uranium in the earth 5&6

Question 1

sun can only form elements up too

Answer 1

iron -56

Question 2

enriched continental crust

Answer 2

1.4ppm of U
U, K and Th are large ‘lithophile’ elements and do not readily fit into the structures of the main High-T forming
minerals
*During magma fractionation in the crust, U, K and Th are partitionned into the increasingly small volume
of residual melt
mantle has much less uranium than primitive

Question 3

earth energy source

Answer 3

radioactive decay of uranium and thorium and potassium -drives mantel convection- decreasing source
heat released during progressive solidification of the core

Question 4

why U enriched in crust

Answer 4

dig atom, doesn’t fit in crystal structure
every time there is partial melt in the mantle U kicked out so it carried to the surface

Question 5

shift from methan to oxygen
reducing to oxidising atmos

Answer 5

U in oxidised for is soluble
can reprecipitate in different locations

Question 6

in situ leach

Answer 6

less energy extensive
more envio friendly
injecting highly acid fluid from a input to an output borehole -dissolves out the valuable metals
worker less exposure

Question 7

uranium resource

Answer 7

can extract it from seawater -expensive
70yr of fuel guaranteed deposits

Question 8

U+6

Answer 8

mobile
oxidised
sometime forms uranyl

Question 9

why doesn’t U fit into structures

Answer 9

lots of electrons
ionically huge

Question 10

U mineralogy
chemically reduced forming…

Answer 10

pitchblende -black, dense, reduced U+4

Question 11

U mineralogy
Ionic radius of U, means it can

Answer 11

substitute for other metals in
silicate and oxide structure

Question 12

zircon use

Answer 12

used for mineral dating
same structure as coffinite (ZrSiO4)

Question 13

uranium 6 (normally bonds to what first)

Answer 13

double bonds to oxygen so it has one either side of it
thermodynamic, strong, stable

Question 14

uranium 6 minerals colour

Answer 14

bright yellow or green

Question 15

some glow in the dark due to

Answer 15

the urinal bond (U6) inside- takes in UV light and expresses it back out)

Question 16

why do uranyl ions stay in the water for a long time

Answer 16

lots of natural ligands naturally are electrostatically attracted to U
create stable aqua complex
most stable when complexed with carbonate

Question 17

Vein deposits

Question 18

Intrusive deposits

Question 19

Unconformity-related deposits

Question 20

sandstone deposits

Question 21

Hematitie breccia complex deposits

Question 22

cobalt-60 rad and photon energy

Answer 22

beta
1.17-1.33MeV

Question 23

stable atoms n:p ratio is close to

Answer 23

1

Question 24

sensible dose on earth

Answer 24

0.2mRad/hr

Question 25

Explain why solar flares or coronal mass ejection events might represent a more acute threat
to space travellers.

Answer 25

These are relatively short-lived periods of very intense radiation exposure for the
space crew. In space it would be very difficult to outpace or ‘dodge’ a flare’s radioactivity because it is so large. A spaceship caught by a CME/flare would experience such intense radiation that the crew would likely be killed either immediately or within a few days of exposure. It would also likely disable all of the
onboard electronics (unless they were shut down in advance) and burn-out any onboard antennae used for communicating with Earth. If the crew did survive the
radiation, they would still perish because parts of the ship would be inoperable.
They certainly wouldn’t be able to communicate with the Earth until the
communications arrays had been rebuilt.
make a ‘life pod’ which acts as a shielded enclosure using a water jacket rather than Pb or W because it can be used for more than just a shield material (e.g. drinking water and a heat sink).

Question 26

Why is it incorrect to have an assumed continuous gamma dose of 8mRad.hr-1
for space travel to Mars?

Answer 26

cosmic flux has lots of different radiation types
table of values isn’t accurate as spectrum of gamma rays
radiation intensity varies with distance from the sun and solar flares
earth and mars not same radiation- mars has less as geometric dilution

Question 27

magnetosphere protects us from

Answer 27

proton (ion) irradiation because the EM field (geo-magnetosphere) directs these around the earth – Aurora Borealis
atmospheric depth (air, clouds etc) act to shield us from most of the rest of the
neutron, X-ray and gamma radiation coming from space.