ML19276F431
| ML19276F431 | |
| Person / Time | |
|---|---|
| Site: | 07109186 |
| Issue date: | 03/15/1979 |
| From: | Macdonald C NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Brodsky R ENERGY, DEPT. OF |
| References | |
| NUDOCS 7903300185 | |
| Download: ML19276F431 (7) | |
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UNITED STATES f
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NUCLEAR REGULATORY COMMISSION g,.
WASHINGTON. D. C. 20555 MAR 151979 FCTR: RHO 71-9186 Department of Energy Division of Naval Reactors ATTN: Mr. R. S. Brodsky Washington, D. C.
20545 Gentlemen:
This refers to your application dated March 9,1978 (NR:RR:LMWissel G#5945), requesting approval of an amendment to the Model No. S-6213 Power Unit Shipping Container.
In connection with our review, we need the infonnation identified in the enclosure to this letter.
Please advise us within thirty (30) days from the date of this letter when this information will be provided. The additional information requested by this letter should be submitted in the form of revised pages to the application.
If you have any questions regarding this matter, we will be pleased to meet with you and your staff.
Sincerely, 0
$4 Charles E. MacDonald, Chief Transportation Branch Division of Fuel Cycle and Material Safety
Enclosure:
As stated 7903300185
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Department of Energy L/
Division of Naval Reactors
?e Model No. S-6213 Power Unit Shipping Container
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General 1.
Design Criteria b'*
For those critical components, including fasteners, failure of l'
which coald cause control rod withdrawal:
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The appropriate design rules to be used should consider g
m the following:
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- Applicable NRC Reg Guide 7.6 rules if elastic analysis method is used; Subsection NB rules of ASME Code III for fasteners.
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- Under the hypothetical accident condition, inelastic N.,
3> q design rules contained in Appendix F of ASME Boiler and
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,. :4 Pressure Vessel Code III if an inelastic analysis method
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is used.
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Any deviations from the abc"o should be delineated and justified.
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yield stress values) are present, the stability of the component
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O B.
For those components which may become aon-ductile at the "i
low service temperature environment or which are under large l,
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'I deformation, the adequacy of component design against fracture failure should be considered basing assumed defects on the
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inspection techniques employed.
Provide material fracture
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toughness data.
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Structural Impact Response Analysis
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The quasi-static impact response analysis results used in design
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O evaluation of structural components should be demonstrated to be A
appropriate with respect to those using an acceptable dynamic
.J analysis method by using static material strength properties.
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. Tie-down (1.4.4)
Separate application of 10g longitudinal, 5g transverse and 29 vertical loads for tie-down design does not comply with 10 CFR Part 71. These loads should be combined.
Normal Transport Condition (1.6.4) 1.
Shock and Vibration (1.6.4)
Revise the analysis by considering the following:
a) Railcar truck spring / damper should be modeled as flexible elements.
b) Multi-axial input excitation functions which are to be applied simultaneously to the package in the analysis should be obtained from an appropriate acceleration-frequency spectrum, c) The analysis /dvaluation should be extended to control rod drive mechanisms and fasteners.
2.
One-Footdrop (1.6.61 Due to differences in weight and content design between the original and amended packages, the adequacy of the amended package design against one-foot drop loadings should be evaluated independently.
Comments General 1 and 2 above also apply.
Hypothetical Accident Condition (1.7) 1.
General Comments General lA, 1B, and 2 apply to all drop impact cases.
2.
30-Foot End Drop (1.7.1.1)
A.
Rebound / Outbound Latches i)
In the g-load capability evaluation of latch / lead-screw system, shear failure potential along the U
45 -shear planes should be included.
. ii)
Provide justification for use of 1/8-inch crack size and 74 ksi/~ in' fracture toughness at -200F and neglect of transient dynamic effects in the latch fracture analysis. Also, provide more detailed information on the mcdel (crack shape, length, and depth and analytical procedure) used in the analysis.
