2. Discovery of Thorium
Thorium was discovered in 1828 by the Swedish chemist Jons Jakob
Berzelius as thorite (ThSiO4)
232Th has Half Life Of 1.4 E10 years! No stable Isotopes
Fertile not Fissile
Atomic Number: 90
Atomic Weight: 232.03806
Phase at Room Temperature: Solid
Element Classification: Metal
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3. Why Thorium when we have Uranium?
Cross section σy = 7.34b, 85; σf <1µb
Fast Flux reduces unwanted isotopes
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Thorium Requires high energy neutron flux Transitioning Thorium Breeds fuel
4. Flaws of Liquid Drop Model
B(A,Z) A= 232, Z=92
Binding energy approximation: 12.83 Mev/A
Actual Binding Energy : 7.615 Mev/A
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5. It’s Magic, You Know!
Double Magic number Z=92, A=232
Closed Shell, Jπ = 0 Making it super stable
Explains The long half life
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6. Thorium In Action 6
Fission product Distribution
Thorium to 233 Uranium fuel
8. Thorium In Nature
Predicted abundance of about 15 parts per million in the earth’s crust
(.0007%), many times greater than that of uranium.
More thorium energy available than all fossil fuels and other nuclear
sources combined
It’s decay thought to be responsible for the earth’s internal temperature.
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Magnified Green
Thorite crystal
9. The FLiBe Juice
FLiBe (Li2BeF4) is a molten salt made from a mixture of lithium fluoride (LiF)
and beryllium fluoride (BeF2).
Molten FLiBe flowing sample's green tint is from dissolved uranium
tetrafluoride.
Melting point of 459 °C, a boiling point of 1430 °C, and a density of 1.94
g/cm3. Its heat capacity is 4540 kJ/m3
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Molten FLiBeFleeb (Plumbus)
10. Thorium is Safe!
The fissile material weapon quality is evaluated by considering three
properties:
The critical mass is different for different isotopic composition of Pu;
weapon yield degradation due to pre-initiation caused by spontaneous
fission neutrons;
weapon stability degradation caused by heat emission.
No enrichment facilities
No 239 Pu generation
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