Nuclear Waste and Management

1. Nuclear Waste
Dr. Vivek Kumar,
SVPCET, Nagpur

2. Nuclear Waste…Why?
•Recently nuclear power has entered many discussions as world
energy needs rise and oil reserves diminish.
•Most opponents of nuclear power point to two main arguments:
meltdowns and nuclear waste.
•Nuclear waste is any form of byproduct or end product that
releases radioactivity.
•How to safely dispose of nuclear waste is pivotal for the
continued operation of nuclear power plants, safety of people
living around dump sites, and prevention of proliferation of
nuclear materials to non-nuclear states.

3. Nuclear Fuel Cycle
Most nuclear waste comes from the byproducts of the nuclear
fuel cycle. The cycle typically is split into three sections: front
end, service period, and back end. There can be intermediate
stages that include the reprocessing of nuclear waste elements.

4. Nuclear Fuel Cycle (Cont.)

5. Classifications
• Nuclear waste is segregated into several
classifications.
• Low level waste is not dangerous but sometimes
requires shielding during handling.
• Intermediate level waste typically is chemical
sludge and other products from reactors.
• High level waste consists of fissionable elements
from reactor cores and transuranic wastes.
• Transuranic waste is any waste with transuranic
alpha emitting radionuclides that have half-lives
longer than 20 years.

6. Low Level Waste
LLW
• Low level waste is any waste that could be
from a high activity area.
• 90% volume of waste
• It does not necessarily carry any radioactivity.
• Split into four catagories: A, B, C, and GTCC.

7. Intermediate Level Waste
ILW
• Intermediate level waste requires shielding
when being handled.
• 7% volume of waste
• Dependent on the amount of activity it can be
buried in shallow repositories.
• Not recognized in the United States.

8. High Level Waste
HLW
• High level waste has a large amount of
radioactive activity and is thermally hot.
• 3% volume of waste
• 95% of radioactivity
• Current levels of HLW are increasing about
12,000 metric tons per year.
• Most HLW consists of Pu-238, 239, 240, 241,
242, Np-237, U-236

9. Transuranic Waste
TRUW
• Transuranic waste consists of all waste that
has radionuclides above uranium.
• TRUWs typically have longer half-lives than
other forms of waste.
• Typically a byproduct of weapons
manufacturing.
• Only recognized in the United States.

10. Creation of Nuclear Waste
• Nuclear waste is generated at all points of the
fuel cycle.
• Front end waste consists primarily of low level
alpha emission waste.
• Service period waste typically includes LLW and
ILW such as contaminated reactor housings and
waste from daily operation.
• Back end waste normally is the most radioactive
and includes spent fuel rods and reactor cores.

11. Front End Waste
• Front end waste consists mostly of LLW and
ILW.
• The primary front end waste is depleted
uranium and radium.
– DU has several uses due to its high density (19,050
kg/m3).
– Mix with uranium to form reactor fuel

12. Service Period Waste
• Consists of mostly ILW.
• Mostly waste produced at the plant during
normal operation.
• Spent fuel rods are the most dangerous waste
produced during the service period.

13. Back End Waste
• Nuclear waste developed during the back end
of the fuel cycle is the most dangerous and
includes most of the HLW produced.
• Most back end waste emits both gamma and
beta particles.
• Also uranium-234, neptunium-237,
plutonium-238 and americium-241are found
in back end waste.

14. Waste Management (LLW)sa
• There are several options available for the
disposal of LLW due to its lack of radioactivity.
• Waste Isolation Pilot Plant
• On-site disposal

15. Treatment (LLW)
• Filtration
• Ion Exchange
• Evaporation
• Incineration
• Compaction
• Solidification

16. Waste Management (HLW)
• Most common utilized option are reactor pools and
dry cask storage.
• Other Options for waste management include:
– Deep Geologoical Storage
– Transmutation
– Reuse
– Launching it into space

17. Treatment
• Most common initial treatment of waste is
vitrification.
– Waste is first mixed with sugar and then passed
through a heated tube to de-nitrite the material.
– This material is then fed into a furnace and mixed
with glass.
– The molten glass mixture is poured into steel
cylinders and welded shut.

18. Treatment (Cont.)
• Mid level active waste is commonly treated
with ion exchange
• Process reduces the bulk volume of radioactive
material.
• Typically, mixed with concrete for a solid
storage form.

19. Treatment (Cont.)
• Synroc is a new method for storing nuclear
waste developed in 1978 by Ted Ringwood.
• Attempts to hold radioactive material in a
crystalline matrix.
• Currently in use for military waste
management at Savannah River Site.
• Can hold 50%-70% volume of waste.

20. Deep Geological Repository
• Most common method for handling nuclear waste.
• Typically kept separate from actual plants and buried
far below ground.
• First used in 1999 in the US.
• Current research is focusing on Yucca Mountain.

21. Transmutation of Nuclear Waste
• Reduces transuranic waste.
• Integral Fast Reactor
• Banned 1977-1981 (U.S.)
• MOX Fuel
– Behaves as low-enriched uranium
• Research now in subcritical reactors.
• Fusion also being researched.

22. Reuse of Nuclear Waste
• Research is being performed to find uses for
nuclear waste.
• Caesium-137 and strontium-90 already used in
industrial applications.
• Some waste can be used for radioisotope
thermoelectric generators (RTGs).
• Overall can reduce total HLW but not
eliminate it.

23. Launch it into Space
• Near infinite storage space
• Completely removes waste from biosphere
• Technical risks and problems
• Political entanglements

24. Conclusions
• HLW is most dangerous byproduct of nuclear power.
• Borosilicate glass most common storage.
• Several venues being researched for the safe disposal
of HLW.