Spent fuel from nuclear power plants is dangerous primarily due to its high radioactivity and long half-life of radioactive isotopes present in the fuel. Radioactive decay of these isotopes emits harmful radiation, which can pose significant health and environmental risks if not properly contained

Recently, India loaded the core of its long-delayed Prototype Fast Breeder Reactor (PFBR) vessel, bringing the country to the cusp of stage II — powered by uranium and plutonium — of its three-stage nuclear programme with issues revolving around nuclear waste management

WHAT IS NUCLEAR WASTE?

• Nuclear waste is generated in fission reactors when atomic nuclei absorb neutrons, leading to their destabilization and breakup, producing energy and different elements. If these resulting elements cannot undergo further fission, they become nuclear waste. Spent fuel from reactors contains radioactive fission products and elements produced during uranium decay, necessitating storage in highly secure facilities to prevent environmental contamination due to its high radioactivity.
• 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.
• Nuclear waste is highly radioactive and needs to be stored in facilities reinforced to prevent leakage and/or contamination of the local environment.

HANDLING NUCLEAR WASTE

• Handling nuclear waste involves addressing the challenges posed by its high radioactivity and heat. Initially, spent fuel is kept underwater for several decades to cool. Subsequently, it can be transferred to dry casks for long-term storage. Countries with extensive nuclear power programs have amassed significant quantities of spent fuel, requiring secure storage facilities for millennia to prevent human contact with highly radioactive materials
• Nuclear power plants also manage liquid waste through treatment facilities. Aqueous wastes containing short-lived radionuclides may be discharged into the environment after treatment. However, depending on their hazard, other liquid wastes can undergo evaporation, chemical precipitation, or be absorbed on solid matrices or incinerated
• Liquid high-level waste, containing most fission products from fuel, is vitrified into a glass-like substance for storage. In India, where spent fuel reprocessing occurs, fission products must be stored as liquid waste due to their inability to fuel reactors like the PFBR, posing potential accident hazards

HOW IS NUCLEAR WASTE DEALT WITH?

Nuclear waste is managed through several methods:

1. Dry-cask Storage: Spent fuel is cooled in pools for a year, then moved to dry-cask storage. It’s sealed in steel cylinders with inert gas, placed in larger chambers.
2. Geological Disposal: Some advocate for burying waste in special containers underground in granite or clay. This ensures long-term storage away from human activity, but risks exist if containers are disturbed.
3. Reprocessing: This involves separating fissile from non-fissile material in spent fuel through chemical treatment. Reprocessing offers higher fuel efficiency but requires specialized facilities and personnel. It also yields weapons-usable plutonium, tightly regulated by the IAEA. Importantly, reprocessing also yields weapons-usable (different from weapons-grade) plutonium. The IAEA has specified eight kilograms of plutonium in which plutonium-239 accounts for more than 95% to be the threshold for “safeguards significance”. It tightly regulates the setting up and operation of these facilities as a result

WHAT ARE THE ISSUES ASSOCIATED WITH NUCLEAR WASTE?

• Nuclear waste management poses significant challenges, as highlighted by cases such as the Asse II salt mine in Germany and the Waste Isolation Pilot Plant (WIPP) in the US. In Asse II, thousands of drums of nuclear waste prompted a costly and lengthy decontamination effort, raising concerns about potential water contamination. The project was estimated to cost €5-10 billion and take around 30 years
• Similarly, WIPP, once considered a model for radioactive waste disposal, experienced an accident in 2014, releasing radioactive materials into the environment and exposing maintenance failures. These incidents underscore uncertainties in waste treatment and repository maintenance.
• There are concerns raised about the effectiveness of liquid waste treatment, questioning the functionality of vitrification plants and the volume of remaining liquid waste to be treated
• He emphasized the prevalence of failures in siting repositories globally and criticized the normative issues of exporting nuclear waste, citing environmental injustice and ethical dilemmas

WHAT DOES WASTE-HANDLING COST NUCLEAR POWER?

• In the 1993 feature, Dr. Tsyplenkov considered a nuclear power plant of 1,000 MWe capacity “operating at a capacity factor of 70% for 30 years”.
• They estimated “the waste management at the front end of the cycle leads to about 10% of the total waste management cost. Of this, about one-third is due to the management of depleted uranium as a waste. The management of wastes from power plant operation accounts for about 24% of the costs and 15% is due to power plant decommissioning. The remaining 50% of costs is associated with the back end of the fuel cycle.”
• In the final estimate, they added, waste management imposed a cost of $1.6-7.1 per MWh of nuclear energy.

HOW DOES INDIA HANDLE NUCLEAR WASTE?

• India operates reprocessing plants in Trombay, Tarapur, and Kalpakkam, as reported by the International Panel on Fissile Materials in 2015
• These facilities process varying amounts of heavy metal per year, contributing to plutonium production for reactors and nuclear weapons
• It was stated by union government in 2015 that nuclear waste generated at power stations is managed on-site, with facilities for treatment and storage. However, concerns were raised regarding the operational performance of reprocessing facilities in Tarapur and Kalpakkam, suggesting potential complications with the PFBR’s operation in the future
• The Trombay facility reprocesses 50 tonnes of heavy metal per year (tHM/y) as spent fuel from two research reactors to produce plutonium for stage II reactors as well as nuclear weapons. Of the two in Tarapur, one is used to reprocess 100 tHM/y of fuel from some pressurised heavy water reactors (stage I) and the other, commissioned in 2011, has a capacity of 100 tHM/y. The third facility in Kalpakkam processes 100 tHM/y.