Thorp knowledge capture

Case Study

Case Study

TÜV SÜD Nuclear Technologies Division has completed a project to capture first-hand operational experience of a major reprocessing facility on the Sellafield site.


Client name: Department for Business, Energy & Industrial Strategy, National Nuclear Laboratory

Industry: Nuclear

Profile: Established in 2008, the National Nuclear Laboratory is the UK’s nuclear research and development capability

Business challenge: First-hand operational experience of Thorp for the benefit of future generations 

Former employees: Solution Informal interview sessions with key staff and captured into a searchable database

Business benefits: Successful delivery of a project to time and cost, using a robust methodology to gather and process highly technical information into a form suitable for future designers and operators

Dates: 2020 - 2021

Business challenge

In 2018, following 24 years of successful operations, the Thermal Oxide Reprocessing Plant (Thorp) on the Sellafield site in Cumbria, completed its final fuel shear. The lessons learned over the lifecycle of the plant hold incredible value for the design, construction and operation of a facility of this scale.

To ensure that this knowledge is preserved for future generations, the National Nuclear Laboratory (NNL), in collaboration with Sellafield Ltd and the Nuclear Decommissioning Authority (NDA), engaged TÜV SÜD to collate this information. The work was funded under the £46M Advanced Fuel Cycle Programme as part of the Department for Business, Energy and Industrial Strategy’s (BEIS) £505M Energy Innovation Programme.


The primary focus of TÜV SÜD’s scope was to gather first-hand experience gained during the operational phase of Thorp (1994 to 2018). However, because many lessons from operations have their roots in development, design and commissioning, these phases in the plant’s story were also considered to provide context for the operational experience.

The project covered the main activities on the plant and associated services including the dissolution of fuel, chemical separation of uranium and plutonium from the high level waste and preparation of uranium and plutonium products for storage.

The findings of the project were drawn from a programme of informal interviews with more than 40 personnel made up of current and former employees of NNL and Sellafield Ltd and their predecessors. Interviewees were selected to ensure a broad range of roles from each phase of the plant lifecycle and operational areas were included. This generated a large volume of data which were collated into a database so that common themes and lessons learnt could be identified and used to prepare the final report.

Business benefits

The project delivered a unique technical document compiled from first hand accounts that identified key operational experience of value in supporting the development, design and operation of future processes. The conclusions of the report were based on a wide spread of historical experience throughout the many process stages of a complex nuclear facility and therefore have relevance to the future designers and operators of other nuclear installations of all sizes.

Add value. Inspire trust.

The technical project team had first-hand experience of the Sellafield site including more than 30 years of direct involvement with Thorp and extensive knowledge of the various challenges that occurred during its operational period. This experience enabled the team to undertake each interview with credibility, facilitated as an informal open conversation to establish the key and important learning based on the personal experience of the interviewee. This was then used to provide an independent assessment of the key learning, drawn directly from all of the interviews.

An adaptive and collaborative approach was used at all stages of the project enabling successful delivery to time and cost even in the challenging conditions of a global pandemic.

The Nuclear Technologies Division of TÜV SÜD has been providing support to the nuclear industry and innovating within the field of nuclear science for over 25 years. The team of highly qualified expert consultants is here to support clients with knowledge on industry best practice and to provide innovative solutions to complex technical and strategic challenges. The team helps clients to achieve safe and secure operations in line with legal and regulatory requirements whilst ensuring value in delivery.

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