Borehole Disposal Facility
Borehole Disposal Facility
Malaysian Nuclear Agency (Nuclear Malaysia) serves as the national radioactive waste treatment center since 1985. Among the type of radioactive waste managed in this center is disused sealed radioactive source (DSRS). Up to today, all DSRS received from all over Malaysia are stored at the interim storage. By the end 2016, the total inventory of DSRS received and stored in the facility has exceeded 12,000 units. Therefore, it is timely for Malaysia to consider the final disposal technology for disposing the DSRS permanently, thus reducing the risk and harm associated with the waste.
Disused Sealed Radioactive Sources (DSRS)
Each sealed radioactive sources have a strength or specific activity. A special characteristic of a radioactive source is the half-life, by which with the increase of time, the activity will be reduced (decay) naturally based on its half-life. Radioactive sources whose activity has decreased to a level that is too low for any application or no longer in-used have to be managed properly as to avoid any danger to human health and the environment. Radiation sources which are commonly used in Malaysia include cobalt-60, strontium-90, cesium-137 and radium-226.
The best option for short-term management of DSRS is to store the radioactive source in a safe and secure facility or to return to the supplier. Storage in a store for a long period until hundreds of years is not the best option because this activity involves high cost. Experts recognize the storage technology for long-term safe and secure with the construction of a disposal facility which capable of storing sources with high activity and has a long half-life values until the activity decreases to safe levels. Construction of disposal facilities should be implemented immediately for the following reasons:
What is Borehole Disposal Facility (BDF)?
The Borehole Disposal Facility (BDF) concept has been introduced by the International Atomic Energy Agency (IAEA) to provide a safe, permanent and cost-effective solution to the long-term management of DSRS. BDF meets the same high standards of long term radiological safety as any other type of radioactive waste disposal. While BDFis designed to be simple and cost-effective, it meets exactly the same high standards of radiological safety that would be expected of any other practice involving radioactivity.
BDF is specially designed to deal with the small – yet still potentially dangerous – quantities of disused sealed sources that are found in many countries.
The BDF system is composed of:
- A mobile remote handling cell to safely package the DSRS;
- High integrity stainless steel packaging to contain the radioactivity;
- One or more disposal boreholes, with 30 - 100 meters deep, to isolate the DSRS from the accessible environment.
Schematic Diagram of Borehole Disposal Facility
(Source by IAEA)
Illustration section through borehole used for disposal
(Source by IAEA)
How does the BDF work?
What are the advantages of BDF?
Borehole disposal facilities have a number of characteristics that enhance waste safety, cost-effectiveness, and physical security. For example, they:
Issues and Challenges:
Nuclear Malaysia is responsible in making sure the implementation of the BDF project encompasses construction and its operation is designed and performed according to the approved specifications. This is achieved by identifying the challenges present at every phases of the project so that any eventuality can be addressed early. Being the first country to implement the BDF project posed a challenge by itself. This will make Malaysia as the reference for other countries that wish to opt and implement the same disposal technology in the future.
Issues involving public safety has always been a priority for Nuclear Malaysia in designing this disposal facility. The researchers are committed to continuously undertake the safety assessment with the assistance from international experts designated by the IAEA and always take into account the views from the stakeholders. The differences in opinions from various parties are handled prudently by Nuclear Malaysia so that the establishment of the BDF will meet all the standards and regulations set by the Atomic Energy Licensing Board (AELB).