The MAGNASTOR System: The New Generation in Multipurpose Storage

The future of dry spent fuel storage has arrived. The NAC Modular, Advanced Generation, Nuclear All-purpose Storage (MAGNASTOR®) System is the first U.S. NRC certified high capacity multipurpose spent fuel storage technology, capable of storing 37 PWR or 87 BWR spent fuel assemblies. Drawing upon lessons learned from designing and licensing three earlier dual/multipurpose technologies, and from fabricating, constructing, and loading over 200 of these earlier multipurpose canister systems (MCS), NAC has developed the MAGNASTOR System to provide improved capacity, thermal performance, operations, and fuel coverage for the growing number of nuclear facilities requiring dry spent fuel storage. MAGNASTOR is a new generation MCS, incorporating lessons learned while considering the handling capabilities of plants requiring dry storage.
MAGNASTOR incorporates unique design, fabrication, and operations features. Among these are:
  • a developed cell basket design that offers the highest spent fuel capacities and simplifies fabrication, while providing high strength and heat removal of up to 35.5 kW
  • a unqiue canister closure design that can improve welding time, reduce personnel dose, and enhance drying performance 
  • a low profile vertical concrete cask design to improve on-site handling and site dose rates, while providing proven, simple construction operation features and maintaining robustness against beyond-design-basis threats
  • a simple, proven transfer system that facilitates transfer without excessive dose or handling
  • a new approach to water removal and canister drying that shortens operation times.



Key Design Parameters

Fuel Specific Data


Maximum Assembly Capacity


Thermal Capacity (Storage)

35.5 kW/33 kW, max.


24 kW max.

Fuel Cool Time     (Storage)

4 yr min.


To meet max. heat load limits

Fuel Initial Enrichment

5.0 w/o /4.5 w/o, U235 max.

Fuel Burnup  (Assembly Avg)

60 GWD/MTU max.

Key System Dimensions


VCC Length - Standard

225 inches (6477 mm)

                     Segmented Body

204 inches (5181.6 mm)

VCC Outer Diameter

136 inches (3454.4 mm)

Canister Cavity Length

Type 1 - 173 inches (4394.2 mm)


Type 2 - 180 inches (4572 mm)

Internal Cavity Diameter

72 inches (1828.8 mm)

Overall Canister Length

Type 1/3 - 185 inches (4699 mm)


Type 2/4 - 192 inches (4876.8 mm)

Canister Shell Thickness

0.5 inches (12.7 mm)

Max Weight on Crane Hook

114 tons/115 tons
(103.4 mtons/104.3 mtons)

Max Weight on ISFSI Pad

160 tons/161 tons
(145 mtons/146 mtons)