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New polymer to reduce radioactive waste in nuclear reactors

Last Updated: Sunday, August 9, 2009 - 12:09

New Delhi: Indian scientists have developed a
new polymer that reduces radioactive waste in nuclear
reactors, making the decontamination process a less expensive

Referred to as `Cobalt Imprinted Polymer`, the compound
selects the radioactive cobalt ions in the nuclear coolants to
dissolve and remove them without altering their properties.

"The polymer is imprinted with a memory for cobalt ions,
source of radioactivity in most nuclear plant coolant
channels. By doing this, the radioactive ions will be trapped
in very small volume of this special polymer.

"So, the amount of radioactive waste volume which is
subjected to immobilisation will be very small," Narasimhan V
Sevilimedu, a scientist with the Indira Gandhi Centre for
Atomic Research, said.

The compound has been synthesised in such a way that they
have pre-designed "holes" to selectively recognise and trap
cobaltions. Such pre-designed selectivity is the key aspect
of such imprinted polymers, he said.

Conventionally, a solution of mild chemicals is used to
remove the corrosion products, i.e. metal oxides by circulating
chemicals in the coolant circuits. The solution comprises both
radioactive and non-radioactive ions, namely cobalt and iron

These conventional resins cannot differentiate between
cobalt and iron ions which have very similar chemical

"This synthesized polymer has been designed to
differentiate and selectively absorb the cobalt ions (both
radioactive and non-radioactive) while rejecting iron ions,"
Narasimhan said.

The polymer can also be used to clean decommissioned
reactors for separating the active waste and concentrating
them in a small volume, he added.

"It (polymer) is able to separate two metal ions
effectively and absorb, thereby net volume required for
trapping the cobalt ions (radioactive and non-radioactive) is
reduced. Hence the subsequent processing cost also will be
reduced," Narasimhan said.

The technology, that was conceptualized, initiated and
tested in India by Narasimhan and his colleague Anupkumar
Bhaskarapillai at Water and Steam Chemistry Division, BARC
Facilities, Kalpakkam, is currently at a laboratory scale.

An article on it was published in `Industrial and
Engineering Chemistry Research`, a journal of the American
Chemical Society.

Bureau Report

First Published: Sunday, August 9, 2009 - 12:09
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