Assessing nanoparticle populations in historic nuclear waste

Legacy ponds at the Sellafield site have been used to store historic radioactive waste for decades and progress is being made in reducing the risks associated with these facilities . Over time, there has been a deterioration in the condition of the ponds and their contents that has resulted in particles being present in solution in the ponds. It is important to characterise these particles, whose size are believed to range in diameter from nanometres to microns, in order to facilitate further reductions in the risks. Commercially-available instrumentation is capable assessing the size and number of particles in a solution, based on their motion, when the particles have diameters large than about 150nm; however, recent research has shown that particles with smaller diameters exhibit different behaviour leading to erroneous measurement results in these instruments. At low concentrations, the motion of nanoparticles with diameters less than about 150nm has been found to be independent of their size, density and material. These findings were obtained by tracking particles using the three-dimensional optical signature, or caustic, which they generate in an optical microscope, that can be several orders of magnitude larger than the particle . In this project, it is proposed to extend this work by developing an instrument that is capable of assessing the number and size of small nanoparticles in a solution that is representative of those recovered from the legacy ponds at Sellafield. The research will be undertaken using existing facilities at the University of Liverpool, initially using simple solutions and then progressing to non-radioactive simulants of the pond solutions. The long-term goal is to transition the technology to the Sellafield site and, hence, the final stage of the PhD project will be to demonstrate the technology on pond solutions using the facilities of the National Nuclear Laboratory.

In GREEN we envisage there are potentially Impacts in several domains: the nuclear Sector; the wider Clean Growth Agenda; Government Policy & Strategy; and the Wider Public.

The two major outputs from Green will be Human Capital and Knowledge:

Human Capital: The GREEN CDT will deliver a pipeline of approximately 90 highly skilled entrants to the nuclear sector, with a broad understanding of wider sector challenges (formed through the training element of the programme) and deep subject matter expertise (developed through their research project). As evidenced by our letters of support, our CDT graduates are in high demand by the sector. Indeed, our technical and skills development programme has been co-created with key sector employers, to ensure that it delivers graduates who will meet their future requirements, with the creativity, ambition, and relational skills to think critically & independently and grow as subject matter experts. Our graduates are therefore a primary conduit to delivering impact via outcomes of research projects (generally co-created and co-produced with end users); as intelligent and effective agents of change, through employment in the sector; and strong professional networks.

Knowledge: The research outcomes from GREEN will be disseminated by students as open access peer reviewed publications in appropriate quality titles (with a target of 2 per student, 180 in total) and at respected conferences. Data & codes will be managed & archived for open access in accordance with institutional policies, consistent with UKRI guidelines. We will collaborate with our counterpart CDTs in fission and fusion to deliver a national student conference as a focus for dissemination of research, professional networking, and development of wider peer networks.

There are three major areas where GREEN will provide impact: the nuclear sector; clean growth; Policy and Strategy and Outreach.

the nuclear sector: One of our most significant impacts will be to create the next generation of nuclear research leaders. We will achieve this by carefully matching student experience with user needs.

clean growth - The proposed GREEN CDT, as a provider of highly skilled entrants to the profession, is therefore a critical enabler in supporting delivery of both the Clean Growth agenda, Nuclear Industry Strategy, and Nuclear Sector Deal, as evidenced by the employment rate of our graduates (85% into the sector industry) and the attached letters of support.

Policy and Strategy: The GREEN leadership and supervisory team provide input and expert advice across all UK Governments, and also to the key actors in the nuclear industry (see Track Records, Sections 3.3 & 5.1, CfS). Thus, we are well positioned to inculcate an understanding of the rapidly changing nuclear strategy and policy landscape which will shape their future careers.

Outreach to the wider public: Building on our track record of high quality, and acclaimed activities, delivered in NGN, GREEN will deliver an active programme of public engagement which we will coordinate with activities of other nuclear CDTs. Our training programme provides skills based training in public and media communication, enabling our students to act as effective and authoritative communicators and ambassadors. Examples of such activities delivered during NGN include: The Big Bang Fair, Birmingham 2014 - 2017; British Science Week, 2013 - 2017; ScienceX, Manchester; 2016 - 2018; and The Infinity Festival, Cumbria, 2017.