This presentation briefly explain PUREX, UREX & other fuel reprocessing method

1. Nuclear Fuel
Reprocessing
Istiak Uddin Sazzad
Shams-E-Alam Prianka
Abu Sayed

2. Energy Independence
Spiraling prices for hydrocarbons and
prospects of their imminent extinction
are encouraging more and more
countries to look at nuclear energy as
an alternative means to ensure their
sustainable development.It’s
becoming increasingly important to link
the objective need for an expanded use
of nuclear energy.

3. World energy needs & nuclear
power
• The world will need significantly increased energy supply in the
future, especially cleanly-generated electricity.
• Electricity demand is increasing about twice as fast as overall
energy use and is likely to rise by more than half to 2040.
• Nuclear power provides over 10% of the world's electricity, and
18% of electricity in OECD countries.
• Almost all reports on future energy supply from
major organisations suggest an increasing role for nuclear
power as an environmentally benign
way of producing reliable electricity
on a large scale.
http://www.tva.gov/sites/wattsbarnuc.htm

4. A Little Background
• Nuclear Power
–Nuclear Weapons
–Nuclear Reactors: Electricity
Production
• The Nuclear Fuel Cycle
• The Nuclear Waste Problem

5. Nuclear Power: Basics
Nuclear Fission
• When the nucleus of an atom splits into two or more smaller nuclei
Nuclear Energy
• The controlled use of nuclear fission
• Nuclear energy is released when a fissile material such as uranium-235
is fissioned in a controlled nuclear chain reaction
• (The chain reaction that releases the
energy of a nuclear weapon is rapid
and uncontrolled)
Uranium
• Symbol – U, atomic # 92
• Occurs naturally in minerals
• Exists in three forms: U-238 (99.3%), U-235 (.7%), and U-234 (.006%)
Plutonium
• Symbol – Pu, atomic # 94
• Found rarely in nature; usually made from uranium
http://www.atomicarchive.com/Fission/Fission1.shtml

6. Nuclear Reactors: How do they
work?
• The controlled (nuclear fission) chain
reaction produces heat, which boils
water, which produces steam, which
drives a turbine, which generates
electricity.
• Most nuclear reactors are Light Water
Reactors (LWR) meaning that they are
cooled and moderated with ordinary water.

7. The Nuclear Fuel Cycle
The Front End
• Exploration, mining, milling, uranium conversion,
enrichment, fuel fabrication
The Service Period
• Use in a nuclear reactor
• Nuclear fuel is generally used for 12-18 months
before it no longer generates enough heat
The Back end
• Storage, transportation, (reprocessing,
transmutation), waste disposal

8. The Nuclear Fuel Cycle
1. Uranium Ore 3. Enriched U (UF6)
2. Yellowcake (U3O8) 4. Nuclear Fuel (UO2)
5. Fuel Rods (zirconium alloy)
1 3
2 4
3.5-5% U-235
5
http://www.mnf.co.jp/images2/2img_pwr.gifWikipedia.org

9. The Nuclear Fuel Cycle
Alternatives: The “once-through” fuel cycle versus
the “closed-loop” (reprocessing) cycle
http://www.mext.go.jp/
english/news/1999/10/j
co-e91012a2.gif

10. The Nuclear Waste Dilemma
• To date, the U.S. has produced more than
50,000 metric tons of Spent Nuclear Fuel
• Where do we put the more than 2000
metric tons of radioactive waste generated
in reactors each year?
– Spent Fuel Pools
– Dry cask storage
– Geological Repository
U.S. DOE

11. On-site storage of SNF
Wet storage
• The great majority of spent nuclear fuel is initially
stored as spent fuel assemblies in water-filled pools
on power plant sites.
• The pools provide radiation shielding and cooling
Dry Storage
• Spent Fuel is usually placed in dry cask storage after 5 years
in wet storage.
• Dry cask storage uses concrete or steel
containers as a radiation shield and is cooled
by inert gas or air.
• The casks are built to withstand the elements
and accidents and do not require electricity,
water, maintenance, or constant supervision
http://infocusmagazine.org/5.2/eng_nuclear_plants.html
U.S. DOE

12. Reprocessing: A Solution?
Reprocessing: The chemical separation of
spent nuclear fuel into its major components.
Wikipedia.org

13. HISTORY
• The first method selected, a precipitation process called
the bismuth phosphate process, was developed and
tested at the Oak Ridge National Laboratory (ORNL)
between 1943 and 1945 to produce quantities of
plutonium for evaluation and use in the US weapons
programs
• The bismuth phosphate process was first operated on a
large scale at the Hanford Site, in the later part of 1944
• The first successful solvent extraction process (PUREX
process) for the recovery of pure uranium and plutonium
was developed at ORNL in 1949.

