ML20155F516
| ML20155F516 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf, 05000000 |
| Issue date: | 06/11/1975 |
| From: | Maccary R Office of Nuclear Reactor Regulation |
| To: | Deyoung R Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20155E140 | List:
|
| References | |
| FOIA-88-91 NUDOCS 8806160413 | |
| Download: ML20155F516 (4) | |
Text
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UNITED STATES z
NUCLEAR REGULATORY COMMtssl0N o
W ASHINGTON, D. C. 20555 p
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,f JUN 11E
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R. C. DeYoung, Assistant Director for Light Water Reactors, Group 1 Division of Reactor Licensing TECHNICAL ASSISTANCE REQUEST (TAR-1579), GRAND GULF 1 AND 2, MARK III CONTAINMEf4T SUPPRESSION POOL DYNAMIC LOADS The question list that was submitted to you on the subject matter on May 30, 1975, has apparently been transmitted to the applicant only informally. As a result of the meetings we had with the applicant to discuss these questions, we find it became necessary to revise some of the questions.
Accordingly, the revised list is attached herewith for official transmittal and subsequent documentation.
We need the written response to these questions at least 2-3 weeks prior to the issuance of an SER on the subject report.
A'o R. R. Maccary, Assistant Director for Engineering Division of Technical Review
Attachment:
As stated cc w/ attach:
F. Schroeder L. Shao A. Giambusso '
W. Butler R. Boyd E. Butcher R.Jedesco I. Sihweil W. Lainas J. Knight S. liou wiso,#
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2 I??6 198 8806160413 880606 CO NOR8 91 PDR
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GRAND GULF 1 AND 2
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P00L DYNAMIC LOADS RE0 VEST FOR ADDITIONAL INFORMATION (REVISED JUNE 10, 1975)
STRUCTURAL ENGINEERING BRANCH 1.
For all the critical load combinations, provide a breakdown of loads, including moments, forces, and' shears, and steel and concrete stresses at the base of the containment wall, the drywell wall and the weir wall, and at locations of maxi-mum meridional forces.
For the drywell, provide a similar breakdown at the top of the lower structural plates of the drywell.
2.
In your planned analysis for revised safety relief valve loads, describe the method of analysis of the drywell and containment walls for the unsymmetrical loading caused by actuation of one or several safety [ relief valves.
3.
Indicate if the design of the cor,tainment base slab or any portions thereof, including the vertical dowels of the con-tainment wall and interior concrete and any other anchors of the drywell plates and containment floor liner plate, is sensitivie to any of the load combinations involving pool swell loads or SRV loads, particularly for the revised SRV loads for which you have not yet completed the analysis.
Furthermore, provide the margin available in the present design that will permit higher pool swell or SRV loads and/or higher load factors without exceeding allowable limits.
Also, indicato if the base slab design is sensitive to any future change in the design and f
layout of the interior structures.
l 4.
On page 3-1, the implication of the last sentence may not be always true.
Depending on the dynamic properties of the contain-ment and the rise time and duration of the various loads, the containment may respond to two or more given loads at the same e.,,_,
-y,
I 3
2-
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time even though the loads occur at different times. In other words, the effects of var,ious loads occurring at different times may combine.
Accordingly, provide justification for combining only the loads that span a given time in the bar charts.
5.
Since most of the dynamic loads discussed in the report have not yet been verified by the ongoing test program, identify in summary form all the structural elements that will have to be redesigned should the loads prove to be significantly higher and indicate how much margin is available in the present design to resist potentially higher loads.
6.
Describe the analysis performed to determine the effects of negative pressures in the suppression pool on the containment and drywell lower liner plates, particularly when combined with effects of high temperatures, seismic loads, and cracking of the concrete and provide a summary of the results.
7.
For all the dynamic loads associated with loss-of-coolant accidents and safety relief valve discharges, describe the procedures used to analyze for the dynamic effects of the loads including procedures for determining natural periods of vibra-tion, dynamic load factors and time of maximum response.
Furthermore, provide a sumary of the results of such an analysis for all the structures surrounding the suppression pool.
Also describe the methods of taking cr,acking of concrete into consider-
]
ation and such discontinuities as the several penetrations in the lower region of the wall.
)
8.
Concerning the load combinations presented in Table 3.2.1 and
)
page 11 of Section II, provide the following:
a.
Justification for not specifying a load combination similar to combination (10) but for the pool swell condition, i.e.,
s
' l with a load factor of 1.5 applied to R.
Attention should B
be given to the fact that R acts on the containment over B
a large area (60' x 360*) and is just as probable and important as is the P 1 ad.
In addition, the fact that CD the containment will not be tested for k makes its leak-g tight integrity under such a load questionable, particularly if stresses reach the value associated with U but without a load factor applied to the load, b.
Justification for the load factors used in combining SRV loads (C or C') with OBE loads.
in the design.of 9.
Justify the use of 1.0 load factor on Rp floors above the suppression pool.
10.
The loads due to T, as shown on page 16 of Section II, seem g
relatively high.
It is also apparent that stresses due to Tg have been relied upon to reduce effective stresses due to other loads.
Drovide assurance and justification that such stresses will be present.
Furthermore, describe the assump.-
tions and procedures utilized to calculate these thermal loads including information on assumed temperatures and thermal gradients, assumed modulus of elasticity of concrete, effects of cracking and the possibility that these loads may be self limiting due to creep and cracking of concrete.
Also, describe the considerations given to thermal loads induced by T
- a 11.
Elasto-plastic behavior of safety-related structures when sub-j jected to large-area abnormal loads, such as the pool swell load on the floor at E1.135'=0", is apparently permitted by the present design.
Accordingly, provide sufficient and detailed justification of why you consider elasto-plastic behavior accept-able and with sufficient margins of safety.
Further, provide de-tails of your stress analysis methods and a sumary of the resulting deformations.
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