How much nuclear waste has India produced in six decades of nuclear power? It sounds like a question with a simple answer. But first comes another question: What does India actually count as nuclear waste?AdvertisementThat distinction matters. In many countries, once nuclear fuel has been used in a reactor, it is treated as waste that will eventually have to be stored permanently underground. India has historically taken a different approach. Much of the uranium and plutonium in a used fuel rod can still be recovered and used again.This is the idea behind the three-stage nuclear programme designed by Homi Bhabha in the 1950s. Uranium is used first; the plutonium produced from it supports fast breeder reactors; eventually, thorium is intended to become a major source of nuclear fuel.Also Read | SHANTI Bill is India’s second shot at nuclear energy leadershipSo, from India’s perspective, spent fuel is not simply garbage. It is also a resource.AdvertisementThe science is real. Much of the original material remains in a used fuel rod. But the way we describe it has consequences.If something is an asset, we expect it to have value. If it is a liability, we expect someone to set aside money to deal with it.For decades, India’s nuclear system has largely treated spent fuel as something that will eventually be reused rather than something that must ultimately be disposed of. That made sense when reactors, reprocessing, regulation and waste management were all controlled by the government.The same government was responsible for both the present and future costs.That arrangement is now changing. The SHANTI Act opens India’s nuclear power sector to private companies. The draft rules under the new law have brought a question that was easier to postpone into sharper focus: Who remains responsible for spent fuel after a private operator is finished with it?Much of the public discussion has focused on nuclear liability, insurance and financial limits placed on operators. But another provision deserves attention. The draft rules require an operator’s financial security to remain in place until all spent fuel has been removed from the reactor’s storage pool.At first glance, that sounds reassuring. But it covers only the early part of the problem.Spent fuel remains in cooling pools for years because it is extremely hot and radioactive after leaving the reactor. Removing it from the pool and putting it into another storage system is, therefore, an important step.But it is not the same as permanently disposing of it. Moving a fuel cask out of a nuclear plant solves a storage problem at that plant. It does not answer where the material ultimately goes.That matters as India brings private operators into the nuclear sector. If an operator’s financial responsibility ends once spent fuel leaves the site’s storage pool, who pays for everything afterwards? Who pays for long-term storage, monitoring and, eventually, permanent disposal?The rules need to answer that clearly. There is another problem with the way India talks about nuclear waste.Officials often point to the fact that reprocessing can reduce the amount of spent fuel that ultimately becomes high-level radioactive waste to only a small fraction of the original material. That can be technically correct. But it can also create the wrong impression. Reprocessing does not make radioactivity disappear. It separates materials.Spent fuel is transformed into several streams: reusable fuel, radioactive waste, contaminated equipment, metal cladding and other materials that must themselves be managed safely. In other words, a smaller quantity of high-level waste does not mean the nuclear industry has no long-term waste problem.The most difficult part is what India eventually has to store for very long periods. That brings us to the geological repository — the underground facility designed to isolate highly radioactive waste from the environment for extremely long periods.India has been discussing such a repository for years.In 2015, a senior BARC official said India would need one only after roughly 30 or 40 years. In January this year, the government told Parliament that such a repository was not expected to be needed in the near future. The problem is that “not needed yet” and “not needed” are not the same thing. There is a legitimate scientific reason for waiting before placing some high-level waste underground. Spent fuel and vitrified waste generate heat, and that heat has to fall sufficiently before permanent disposal becomes practical.But the difficult part is not simply building the repository.It is finding a suitable location, studying the geology, building the institutions around it and, perhaps hardest of all, obtaining public and political consent. Finland spent decades developing its repository programme. The United States spent decades struggling with Yucca Mountain before the project effectively stalled.The lesson is simple: A repository can take decades to plan, even when the waste itself is not yet ready to go into one. India risks confusing these two clocks. The waste may not be ready for permanent disposal. But that does not mean India can postpone deciding where the permanent disposal system will eventually come from.This is why the consultation on the new nuclear rules matters.India does not need to abandon reprocessing. Nor does it need to treat every used fuel rod as worthless waste. Bhabha’s insight — that India’s limited uranium resources make it sensible to recover valuable material — remains important. But recognising spent fuel as a resource should not allow the country to forget that some material will eventually require permanent management.Three relatively simple changes could close that gap.First, India could impose a small, ring-fenced charge on every unit of nuclear electricity generated. The money could accumulate from the beginning of a plant’s operation for long-term waste management and disposal. Second, an operator’s responsibility should not automatically end when spent fuel leaves its reactor site. The rules should make clear who remains financially responsible until its long-term management is secured. Third, India should set a date not for opening a geological repository, but for starting the search for one.The argument for waiting until the waste is ready sounds reasonable. But by then, much of the time needed to find a site and build public consent may already have been lost.India was right to see value in its spent nuclear fuel. But “too valuable to bury” does not mean “nothing ever needs to be buried.” For 60 years, those two ideas have sat comfortably beside each other. India’s nuclear expansion now requires us to decide where one ends — and the other begins.The writer is a physicist at the University of North Carolina at Chapel Hill