Nuclear Energy Programme is imperative for the execution of the ambitious plans of the Indian Government
RK Sinha,, Former Chairman of Atomic Energy Commission (AEC) and Secretary of Department of Atomic Energy (DAE); and present Homi Bhabha Chair Professor
RK Sinha,, Former Chairman of Atomic Energy Commission (AEC) and Secretary of Department of Atomic Energy (DAE); and present Homi Bhabha Chair Professor

Nuclear Energy Programme is imperative for the execution of the ambitious plans of the Indian Government for the country’s economy. Energy hungry Indian economy needs nuclear power. Former Chairman of Atomic Energy Commission (AEC) and Secretary of Department of Atomic Energy (DAE); and present Homi Bhabha Chair Professor Dr. Ratan Kumar Sinha gave an elaborate interview to Nuclear Asia where he touches upon the peculiarities of the Indian nuclear programme, including Advanced Heavy Water Reactor (AHWR) and membership in Nuclear Suppliers Group (NSG).

Dr. Sinha, who has been closely associated in the design and development of India’s first thorium-based Advanced Heavy Water Reactor, talks about how the project is going to serve as technology demonstrator for setting up highly safe nuclear facilities in close proximity to population. He also calls India’s entry to the Nuclear Suppliers’ Group (NSG) as a mere formality.

Do you think that India’s failure to make it to the NSG is a jolt for its Civil Nuclear Power Programme?

I do not think that the current hindrance in the Indian membership of NSG can be termed a ‘jolt’. India has been and will continue to be a responsible partner in international civil nuclear trade, both as an importer and as an exporter – fully meeting the guidelines of NSG. Indian membership of NSG will be a logical and important affirmation of this reality.

You were one of the architects of the indigenous Advanced Heavy Water Reactor (AHWR). What is its current status? Has a site for the same been identified?

The design and development of AHWR is sufficiently complete to initiate the activities leading to its construction. The innovative passive features of this reactor have been validated through experiments and simulations. A major experimental facility has been established to explore additional margins in the design of the natural circulation based coolant circulation system of this reactor. As stated in answer to a recent Lok Sabha question the Government, in December 2016, has accorded in-principle approval for the Tarapur Maharashtra Site for locating the 300 MWe Advanced Heavy Water Reactor.

India has aimed at tapping into its vast thorium reserves since 1950’s. Will these thorium-fuelled AHWRs be functional by 2020s as was earlier aimed for?

This question requires a detailed answer to explain the main objectives of AHWR.

In any densely populated country, in order to facilitate necessarily large scale deployment of nuclear power to provide adequate carbon-free base-load generation capacity, it will be necessary to build future nuclear power plants of such designs that may be considered to be eligible for exemption from the otherwise mandatory requirements of providing exclusion and low population zones around the plant site.

AHWR will demonstrate advanced passive safety technologies that are considered relevant for building a large number of next generation nuclear reactors, reasonably close to population centers. On account of our experience with Pressurised Heavy Water Reactors, we chose to develop this reactor using the pressure tube configuration, and retained heavy water as an efficient moderator.

With or without thorium, the needed passive safety technologies have to be in place even before we reach the third stage. Accordingly, AHWR has been designed and developed to be the technology demonstrator for a reactor that will meet – without any significant radiological impact in the public domain – the challenges of severe external events (natural and man-made), equipment malfunctions, operator errors, terrorist attacks and insider threats. The reactor is designed to meet these challenges without needing any external or internal source of power, any external source of water, or any emergency operator actions.

Among the options for the third stage molten salt reactors, accelerator driven systems and fusion-fission hybrids could be suitable options. Bhabha Atomic Research Centre (BARC) is already working on the molten salt technologies, to begin with.

We cannot, however, jump to the third stage in a hurry. To get there we must go through the necessary first stage (uranium-fuelled water-cooled reactors) and second stage (plutonium-fuelled Fast Breeder Reactors) of our nuclear programme to build sustainable fuel supplies to launch the third stage. In this context it is apt to reproduce one of my statements quoted in the Wikipedia article on Thorium Fuel Cycle: “Thorium is like wet wood […it] needs to be turned into fissile uranium just as wet wood needs to be dried in a furnace.”

So, the short answer to your question is: it is not envisaged to build a series of AHWRs in our country, at least not now, in the present circumstances.

What are the advantages of the closed fuel cycles that India has been advocating for a long time and do you see greater appreciation coming from the international arena in this regard?

The International Atomic Energy Agency (IAEA) website provides a simple calculator to work out some fuel cycle related parameters. A typical case study using this calculator, with default parameters (actual numbers may vary from reactor to reactor) shows that to produce 1 million units (MU) of electricity a Pressurised Heavy Water Reactor (PHWR) needs nearly 18 kg of mined uranium, as against nearly 25 kg of mined uranium (converted to nearly 2.8 kg. of enriched uranium) needed for a Pressurised Water Reactor (PWR).

The spent fuel of PHWR, corresponding to 1 MU electricity generated, amounts to nearly 18 kg. In an open fuel cycle case all of it needs to be eventually (after waiting for 3-4 decades for letting the short lived radioactivity decay down) disposed off in a geological repository.

In the closed fuel cycle, as brought out by the IAEA calculator, after the removal of uranium and plutonium from the PHWR spent fuel all that is left behind (corresponding to 1 MU electricity generation) is about 132 grams of fission products and 533 mg of minor actinides. Most of the fission products reduce to low levels of radioactivity after storage for three to four decades of on-site storage. Some of the long lived actinides, and useful radioactive products can be separated for useful applications. This technology has also been developed by BARC. You may like to see a news item pertaining to the use of Cesium-137, extracted from spent nuclear fuel, for cancer therapy in Indian hospitals. Even if we did not extract the useful minor actinides and fission products all that is left after producing one million units of nuclear electricity, using closed fuel cycle, is less than 150 g of waste that needs to be encapsulated in non-leachable glass.

Closed fuel cycle enhances the energy potential of uranium multifold (perhaps 60 times). India has adopted closed fuel cycle right from the inception of its nuclear programme. Some other countries such as France, and Russia have also adopted closed fuel cycle. As a part of its international civil cooperation agreements India has the right to reprocess the spent fuel arising out of imported uranium, and safeguarded NPPs, in safeguarded reprocessing plants.

Could you elaborate how the Compact High Temperature Reactor (CHTR) will be crucial for India’s endeavours to attain power sufficiency?

The CHTR is designed to serve as a technology demonstrator for producing process heat at very high temperature for generating hydrogen using chemical-thermal water splitting reactions. It has also been designed to possibly serve as a portable power pack to serve in remote areas. This reactor is not intended for commercial power generation in the near term.

What is the purpose of building another Dhruva?

The Dhruva reactor at BARC has served for more than thirty years now. Even though it is still functioning at near full capacity it may, after a few years, become a candidate for repeated inspections and maintenance as a part of ageing management activities. Today Dhruva is the only source to produce medical and industrial radioisotopes through reactor irradiation in our country. Another large research cum isotope production reactor will not only address the vulnerability arising out of potential maintenance and inspection outages for Dhruva, but also add to the much needed additional indigenous capacity for radioisotopes production and provide additional advanced in-core experimental research facilities.

In a big power push, the Indian Government this year sanctioned construction of 10 PHWR reactors. Do you think the Indian industry has the wherewithal to bring this project to fruition?

The Indian industry rose to meet the challenges of nuclear manufacturing and construction during the early years of the technology denial regime. It has sufficient range and depth to meet the challenge of the numbers. Indeed, the serial construction of ten reactors offers an opportunity to cut down costs and time for building these reactors.