ML18156A176

Enclosusecond Request for Additional Information (Letter to R. Ngwayah Second Request for Additional Information for the Review of the Model No. HI-STAR Atb 1T Package)

ML18156A176
Person / Time
Site:	07109375
Issue date:	05/29/2018
From:	Pierre Saverot Spent Fuel Licensing Branch
To:	Ngwayah R Holtec
Saverot P
Shared Package
ML18156A173	List: ML18156A174 ML18156A176
References
CAC L25285, EPID L-2017-LLA-0059
Download: ML18156A176 (16)

Text

Witte, M., et al., "Evaluation of Low-Velocity Impacts Tests of Solid Steel Billet onto Concrete Pads, and Application to Generic ISFSI Storage Cask for Tipover and Side Drop", Lawrence Livermore National Laboratory, UCRL-ID-126295, Livermore, California, March 1997" MAT_PSEUDO_TENSOR

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"the ceramic mesh screens are not directly activated by the neutron flux in the core. The ceramic mesh screens may have surface contamination present (from contaminated spent fuel pool water), but this is no different from the surface contamination that may be present on other waste content."

maximum permissible Co-60 activity of non-fixed surface contamination

Neutron radiation - this source is negligible for activated steel components, and is therefore not considered in the dose analyses."

Radiation ShieldingConfirm that the contents used in the shielding analysis are consistent with those specified in the General Information section of the application. If the package is designed for multiple types of contents, ensure that the contents producing the highest external dose rate at each location are clearly identified and evaluated."

The limits for maximum specific activity of contents for each Waste Package Type in Table 7.1.2 have to be met by the most activated portion of any single waste item.most activated portion of any single waste item."Material Properties"If the shielding model considers a homogenous source region (rather than a detailed heterogeneous model of the contents), ensure that such an approach is justified."

"Generally BTCs will not be loaded with segments of exactly the same geometry. Segments are not stabilized in the BTC, and will move if the BFA-Tank is upset.""it is assumed that the plate rotates 45 degrees, which exposes a section about 300 mm wide along the entire length of the tank."

"the materials used to construct the BFA-Tanks and the BFA-Tank Cassettes, which are loaded inside the HI-STAR ATB 1T transport cask, do not require fracture toughness testing for the following reasons - A relocation of the top or bottom plates of the BFA-Tank Cassette, on the other hand, cannot be entirely ruled out based on geometric considerations. Therefore, as described in Section 5.3.1.1.2, a sensitivity study has been performed in Chapter 5 to determine the external dose rate at 1-meter assuming that roughly one quarter of the BTC bottom plate is conservatively removed from the analytical model. As shown in Table 5.4.4, the calculated dose for this extremely conservative geometry is less than the regulatory limit by a factor of almost 2."**

"Ensure that any changes in configuration (e.g., displacement of source or shielding, reduction in shielding) resulting under normal conditions of transport or hypothetical accident conditions have been included, as appropriate."