ML19294A915
| ML19294A915 | |
| Person / Time | |
|---|---|
| Issue date: | 10/31/1978 |
| From: | Vassallo D Office of Nuclear Reactor Regulation |
| To: | Engelhardt T NRC OFFICE OF THE EXECUTIVE LEGAL DIRECTOR (OELD) |
| Shared Package | |
| ML19294A895 | List: |
| References | |
| TASK-AS, TASK-BN-101 BN--101, BN-101, SECY-79-88, NUDOCS 7905080259 | |
| Download: ML19294A915 (7) | |
Text
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ENCLOSURE G to Containment Buckling i
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October 31, 1978 J{ )
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HEMORANDUM FOR:
Thomas F. Engelhardt, Acting Hearing Division Director and Chief Counsel, OELD
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FROM:
D. B. Vassallo, Assistant Director for Light '.Jater g l Reactors, Division of Project Management, ONRR
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SUBJECT:
BOARD NOTIFICATION - BUCKLING (BN-101) a 3
OELD (J. Scinto memo of October 11,1978) did not agree with our
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recom.endation against notifying Boards at this time of potential changes in buckling criteria.
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We have no objection to providing any of the backup information i
contained in our original memo, and also enclosed here, to Boards.
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The Board letter, I think, should also include the last two para-graphs of Q 130.21, also enclosed, which express the staff position.
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All Boards on the service list time frame should be notified. Our
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D. B. Vassallo, Assistant Director y
for Light Water Reactors i
yb Division of Project Management
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Enclosures:
As Stated v
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Boards to be Notifiec Black Fox Cherokee FNP Hartsville Hope Creek McGuire Montague Perkins Phipps Bend St. Lucie Yellow Creek I
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& l /Y h kN$ h ek ACNGS-PS AR Ef4 CLOSURE li to Containment Buckling Item No.
(130.21 In Sections 5.0 and 6.0 it is stated that the design of the March 24, steel containment will be in conformance with the requirements 1978) of ASME Code Section III Subsection NE and Regulatory Guide 1.57 and that a factor of safety of two against buckling is used. Since the actual factors of safety against buckling will be different for different load combinations, indicate the actual factor of safety for each load combination as shown in i
Table 6.1-1.
Also describe the method of analysis used to com-pute these factors of safety.
In a report entitled " Stability Criteria for Primary Metal Con-tainment Vessel Under Static and Dynamic Loads" written for CE by B L Critterley of Anamet-Laboratory, Inc, a factor of safety against buckling ranging from 2.0 to 2.75 is recommended. Also recently the 1977 summer addenda of the ASME Code requires a factor of safety of between 2.0 and 3.0 against buckling de-pending upon the applicable service limits.
Due to the lack of experimental data and uncertainties in es-tablishing the theoretical buckling load, we have an ongoing technical assistance program to study this issue.
It is ex-j pected that any final design recommendations or guidelines resulting from this program will be evaluated for possible use in our licensing review work. We are not at this time in a position to make any changes to previously accepted criteria.
However, we urge you to study your buckling criteria further and form a strong technical basis for your approach. As indi-cated above, through the help of our outside consultant, i
we shall develop our techincal position and shall decide the ex-tent to which the position thus developed will be applied to previously accepted application.
RESPONSE
The response to this item is located in revised PSAR Table 3.8-2.
This table will be duplicated and will replace Figure 6.1-2 of the Containment 45 1
Structures Design Report (CSDR). This revised figure will be included in (g)
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the next revision of the CSDR.
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K130.21 (U)-Upda te Am. No. 45, 5/17/78
e ACNGS-PSAR TABLE 3.8-2 BUCKLING CRITERIA FOR CONTAINMENT VESSEL I.
Method of Determining Critical Buckling Stress in the Cylindrical Shell Ihe methods used for calculating the critical buckling stresses in the cylindrical shell will be based on correlated results of theoretical and experimental investigations of stiffened and unstiffened vessels.
The selected methods will be those which account for imperfections of the same degree which will be allowed in the vessel fabrication. Bo th clastic and inelastic buckling behavior will be considered as follows:
a) Critical Elastic Buckling Stresses:
- 1) Axial - Computation of critical buckling stress will be based on an approach which includes consideration of ring stiffeners such as that described on page 18 of Reference (1) or similar.
