Casks used for shipping spent nuclear fuel are designed to protect against potential radiation exposure for the public during any accident condition. They are rigorously designed and tested in accordance to requirements established by the Nuclear Regulatory Commission and the Department of Transportation in volumes 10 and 49 of the Code of Federal Regulations.
The casks are about 15 times thicker than a gasoline tank truck shell and they include three inches of stainless steel with thick lead radiation shields. Typically, for every ton of fuel, there are more than three tons of protective packaging and shielding.
Casks are designed and tested to withstand crashes, fire, water immersion and puncture. To be certified, a cask design must withstand a sequence of four tests that measure its performance in specified crash and fire accident conditions. This means the casks are designed to contain its contents in the event an accident occurs.
For more on the safety of the transportation of nuclear waste, go to:
Public routes used for the transport of nuclear materials must meet strict safety requirements before nuclear fuel is transported. Department of Transportation regulations require carriers of certain controlled radioactive materials, such as spent fuel, to use the safest routes available. Risk assessments of the transportation of radioactive materials evaluate factors such as accident rate, transit time, population density and other vehicles sharing the route and time of day.
The DOT identifies "preferred routes," which consist primarily of interstate highways and bypass routes around cities, where such bypass routes exist, or an alternative route selected by a state routing authority. If the routing authority selects an alternate route, it must demonstrate by a routing analysis that using the alternate route does not increase overall risk. Alternate route selections must be preceded by consultations between DOT and affected state and local authorities before such designations can go into effect.
Most materials being transported are monitored by global satellites, and are monitored at all times during the transportation process.
Specialized trucking companies handle spent nuclear fuel shipments in the United States. These experienced, specially licensed companies haul all kinds of hazardous materials more than 50 million miles annually. Vehicles are state of the art, equipped with computers that provide an instantaneous update on the truck's location and convey messages between driver and dispatcher through a satellite communications network. Drivers receive extensive training and must be certified by the federal government.
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Over the past 40 years, about 3,000 shipments of spent nuclear fuel have navigated more than 1.7 million miles of U.S. roads and railways. Of all this travel, no radioactive materials have been released resulting from an accident or any other cause. During this same period, there have been about 98 million kilograms of spent nuclear fuel shipped worldwide, with no record of any release of radioactive material.
The nuclear industry's commitment to safe packaging and security has produced a safety record that would be difficult to match. The basic safety measures undertaken in the transportation of nuclear material ensures that the industry's safety track record will remain.
Each year, 100 million shipments of hazardous material navigate America's roadways, railways, airspace and shipping routes. Approximately half of these shipments are by truck. Of these hazardous shipments, only 2 to 5 million involve radioactive material. Most of these shipments are radioisotopes for medical and industrial use.
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Ninety spent fuel casks have been involved in accidents since 1970. None of these accidents resulted in any release of radioactive material, so a direct extrapolation has no meaning. Estimates of accidental releases that might happen because more casks are being shipped depend on results of cask testing. The impact tests required by Federal Regulation exert forces on the casks that are greater than impact forces (g-forces) in the worst recorded accidents. Temperatures produced in the casks by the regulatory fire tests are higher than those in any recorded fire accident, including the recent Baltimore tunnel fire.
(Note: The standard involves both temperature and duration: it is a fully engulfing fire of temperature 1,480 degrees F for half an hour. The Baltimore tunnel fire spiked at 1,500 degrees F for a few minutes, and it's not known whether it would have been "fully engulfing." It takes a cask in a fully engaging fire more than an hour at the regulatory temperature to heat the seals to where they start to degrade, and more than four hours to reach fuel rod burst temperatures).
Sandia Laboratories conducted three extra-regulatory types of tests:
The casks emerged with only minor damage from all of these tests, and in none of the tests did the casks fail to hold their contents. Nonetheless, the Department of Energy analyzed the "maximum reasonably foreseeable accident" -- an accident that has a one-in-ten-million chance of happening.
(Note: All accidents are defined by impact speed and fire temperature, and the maximum accident by where it occurs and under what weather conditions as well. The "one-in-10 million" accident would happen in one of the 20 most populated cities in the U.S. (population between 1 million and 5 million), in atmospheric stability that only happens 5 percent of the time, at a cask impact speed of 120 miles per hour combined with a temperature between 750 and 1,000 degrees C (1,390 to 1,840 degrees F).
While there would be more shipments of nuclear waste and fuel in the coming years as a result of the opening of Yucca Mountain, the probability of radiation exposure resulting from an accident would remain low simply because the same casks would be used and the same safety precautions and procedures would be followed in the increased shipments.
To learn about radiation dosage, please go to the following link:
The purpose of the Nuclear Waste Policy Act of 1982 was to select and characterize a site that, with appropriate engineering design and operation, can meet with high confidence the regulatory standard for public health and safety. Yucca Mountain exceeds those requirements.
For decades, the National Academy of Sciences has recommended disposing waste in rock, deep underground to ensure the protection of public health and the environment. Nuclear scientists and engineers, after carefully scrutinizing peer-reviewed data and analysis, have concluded that the Department of Energy's selection of Yucca Mountain more than meets this criterion.
The repository at Yucca Mountain would be located 1,000 feet below the earth's rocky surface, 1,000 feet above the water table and in a remote area of the Nevada desert. The unique combination of rock characteristics and the deep water table make the Yucca Mountain site capable of isolating the spent nuclear fuel and high-level radioactive waste for centuries.
In addition, the Yucca Mountain site is remotely located on federal land more than 90 miles from any major population center. The Nellis Air Force Range surrounds the Nevada Test Site on three sides; the site has a highly effective rapid-response security force; and the airspace above Yucca Mountain is restricted.
Last updated June 5, 2012, 2:26pm CDT.