NURES® treatment for Grafenrheinfeld NPPs radioactive waste

Grafenrheinfeld PWR nuclear power plant, located in south Germany, started its decommissioning phase in 2015. During 2020-2022, approximately 1300 tons of radioactive wastewater - originated from the primary circuit, spent fuel pool, and from other auxiliary systems - had to be emptied from the storage tank for dismantling work. A major goal of the NPP operator was to keep the amount of radioactive waste as low as possible. Fortum assisted in the decommissioning project by reducing the liquid radwaste quantities by a factor of thousands using NURES® technology, proven in decades of projects around the globe.

Case description

Fortum worked as the technology provider for delivering a radioactive wastewater treatment system to Grafenrheinfeld Nuclear Power Plant. The work was conducted in two distinct phases: system design phase and implementation phase.

In design phase the properties and requirements for the project in question were developed. Fortum’s patented NURES® technology, based on 100% inorganic, highly selective, granular ion exchange materials, is a modular and turn-key technology that can be used to clean multiple sources of radionuclides in radioactive liquid. In Grafenrheinfeld, CoTreat, SbTreat and CsTreat were utilized, alongside a prefiltering module to collect suspended solids in the liquid.

After finalizing design for the project, the NURES treatment plant was manufactured and designed in Finland after which it was installed and commissioned at the project site where it was used from 2020 until 2022 to treat the said radioactive wastewater.

NURES®

NURES® technology purifies liquid radioactive wastewater and reduces its volume to a fraction of the original. The technology was originally developed for the Cs (cesium) removal process at the Loviisa NPP. NURES® treatment results in a liquid, free from nuclides, and radioactive NURES® material.

Fortum’s NURES® treatment plant are especially suitable for treating challenging contaminated liquids, because

Drying of high salt liquid (including inorganic salts and boric acid) has high OPEX and low volume reduction
Selective filtration only intercepts radionuclides, leaving the salts in the liquid
Mobile, automated and flexible system engineering.

Core of the NURES® technology is four different ion exchangers:

CsTreat®

Based on hexacyanoferrate

Removes universally Cs isotopes

Operating pH 1-13

SrTreat®

Based on modified titanium oxide

Primarily removes Sr isotopes, works also for Pu and Zn

Operating pH >7

CoTreat®

Based on modified titanium oxide

Primarily removes Co isotopes, works also for corrosion products and transuraniums

Operating pH 4-8

SbTreat®

Based on zirconium oxide

Primarily removes antimony oxyanions, works for other oxyanions (e.g., iodine species)

Operating pH <8

Our approach

Fortum offered PreussenElektra nuclide removal for 1300 m³ of radioactive wastewater. The main radionuclides in the waste were Sb-125, Mn-54, Co-60, Ag-100m, Te-123m, Cs-134, and Cs-137. The activity of these nuclides ranged from 100 MBq/m³ to 100 GBq/m³. The scope of the project was to decontaminate the liquids below the limits for free release.

The installed system consisted of a feed tank, a pre-filter, three NURES® modules, a chemical station, and a mixer tank, all of which could be fit inside one 40 m³ room and could treat up to 30 m³ of radioactive waste in a week. The system was also highly automated, requiring less than 30 minutes of manual work per day.

All spent NURES® ion-exchange columns could be placed into one 1 m³ final disposal package, resulting in a volume reduction factor of at least 1300, as the original waste amount was 1300 m³.

The NURES® nuclear wastewater treatment technology has demonstrated its capability in handling challenging wastewater in nuclear decommissioning processes. In particular, a mobile filtration-based system provides maximum volume reduction factor and great flexibility that are important to achieve excellent purification results and significant cost savings. The NURES process can also be used in other applications where the wastewater has a high salt concentration.

Coupled with certain pre-treatment steps (e.g. selective oxidation process), the mobile treatment process are well versed for handling other types of liquid wastes generated in nuclear decommissioning projects. The mobile system can be disassembled and moved to the next location for liquid waste treatment in other decommissioning projects

Mutually beneficial cooperation

By completing the project, Fortum’s NURES® experts gained extensive experience of the local environmental laws and regulations as well as best practices of using NURES® in a commercial power plant decommissioning project. The exceptional results from the processing provides further evidence of NURES® technology working phenomenally in commercial nuclear power plant decommissioning. Seamless communication with the locals on site likewise greatly benefited all parties in the implementation phase of the project.

The assembly of the plant was done during the summer 2020 and liquid treatment was completed in the September 2022.

"Customer had a very tight schedule, as they needed to have all the liquid to be decontaminated and treated during 2020 to be able to continue the following decommissioning process. In the project plan this was the critical part in the project", says Martin Lerche, Product Manager for NURES®.

"The project has proceeded as it should and on schedule. It's also great that this was the first project of its kind in Germany. In addition, despite of the challenges caused by the Covid-19, we have had very good feedback from the customer and the whole system has worked well", Martin Lerche continues.

The customer was also very pleased with the results and the service provided by Fortum.

"We were pleasantly surprised with the absorption capacity of the NURES filters, since according to the planning a significantly higher filter requirement was expected. After commissioning and after completion of the trial run, the system ran reliably, without faults and with minimal maintenance", Sebastian Hahn from PreussenElektra comments.

Martin Lerche

Sales Manager, NURES®
Tel: +358414584918
martin [dot] lerche [at] fortum [dot] com

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