Process instrumentation for a nuclear waste treatment plant

Australia's Nuclear Science and Technology Organisation (ANSTO) is one of Australia’s largest public research organisations. The institute is widely recognised as an international player in the field of nuclear science and technology.

ANSTO has developed the Synroc^® technology which is regarded as global best practice in the safe treatment of complex nuclear waste, including actinide bearing materials, radioiodine, and molten salts from spent fuels. The benefit of this technology is demonstrated in an automated process plant (Synroc Waste Treatment Plant) that the organisation operates near Sydney. The objective of the plant is to treat the liquid by-product of Molybdenum-99 (Mo-99) nuclear medicine production.

The liquid waste from Mo-99 production is captured, stored, and characterised in tanks before it is processed within a hot cell by introducing the Synroc formulation. The tailored liquid additive undergoes mixing before it is converted into a granulated powder via a drying process. Subsequently, the powder is then dispensed to a specially designed canister which is then sealed and placed into a Hot Isostatic Press (HIP) where heat and pressure are applied for waste form consolidation. The final solid product is volume-reduced, durable and a disposal-ready waste form.

While the liquid Mo-99 production waste is radioactive, various manufactured components needed to be interrogated for material compatibility within the environment prior to commissioning. One of the main challenges was finding an instrument supplier with experience in radiation sensitive environments.

With a long track record in nuclear applications, offering a wide range of radiation hardened products and components, KROHNE was able to qualify as a preferred instrument supplier.

The instruments in contact with the Mo-99 waste were the first to be specified. This included the POWERFLUX 5300, an electromagnetic flowmeter designed for nuclear environments, which is used for the waste feed and feed control. The most critical installation involved the double remote POWERFLEX 2200 guided radar level transmitter used for waste tank level measurement. To maintain ventilation confinement, various OPTIBAR DP 7060 differential pressure transmitters are used for pressure control and monitoring of the hot cell.

In total, the instrument selections covered various applications incl. flow, level, pressure, and temperature measurement as well as different media – from liquid Mo-99 waste to chemicals and process condensate to clean water. KROHNE supplied among others:

• 5 POWERFLUX 5300, 3 OPTIFLUX 5300 and 4 OPTIFLUX 4300 electromagnetic flowmeters
• 2 POWERFLEX 2200 guided radar (TDR) level transmitters
• 25 OPTIBAR DP 7060 differential pressure (DP) transmitters
• 30 OPTIBAR PM 5060 pressure transmitters
• 4 OPTIMASS 6400 and OPTIMASS 7400 Coriolis mass flowmeters
• 2 OPTIWAVE 7500 80GHz FMCW radar level transmitters
• 1 BM26A-1000 magnetic level indicator with LT40 reed chain transmitter
• 3 H250 M40 variable area flowmeters

Most instruments have been provided in rugged stainless-steel housing. Critical instruments were proven and demonstrated on a smaller pilot plant to verify the concept before the customer selected the instrument supplied for the Synroc Waste Treatment Plant.

Selecting KROHNE allowed ANSTO to have a supplier for radiation specific measurements as well as standard applications. Given its vast experience in nuclear applications, KROHNE was able to supply the instruments for a number of unique measurements in contact with nuclear waste.

KROHNE offers various devices designed to operate in nuclear applications inside and outside the nuclear power industry, many of which can also be qualified according to IEEE 323, IEEE 344 and RCC-E standards and designed as per nuclear construction codes such as ASME Section III or RCC-M.