GLOSSARY[e1]
Overpack-A process which encapsulates damaged packages in a larger package.
500L drumUunshielded cylindrical waste package which has a volume of 500L. Normally contains ILW.
3m3 drumuUnshielded cylindrical waste package which has a volume of 3m3. Normally contains immobilised radioactive ILW sludge.
3m3 boxuUnshielded waste package which has a volume of 3m3. Normally contains solid radioactive ILW waste.
300 year time after entry of emplacement of the first package into
Monitoring Periodthe PGRC facility. During this period packages will be inspected to chart their condition, taking remedial action where necessary.
3D MappingAa Non Destructive Testing method which emits waves and receives the reflected waves. Such method could detect surface cracks and dimensions of an objectmeasures the dimensions of a package.
Backfillingfilling the PGRC with concrete. This is envisaged to occur
at the end of the 300 year Monitoring Period.
ConcreteaA cementitious based composite which consists of cement, water, coarse aggregate and fine aggregate.
ColdaAn environment that contains levels of radiation that are
suitable for
humans to work in.
ContaineraAn empty stainless steel package which has no grout or any waste forms in it.
DecontaminationtThe complete or partial removal of contamination by a
deliberate
physical, chemical or biological process.
Direct wWorkers visually inspecting a package with the naked eye. Primarily
Viewing Primarily through an oil filled shielded window which
provides protection from the
radiation.
DPIDye Penetrant Inspection method is a Non Destructive Testing method. By allowing dye to seep into cracks, and cleaning the surface, one could identify the presence of a crack can be easily
identified.
Encapsulation Immobilisation of solid waste by mixing it with a matrix material within a container in order to produce a more stable waste form.
GPRGround Penetrating Radar is a Non Destructive Testing method. By transmitting and receiving radio waves and receiving it, one could determine the attenuation of concrete can be determind. It is being used to monitor the curing of concrete structures.
Grabthree armed lifting crane to lift/move a 500L drum.
GroutAa cementitious based composite used to immobilise waste. It mainly consists of cement, water and fine aggregate. This will be used in the Overpacking procedure.
Half-lifetThe time required for half the number of nuclei of a specific radionuclide to undergo radioactive decay.
HotAan environment that contains levels of radiation that are too
high for
humans to work in.
HarwellCcurrent (February 2007) home of Nirex, UK where ‘ILW stored just below surface’ is being removed, inspected, and stored. This waste will be transferred to the PGRC when built.
IndirectVisual inspection of a package using indirect means such as cameras.
Viewing
ILWIntermediate Level (Radioactive) Waste; wastes with radioactivity levels exceeding the upper boundaries for Low Level Waste whose heat generation is low and but which do not require heating to need not be taken into account in the design of storage or disposal.
ImmobilisationcConversion of waste into a less mobile or non-mobile form by, for example grouting or encapsulating.
IndirectVisual Inspection of a package using indirect means such
Viewingas cameras.
MagnoxGhas cooled fission reactor using un-enriched uranium as the fuel, with magnesium alloy as cladding., theThis reactor type was used in the UK’s first generation nuclear power plants.
Master/SlavetTools currently used to inspect and rework waste drums
Manipulators tthat are being
Manipulator extracted from ‘just below (MSMs)surface’
storage at Harwell.
NirexUK Nirex Ltd. A company jointly owned by DEFRA and the DTI that advises nuclear site operators on the preparation of safety case submissions to the regulator for the conditioning and packaging of radioactive waste.
Oil filledaAllows direct viewing into hot areas of the Inspection and
shieldedOverpacking Cells whilst providing protection from the
windowe dangerously
window hhigh levels of radiation within the cellsse ‘hot’ areas.
Overpackinga process which encapsulates damaged packages in a larger container
Packagea sealed 500L drum, 3m3 box or 3m3 drum containing
radioactive waste.
PGRC Phased Geological Repository Concept is the concept facility which will manage radioactive waste in the long term, which includes storage, 300 year Mmonitoring Period and Bbackfilling in a phased geological disposal method..
Radionuclide aA nucleus of an atom that possesses properties of spontaneous disintegration. Nuclei are distinguished by their mass and atomic number.
ReworkingmMinor repair work on degrading or damaged packages. and to prevent further minimise further degradation from occurring.
Sievert (Sv)The SI unit of radiation dose.
StillageaAtool container for holdingusedto facilitate four 500L drums. The drums are only extracted from a stillage when being individually inspected in the Inspection Cell or overpacked in the Overpacking Cell.It is being used to enable stacking and transport of 500L drums more efficiently.
Storage VaultAa facility within the PGRC which is being used to store the waste packages.
Transfer Tunnel tThe tunnel which connects all inspection cells together and with the overpacking cell. A rack and pinion system will be adopted.
Twist Locka crane locks into this feature to move/lift a package. A T-
(T-Lock)Lock is used on a 3m3 box, 3m3 drum and stillage.
Vaultsee ‘Storage Vault’.
Wastesee ‘Package’.
Package
Radiation Terms[1]
Absorbed the amount of energy actually absorbed in a material. Dose Used for any type of radiation and any material.
Alphaa particle emitted from the nucleus of an atom, that contains two protons and two neutrons. It is identical to the nucleus of a Helium atom, without the electrons.
Betaa high speed particle, identical to an electron, that is emitted from the nucleus of an atom
Equivalent ‘Absorbed Dose’ in human tissue related to the effective
Dosebiological damage of the radiation
Gamma Rayelectromagnetic waves or photons emitted from the nucleus of an atom.
Gray (Gy)unit used to measure Absorbed Dose. One gray is equal to one joule of energy deposited in one kg of a material. The unit gray can be used for any type of radiation, but it does not describe the biological effects of the different radiations. Absorbed Dose is often expressed in terms of hundredths of a gray, or centi-grays.
Sievert (Sv)SI unit used to measure Equivalent Dose. This relates the absorbed dose in human tissue to the effective biological damage of the radiation. Not all radiation has the same biological effect, even for the same amount of absorbed dose. Equivalent Dose is often expressed in terms of millionths of a sievert, or micro-sievert. To determine equivalent dose (Sv), you multiply absorbed dose (Gy) by a quality factor (Q) that is unique to the type of incident radiation.
Becquerel SI unit of activity equal to one disintegration per second[2].
(Bq)Phased Geological Repository Concept (PGRC)PGRC is the concept facility which will manage radioactive waste in long term, which includes storage, monitoring and backfilling.
Minor ReworkingMinor repair work on damaged packages and to prevent further corrosionminimise further degradation from occurring..
GroutA cementitious based composite used to immobilise waste. It mainly consists of cement, water and fine aggregate. This will be used in the Overpacking procedure.
ConcreteA cementitious based composite which consists of cement, water, coarse aggregate and fine aggregate.
[1] Idaho State University, USA
(unknown) ONLINE “Radiation related terms”. [Online]. Last viewed 2007 April 18. Available:
[2] NDT, (unknown) ONLINE “Glossary of Terms for Radiographic Testing”. [Online]. Last viewed 2007 April 18. Available:
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