Atomic energy panel looks to secure spent nuke fuel

The specialist panel appointed by the country's nuclear regulator Atomic Energy Regulatory Board to assess safety provisions at existing atomic power plants will comprehensively review the storage of spent fuel at all nuclear power plant sites.

This is besides a reassessment of the general preparedness of the 20 operational reactor units to deal with exigencies such as the Fukushima disaster in Japan, sources said. Nuclear Power Corporation of India Ltd (NPCIL) has already announced steps to enhance safety.

The focus on spent fuel storage stems from the ongoing Japanese experience, where reactor meltdown fears have now been overshadowed by worries on the safety of spent fuel pools, which store the fuel rods after use in the reactor.

In existing stations in India, the spent fuel pools are generally stored in proximity to the reactor units. Even for the proposed mega 9,900-MWe Jaitapur project in Maharashtra, NPCIL plans to store the spent fuel in an underwater storage facility adjoining the reactor building inside the project premises till the Government establishes a fuel reprocessing facility.

Equipping spent fuel pools with backup water-circulation systems and reserve generators for the water-circulation system – something that the Fukushima reactors did not have – is among the options, analysts said. Others include a process called “dry cask storage,” which Germany has tried out successfully, despite the high costs it entails.

In Japan, reports of serious damage to the still-potent spent fuel at Japan's Fukushima Daiichi nuclear plant's No. 4 reactor are creating new worries for nuclear operators around the world.

The spent fuel storage pools are packed with radioactive uranium and are housed near the reactors to facilitate easy transfer of the fuel rods.

Unlike the reactors though, spent fuel pools are not housed in any sort of sealed containment and instead the fuel rods are packed tightly together in pools of water. The spent fuel rods give off considerable amounts of “decay heat” and thus must be submerged in constantly circulating water or boric acid. If exposed to air for a day or two, they begin to combust, giving off large amounts of radioactive Caesium 137, a highly toxic, penetrating radioactive element with a half-life of around 30 years.

Expensive security

Germany adopted the “dry cask storage” around two decades ago. Instead of storing huge amounts of spent fuel in pools with only roofs over them, small amounts of spent fuel rods are surrounded with inert gas inside large steel casks. While these casks are said to be quite stable and secure, the process is said to be extremely expensive.

The 10-member panel headed by former the AERB Chairman, Mr S.K. Sharma, is slated to submit an interim report shortly on the possible safety measures. The recommendations made by both task forces – AERB and NPCIL – would be implemented with AERB's approvals in due course, officials said.

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