A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

T

tank:
A tank container, a portable tank, a road tank vehicle, a rail tank wagon or a receptacle with a capacity of not less than 450 litres intended to contain liquids, powders, granules, slurries or solids which are loaded as gas or liquid and subsequently solidified, and of not less than 1000 litres intended to contain gases.  A tank container shall be capable of being carried on land or on sea and of being loaded and discharged without the need of removal of its structural equipment, shall possess stabilizing members and tie-down attachments external to the shell, and shall be capable of being lifted when full. [41]

thorium series:
The decay chain of thorium-232.
Namely, thorium-232, radium-228, actinium-228, thorium-228, radium-224, radon-220, polonium-216, lead-212, bismuth-212, polonium-212 (64%), thallium-208 (36%) and (stable) lead-208.

thoron:
Radon-220.

tissue equivalent material:
Material designed to have interaction properties when irradiated similar to those of soft tissue.
Used to make phantoms, such as the ICRU sphere.
The tissue equivalent material used in the ICRU sphere has a density of 1 g/cm3 and an elemental composition, by mass, of 76.2% oxygen, 11.1% carbon, 10.1% hydrogen and 2.6% nitrogen, but materials of various other compositions (e.g. water) are considered suitable for particular applications [49].
The term tissue substitute is also used with the same meaning.

tissue weighting factor, wT:
Multiplier of the equivalent dose to an organ or tissue used for radiation protection purposes to account for the different sensitivities of different organs and tissues to the induction of stochastic effects of radiation. [40]
The tissue weighting factors recommended by ICRP for calculating effective dose are:

Tissue or organ

wT

Gonads

0.20

Bone marrow (red)

0.12

Colon a

0.12

Lung

0.12

Stomach

0.12

Bladder

0.05

Breast

0.05

Liver

0.05

Oesophagus

0.05

Thyroid

0.05

Skin

0.01

Bone surface

0.01

Remainder b

0.05

a The weighting factor for the colon is applied to the mass average of the equivalent dose in the walls of the upper and lower large intestine.

b For the purposes of calculation, the remainder is composed of adrenal glands, brain, extrathoracic region, small intestine, kidney, muscle, pancreas, spleen, thymus and uterus. In those exceptional cases in which the most exposed remainder tissue receives the highest committed equivalent dose of all organs, a weighting factor of  0.025 shall be applied to that tissue or organ and a weighting factor of  0.025 to the average dose in the rest of the remainder as defined here.

transboundary movement:
1.   Any movement of radioactive material from one State to or through another.
2.   Any shipment of spent fuel or of radioactive waste from a State of origin to a State of destination. [13]

transport:
1.   The deliberate physical movement of radioactive materials (other than those forming part of the means of propulsion) from one place to another.
The term transportation is also used, particularly in US English or where there is a need to distinguish this meaning of transport from meaning (2).

  • international nuclear transport: [The carriage of a consignment of nuclear material by any means of transportation intended to go beyond the territory of the State where the shipment originates beginning with the departure from a facility of the shipper in that State and ending with the arrival at a facility of the receiver within the State of ultimate destination.] [26]
    More recent texts use the term transboundary movement for a similar concept.

2.   The movement of something as a result of being carried by a medium.
A general term used when a number of different processes are involved.  The most common examples are heat transport— a combination of advection, convection, etc. in a cooling medium — and radionuclide transport in the environment — which could include processes such as advection, diffusion, sorption and uptake.

transportation:
See transport (1).

treatment:
See waste management, radioactive (1).