Isotopes are same number of
different number of
Radioactivity is when a nucleus becomes
due to too many
Radioactive Decay is the process in which a
atom becomes stable by emitting an
Radioactive Half Life is the amount of
that a quantity of radioactive material requires to decay to
of its original amount.
Characteristics: Highly energetic particle consisting of 2
emitted from the
Organ of interest
Means of production: Radioactive decay of uranium and activation products from defective or
Source Geometry: Alpha particles travel only a few
systems when a fuel failure has occurred.
Characteristics: A high speed
Emitted from the nucleus. Mass =
amu. Negatively charged.
penetrating, but more than
Stopped by plastic or glass ~ 1cm thick.
Organs of interest:
Means of Production: Radioactive
products. Source Geometry:
systems. Beta dose rate
very rapidly as you approach the sources.
Characteristics: Energetic form of electromagnetic energy. No
emits a specific energy gamma photon.
Penetrating Power: Travels
distances in air.
by dense materials like lead. Organ of interest:
Means of production:
- when a neutron is captured by a nucleus of an atom, a gamma ray is emitted.
- occurs at point of fission.
- when fission and activation products decay. Source Geometry:
source - hot particle.
source - pipe.
source - reactor face.
- defuelled channel.
Characteristics: Mass of
amu. Normally located in the
electrical charge. Neutron radiation is the only type of radiation that can cause other materials to become
penetrating. Shielded with
materials. Organs of interest:
Means of Production:
Neutrons - Fissioning of fuel in the reactor.
Neutrons - Gamma energies (photons) grater than 2.2 MeV interact with
in heavy water to produce photoneutrons. Source Geometry: Neutron
Characteristics: A radioactive isotope of
with a radiological T 1/2 of
hazard only. Decays to Helium-3. Exposure Pathways
Organs of interest: Whole body. Effective half-life of
to remove 1/2 of the tritium from your body through biological elimination. Means of Production:
activation of Deuterium Oxide (D2O).
Characteristics: Fine particulates of
material suspended in
They can be
lived. Exposure Pathways:
Organ of interest: Dependant on
process and the
Characteristics: Noble gases are
hazard. Exist as a
with uniform dose rate within the cloud. Decay to short lived airborne particulate. Exposure Pathways:
Organ of interest:
Characteristics: Radioactive isotope of carbon.
emitter. Radiological half-life of
years. Two forms:
- Whole body.
- Lungs. Means of Production:
Activation of Oxygen and Carbon by air ingress into systems.
Activation by Nitrogen ingress into systems.
products that are distributed on a surface. Fixed Contamination is
to remove. Loose Contamination is
Particle are discrete radioactive particles approx
in size and >
mrem/h contact. Exposure Pathways:
if becomes airborne. Organ of interest: Fixed Contamination;
to the whole body,
to skin, eyes and extremities. Loose contamination; Dependant on solubility. Hot Particles;
on the system.
of system components (valves, etc). Machining/Grinding of radioactive materials. Planting out on inner surfaces of
setting out on surface. Decay of
Liquids. Exposure Pathways:
hazard dependant on dose rates.
if an uptake occurs. Organs of interest: Dependant on radionuclide's in liquid. Means of Production: Mechanical
of reactor system components.
of nuclear systems. Handling of contaminated liquids, e.g. D2O drums.
of equipment from irradiated fuel facilities. The handling of liquid sources (normally in laboratories).
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