ML19262A104
| ML19262A104 | |
| Person / Time | |
|---|---|
| Site: | 07109081 |
| Issue date: | 10/02/1979 |
| From: | Macdonald C NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | James Corbett CHEM-NUCLEAR SYSTEMS, INC. |
| References | |
| NUDOCS 7910260355 | |
| Download: ML19262A104 (4) | |
Text
.
P OL.
/[
h UNITED STATES
- ' ~ g( ',E
{
g NUCLEAR REGULATORY COMMISSION WASHINGTON, D C. 20555
'o e
g.
N..v /
..+
FCTC: RHO 007 0 2 1979 71-9081 Chem-Nuclear Systems, Inc.
ATTN: Mr. J. Stewart Corbett P.O. Box 1866 Bellevue, WA 98009 Centlemen:
Tais refers to your application dated July 17, 1979, as amended, requesting 1.n amendment to the Model No. CNSI-1600 packaging.
In connection with our review, please provide the information requested by the enclosure to this letter.
Please advie,e us within thirty (30) days from the date of this let :er when this infermation will be provided. The additional information requested by this letter should be submitted in the form of revised pages to the consoli-dated safety analysis report in order to preserve the continuity of your application.
If you have any questions rcgarding this matter, we will be pleased to meet with you and your staff.
Sincerely, Charles E. MacDonald, Chief Transportation Certification Branch Division of Fuel Cycle and Material Safety 1217 053 79102603 5_S
Chem-Nuclear Systems, Inc.
Model No. CNSI-1600 Packaging 02 M Encl to ltr dtd General 1.
Structural design criteria shculd be specified (cf. NRC Regulatory Guide 7.6 for containment vessel design and ASME Code III - NB for weldment and bolt designs).
2.
Temperature effects on material strength and ductility properties should be considered in the analysis.
Package Description Revise the drawings to clearly show all pertinent safety features, including all lid, plate, and shell dimensions, material types, weldments, solid cross scctions, gaps, closure devices, etc.
General Standards for All Packaging Tie-Down Devices - Provide justification tar neglecting the shear force component in evaluating tie-down lug stress as the direction of cable tensile force may not coincide with that of the tie-down lug. Also the elevated temperature effect on lug yield strength should be considered in the evalua tion.
Nomal Conditions of Transport for a Single Package Free Drop - Provide an analysis showing that the cask containment vessel design is adequate under the 2-foot free drop impact loading (cf. item General above).
30-Foot Free Droo 1.
General (Applicable to Top and Bottom End, Side and Oblique Drop Impact Cases) a.
Provide stress evaluation for the cask containment vessel components.
If the quasi-static method of impact stress analysis is used, the dynamic amplification effects (if any) should be considered. Also static material strength (yield stress, ultimate strength, etc.)
should be used in stress evaluation.
Consider effects of multiple stress components and induced lead pressure loading (if any) in the stress evaluation.
121/
054
. b.
Provide data to show that strain rate and temperature have no significant effect on mechanical properties (shear and crush stresses and strains) of the overpack fill material (foam). Also describe the test specimen and test condition in obtaining the roam stress-strain relations and provide justification for use of the uniaxial test data in the 1-load analysis of the cask impact problems as the strain state at the center section :nay approach a plane strain state.
2.
Corner Drop Bottom Corner Drop - Revised the g-load analysis to include the effect a.
of direct (in-plane) and bending resistances of steel shells and end plate at the impacted region on g-load results.
In the crush analysis at the impacted region either justify the following or revise the analysis if justification canr.ot be made:
(i) use of 5 ksi lead flow stress in the analysis considering the elevated temperature effect, (ii) the analytical method used in accounting for steel shell/
plate deformation effects and use of 45 ksi dynamic flow stress. Also evaluate containment shell/ plate stresses in the impacted region (cf. Item 1 above).
b.
Top Corner Drop - Show that the impact limiter would not be sheared off under various corner and oblique angle drop impact cases. Lid bolt stress evaluation should be revised to include the effects of nanlinear force distribution at the impacted surface on bolt stresses, combined direct and shear stress effects on the plastic flow (failure) condition, elevated temperature effects on material strength properties, possible dynamic amplification effect, on bolt stresses, and impact orientation angle effects on Jolt shear stress. Also see Item 1 above.
3.
End and Side Drops - See Item 1 above. Both top and bottom end drop and side drop cases should be considered.
Puncture The pun::ture evaluation should be extended to the bottom corner drop puncture case, in whicn the corner was damaged by the preceeding 30-foot free drop impact loading. Consider the following:
Accumulated damage effects and reduction in lead thickness effects.
Elevated temperature effects, which can reduce lead-backed plate puncture energy absorbing capacity by about 20% at 200 F temperature from that of room temperature.
Test data scattering effects and other uncertainties, which should be accounted for by application of design safety factor in conjunction with use of empirical puncture analysis equation.
1217 055
e 3
The existing cask shell or plate puncture equallons such as Nelms' for the lead-backed case are developed on the basis of test data of single layer steel plate or shell backed-up by a thick layer of lead. The required cask shell thickness calculated by using such an empirical equation should not be compared with the total thickness of lead-backed laminated steel shell because it is outside tne range of applicability of Nelms' equation (or its applicability in the present problem is yet to be demonstrated).
Leak Testing Specify leak testing criteria and procedures prior to each shipment and periodically show that the sensitivities and testing schedules are adequate for safe use of the packages. Regulatory Guide 7.4 may be used for periodic testing.
For assembly verification it is recommended that a test of sufficient sensitivity to limit the maximum release to a type A quantity in cm3 sec, would not be required.10 days is used, however, a leak test sensitivity gr 0-3 at3
/
The mi it.sm sensitivity of 1x10-at-cm /sec (air at 1 atm and 25*C leaking to a 10- at ambient) as specified in ANSI N14.5 should be met.
1217 056
.