14. Bismuth phosphate process

15. Products of Reprocessing
• Uranium
– .6% U-235 and 99.4% U-238
• Plutonium
• Minor Actinides
– Americium
• Major long-term heat source
– Neptunium
• Major source of radiation
– Curium
• Fission Products
– Strontium-90, Cesium-137
• Generate large amounts of heat for the first 50-80 years after disposal
• Removal from the repository would reduce the amount of space needed
– Iodine-129, Technetium-99
• Mobile isotopes that can easily travel through geological formations
• Major contributors of radiation to biosphere

16. Reprocessing: Methods/Techniques
PUREX:
Plutonium and
Uranium
Extraction
Most widely used
method
Results in a pure
stream of
plutonium
UREX: Uranium
Reduction
Extraction
Replacement for
PUREX
Results in pure
uranium stream
The plutonium
remains mixed
with the fission
products and
minor actinides
UREX+
Refinement of
the UREX
process
Pyroprocessing
Reduces the liquid
waste that remains
in the UREX
process

17. Evolutionary Technologies
• COEX (France) :
-UO2 and MOX from LWR, high BU fuels, MOX from Fast
Reactor
• NUEX (UK) :
-UO2 from LWR
• Simplified PUREX (Russia):
-UO2 from LWR
• THOREX (INDIA) :
-ThO2 irradiated in research Reactor
• NEXT (Japan):
-MOХ from FR
• REPA (Russia):
-UO2 from LWR

18. International Reprocessing
• About 30% of the world’s LWR spent fuel
is reprocessed using PUREX
• Among the nuclear-armed states, France,
India, Russia, and the
United Kingdom engage
in reprocessing
• Japan is the only non-
nuclear-armed state
that has a civilian reprocessing program

19. World Commercial
Reprocessing Capacity
(tonnes per year)
LWR fuel
France, La Hague 1700
UK, Sellafield
(THORP)
600
Russia, Ozersk
(Mayak)
400
Japan (Rokkasho) 800*
Total LWR (approx) 3500
Other nuclear fuels
UK, Sellafield
(Magnox)
1500
India (PHWR, 4
plants)
330
Japan, Tokai MOX 40
Total other (approx) 1870
Total civil capacity 5730

20. PUREX Process
• “Plutonium and Uranium Recovery by
Extraction”
• History
– 1960s
– United States use, disuse
– International use

21. PUREX Process
• Technology
– uses solvent extraction
(liquid-liquid system)
– basis for advanced fuel
cycles
• Generation IV reactors

22. The Purex process has the following major
steps
• Decladding or dejacketing
• Dissolution
• Feed preparation
• Co-decontamination and Partition cycle
• Final U purification cycle
• Final Pu purification cycle
• Pu and U reconversion to their oxides.

23. Decladding/Dejacketing
• Commons cladding materials are
aluminium, zircaloy and stainless
steel etc.
• the fuel assemblies are chopped
• Then dissolved in nitric acid
• the cladding materials remaining
undissolved.

24. Dissolution
• Uranium dioxide dissolves in nitric acid by the
reaction:
3UO2 + 8HNO3 → 3UO2(NO3)2 + 2NO + 4H2O
• Uranium is present in sixth valence state
• Plutonium mostly in tetravalent state.
• The tetravalent state of total plutonium is ensured by
further addition of NaN02

25. Solvent Extraction with TBP
Tributyl phosphate(TBP) as an Extractant
• Highly selective for U and Pu.
• Cheap and available
• High boiling point (266°C) and is non-volatile.
• High chemical, thermal and radiation stability.
• low extractability for fission products resulting in
excellent purification of U and Pu.
• high density (0.973) and high viscosity.
*TBP is diluted with kerosene.

26. Solvent Extraction with TBP
Extraction of uranium and plutonium
• Uranium in tetravalent state
• Plutonium in hexavalent state

27. Co-decontamination and Partition cycle
Co-extraction
• The aim is to separate U and Pu together from
fission products.
• The centrifugal contactor consists of extraction
and scrub section
Partitioning
• The co-extracted U and Pu is taken to the
partitioning contactor where uranium and
plutonium are separated from each other.

