Nuclear Waste

Nuclear Waste

GS3 - Infrastructure | Science & Technology

Table of contents

Why in the News?

  • Recently, India loaded the core of its long-delayed prototype fast breeder reactor (PFBR) vessel, bringing it to the cusp of stage II — powered by uranium and plutonium — of its three-stage nuclear programme.
  • By stage III, India hopes to be able to use its vast reserves of Thorium to produce nuclear power and gain some energy independence.
India's Three Stage Nuclear Program | UPSC
  • But the large-scale use of nuclear power is accompanied by a difficult problem: waste management.

What is Nuclear Waste?

  • Radioactive waste is a type of hazardous waste that contains radioactive material and its byproducts.
  • Radioactive waste is a result of many activities, including:
    • Nuclear medicine
    • Nuclear research
    • Nuclear power generation
    • Spent fuel rods
    • Nuclear decommissioning and dismantling
    • Rare-earth mining
    • Nuclear weapons reprocessing

Generation of Radioactive byproducts

  • They are generated as a result of nuclear fission.
    • In a fission reactor, neutrons bombard the nuclei of atoms of certain elements. When one such nucleus absorbs a neutron.
    • It destabilises and breaks up, yielding some energy and the nuclei of different elements.
    • For example, when the Uranium-235 (U-235) nucleus absorbs a neutron, it can fission to barium-144, krypton-89, and three neutrons.
    • If the ‘debris’ (barium-144 and krypton-89) constitute elements that can’t undergo fission, they become nuclear waste.

Spent fuel rods

  • Fuel loaded into a nuclear reactor will become irradiated and eventually have to be unloaded.
  • At this stage, it is called spent fuel.
  • Spent fuel rods after energy production contains radioactive isotopes.

Examples of Nuclear Waste

    • Argon 41
    • Radioiodine
    • Cobalt-60
    • Strontium-90
    • Tritium 
    • Caesium-137

Nuclear waste is highly radioactive and needs to be stored in facilities reinforced to prevent leakage into and/or contamination of the local environment.

What are the types of Nuclear Waste?

Types of Nuclear Waste | UPSC

High-level waste (most dangerous)

  • Spent fuel rods, liquids from reprocessing fuel.
  • Needs isolated storage for thousands of years.
  • It is primarily uranium fuel that has been used in a nuclear power reactor and is “spent,” or no longer efficient in producing electricity.
  • This includes radioactive isotopes of lighter elements such as cesium-137 and strontium-90. These isotopes, called “fission products,”. 

Intermediate-level waste

  • Filters, cladding from fuel rods, reactor components.
  • Requires careful management.

Low-level waste (least dangerous)

  • It includes items that have become contaminated with radioactive material.
  • Examples: Protective clothing, tools with low radiation contamination, shoe covers, wiping rags, filters, etc.
  • These are disposable in shallow burial sites.

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What happens to the Nuclear Waste?

  • Spent fuel rods are still highly radioactive and hot due to residual decay heat.
  • They are initially stored in water pools inside the reactor facility for several years to allow them to cool down.
  • After cooling, they are transferred to dry cask storage on-site.
    • These casks are heavily shielded containers designed to safely store spent fuel rods for decades.

How can Nuclear Waste be disposed of?

Shallow Burial

  • Low-level waste, with minimal radioactivity, is disposed of in specially designed shallow burial sites with liners to prevent contamination of soil and groundwater.
  • These sites are constantly monitored.

On-Site Storage

  • Intermediate-level waste is typically stored on-site at nuclear facilities in shielded containers.
  • Concrete casks or vaults are common storage solutions.

Geological Disposal

  • This is a potential long-term solution for high-level waste disposal.
  • The waste is encapsulated in special containers and buried deep underground in stable geological formations like granite or clay.
  • But,
    • Studies have pointed to the risk of radioactive material becoming exposed to humans if the containers are disturbed, such as by nearby digging activity.


  • For high-level waste storage, vitrification is a process where the waste is converted into a glass-like substance for improved stability and containment.


  • It is the technology that separate fissile from non-fissile material in spent fuel.
    • It presents the advantage of higher fuel efficiency.
  • Some countries reprocess spent nuclear fuel to extract reusable fissile material like plutonium. (Like India)
  • But,
    • Because spent fuel is so hazardous, the reprocessing process is complex, and expensive, and creates additional waste streams needing disposal.


  • This theoretical approach involves using advanced reactors to convert long-lived radioactive isotopes in waste into shorter-lived or stable isotopes, reducing their radioactivity.
    • Transmutation technology is still under development.

What are the challenges of Nuclear Waste Management?

  • Safe Storage: Finding a secure location for long-term (thousands of years) isolation.
    • Spent fuel rods remain radioactive for thousands of years, posing a long-term waste management challenge.
  • Transportation & Storage Technologies: Safe methods to move and store waste are crucial.
    • Safe and secure storage of these rods is crucial to prevent radiation leaks and environmental contamination.
  • Accident Risks: Contamination of water resources from leaks or accidents during storage/transport.
  • Unknown unknowns: Uncertainties about long-term behavior of waste storage sites and reprocessing effectiveness.
  • Ethical Concerns: Equity in waste storage (environmental justice) and burden sharing between generations.
  • Cost factor: Waste management adds significantly to the cost of nuclear power generation.

What is the India's Scenario?

  • According to a 2015 report from the International Panel on Fissile Materials (IPFM), India has reprocessing plants in Trombay, Tarapur, and Kalpakkam.
India's Nuclear Fuel Reprocessing Plants | UPSC
    • The Trombay facility reprocesses 50 tonnes of heavy metal per year (tHM/y) as spent fuel from two research reactors.
      • It produces plutonium for stage II reactors as well as nuclear weapons.
    • Of the two in Tarapur
      • One used to reprocess 100 tHM/y of fuel from some pressurised heavy water reactors (stage I).
      • The other, commissioned in 2011, has a capacity of 100 tHM/y.
    • The third facility in Kalpakkam processes 100 tHM/y.
  • India has adopted the Closed Fuel Cycle option.
Closed Fuel Cycle | India | Nuclear Reactor | UPSC
    • It involves reprocessing and recycling of the spent fuel.
  • Reprocessing plants extract plutonium for further use (stage II reactors and potentially weapons).
    • During reprocessing, only about 2-3% of the spent fuel becomes waste.
    • This waste is called high level waste (HLW).
    • It is converted into glass through vitrification.
    • The vitrified waste is stored in a Solid Storage Surveillance Facility for 30-40 years beforethe its disposal.
    • The need for a final disposal facility will arise only after three to four decades.
  • On-site storage facilities for low and intermediate waste with environmental monitoring.

Also, delays in the Fast Breeder Reactor (PFBR) program raise concerns about reprocessing plant efficiency. Why?

  • According to the IPFM report
    • The PFBR’s delays suggested the Tarapur and Kalpakkam facilities must have operated quite poorly, with a combined average capacity factor of around 15%.
    • If and when the PFBR starts functioning and spent fuel from it is discharged – it will bring its own complications.
      • Because it will have a different distribution of fission products and transuranic elements.
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