On nuclear energy, it can’t be business-as-usual

The only way out then is to start recycling uranium and, more importantly, thorium. This would bring down the need for mined uranium by an order of magnitude (maybe two). We have to be in this mode by the time we reach around 25 GWe nuclear generation capacity, since by then, uranium requirements in the present mode would reach around 8-10 per cent of the current global uranium production and access to uranium would become difficult. That day is only around 10 years away, going by the current projections. Recycled nuclear fuel would then be necessary to sustain the capacity addition growth rate.

We have already closed the nuclear fuel cycle and produced enough MoX fuel for recycling in the 500 MWe Prototype Fast Breeder Reactor, the next frontier for power generation capacity growth. The large-scale deployment of these reactors that would use recycled fuel and breed much more, however, is still eluding us. While this remains important and we need to catch up as soon as possible, we need a quick solution to tide over the impending slowdown in nuclear capacity addition rate on account of fuel-supply constraints. We faced a similar situation earlier that was resolved through the opening of international civil nuclear cooperation. This gave us access to global uranium markets.

Such a solution would lie in looking at fuel cycle options rather than reactor options. Thorium, which has been our long standing hope for India’s true energy security, can be irradiated along with high assay low enriched uranium (HALEU) in pressurised heavy-water reactors (PHWRs) at scale. The used fuel that would arise can be recycled to set up additional power generation capacity including through the molten salt reactors (MSRs), which would be necessary in the third stage of our nuclear power development anyway. Rather than wasting time running behind foreign vendors pursuing their own interests, disregarding India’s true needs, we should set our technological goals and leverage our market strength to mobilise domestic and foreign capabilities to achieve them. While recycling spent uranium fuel along with plutonium in fast reactors remains a superior option, recycling HALEU-thorium fuel is the next best alternative. It would allow the programme to grow as long as the irradiated fuel feed is available. Additionally, we will move closer to our long-term objectives while overcoming the fuel supply constraint that is bound to arise.

Thorium, apart from its energy value, has some unprecedented advantages. These come with significant economic gains particularly in PHWRs. The operation and safety performance of the reactors improve, and, in addition to savings in mined uranium, the quantity of fuel bundles needed and later managed reduces drastically. Most importantly, the fuel cycle becomes proliferation-resistant, virtually eliminating the security risks related to diversion by malevolent elements. HALEU-thorium fuel bundles are of the same external geometry and can be deployed without any significant change in the reactor design. Most importantly, accumulated spent fuel becomes a feed for fueling thorium-uranium molten salt reactors. Such reactors and the necessary fuel cycle technology should be developed and deployed on priority. Going forward, one could integrate spallation neutron sources in such MSRs, enabling the growth objectives that had necessitated fast breeder reactors.

The plans to establish a number of Bharat Small Reactors (BSR) in an innovative public-private partnership mode are indeed welcome. Along with the 700 MWe PHWRs, which must form the main workhorse for capacity addition, BSRs could play a supportive role. HALEU–thorium fuel can be leveraged in both to enable the continuation of capacity addition beyond the time uranium supply constraint sets in, despite delays in the Fast Breeder Reactor programme.

Small Modular Reactors are a new craze in the nuclear industry. But India already possesses the largest experience in the small reactor category through its commercially successful and robust 220 MWe PHWRs. In contrast, no SMR product has yet been deployed in numbers. A sizable order book is a prerequisite for an SMR business. Having said that, there are a number of retiring coal plant sites that could be leveraged, provided the design of the reactors is safe that there would be no anxiety about evacuation in case of accidents. Moreover, most of the sites would not have space for an exclusion radius. India should thus consider only such SMRs that can meet these criteria and are fully manufactured in India to remain economically competitive. The AHWR-300-LEU, which was fully developed, met such criteria along with use of thorium. Unfortunately, that has not been pursued.

It is worth recognising that most of what is stated above would necessarily mean delivery by our laboratories like Bhabha Atomic Research Centre, IGCAR, etc. That needs to be ensured. The private sector, while it needs to be mobilised to scale up the programme has, at best, a secondary role. The reverse would cause irreversible damage.

The writer, a nuclear scientist, was director of Bhabha Atomic Research Centre