of thermal and mechanical forces that have the potential to damage the vital containment functions of the package.

Accident consequence value:

The estimated collective dose that would be received by a population as a result of an accident scenario.

Accident scenario:

A postulated sequence of events during a transportation accident that result in the application of elevated thermal and mechanical loads to a transportation package.

Accident source term:

The amount of radioactive material released from a loaded transportation package in an accident.

Actinides:

Any of a series of chemically similar radioactive elements with atomic numbers ranging from 89 (actinium) through 103 (lawrencium). This group includes uranium (atomic number 92) and plutonium (atomic number 94).

Activity:

The rate of decay of a radioactive isotope.

Acute radiation exposure:

A radiation exposure that occurs over a relatively short period of time (e.g., seconds to hours). A chest X-ray is an acute radiation exposure.

Affected communities:

Communities that are impacted by a transportation program, for example, communities along a route used to ship spent fuel and high-level waste.

Agreement State:

States that have assumed authority under Section 274b of the Atomic Energy Act to license and regulate by-product materials (radioisotopes), source materials (uranium and thorium), and certain quantities of special nuclear materials.

Atoms for Peace Program:

A U.S. program begun under the Eisenhower administration to supply research reactor technology and nuclear fuel to foreign nations that agreed to forgo the development of nuclear weapons.


Bare-fuel packages:

See Package.

Becquerel:

A unit of radioactive decay equal to 1 disintegration per second.

Bounding accident scenarios:

Physically realistic accident scenarios that would be expected to produce large thermal and mechanical loading conditions.

Burn-up:

A measure of the degree to which the uranium-235 in nuclear fuel has been used up (fissioned), which determines the amount of radioactivity and heat generation in the fuel after it has been removed from the reactor.

BWR:

Boiling water reactor, a type of nuclear reactor in which the reactor’s water coolant is allowed to boil to produce steam. The steam is used to drive a turbine and electrical generator to produce electricity.

Byproduct material:

Defined by the Atomic Energy Act as radioactive material (except special nuclear material) yielded in or made radioactive by exposure to the radiation incident to the process of producing or using



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