Terry R. Hunt

Transportation of High-Level Radioactive Waste

There are over 100 nuclear power plants in the United States, each of which converts radiation energy from nuclear fuel into electricity. Although nuclear reactor fuel remains dangerously radioactive for many thousands of years, it loses its ability to create electrical energy efficiently after a relatively short time and periodically must be replaced. The spent nuclear fuel is classified by the Nuclear Regulatory Commission (NRC) as high-level radioactive waste, the handling and storage of which the NRC closely regulates. Because a large-scale permanent repository for high-level radioactive waste in Yucca Mountain, Nevada, is still in the planning stages and is not slated to open until 2010, most spent fuel is stored at the sites where it is produced. However, some of the spent fuel is transported between sites in order to share storage capacity, to research facilities, and for other reasons. The opening of the permanent repository will also lead to more frequent transportation of high-level radioactive waste. Because of the extreme hazard that high-level radioactive waste poses to public health and the environment, special precautions must be taken for its safe transport.

The NRC regulates the packaging and labeling of high-level radioactive waste for transport in coordination with the Department of Transportation (DOT), while DOT regulates its actual transport. In general, spent fuel is shipped by truck and by rail. In order to shield the public and the environment from the dangerous levels of radiation in spent reactor fuel, it is shipped in large, heavy containers called "casks." The NRC dictates standards for both the design and manufacture of spent fuel casks. The casks are rigorously tested under simulated accident conditions in order to ensure that their structural integrity cannot be compromised by impact, puncture, fire, or submersion in water. Although it is impossible to completely eliminate all radiation even from an intact cask, any radiation that does escape must meet NRC radiation dosage standards to protect those who might be exposed to casks while they are being transported. In addition, shippers must follow NRC-approved routes when transporting spent nuclear fuel.

Over the past 25 years, there have been over 1,300 shipments of spent nuclear reactor fuel without a release of radiation despite the occurrence of four accidents. With the opening of the permanent repository at Yucca Mountain, it is estimated that the number of shipments of spent fuel will increase dramatically, numbering in the tens of thousands in the first 24 years of the repository's operation. In anticipation of that situation, the NRC has conducted scientific studies and risk assessments and has concluded that the transportation of spent fuel will continue to be safe at the anticipated levels. The NRC estimates the risk of an accident that could cause a small release of radioactive material to be one in 1,000 and that of a large release to be less than one in 1,000,000.

In addition to prevention of accidents, the NRC takes measures to minimize the possibilities of sabotage or other malicious acts. These include coordination with law enforcement, requiring notification of the NRC and of the states through which the shipment will travel, monitoring of the shipment, the use of armed escorts in populated areas, and the use of immobilization devices.