Audits and the waste data trail

14 February 2024



The layered system of governance for nuclear materials generates huge volumes of data across multiple stakeholders in multiple jurisdictions. Now, blockchain technology may help to address a major data challenge faced by the nuclear industry.


Above: Organisations such as Finland’s Radiation and Nuclear Safety Authority (STUK) have already tested blockchain technology (Photo credit: IAEA)

Nuclear governance comprises a complex web of obligations from the local to national, bilateral, regional and international levels applied at each stage of the nuclear fuel cycle. It is a system designed to avoid disruption, focusing rightly on maintaining and certifying the safe, secure and peaceful use of nuclear material and technology. This layered system of governance generates large volumes of data across multiple stakeholders in multiple jurisdictions. It also engenders a resistance to new technologies which has left many operators and regulators stuck with clunky, siloed legacy systems, and labour-intensive manual or paper-based processes.

With digitisation and emerging technologies producing even more data-rich environments, information management systems today need to capture and protect both a greater variety and a growing quantity of data, including metadata. Blockchain technology is offering solutions for adding audit trails to digital data, ensuring a distributed record of who did what and when to what file, allowing all stakeholders to verify an action that was taken this morning, or 10 days ago, or 10 years ago, was the right one.

Organisations such as Finland’s Radiation and Nuclear Safety Authority (STUK) and Sellafield Ltd have already tested blockchain technology and demonstrated that it offers data authentication, transparency and immutability.

This enables full visibility of waste streams and enhances nuclear material accountancy and compliance with national legislation and confidentiality rules.

The data challenge

Data collected by organisations responsible for radioactive waste repositories must be managed over long timelines, typically beyond 100 years. This data includes everything from waste characterisation to environmental monitoring, nuclear safety, security and safeguards.

As a country’s nuclear fuel cycle matures, the quantity, type and quality of data increases throughout the different stages of decommissioning facilities, repository development and regulatory and community approvals, for example pre-siting, siting, site characterisation, construction, operations, pre-closure and closure. For used fuel from reactors, the task becomes more challenging given physical inspection of the material becomes impossible once it is placed more than 400 metres underground.

For STUK, “the significance of data integrity is immense when it comes to safeguarding the geological repository at Olkiluoto. The underground facility is the world’s first for used fuel and the first for the application of European and international safeguards at the back end of the nuclear fuel cycle”.

In the UK, the Nuclear Decommissioning Authority (NDA) is responsible for the country’s nuclear waste management. NDA’s largest operation, Sellafield Ltd, hosts 80% of the UK’s nuclear waste inventory, where waste volume is expected to grow from 202,000 cubic metres in 2019 to 4.3 million cubic metres by 2135. With one in five steps of the nuclear waste tracking process relying on paper or manual steps, the ability to currently locate and track radioactive waste data moving through the NDA estate requires significant effort involving multiple actors, siloed databases and legacy systems. This is particularly difficult every three years, when the UK’s radioactive waste inventory is updated. This involves collecting information regarding more than 1,300 radioactive waste streams and 60 radioactive material streams.

Metadata accompanying nuclear waste data is also growing and can be difficult to manage if not captured at the time it is created. Metadata on a waste container, for example, can represent its technical attributes, ID, who has accessed it, information related to sensors/devices (including instrumentation health and status), and the origin and definitions of the chemical and radionuclide inventory in the waste.

Metadata can help make data easier to find though, as well as understand its origin/provenance/authenticity, and enable explainable machine-learning and AI in valuable datasets used over time. The OCED’s Nuclear Energy Agency established the Radioactive Waste Repository Metadata Management (RepMet) project in 2014, with recommendations for a set of metadata that can be used by national radioactive waste programmes to manage and harmonise radwaste repository data for long-term management and use. RepMet did not consider technological options for data management, but STUK and Sellafield UK’s blockchain tests identified benefits for supply chain operations and long-term data management.

Blockchain benefits

Blockchain is a subset of distributed ledger technology (DLT), the catch-all category for decentralised digital databases that can include a wide range of participants and data sources from multiple locations. These platforms encrypt, timestamp, replicate and store cryptographically “hashed” data into an immutable ledger which in turn becomes the single source of truth for a distributed set of participants.

Data is appended and embedded making it extremely difficult to manipulate, allowing stakeholders to interact in a trusted environment. To increase security, generally no data files are physically stored on the blockchain. Instead, only the hash and/or metadata is posted.