28. Co-decontamination and Partition
cycle
Fig- Scheme for extraction of U and Pu

30. Variations on PUREX Process
• UREX+
– Addition of AHA removes 99.9% Ur and 95%
Tc
TRUEX, DIAMEX, SANEX
• Pyroprocessing
– Non-aqueous
• Many others

31. UREX PROCESS
• Uranium and technetium extraction process
developed under the US Advanced Fuel Cycle
Initiative (AFCI) program
• Advanced version of PUREX process in which
plutonium remains in the raffinate along with
other minor actinides and fission products
• To account for proliferation issue acetohydroxyl
amine is used as a complexing agent to prevent
extraction of plutonium in the product stream

32. UREX PROCESS
• Main goal : recover > 99.9%
Uranium,>95% Technetium in separate
product streams
• Demonstration : at the laboratory scale at
the Savannah River National Laboratory
using irradiated fuel from the Dresden
BWR

33. UREX PROCESS

34. UREX PROCESS

35. UREX PROCESS
• Extraction section
– Feed containing spent fuel dissolved in HNO3 is fed
into the extraction section
– Contacted with fresh solvent 30% tri-butyl phosphate
(TBP) dissolved in n-dodecane
– U and Tc are separated from the dissolved spent fuel
– The raffinate containing transuranic (TRU) and all
fission products (FP) except technetium becomes the
feed for CCD-PEG process
*CCD-PEG : chlorinated cobalt dicarbollide –
polyethylene glycol

36. UREX PROCESS
• Scrub section
– Complexant /reductant is added to form
complex with the plutonium (Pu) and
neptunium (Np) and hence prevent their
extraction

37. UREX PROCESS
• Strip section
– Uranium and technetium is stripped off from
the loaded solvent by using dilute nitric acid in
the strip section
– Generally high concentration of nitric acid is
used in the strip section to strip off uranium
and technetium from loaded solvent

38. UREX PROCESS
• The complex formation of neptunium and plutonium and
extraction of technetium can be increased by using low
concentration of nitric acid both in the feed as well as in
the scrub.
• Highly concentrated nitric acid is used for stripping off
technetium from the solvent.
• Uranium is separated from the solvent using dilute nitric
acid
• The addition of acetohydroxamic acid greatly diminishes
the extractability of plutonium and neptunium, providing
somewhat greater proliferation resistance than with the
plutonium extraction stage of the PUREX process

39. acetohydroxamic acid

40. VERSIONS of UREX PROCESS

41. ADVANTAGES
• For countries with a limited amount of naturally
occurring uranium, such as Japan, reprocessing is
an integral part of the nuclear fuel cycle
• Extends the life of available uranium, and in some
countries it is seen as a very efficient use of energy
• An effective way to significantly reduce the amount
of waste to be disposed; only about three percent of
the original quantity of nuclear material remains
unusable, high-level waste.
• Closed fuel cycle – consistent uranium supply

42. DRAWBACKS
• Increase the risk of nuclear terrorism
• Increase the ease of nuclear proliferation
• Toxicity from Pu
• Economically not feasible for some
countries

43. Reprocessing and Nuclear
Terrorism
• Traditional spent nuclear fuel is “self-
protecting” because the spent fuel
assembly (containing the plutonium) has a
radiation dose rate that would be fatal to a
potential thief/terrorist (or scientist) within
half an hour. 8
• Once the plutonium is separated out, it is
no longer “protected” by the radioactive
fission products with which it was formerly
mixed.

44. Separated plutonium: What’s the
big deal?
Proliferation concerns
• The worlds stockpile of separated
civilian plutonium has reach 250
tons.
• The radiation dose rate from
separated plutonium is so low that
it can be safely carried in an
airtight container.8
• Eight (8) kilograms of plutonium
is required to produce a nuclear
bomb.

45. Reprocessing: Economics
Case Study: France
“If France were to stop reprocessing in
2010, it would save $4-5 billion over the
remaining life of its current fleet of power
reactors.”
Case Study: Japan
“Japan recently estimated that the total
extra cost for reprocessing 32,000 tons of
its spent fuel and recycling the plutonium
would be about $60 billion. 10

46. Conclusions
• Reprocessing technology is available at
both the laboratory and industrial scales.
• Potential for future advancement:
– Economic incentives
– Environmental incentives

47. References
1. “Stuck on a solution”
Allison McFarlane
Bulletin of the Atomic Scientists, May/June 2006
http://thebulletin.metapress.com/content/8l138g1h42h77301/fulltext.pdf
2. “Is Big LULU Back In Town? The Revitalization of Nuclear Power”
Fred Bosselman
Planning & Environmental Law, October 2005 Vol. 57, No. 10 | p. 3
3. “The Nuclear Fuel Cycle”
Uranium Information Center Ltd.
http://www.uic.com.au/nfc.htm
4.
A. “Nuclear Fuel Cycle”
Wikipedia
http://en.wikipedia.org/wiki/Nuclear_fuel_cycle
B. “Nuclear Power”
Wikipedia
http://en.wikipedia.org/wiki/Nuclear_power
C. “Nuclear Reprocessing”
Wikipedia
http://en.wikipedia.org/wiki/Nuclear_reprocessing