For the Post-Accident Flooded loading condition only the 45(U).
computation will include the stif fening ef fect of the inte rnal Q130 water pressure by utilizing the methods of Reference (2) or
.21 similar.
Q130
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- 2) Circumferential - Computation of critical buckling stress will include consideration of ring stif feners and be based on an approach similar to the ASME Code,Section III, Sub-section NE, Summer 1974 Addenda, including the update of Pa,ra. NE3133 thru the Winter 1975 Addenda.
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- 3) Shear - Computation of the critical stress adil be based on the approach described on page 24 of Reference (1) or similar.
b) Critical Inelastic Buckling Stresses:
- 1) Axial - When the elastica 11y calculated value of the critical axial stress exceeds the proportional limit (0.55 yield) the critical value to be used in design will be calculated using inelastic correction similar to that described in Section 3.3
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of Reference (3).
- 2) Circumferential - When the elastica 11y calculated value of the critical circumferential stress exceeds the proportional limit the critical value to be used in design will be calculated using ASNI Code,Section III, Appendix VII, Figure VII-1101-2.
- 3) Shear - When the elastica 11y calculated value of the critical shear stress exceeds 0.577 yield the critical vslue to be used in design shall be 0.577 yield.
(U)-Upda te 3.8-81 Am. No. 46, 7/14/78
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ACNCS-PSAR II.
Factors of Safety and Interaction Check a) The following factors of safety wil'1 be applied to the actual stresses in t he interaction checks:
- 1) Operating and Accident Conditions - If the critical buckling in the elastic range (at or below 0.55 yield) stresses are a factor of safety of 2.75 vill be used.
In the inelastic range (above 0.55 yield) as the calculated critical values get closer to the material's yield strength a
the mode of failure would increasingly resemble yielding rather than a sudden type failure. To provide continuity between the ASME Code stress intensity rules (which provide safety factor approximately equal to 2.0 against yield a
j failure) and the buckling rules, the inelastic factor of safety will be varied linearly from 2.75 when the critical stress is just above 0.55 yield down to 2.0 when the critical i
stress is at yield or above.
- 2) Post Accident Flood Condition - A factor of safety of 2.0 vill be used in both the elastic and inelastic range.
b) Elastic Interaction 45(Uh Q130 The following relationship will be satisfied when the critical 1
stresses
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in the cylindrical shell are in the elastic range:
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Actual Axial x F Actual Circumferential x F g
g Critical Axial Critical Circumferential I
[ Actual Shear x F )
2 d
f 1.0
\\Critica1 Shear
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where:
F3 = Factor Safety = 2.75 for Operating and Accident Conditions and 2.0 for Post Accident Flood 4
c) Inelastic Interaction
_. _ _. When the critical stresses are in the inelastic range the inter-
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action in II-E above shall be satisfied using the elastically cal-
, culated values (Para I-A above) for the critical stresses, j
' In addition the following relationship will be satisfied using the t
inelastically calculated values (Para I-B above) for the critical stresses:
1 Actual Axial x F 3(Actual Shear x F y
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Critical Axial
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(Yield Stress)
(U)-Upda te
.8-81a Am. No. 46, 7/14/78
L ACNGS-PSAR Actual Circumferential x F2 3(Actual Shear x F )4 7,
3 Critical Circumferential Y
(Yield Stress)2 shere:
y = Factor safety in the inelastic range = varies from 2.75 to 45(Uh F
2.0 as per Para II-A 9130 21 Q130 F3 = Factor safety at yield = 2.0
.22 III.
Stability Check and Stiffener Adequacy The buckling stability of the vessel and the adequacy of the stiffeners will be demonstrated ',y analysis using the public domain computer program BOSOR IV or update.
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i (U)-Update
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3.8-81b eon. No. 46, 7/14/78
ACNCS-PSAR REFERENCES 1.
- Citerley, R.L., Anamet Labs, " Stability Criteria for Primary Metal Containment Vessels Under Static and Dynamic Loads", August 1977.
2.
"The Stability of Thin Walled Unstiffened Circular Cylinders Under Axial Compression Including the Ef fects of Internal Pressure", Harris, et. al, Journal of the Aeronautical Sciences, 8/57.
Q130 }
45(U nd 3.
Timoshenko and Gere, Theory of Elastic Stability, 2 Edition, 1961.
.21 Q130
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(U)-Update 3.8-81c Am. No. 46, 7/14/78