We are pleased to announce that Southern California Edison (SCE)has awarded an Engineering, Procurement, Construction (EPC) contract to Holtecto place the used fuel inventory of the two retired San Onofre NuclearGenerating Station (SONGS) reactors into dry storage. Under the contract,Holtec will construct a HI-STORM UMAX underground storage facility to store2,668 used fuel assemblies in the MPC-37 multi-purpose canister, eachcontaining 37 used fuel assemblies. HI-STORM UMAX is an acronym for Undergroundand MAXimum Safety and Security. Holtec will also perform pool-to-pad loadingservices for all used fuel and non-fuel waste stored in the spent fuel pools ofSONGS Unit 2 and 3. To insure a long service life in the site's salt airenvironment, SCE has selected the most corrosion resistant grade of stainlesssteel, 316L grade austenitic stainless steel, for the confinement boundary ofthe MPC in lieu of the commonly used 304 grade. Likewise, all external surfacesof the storage cavity in contact with the ambient air will be upgraded fromcarbon steel to stainless steel to minimize in-service maintenancerequirements.

Designed for the post-9/11 age, the HI-STORM UMAX’s large subterraneanstainless steel lined concrete monolith will store the MPCs in fortifiedcavities designed to withstand any conceivable threats to its integrity;including tsunamis and earthquakes of intensities exceeding any recorded onearth. Other threats considered in the system design include hypotheticalevents such as impact from a crashing aircraft, a severe fire (from the burningjet fuel), and a long lasting massive flood. 

The low profile of the HI-STORM UMAX storage system will non-obtrusively blendwith the environment. The SONGS underground used fuel storage facilitydefense-in-depth features will also include a state-of-the-art aging managementsystem designed to predict the potential onset of corrosion damage to theintegrity of the MPCs decades before any indications are seen. 

Another HI-STORM UMAX ISFSI, at the Callaway Nuclear Plant in Missouri, isunder construction under a turnkey contract between Ameren and Holtec and isscheduled to be commissioned in 2015. The HI-STORM UMAX ISFSIs at SONGS andCallaway are successors to the first underground storage system devised andimplemented by Holtec for PG&E's Humboldt Bay site in 2007.

The underground storage technology pioneered by Holtec in the past decade iscovered by U.S. patents assigned to the Company, which are listed below: 

• 61625869 (provisional)
• US7068748B2
• US7590213B1
• US7330526B2
• US8098790B1
• US7933374B2
• US8351562B2
• US20140226777A1/WO2013036970 (pending)
• US7676016B2
• US20110286567 (pending)
• US20100150297 (pending)
• US8625732

In our view, selection of the underground storage system at SONGS,together with the use of underground storage at Humboldt Bay and the HI-STORMUMAX at Callaway are validation that either the HI-STORM UMAX or adensified version of the underground storage system called HI-STORM Subterra,(if the land area use is to be further minimized) are ideally configured toserve as the storage technology for the consolidated interim storagefacility(ies) contemplated by the U.S. government. Holtec’s underground usedfuel dry storage technologies present robust solutions for storing the nation’sused fuel in interim storage pending the construction of a repository.

Holtec International is aglobal leader in used nuclear fuel dry storage technologies. Holtec hassupplied over 700 dry storage systems worldwide. Holtec’s dry storage systemsare currently in use at over 70 nuclear units across nine countries.