The following violation of very low safety significance (Green or SLIV) was identified by the licensee and is a violation of NRC requirements, which meet the criteria of Section 2.3.2 of the
NRC Enforcement Policy,
NUREG 1600, for being dispositioned as an
NCV.
10 CFR Part 50 Appendix B, Criterion III, Design Control, states, in part, that the design control measures must provide for verifying or checking the adequacy of design by methods such as design reviews, alternate or simplified calculational methods, or by a suitable testing program. Contrary to the above the licensee failed to verify adequacy of the design for HI-STORM 100 cask system laydown areas in the reactor building. The licensee identified that during various stages of fuel transfer operations inside the plant, analysis shows that the casks would uplift during a seismic event resulting in additional impact loads on the structural floors as well as the low profile transporter. The licensee, however, did not evaluate the affected structures for the additional impact loads. The licensee entered this issue into the
CAP as
IR 01251532,
IR 01266469, and
IR 01268258 and completed revised analyses and plant modifications where necessary. The finding was determined to have very low safety significance.
10 CFR 72.146 Design Control, states, in part, that the design control measures must provide for verifying or checking the adequacy of design by methods such as design reviews, alternate or simplified calculational methods, or by a suitable testing program. Contrary to the above the licensee failed to verify adequacy of the design of the HI-STORM 100 lift
yoke. The licensee identified that they failed to adequately determine the bending stresses in lifting pins and shear stresses in the pin supporting plate and the definition of a dual load path component was incorrectly applied to the strong back components of the lift
yoke. The finding was determined to have very low safety significance because the revised calculations decreased the rating of the lift
yoke from 125 tons to 110 tons, and the maximum lifted load is less than 110 tons. The licensee entered this issue into the
CAP as
IR 1327578 and
IR 1293137 and implemented the corrective actions to revise the calculations and de-rate the lift
yoke.