B.
Upper / Lower Core Barrel Joint Analysis (pp. 1.104)
Revise the analysis to include effects of stress concentration due to bolt cross-sectional area change and nonlinear (rather than linear) post-yielding material behavior (which could cause the core barrel bolts to develop larger stresses than those under the linear case).
Extend the above analysis to the low temperature environment case.
3.
30-Foot Side Drop (1.7.1.2)
A.
G-load Analysis Revise the analysis to account for the following effects on g-load, deflection-relationship:
- Ccler side weight (dynamic load).
- Compressive area increase (i.e., use of compressive engineering stress-strain relation o =a II+I'l)/(I-ICI))'
c t which would cause compressive stress to increase by 50% from the tensile one at 20% engineering strain.
- Multi-axial stress effects at the crashed area.
B.
Main Flange Stud and Container Analysis (p. 1.129) i) The quasi-static container analysis that generated bending moment results for uses in the stud evaluation should be revised to account for the following effects:
Interaction effects of core barrel and outer container (through the lower adapter support) on dynamic responses of both structural components.
- Shear deformation and rotatory inertia effects.
ii) The stud stress evaluation should include the stresses caused by the core barrel bending moment at the barrel head area. The load carrying capacity analysis of studs should be revised to include the analysis of strains and show that all strains are within the allowable strain limit. Also, show that the studs would fail (fracture) under the low service temperature environ-ment.
C.
Core Barrel and Closure Head (1.7.1.2.4) i) Core Barrel Joints
- Provide a detailed sketch of core barrel joints including bolts, flanges, bushings, etc.
- The combined shear and bending stress effects should be considered in the design evaluation.
Also, show that the case considered is more critical than that the shipping studs are located nearest to the neutral-axis, and note the comments (except for the first part) given in 3B(ii) above.
ii) Clamp Ring Stud Evaluation-Bending and shear stresses should be contined by taking into consideration the effect of presence of longitudinal hole in the studs.
4.
30-Foot Oblique and Corner Impacts (1.7.1.3 and 1.7.1.4)
Due to the fact that the combined stress effects arising from cblique impact bending moment and shear and axial force components need not be less critical than those under the end or side impact loading, the following additional steps should be taken:
- Demonstrate that package design is adequate under the bottom corner impact loading.
. - Determine the minimum top oblique impact angle (measured from the vertical plane) that would cause a latch to open and evaluate the design adequacy of latch / lead screw systems under that oblique or the top corner impact loading condition, whichever is more critical.
If, as in the top end impact case, the lead screw / scram shaf t assembly buckles in the oblique impact case, the post-buckling deformation and combined (axial and shear force) bending moment effects should be considered in the evaluation.
5.
Puncture Analysis (1.7.2)
Unless it can be shown that the punch bar would actually fold-over (buckle) at the incipient punch yielding state, the puncture analysis / evaluation should be revised to show that an excessive control rod withdrawal event would not occur by taking the following points into consideration:
- The effects of punch material strain hardening and strain rate and compressive cross-sectional area increase should be considered,
- Ultimate shell shear strength to be used in the analysis in no case should exceed 60% (rather than 75%) of ultimate tensile strength at temperature.
- Contribution of additional cask
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downward displace-ment a'fter initial cask / punch contact on applied puncture energy should be considered.
- Validity of using the scale model test results in the cask puncture problem of a container with thickness not equal to 1.28 inches and diameter not equal to 102.6 inches is questionable due to violation of scaling laws.
Various critical drop puncture cases (except for the 3.3-inch shell wall puncture case) which could affect the control rod drive mechanisms at the cover end of the power unit should be considered. Also, consider the cummulative damage effects if this would lead to a more critical package design.
. 6.
Drawing Provide consolidated structural drawing of control drive mechanism and surrounding fuel module / motor tube / clamp ring assembly that show the layout, e.ubcomponent names and longitudinal and transverse constraints of the components.