Software Developer

ANSWERS is currently recruiting for a talented Software Developer to join a multidisciplinary development team developing next generation computational modelling software for analysis of nuclear reactor physics. This role will present an enthusiastic and motivated individual with a unique opportunity to be involved in the creation of a brand-new software product from the ground up, to work with cutting-edge technology to establish the new state-of-the-art in industrially applied physics codes, and to support the design and operation of existing and new nuclear reactor systems worldwide for decades to come. Key Responsibilities will be:

• Collaborate with the ANSWERS reactor physics team to translate mathematical and physics models into practical, easy-to-use software for use by a wide-ranging customer base including industry, academia and government professionals
• Design, implement and optimise high-performance algorithms for simulations on a variety of computer architectures, from single workstations to modern HPC platforms featuring a combination of CPUs and GPUs
• Provide a robust and scalable software code base for complex scientific computations, which can scale, evolve and adapt to future reactor physics requirements
• Ensure the development of quality software according to ANSWERS procedures, through testing, documentation and version control, and to help these procedures and policies develop to meet the latest requirements
• Lead and drive the software development and testing process with a view to continuous improvement. Your perspective and your voice will be critical to shaping a robust, future-proof solution and ensuring the success of this project.

• Strong knowledge and experience of using C++, Python
• Knowledge of parallel computing methods and performance optimization
• Familiarity with common system tools including build systems, version control, code documentation methods
• Experience of using GPU acceleration methods
• Desirable:
• Knowledge and experience of Fortran and Java
• Experience in UI development for scientific software and visualisation of data
• Background, knowledge or previous experience in nuclear engineering, reactor physics or related fields.
• Previous experience of the implementation of physics or mathematical methods to computational modelling codes
• Experience of implementing distributed and shared memory parallelisation methods on CPU-based HPC architectures
• Ability to start in early 2026

People are our greatest asset, and we offer a competitive package to retain and attract the best talent.

In addition to the benefits you'd expect, UK employees also receive free single medical cover and digital GP service, family-friendly benefits such as enhanced parental leave pay and free membership of employee assistance and parental programmes, plus reimbursement towards relevant professional development and memberships.

Work-life balance and flexibility is a key focus area for us. We're happy to discuss hybrid, part-time and flexible working hours, patterns and locations to suit you and our business.

About the Opportunity

The ANSWERS® Software Service has, for over 40 years, supplied both the UK nuclear industry and the wider international market with high quality software and consultancy services in the areas of reactor physics, radiation shielding & dosimetry, criticality assessment and nuclear data. Our dedicated team of specialist engineers, physicists, mathematicians and software developers produce bespoke software packages for computational modelling of complex physics. Our worldwide customer base is supported by a dedicated helpline with experienced consultants and analysts to provide comprehensive advice in computational modelling of nuclear engineering problems.

At Amentum, we're not just solving problems; we're engineering the future. Our team is driven by an unyielding commitment to innovation, integrity, and collaboration, tackling some of the most significant challenges in science, security, and sustainability. If you're passionate about making a real impact and want to be part of a community that values ethical excellence, this is the place where your ambition can thrive. Here, we believe that success comes from continuously pushing boundaries and working together to deliver on our promises. We embrace challenges with confidence and are dedicated to creating a secure and vibrant future for all. We'll inspire and empower you to deliver your best work so you can evolve, grow and succeed - today and into tomorrow. We offer an exciting range of opportunities to develop your career within a supportive team who always strive to do the right thing for our people, clients and communities., This role will involve an initial familiarisation period at our Dorchester office, where the team for deterministic reactor physics code development is based. Following this, the position can develop into a hybrid / remote role at any of our offices in Dorchester, Warrington or London. Consideration will also be given in respect to part time & flexible working hours. Our Culture Our values are built on a strong foundation of safety, integrity, and respect for every individual. People are at the heart of our mission, and we believe in supporting one another through a culture of care and collaboration. We strive to create a workplace where everyone feels they belong and can thrive. Supporting mental wellbeing and fostering a sense of connection are essential to how we work. When we embrace different perspectives and work together, we become more innovative, more agile, and more successful.