did not want to be constrained at that point by determining a percentage of shipments that would be conducted by each mode. Trains can carry considerably higher payloads than legal weight truck or overweight truck, which means that fewer overall shipments would be needed. There is less routing flexibility with rail transport, however, and transit times may be longer. In 2004, OCRWMmade the decision to ship by “mostly rail” (DOE 2004, p. 18558). Nevertheless, the program acknowledged that it would also need to use other modes of transport to some degree for repository shipments. “Legal weight truck” is the designation used for tractor trailers that do not exceed a fully loaded weight of 80,000 pounds. These trucks are commonly seen on the nation’s highways. Some benefits of shipping by legal weight truck include relatively low equipment costs, flexible routing, numerous potential carriers, and compatibility with shipping and receiving facilities. Drawbacks of utilizing this mode include the need for more shipments, because each truck can carry a relatively small number of spent fuel assemblies: two pressurized water reactor elements or five boiling water reactor elements. “Overweight trucks” utilize additional wheels and axles to carry heavier payloads than legal weight trucks. With special permits, overweight trucks transporting spent fuel and high-level waste could weigh up to 120,000 pounds fully loaded, allowing for the transport of more fuel assemblies per shipment. The benefits of transporting by overweight truck are similar to those of legal weight truck, but drawbacks include the need to obtain permits, potentially slower travel speeds, and potential routing restrictions because of the weight of the packages. OCRWM did not consider the issue of permitting to be a potential obstacle, however, because a 1990 study conducted by the American Association of State Highway and Transportation Officials had documented that trucks with loaded weights between 80,000 and 109,000 pounds are routinely issued permits by the states (DOE 2007a, p. 8). For even heavier loads — for example, shipping rail casks via truck — OCRWM would need to use heavy haul trucks (DOE 2006d). Heavy haul trucks could be used to transport rail casks from shipping sites that lack direct rail access to the nearest railhead, at which point casks would be transferred onto railcars for shipment to the repository. Like other overweight trucks, states must issue permits for each heavy haul truck shipment. The final transportation mode that may play a part in OCRWM’s shipments is barge. This mode would likely be considered for shipping from reactors located on navigable waterways, especially if these facilities lack good rail or truck access. Barge shipments have been used in the past to transport heavy reactor components to nuclear facilities during construction and repair. Barges can carry substantially heavier loads than trains or trucks but have slower transit times and routing constraints. Utilizing barge shipments is a point of controversy for some states. While the Northeast and South have expressed interest in exploring barge shipments as a way to avoid rail or truck shipments through heavily populated areas,
MIX OF TRANSPORTATION MODES Although OCRWM’s environmental impact statement indicated the number of casks that would be transported by rail, truck, and heavy haul from each site, these numbers were intended specifically to support the environmental impact assessment. OCRWM never prepared a description, for transportation planning purposes, of what mode each site would use for shipping and how many shipments would take place. Shipping mode will dictate the number of shipments from each site and influence routing decisions, as well as impact the states’ training efforts prior to shipments. OCRWM has strived to maintain flexibility in its transportation planning as a way to deal with the “uncertainties and complexities” of the repository program. As observed by the NAS, “DOE’s desire for flexibility conflicts with the states’ preference for early and specific decisions on transportation” (NAS 2006, p. 226). OCRWM determined in 2004 that shipments from the 76 commercial reactor sites and five DOE sites to a federal repository would occur by “mostly rail.” However, according to OCRWM, 25 commercial reactor sites do not have direct rail access (Thrower et al. 2008, p. 5). An additional six commercial sites do not have the capability to load rail casks. OCRWM is therefore considering the use of several different modes as well as intermodal shipments for repository shipments. A key issue in transportation planning is the mode by which OCRWM will ship spent fuel and high-level waste. Early on in its transportation planning efforts, OCRWM made the decision to proceed with operational planning in a manner that would allow for shipment by rail, truck, and barge 15 (DOE 1986c). OCRWM
15 OCRWM has also explored the possibility of using multiple modes of transportation in a single shipment. These intermodal shipments could combine any of the transportation modes mentioned in this section. For more information, see the section on Intermodal Shipments.
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