Blockchain technology is often associated with cryptocurrencies which detracts from its more useful applications for tracking supply chains, processes, documents and files. Bitcoin, considered the technology’s flagship, is the world’s first open blockchain; a platform that allows anyone with an internet connection to participate in a system of digital payments. Most enterprise solutions employing blockchain today are private, permissioned systems, restricting access to relevant stakeholders and consensus on validation. Indeed, the Government of Estonia was already developing the first permissioned blockchain platform before the Bitcoin Whitepaper was published in October 2008.

Since then, advances in private, permissioned and hybrid (a mix of public and permissioned) blockchain platforms have broadened to secure transactions of all types, whether linked to high value assets such as diamonds, reducing invoice discrepancies or providing provenance for the carbon offset market in the aviation industry.

DLT excels at using data and metadata in various ways. Once added to the DLT platform, metadata is stored permanently and cannot be changed. This makes metadata reliable and tamper-evident, providing a high-level of assurance to users that the information is trustworthy. DLT also enables data transparency to those authorised, making it easy to track the history of specific metadata, such as origin, ownership, and status of an asset or transaction. Metadata can be added to provide additional information about an asset such as date, time and parties involved. Metadata is also used to automatically perform specific actions based on predefined conditions, for example, sending a notification if a specific waste container has not moved by a specified date as required.

Accounting data tracking

Several studies and proof of concepts have focused on the potential for DLT to create greater efficiencies in nuclear material accounting and tracking radioactive waste.

In 2019, STUK partnered with the Stimson Center in Washington, DC, and the University of New South Wales (UNSW), in Sydney, Australia, to develop a first-of-its-kind prototype, known as SLAFKA, that uses distributed ledger technology for tracking nuclear material at the national level. The prototype demonstrated how DLT could be used to validate data trustworthiness and increase efficiencies in reporting and information sharing.

SLAFKA demonstrated that nuclear material accounting data can be tracked, streamlined, and reconciled. DLT essentially serves as a single, continuous inventory change report, with data being added in near real time enabling operators and regulators to monitor changes as they occur. This improves the effectiveness of routine inspection plans and allows regulators to provide more immediate feedback about the quality of information reported.

These results could be particularly relevant for the UK’s Safeguards Information Management and Reporting System (SIMRS) which is used for compiling data under the UK Voluntary Offer Agreement with the International Atomic Energy Agency (IAEA). According to the Office for Nuclear Regulation Safeguards Annual Report, there were more than 1,000 reports with hundreds of thousands of lines of data compiled for the 2022 reporting period.

In 2020, a partnership on a proof of concept between Digital Catapult, the UK authority on advanced digital technology, Sellafield, and DataTrails demonstrated DLT as a tool to address productivity challenges and data sharing issues across the NDA’s nuclear estate, specifically tracking low-level nuclear waste. With approximately 20% of the steps in tracking nuclear waste relying on paper or manual traceability, the solution had to:

  • Provide global waste visibility
  • Deliver continuous information assurance with accessibility, security, and resilience
  • Integrate with existing internet of things (IoT) sensors
  • Allow device-agnostic access
  • Ensure compliance with waste acceptance criteria
  • Result in cost savings and process improvements.

This partnership successfully demonstrated an easy, efficient way to capture data across Sellafield’s entire digital estate without changing existing databases or data capture techniques to provide a single source of truth.

SLAFKA and the Sellafield POCs have shown that DLT can eliminate errors, save time and significantly reduce costs by improving data transparency, multi-party coordination and multi-party visibility. This is achieved through item-level traceability and audit trails, in line with national and international rules and regulations. DLT can also be integrated into existing data management systems and enhance physical inspection processes (whether for safety, security or safeguards) including compliance and audit reporting.

Other nuclear regulators and operators are starting to consider blockchain technology for tracking nuclear assets and the International Atomic Energy Agency (IAEA) has included DLT on the agenda of its Emerging Technologies workshops since 2018. It is becoming understood as a technology that reinforces resistance to disruption, providing immutable audit trails for generations to come.


Author: Cindy Vestergaard, VP Special Projects and External Relations at DataTrails

SLAFKA uses distributed ledger technology for tracking nuclear material at the national level (Source: SLAFKA)
At Sellafield one in five steps of the nuclear waste tracking process relies on paper or manual steps (Photo credit: ONR)
Blockchain is the single source of truth for a distributed set of participants


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