14 15 Flashcards
Mox
mixed oxide fuel
separating plutonium from everything else- but not good cause ppl use plutonium for weapons
nuclear waste
mining & milling -large volumes of mine tailings
Spent fuel
decommissioning of nuclear facilities
nuclear waste-recycling
if you separate out the fission products it produces from U and plutonium
you get concentrated fiffion products in nitric acid
so concentrated it precipitates
very radioactive and dangerous
dry it out then set it in glass
secondary waste
Derived from the process of
handling or processing
radioactive materials.
- Largest volume of waste
- Least radioactivity
- e.g. reagents, solvents, plant,
protective clothing etc.
more secondary but less dangerous
how radioactive for deep burial disposal
4,000 alph, 12000 beta/gamma Bq/g
waste classification
need to consine waste to right catorgory as deep disposal is extremely expensive
high level waste
very hot- facility need to be able to deal with heat (corrosion faster when hot)
spent fuel -high level waste
sits in pond for at least a year and cooled
can’t go underground until surface temp is under 100oC (50yrs)
Objectives of waste management are to
- Minimise the production of secondary waste
- Convert waste forms into the least practicable volume of a solid that is suitable for long-term storage/disposal
- Keep environmental impact as low as is reasonable attainable (ALARA).
Always within strict limits set by regulatory bodies
Mill Tailings (long answer chill out about memorising)
Mill Tailings from Uranium mills are a type of waste specific to
countries, which mine uranium.
– Not relevant to the UK United Kingdom.
– Mill tailings commonly have low levels of radioactivity and
comprise a dirty mix of ore material including elements such as
Thorium and Radium.
– Tailings leave the mill as a radioactive sludge, and are allowed to
dry.
– Radioactive mine tailings sites provide an obvious contamination
hazard (water supplies, wind-blown dust etc.)
radioactivity vs time
high level waste drops off first
U radiation increase with time as the daughters are more reactive than U
Storage
Typically in surface facilities, where
material is being ‘stored’ indefinitely or pending future disposal. Some facilities may store material for decades or centuries placing an economic burden on future generations.
Disposal
Material is isolated (typically
underground) from humans and the environment. Isolation can be permanent and future generations
can ‘ignore’ its existence
nuclear waste disposal
legacy mine working
going back to U mines and putting the waste back where it is from
good as tunnels are already there so less expensive
maybe ppl could steal it
government don’t like it
Low level waste disposal
LLW is typically disposed in ‘nearsurface’ facilities, at either at Ground level, or In caverns just below ground
level (at depths of 10m’s)
cost low
not safe enough for dangerous waste
isolating it from water
could be a problem with sea level rise
