A new milestone in the removal of nuclear sources
In depth - March 10, 2016

A new milestone in the removal of nuclear sources

The International Atomic Energy Agency (IAEA) has conducted tests in Croatia for the application of a new technology that will facilitate the safe storage of nuclear waste and at the same time make it more affordable to developing countries.

This method consists of placing sealed sources inside a narrow hole a few meters underground, and then covering them

Practically all countries use radioactive sources in health care, industry and other sectors. Many, however, lack the necessary equipment or qualified staff to manage these sources when they become unusable. Under normal circumstances, and according to IAEA's estimations, a developing country that uses sealed radioactive sources could generate hundreds of unusable low-level sources over the years.

A new technology

A promising new technology will help to move and store sealed low-level radioactive sources, paving the way for a new disposal method for small quantities of radioactive waste worldwide. This method consists of placing sealed sources inside a narrow hole a few meters underground, and then covering them. This would allow countries to safely dispose of their own radioactive waste sources. Last year, IAEA tested this new technology in Croatia, without using real radioactive materials.

In most developing countries, radioactive sources are stored temporarily. Some developed countries have disposal facilities close to the surface. The new method for waste storage represents a long-place solution since it helps to protect people and the environment.

A new milestone in the removal of nuclear sources
IAEA engineers and a Croatian radiation protection company test a new system used to safely and securely dispose of low-activity sources in boreholes (Imagen source © Laura Gil Martínez and Dean Calma / IAEA Office of Public Information and Communication)

Improving nuclear safety is the reason behind the development of this new method

Viable and affordable

The team tests carried out by IAEA engineers in Croatia confirm the viability of a system that is used to safely transport and insert low-level radioactive sources, as part of a system that eliminates these sources by placing them inside boreholes.

This technology, developed for low-level disused radioactive sources, depends on a robust metal platform and a movable container or transfer cask to move the sources to the borehole. According to IAEA, this system is simple and affordable and can be applied globally.

Prevention against theft and terrorism

Improving nuclear safety is the reason behind the development of this new method. Since disused radioactive sources are still radioactive, IAEA wants to limit the chances that these sources could be captured and used for other purposes. Once the waste is inside the borehole, it is not easily accesible to anyone.

The original borehole idea was developed by the South African Nuclear Energy Corporation (NECSA), and later adopted by IAEA to incorporate the removal of sources with higher radiation levels. Nowadays, technical preparations and safety analyses for the boreholes are done in several countries including Malaysia and Philippines, which means that it will be possible to implement this method in the coming years.

The technology for drilling the ground and making the borehole is similar to that used for the extraction of water, and is widely available in most countries, including the less developed ones.

A new milestone in the removal of nuclear sources
The sealed canisters that will be planted in the borehole have different sizes, depending on the dimensions of the sources they will contain (Imagen source © Laura Gil Martínez and Dean Calma / IAEA Office of Public Information and Communication)

Sources: from where to where

Radioactive sources are often used in medicine and industry, from radiotherapy machines for cancer treatment to industrial tools for the sterilization of possible medical supples. The most common sealed sources have low radioactivity levels or a short-medium life, which means that they remain radioactive during just a few months or several hundred years.

Before being disposed of, all the sources are handled and re-packaged through a conditioning process. With this preparation, hundreds of sources (the usual amount generated each year by a developing country) take up less than one cubic meter.

Once the borehole has been prepared, the conditioned sources are loaded on to a special container and sealed. The sealed container is placed inside the transportation cask and introduced into the borehole.

Source: IAEA

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