The Australian Nuclear Science and Technology Organisation (Ansto) said on 9 April that construction of a first-of-a-kind facility to immobilise waste from the production of molybdenum-99 (Mo-99) is expected to be completed in early 2020. The new facility will use Ansto Synroc technology to immobilise waste from Mo-99 production, known as SyMo. The Mo-99 is produced in Ansto’s OPAL multipurpose reactor. “Today, Ansto Synroc combines waste form design and process technologies to immobilise and terminate nuclear wastes creating a technology tailored for intermediate level liquid waste.” said Gerry Triani, Ansto Synroc Technical Director. “It is also a flexible platform technology that can be modified to suit other waste streams.”

Ansto Synroc technology was developed over many years. It integrates the design of both the waste form and process technology to immobilise and terminate nuclear waste, minimise volume and provide a durable and safe solution for final storage of radioactive waste. The Synroc waste treatment plant will process the intermediate level liquid waste from nuclear medicine production that will be piped underground directly to the waste treatment plant from the new molybdenum-99 production facility.  

The liquid waste is pumped from an underground holding tank to a high point in the shield enclosure, where it is injected into the process chamber. The stream is mixed with the Synroc additive to form a granular powder. This cascades into a thermal processing unit before being dispensed to a stainless steel canister, which is then subjected to hot isostatic pressing (HIP), consolidating the powder into a durable solid and reduces its volume.

“We have demonstrated an engineering-scale process technology using surrogate chemistry. This provides an example of an operational plant to prospective clients of the Ansto Synroc technology and gives us added credibility,” said Triani. “Using gravity to cascade the processed wasteform to the canister is a neat solution that produces powder on demand and reduces the radiological load within the facility.” 

The new plant will be fully automated, with operations being monitored remotely from a control room. That automation extends to HIP processing, which will be the first example of the technology being used in a nuclear process environment. “The HIP system that we have commissioned is unique in its own right. In traditional applications, workers are used for loading and unloading parts into the HIP vessel. Our system has an automated part loading system that lifts the canister into the chamber and unloads it following processing,” Triani noted.

“Once the equipment is placed in the shielded enclosure we will conduct performance tests at a unit operations level. Then we will move towards fully integrated testing to ensure that the entire end to end process functions is tested.” Ansto will then confer with the Australian Radiation Protection and Nuclear Safety Agency (Arpansa) for a cold commissioning licence, and following cold testing, for a hot commissioning licence. The SyMo operational readiness team will be trained at the demonstration plant, which is located in another Ansto building.

Triani is enthusiastic about global opportunities for Ansto Synroc. “Our technology maturation approach has paid off. We have already had expressions of interest from overseas interests keen to explore our immobilisation technology for other types of nuclear waste streams. We can evaluate those approaches using our knowledge and expertise.”