FBR/TBR: the future of nuclear reactors

[amardeep mishra]

Here is my little analysis, as to why FBRs/TBRs are better that rivals for PWRS/PHWR
1) A breeder reactor is designed to create more
fissile material (nuclear fuel) than it consumes.
Depending on the Breeding Ratio of a reactor,
it can produce new fuel at a greater or lesser
rate. The Breeding Ratio represents the number
of new fissile atoms created for each fission
event. The theoretical upper limit for the
Breeding Ratio is 1.8, while most breeder
reactors are designed to produce just about as
much fissile material as they consume.
The greatest advantage of FBR is after an initial
loading of enriched U or Pu, it can thereafter be
powered just by periodic loadings of
unenriched (natural) uranium or thorium.
Thorium is about four times more abundant in
the Earth’s crust than uranium, poses very
little weaponization risk, and produces nuclear
waste which decreases in intensity to
background levels much quicker than the
waste from a conventional plant.
Breeder reactors can produce bomb-ready
nuclear fuel, such as plutonium. This problem is
addressed by a stage in nuclear preprocessing
where other elements such as curium and
neptunium are added in tiny quantities to the
plutonium. This form of processing has no
effect on the use of plutonium as a reactor fuel,
but makes it extremely difficult to use the
material to create an atomic bomb, even if
utilizing a very sophisticated design.
2)all conventional reactors have a burn up
of about .5-.8(which means they produce
about 50-80% of fissile material they
consume),though the current trend is shifting
towards manufacturing PWRs with very high
burnups,they can never achieve the breeding
ratios of a fast breeder reactor,infact in
america,thanks to high burups of their reactor
design,they are able to produce 1/3 of their
total nuclear energy based on bred fissile
material,so,in a way,FBR helps increase the
productivity,it breeds enough fissile material
for other reactors
indian has successfully mastered the 1st stage
of breeder reactor(FAST breeder reactors)
where initially a Pu loading is given in the core
and the fuel cycles consists of subsequent
loading of natural uranium,our 2nd stage is to
design THERMAL fast breeder which sustains
on only the subsequent fuel cycles of
"thorium"(india's first experiemtal 45MWe FBR
went critical in october 1985)
3)and FBR has a very distinct advantage in the
sense that it also has the ability to process the
radiotoxic wastes depending on the design of
the reactor,In principle, breeder fuel cycles can
recycle and consume all actinides, leaving only
fission products. So, after several hundred
years, the waste's radioactivity drops to the
low level of the long-lived fission products. If
the fuel reprocessing process used for the fuel
cycle leaves actinides in its final waste stream,
this advantage is reduced.(i mean subjected to
the of presence of "breeding blanket" around
the main fuel assembly)
4) i assume nuclear engineers here on this forum are aware of the dwindling
stock of uranium,infact as a matter of fact the
thorium reserves are many times higher than
those of uranium,it QUITE logical,that the
whole world will have to look towards thorium
based energy in near future
here are a few projects goin on in many
countries
1)phenix and superphenix constructed by
france(infact 1200MW SP is the world's largest
FBR till now)
2)KNK-II of germany
3)indian FBR and later TFBR
4)british dounrey FBR
5)soviet BN-350 and BN-600
disadvantages-
here the coolant is liquid sodium,which means
it cant be effectively used for naval
propulsion,because a breach in the core would
result in fire,and would spiral out of
control,though FBRs,or TFBRs can be
EFFECTIVELY USED in ground based platforms
quite frankly,there aint any disadvantages
of FBR,except itz cost,though that too would
reduce as the newer technologies come in,AND
THE SHEER ADVANTAGES OF A FBR HEAVILY
OUTWEIGH ITZ cost-based
"DISADVANTAGES"

 

[A$HU]

