HLW (High-Level Waste)
High-level Radioactive Waste is the waste that comes from producing nuclear materials for defense purposes, ultimately this waste is stored as sludge, liquid, or pellets, and must be solidified before manufacturers or labs can dispose of it.
About High-Level Waste
High-Level radioactive liquid waste (HLW) containing most (99%) of radioactivity in the entire fuel cycle is produced during reprocessing of spent fuel. A major stream of this waste is the aqueous radioactive waste generated from the first cycle extraction of the spent fuel processing. Also, solid waste is not suitable for disposal in near-surface disposal facilities due to the significant concentration of long-lived radionuclides or decay heat above the prescribed limits and may also need to be regarded as high-level waste. Issue of the long-lived radioactive waste has been the focal point of debate for the success of nuclear power. Planning for management HLW thus takes into account the need for their effective isolation from the biosphere and their continuous surveillance for extended periods of time spanning several generations. To meet this objective in the long term, a waste isolation system comprising multiple barriers is employed so as to prevent the movement of radionuclides back to the human environment.
Management of High-Level Waste
High-Level radioactive waste gets generated during reprocessing of spent fuel. Most of the radioactive isotopes in high-level waste emit a large amount of radiation and have long half-lives. The management of high-level waste in the Indian context is carried out in the following three stages-:
1. Immobilization of high-level liquid waste into inert vitrified borosilicate
glasses through a process called ‘vitrification’.
2. Engineered interim storage of the verified waste for passive cooling and
surveillance over a period of time, and qualified it for subsequent disposal.
3. Disposal of the verified waste in a deep geological repository.
Safe management of radioactive waste has been accorded high priority right from the inception of our nuclear energy program. As a result of rugged design with ‘a defense in depth concept, well-established practices and safety review by an independent agency, and excellent track record for safe management of radioactive waste in India has been demonstrated for more than five decades. Consistent efforts in R&D have enabled the indigenous development of novel processes and technologies in the field of management of radioactive waste and their deployment to realize waste volume minimization, effective isolation of radionuclides in the engineered matrix, minimization of discharges and extracting wealth from waste by separating useful radionuclide from radioactive waste for societal applications. Such developments enabled the country to be a front-runner in the field of radioactive waste management in the world.