Intermediate-level radioactive waste (ILW)

This waste emits higher levels of radiation, needs extra shielding and can remain radioactive for a longer time. 

Examples include waste from nuclear medicine production and some of the waste from operating the OPAL nuclear research reactor in Sydney.

Volumes

The data estimates the waste’s volume after it has undergone future waste conditioning processes, where the waste holder has provided this information. 

Some waste holders provided waste volumes that do not consider future waste conditioning or packaging that disposal may require.

The total numbers in Table 6 are slightly different from Table 1 because we have limited the numbers to 3 significant figures.

Where volume is less than 1m³, we have rounded up to 1m³.

Figure 7 and Figure 8 show the volumes of ILW held by the different organisational groups, and what proportion each organisational group holds of the total inventory of ILW. ANSTO and Defence hold the majority of ILW waste.

Radioactivity

Like in 2021, the 2024 ILW inventory in Table 6 does not include nuclear materials. We discuss these in another section of the report.

Uncertainties

Waste holders have estimated ILW volumes incorporating assumptions about future treatment and conditioning processes required for disposal.

There is significant uncertainty on estimated volume for some waste streams.

We have based the total ILW activity on reported values. However:

• some waste streams included estimates on volume but not activity
• some waste streams included estimates on activity not volume
• estimating radioactivity is particularly uncertain due to the nature of radioactive decay
• we have limited the numbers to 3 significant figures to reflect the uncertainties.

Radionuclide breakdown

These figures only include the waste streams where we received radionuclide activity values. The activity values are expressed as multiples of ten to the power n. For example, 2x10³ is 2x10x10x10 = 2000. 

Cobalt-60 (Co-60) is the biggest contributor of radioactivity in the ILW waste streams. 

Co-60 is commonly produced in components of nuclear reactors. This is where the stable isotope cobalt-59, contained in metal structures, is exposed to neutrons and converted to Co-60. 

Figure 10 and Figure 11 show the radionuclide activity within the total ILW activity in the 2024 report.  

Figure 10 shows the main radionuclides that contribute most of the activity in the ILW waste streams. Figure 11 displays the ‘Other’ radionuclides featured in Figure 10. There are other radionuclides with even lower activity that we have not included in Figure 11.