The spent nuclear fuel (SNF) from India’s nuclear power reactors at Kudankulam in Tamil Nadu, being operated by the state-run Nuclear Power Corporation of India (NPCIL) in collaboration with the Russian state atomic energy corporation Rosatom, who are the equipment suppliers and technical consultants for the project, will be stored initially in the spent fuel storage pools within the reactor buildings and thereafter in the away-from-reactor (AFR) facility to be set up at the site, till it is taken for reprocessing, the Minister for State at the Prime Minister’s Office (PMO) Jitendra Singh informed the Parliament earlier this week.
In a written reply to the Lower House of Parliament, Singh said that currently the process of obtaining various clearances for setting up the AFR at Kudankulam is in progress. He also said that India is pursuing a closed fuel cycle, where there is very little quantity of radioactive waste generated. Moreover, technologies for separation, partitioning and burning of waste are being developed in the country, which will further bring down the quantity of radioactive waste. This was in response to a House member’s question on whether India possesses recycling facilities for spent nuclear fuel from Pressurized Water Reactors (PWR) and Light Water Reactor(LWR) reactors being operated in the country.
In response to another related question, the Minister also said that considering the small quantity of radioactive waste involved, there is no need for considering the construction of an underground Deep Geological Repository in the near future for the disposal of the country’s nuclear waste. Two 1,000 MW units each at Kudankulam are already connected to the grid, while units 3 and 4 are in various stages of construction.
Singh had told Parliament last year that India has adopted the closed fuel cycle approach where spent nuclear fuel is regarded as a resource material. “Closed fuel cycle aims at reprocessing of spent fuel for recovery of uranium and plutonium and recycling them back to the reactor as fuel. This finally leads to a very small percentage of residual material present in spent nuclear fuel requiring their management as radioactive waste,” he had said. He also said that the high-level radioactive waste also contained many useful isotopes like Caesium-137, Strontium-90, and Ruthenium-106 and that with the advent of new technologies based on the partitioning of waste, emphasis is being given to the separation and recovery of these useful radioisotopes so as to make use of the waste for various other applications.
India’s nuclear power programme was conceived in the late 1960s as a closed fuel cycle to be achieved in three stages. The spent fuel generated from one stage would be reprocessed and used in the next stage of the cycle to produce power. Thus, the closed fuel cycle was designed to “breed” fuel and to minimize generation of nuclear waste. This three-stage nuclear power production program in India had been conceived with the ultimate objective of utilising the country’s vast reserves of thorium-232. India has the world’s third largest reserves of thorium. The first stage envisages the use of PHWRs to produce energy from natural uranium. Besides energy, PHWRs also produce fissile plutonium (Pu)-239. The second stage involves using the indigenous fast breeder reactor (FBR) technology fuelled by Pu-239 to produce energy, as well as more Pu-239. By the end of the second stage of the cycle, the reactor would have produced, or “bred” more fissile material than it would have consumed. The final stage of the cycle would involve the use of Pu-239 recovered from the second stage, in combination with thorium-232, to produce energy and fissile uranium (U)-233 using “thermal breeders”. This production of U-233 from thorium-232 would complete the cycle, while the U-233 would then be used as fuel for the remaining part of the fuel cycle.
While India has successfully completed the first stage of its nuclear programme, the second stage is taking much longer than envisaged earlier. The first 500 MW Pressurized Fast Breeder Reactor (PFBR), being set up at the Madras Atomic Power Station in Kalpakkam, Tamil Nadu, has suffered from significant time and cost delays. Minister Singh had told Parliament earlier this year that India’s first prototype PFBR will be commissioned and operationalised in December 2021.
The PFBR in Kalpakkam will use a mixed oxide of Pu-239 – derived from reprocessed spent fuel from the thermal PHWRs – and uranium-238 as fuel to generate energy. This nuclear reaction will also produce more Pu-239 by converting both U-238 in the fuel mix, as well as a blanket of depleted uranium surrounding the core, into plutonium. This plutonium will then be processed and used as nuclear fuel in a chain of commercial FBRs in the second stage of the nuclear programme.