high seismic input" in the statement:
" Equally acceptable methods include comparison to analyses of similar equipment performed for different plants with acceptably high seismic input." Clarification of this item in a more specific manner is needed.
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g (5)
Item 1.c indicates that the effect of torsion will be included by augmenting horizontal response spectra in accordance with the criteria to be used for structural evaluations.
It is our understanding that, for the structures, you will be calculating the structural stress due to torsion and then adding this to the calculated earthquake stress rather than augmenting spectra.
We do not understand how you would be augmenting spectra to account for torsion in the reactor coolant system analysis.
Describe the procedure for the reactor coolant system in detail and clarify this point.
(6)
Items 2. and 3. do not indicate that torsion will be accounted for piping other than the reactor coolant loops and for mechanical equipment. Justify this approach.
(7)
Items 1.d. 2.d and 3.c indicate that compressive loads up to 0.9 critical buckling may be allowed (apparently for piping supports).
However, the ASME Boiler and Pressure Vessel Code allows only 0.67 critical buckling. Justify your approach.
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