Funding opportunities

Nuclear Waste Services Research Support Office post-doctoral call in Understanding the Mechanisms of Zirconolite Leaching

Full submission deadline:

Monday 24th June 2024, 16:00

Nuclear Waste Services (NWS), via their Research Support Office (NWS RSO) is requesting applications for a Post-Doctoral Research Associate (PDRA) project “Understanding the Mechanisms of Zirconolite Leaching” in the Materials Science area.

The aim of the NWS RSO is to develop a portfolio of research projects focused on NWS research priorities. The specific aims of the NWS RSO are to:

  • Develop the high-level skills required for the NWS research mission over the coming decades, and to help deliver the next generation of geological disposal researchers.
  • Expand the academic geological disposal research community throughout the UK and internationally.
  • Encourage collaboration and communication between NWS and the academic community.


The research project in Materials Science is expected to have a duration of 24 months, and the target start date is July 2024. The project proposal indicative budget is £350,000. The assessment and contractual arrangements for the project will be administered by Nuclear Waste Services. The NWS RSO is seeking proposals from academic lead investigators for a PDRA based project within their group. The lead investigator and will be responsible for recruiting a suitable candidate by the target award start date.

There is an expectation that the findings and results, from the work undertaken as part of the projects, will be free to publish but explicit permission must be received from NWS prior to publication.

Call structure:

Request for proposal sent on: 7th May 2024
Clarifications period closes on: 27th May 2024
Request for proposal closes on: 24th June 2024


All clarification questions (including commercial, technical and terms and conditions) must be sent before the clarification period is closed and addressed to the NWS RSO via

Any clarification questions to the scope of the project and/or grant agreement terms will only be considered during the Clarification period stated above and will not be accepted after proposal submission.

Proposals will be accepted as .pdf documents and supporting materials emailed to the RSO inbox: Exchanges between academics and NWS staff during the tender period is strongly discouraged. Applications will be assessed by a Nuclear Waste Services (NWS) panel of key stakeholders.


Clarification Q&A 

(See drop-down for answer) 

1) It is stated that zirconolite dissolution should be investigated for the well characterised end-member CaZrTi2O7 system. Could NWS please clarify what constitutes 'well-characterised'. We are taking this to assume high phase purity to within 1 - 3 wt.% accessory Zr/TiO2 which is commonplace for materials fabricated by the solid state route, with stoichiometry constrained to within +/- several at.% that of the nominal precursor. 'Well-characterised' implies phase confirmation by diffraction and SEM, alongside density and EPMA for high accuracy compositional analysis. Could this please be explicitly clarified?

The term “well characterised” should be taken to mean a high phase purity system (specifics to be agreed with NWS prior to commencement of the work) with supporting confirmation of phase purity provided by a suite of complementary analytical techniques (to be described within the application by the supplier).

2) Previous work indicates that the addition of excess ZrO2 may buffer against undesirable CaTiO3 during synthesis - can NWS specify whether: • A single phase product is preferable allowing for small modifications in stoichiometry in the CaZrxTi3-xO7 system, or, • It is preferred to obtain a phase composition whereby Ca1.00Zr1.00Ti2.00O7.00 is targeted, allowing with preservations for a secondary Zr/TiOx phase not more than several wt.%

A single-phase product is preferrable. Specifics in terms of minor modifications in stoichiometry are to be agreed with NWS prior to commencement of the work.

3) Could NWS please clarify the preferred precursor production route? CaZrTi2O7 and indeed U-doped precursor material (see below) could feasibly be produced by either: high energy planetary milling oxide precursors (ideally CaTiO3, ZrO2 and TiO2) to a wet slurry, followed by drying, sieving and pelletisation prior to high temperature sintering, or, mixing of alkoxide-nitrate solutions followed by high temperature calcination, homogenisation and then high temperature sintering. It is considered that whilst the former method is arguably more suitable for scoping trials requiring high sample throughput to identify preferred compositions, the alkoxide-nitrate route is likely to produce a more reactive precursor with a greater specific surface area. For the U-doped material, this protocol would be modified slightly, whereby a precursor composition is prepared for all cations except uranium; the above procedure is repeated, and UO2 is added at the required concentration in a secondary milling stage. As I understand, the HIP flowsheet would essentially follow this route. Could NWS please clarify their preferred production route.

NWS do not have a preferred precursor production route, the supplier should define an appropriate route to achieve a high purity, well-characterised end-member CaZrTi2O7 system as part of the application process.

4) Could NWS please clarify the preferred targeted U-doped composition, i.e. is this the RWM-1 (Fe) doped composition developed within the RWM313 project? Moreover, are we to assume that there is scope within the project to further refine sintering conditions to maximise product quality e.g. variation in sintering parameters and/or the addition of pelletisation/sintering aids?

The targeted U-doped composition will be agreed with NWS prior to commencement of the work. There will be very limited scope for refinement of conditions for material production as the focus of this project is to provide mechanistic understanding of zirconolite leaching, with specific emphasis on the determination of congruent or incongruent dissolution processes.

5) There is evidence that cold isostatically pressing green body pellets can enhance the density of zirconolite pellets produced by the CPS route. Would it be possible to assign ~ £4.7k within the budget to purchase a laboratory scale MesoCIP unit that could be used to CIP U-active zirconolite pellets? As far as we are aware this capability is not present.

Any equipment deemed necessary to effectively delivering the core aims of the project should be articulated as part of the application process.

6) Could NWS please clarify the scope of the dissolution testing? We are working to the assumption that this is based on the ASTM C1308 protocol developed within RWM313. Moreover, could the preferred temperatures and leachate compositions?

The supplier should outline the experimental methodology and conditions they believe to be best suited to addressing the core aims of the project. NWS are open to all credible experimental approaches and matrices to deliver the core aims of the project.