Here is my little analysis, as to why FBRs/TBRs are better that rivals for PWRS/PHWR
1) A breeder reactor is designed to create more
fissile material (nuclear fuel) than it consumes.
Depending on the Breeding Ratio of a reactor,
it can produce new fuel at a greater or lesser
rate. The Breeding Ratio represents the number
of new fissile atoms created for each fission
event. The theoretical upper limit for the
Breeding Ratio is 1.8, while most breeder
reactors are designed to produce just about as
much fissile material as they consume.
The greatest advantage of FBR is after an initial
loading of enriched U or Pu, it can thereafter be
powered just by periodic loadings of
unenriched (natural) uranium or thorium.
Thorium is about four times more abundant in
the Earth’s crust than uranium, poses very
little weaponization risk, and produces nuclear
waste which decreases in intensity to
background levels much quicker than the
waste from a conventional plant.
Breeder reactors can produce bomb-ready
nuclear fuel, such as plutonium. This problem is
addressed by a stage in nuclear preprocessing
where other elements such as curium and
neptunium are added in tiny quantities to the
plutonium. This form of processing has no
effect on the use of plutonium as a reactor fuel,
but makes it extremely difficult to use the
material to create an atomic bomb, even if
utilizing a very sophisticated design.
2)all conventional reactors have a burn up
of about .5-.8(which means they produce
about 50-80% of fissile material they
consume),though the current trend is shifting
towards manufacturing PWRs with very high
burnups,they can never achieve the breeding
ratios of a fast breeder reactor,infact in
america,thanks to high burups of their reactor
design,they are able to produce 1/3 of their
total nuclear energy based on bred fissile
material,so,in a way,FBR helps increase the
productivity,it breeds enough fissile material
for other reactors
indian has successfully mastered the 1st stage
of breeder reactor(FAST breeder reactors)
where initially a Pu loading is given in the core
and the fuel cycles consists of subsequent
loading of natural uranium,our 2nd stage is to
design THERMAL fast breeder which sustains
on only the subsequent fuel cycles of
"thorium"(india's first experiemtal 45MWe FBR
went critical in october 1985)
3)and FBR has a very distinct advantage in the
sense that it also has the ability to process the
radiotoxic wastes depending on the design of
the reactor,In principle, breeder fuel cycles can
recycle and consume all actinides, leaving only
fission products. So, after several hundred
years, the waste's radioactivity drops to the
low level of the long-lived fission products. If
the fuel reprocessing process used for the fuel
cycle leaves actinides in its final waste stream,
this advantage is reduced.(i mean subjected to
the of presence of "breeding blanket" around
the main fuel assembly)
4) i assume nuclear engineers here on this forum are aware of the dwindling
stock of uranium,infact as a matter of fact the
thorium reserves are many times higher than
those of uranium,it QUITE logical,that the
whole world will have to look towards thorium
based energy in near future
here are a few projects goin on in many
countries
1)phenix and superphenix constructed by
france(infact 1200MW SP is the world's largest
FBR till now)
2)KNK-II of germany
3)indian FBR and later TFBR
4)british dounrey FBR
5)soviet BN-350 and BN-600
disadvantages-
here the coolant is liquid sodium,which means
it cant be effectively used for naval
propulsion,because a breach in the core would
result in fire,and would spiral out of
control,though FBRs,or TFBRs can be
EFFECTIVELY USED in ground based platforms
quite frankly,there aint any disadvantages
of FBR,except itz cost,though that too would
reduce as the newer technologies come in,AND
THE SHEER ADVANTAGES OF A FBR HEAVILY
OUTWEIGH ITZ cost-based
"DISADVANTAGES"

There are two ways of obtaining energy from thorium.First one is the difficult way i.e The liquid fluoride thorium reactor, a thermal breeder reactor which uses the thorium fuel cycle in a fluoride-based molten liquid in which the chinese are said to be interested and are already making rapid developments in its research and their scientists announced couple of years ago at a convention in oak ridge national laboratory the reactor will come to fruition in 20 years and the second technology on which india is working on has been already tried and abandoned by Us,france,germany and russia way earlier,due to high costs and less efficiency.

 

[amardeep mishra]

Well, thorium fuelled MSR is our next logical step...I think thats the 3rd stage of our nuclear reactor programme