Our People

Our group is made up of a multi-disciplinary team of professional scientists, engineers and software developers, each with their own areas of specialism:

David Holton - Dr David Holton is an internationally recognised expert in geological disposal. He is currently Chief Technologist at Jacobs responsible for the technical quality of all work in geological disposal delivered to customers both in the UK and overseas. His research experience has spanned a broad range of scientific and technical disciplines: geology; hydrogeology; dispersion of solutes in the environment; engineering design; environmental safety; modelling of coupled processes (THMC) in geological and engineering materials; and modelling of natural geological processes.

Nick Jefferies - Nick Jefferies is a highly experienced geologist with more than thirty years' experience of providing geological, hydrogeological and wider environmental consultancy. His principal areas of expertise are site characterisation, decommissioning and remediation of nuclear sites.

Andrew Hoch - Dr Andrew Hoch is a theoretical physicist with over three decades' experience of working on a range of issues surrounding the disposal of radioactive waste (corrosion of waste containers, groundwater flow and transport, geochemical evolution of the near field, and gas generation and migration), for clients both in the UK and overseas. Andrew has a unique background in the modelling of both physical and chemical processes in geological disposal facilities.

Steven Joyce - Dr Steven Joyce is leader of the geological modelling team for Jacobs at Harwell. His main focus is on carrying out and managing modelling and software development projects associated with groundwater flow and transport. Applications have included modelling the evolution of groundwater systems at deep geological disposal facilities in crystalline rocks. Steven has over 15 years of groundwater modelling experience and over 20 years of scientific software development experience.

Ben Swift - Ben Swift has over 20 years' experience of working on nuclear waste packaging and disposal issues, for organisations both in the UK and overseas. Much of his work has concerned waste package issues during all stages of the life-cycle, including storage, transport and following disposal in a facility. Ben is an expert in both developing and applying models for a wide range of processes important to the behaviour of waste packages, and in particular in modelling gas generation from radioactive waste materials.

David Roberts - Dr David Roberts is an experienced environmental and waste management modeller, with an emphasis on the development of groundwater pathway assessment scenarios and models. David's knowledge of safety cases spans both national and international examples. His key skills include the development of groundwater flow and transport models; understanding radiological risk assessment methods and regulatory requirements; and writing technical reports accessible to a range of audiences.

David Applegate - Dr David Applegate is an experienced computational physicist specialising in radionuclide transport and groundwater modelling. He is also an expert in GoldSim modelling. David is the lead developer of Jacobs' groundwater and transport modelling software package, ConnectFlow, and has implemented a range of important developments. He uses a diverse set of tools for software development, including Fortran, Java, Perl, Python and the MPI library for parallel programming.

Hannah Woollard - Dr Hannah Woollard is a mathematical modelling consultant who joined Jacobs in 2009, following a PhD in applied mathematics. She has worked on a variety of modelling projects both nationally, for LLW Repository Ltd., Sellafield Ltd., the NDA and NuGen, and internationally, for SKB and Posiva. More recently, she has led the work on geological and hydrogeological modelling of Quaternary deposits in Cumbria, using continuous porous medium (CPM) models in ConnectFlow.

Pete Appleyard - Pete Appleyard is the software manager for ConnectFlow. He has a background in Physics and works primarily on development of ConnectFlow and modelling projects. He has developed, tested and verified numerous product releases and new software developments, and has done extensive modelling using ConnectFlow for customers in the UK, Sweden and Finland, in addition to responding to support queries from ConnectFlow users.

Simon Myers - Dr Simon Myers is a mathematical modeller who works on a variety of projects for customers in the nuclear industry. Simon has developed and updated software toolkits, including SMOGG (gas generation calculation), TDT (Thermal Dimensioning Tool), and supports Jacobs' groundwater modelling team, including the implementation of new functionality in ConnectFlow.

Vasileios Tsitsopoulos - Dr Vasileios Tsitsopoulos is an applied mathematician with significant experience in fluid mechanics, heat transfer, asymptotic methods, numerical techniques and coupled process modelling. Vasileios has substantial experience in the development and use of numerical software for groundwater, coupled THM and contaminant transport modelling using ConnectFlow, FRAC3DVS_OPG, COMSOL Multiphysics, PFLOTRAN and TOUGH2, as well as in software development using MATLAB, Maple, Fortran and Python.

Tom Williams - Dr Tom Williams is a computational physicist with a PhD from the University of York. His role is centred on ConnectFlow modelling, with a focus on the DFN concept; amongst others, he has been extensively involved in modelling activities in support of the geological disposal programmes in Finland and Sweden. In the process, he has developed skills in database design and analysis for the conceptualisation and parameterisation of DFN models based on large integrated datasets. He is also involved in ConnectFlow development.

Freddie Mather - Dr Freddie Mather has several years' experience in mathematical modelling, both numerical and analytical. He has expert knowledge of fluid mechanics and thermodynamics, and has extensive experience of implementing optimisation algorithms for both serial and multiple processors. Since joining Jacobs in 2019, Freddie has contributed to hydrogeological modelling projects of near-surface Quaternary deposits and of fractured crystalline bedrocks.

Javier Rodriguez Corral - Dr Javier Rodriguez Corral joined Jacobs in 2019 as a geological modelling consultant. In addition to providing support on ConnectFlow modelling projects, he has significant experience with several modelling packages for geotechnical design such as PLAXIS, LUSAS and Settle3D.

Guanqun Gai - Dr Guanqun Gai holds a PhD from the University of Liverpool in aerospace engineering and joined Jacobs in 2019. Guanqun's research involved the development of computational models of aircraft aeroelasticity and structural dynamics. This relied heavily on Python/MATLAB programming and resulted in several publications. He has worked on several software development tasks and has provided support to hydrogeological modelling projects.

JieJie Wu - Dr Jiejie Wu joined the team as a Mathematical Modelling Consultant after completing her PhD at the University of Manchester. Jiejie has been providing mathematical models for thermal (T), hydraulic (H) and mechanical (M) processes in the geological disposal facilities, underground water safety assessments, and other geological disposal projects. She is an expert in the use of finite element modelling tool, COMSOL Multiphysics, which can be used to solve a wide range of physics problems.

Chris Coleman - Dr Chris Coleman is a Chartered Geologist specialising in the development of 3D digital geological models used for engineering decision making and hydrogeological studies. He has an expertise in Quaternary geology and geomorphology. Chris has extensive experience of site characterisation delivery, including geophysical techniques, as well as the integration and management of site characterisation data and communication of variability and uncertainty in ground conditions to clients.

Amber Pavey - Amber Pavey is a geologist, joining Jacobs in 2021 following previous work developing 3D geological models, including for Sellafield Ltd. She has a strong geological background, including a masters project focused on interpreting 3D seismic data.