Statement of civil incidents meeting the Ministerial Reporting Criteria reported to ONR - 1 April to 30 June 2026

During the reporting period 1 April – 30 June 2026 there were 3 incidents within Great Britain that met the Ministerial Reporting Criteria (MRC) agreed between ONR and DESNZ.

• Full details of current MRC

A statement providing a summary of these incidents is appended to this letter. Two of the three incidents occurred during the period (Incident ID 6216 and 6457.) The third forms part of this statement because there was an increase in International Nuclear and Radiological Event Scale rating, from INES 1 to 2, during this quarter for an incident reported to ONR during Q1 of 2026 (Incident ID 5982.)

In addition, ONR is now in a position to provide a summary of an incident that occurred in Q1 of 2026, the earlier reporting of which was delayed due to insufficient information being provided initially by the dutyholder. (Incident ID 6045/6 refers.)

Incident 6216

Incident description

On Thursday 16 April 2026, Springfields Fuels Limited (SFL) transported four shipping containers containing Category 3 nuclear material to Liverpool Port, for onward export.

Before leaving the port, there was no formal handover of security responsibilities to the receiving agent. Furthermore, due to an administrative error, only three of the containers were loaded on the vessel when it departed in the early hours of Friday 17 April.

Later that day, SFL contacted ONR and requested approval to move the outstanding container back to a licenced site on Monday 20 April.

Dutyholder’s response

SFL requested approval from ONR to return the remaining container to its site in Salwick, Preston on Monday 20 April. SFL was informed that Liverpool Port is not licenced to store nuclear material and while ONR is content that the Ship and Port Facility (Security) Regulations 2005, are adequate for short-term transiting of material, storing material over a weekend was not acceptable. However, SFL stated that due to driver availability and insurance restrictions, the container could not be recovered until Monday 20 April. ONR granted approval to move the container, which was recovered by SFL on 20 April.

SFL are complying with the Enforcement Letter (see below) and have updated their training procedures relating to the transportation of Category 3 nuclear material.

ONR’s actions

ONR issued SFL an Enforcement Letter, requiring a full investigation and updating of their Transport Security Statement (TSS). The revised TSS is to address the causes of the identified non-compliance and ensure that additional contingency measures are in place to recover material at short notice when further transportation by sea does not take place.

This action is to be completed by 30 September 2026, at which point ONR will review the adequacy of the revised TSS.

Incident 6457

Incident description

Topspeed Couriers Ltd was carrying a Type A package containing radioactive material in the form of a 555 GBq special form Selenium-75 source intended for use in industrial radiography. The package was delivered to the wrong location in Aberdeen.

After approximately one hour, the organisation which had incorrectly received the package delivered it to the correct consignee which is located a short distance away. Both organisations are involved in the oil and gas industry.

Process failures by the correct consignee organisation in the handling of the package once it had been received also resulted in an employee receiving a radiation dose which was well below the annual legal limit.

There was no release of radioactive material.

Dutyholder’s response

The dutyholder informed a ONR Transport Competent Authority inspector of this incident during a recent inspection. After internal discussions within ONR, this incident was judged notifiable and the dutyholder was asked to submit an INF1 form which it subsequently did.

The dutyholder has undertaken an initial investigation into the incident, identifying root causes which included not checking documentation in line with processes and using an incorrect navigation system. The dutyholder has also identified corrective actions including refresher training and improvements to processes and procedures.

The dutyholder is undertaking further investigations to ensure all learning relating to the incident is captured and will provide a follow up report to ONR.

ONR’s actions

ONR contacted the dutyholder to request that they submit an INF1 form for this event. Having reviewed the information provided in the INF1 form, and the dutyholder’s initial investigation, the dutyholder was requested to provide a follow up report for the incident detailing the outcome of its investigation which ONR will examine to determine an appropriate regulatory response.

Incident 5982

Incident description

In 2022 an individual received an internal dose (exposure) from the inhalation/ingestion of radioactive material greater than the annual statutory whole-body dose (Effective Dose) limit (20mSv - IRR17 Reg. 12(1) & Schedule 3 Part 1 Para 1).

Since this event in 2022, the individual has been subject to annual biological sampling and monitoring. The biological samples provided have matched the expected decay / excretion curve. However, in October 2025 the individual provided an annual sample which did not match this curve, which indicated the individual had been subject to an additional internal exposure event (a new dose intake).

The Sellafield Ltd Approved Dosimetry Service (ADS) has assessed the exposure received from this additional internal exposure event as 9.8 mSv (millisievert). This results in an effective dose (whole body dose) of 10.21 mSv when combined with the operational measured external dose of 0.41 mSv. The ADS estimate that an intake is likely to have occurred between the 9 -10 October 2025 based on the excretion curve generated from the results. The effective dose met the ONR reporting criteria.

A review of work activities undertaken by the individual between September and October 2025 has since been carried out, but this has not identified any activities which may have led to the individual receiving a new dose intake. This is corroborated by the information obtained during Sellafield Ltd’s initial fact finding.

A Sellafield Management Investigation was initiated to consider the facts and circumstances, and to try and establish the root cause of the dose intake. In the meantime, the individual remains in work but has been restricted from entering any controlled areas.

Sellafield Ltd has completed a review of Condition Reports (CR) from September and October time. This identified only one ‘radiological / contamination’ related event during the period within the building where the individual currently works. This was investigated, and by reviewing the decay patterns and applying specific analysis, it was confirmed to be radon related and hence can be discounted as a cause for the dose intake.

There has been no indication of any exposure to other individuals or events of significance in this building over the last 12 months. For this reason, there has been no pause to any activities within the facility. If any additional information comes to light, Sellafield Ltd will reconsider this position.

Dutyholder’s response

Notified the individual of the new dose intake. Made individual an appointment with the site doctor and have offered support from the Radiation Protection Advisor (RPA). Sellafield Management investigation initiated.

As a result of their Management Investigation (MI), Sellafield Ltd established that some of the learning from the 2022 MI had not been actioned correctly. The required actions were not identified as part of the Corrective Action Effectiveness Review, key learnings were missed and gaps continued to exist. Inconsistencies and failures in supervision and post-job monitoring were also highlighted. Sellafield Ltd Site Sentencing Authority judged that as a result the INES rating should be raised to a Level 2 incident.

ONR’s actions

Preliminary enquiries carried out on-site and during follow up discussions (4 and 11 February 2026 respectively).

Advice from ONR Radiological Protection specialist is that the harm from a radiological perspective is equivalent to a medical CT Intervention of the torso. This is a small fraction of a percentage increase in fatal cancer risk above that from natural exposure.

Given that;

• The dose limit did not exceed the statutory level defined in IRR17 Reg.12;
• Sellafield Ltd has completed a MI and identified the corrective actions required;
• The general level of compliance in this area is good; and
• Sellafield Ltd was unable to pinpoint a specific incident or clear timeframe where the individual received the internal dose, and applying the ONR Enforcement Policy Statement and Enforcement Management Model, the outcome of ONR initial enquiries indicates that enforcement action would be disproportionate.

Implementation of corrective actions will be monitored by ONR through routine engagement with Sellafield Ltd.

Incident 6045/6046

Incident description

On 27 February 2026, Sellafield Ltd incorrectly transported a residual quantity of plutonium oxide, in an unsuitable package, to a National Nuclear Laboratory (NNL) site in Workington, Cumbria, rather than to its intended destination at Sellafield site. The package was accepted at the NNL facility before being recovered and returned to Sellafield site once the error was identified. Sellafield Ltd notified ONR on 02 March 2026 about this potential regulatory breach for the transport of radioactive material, and ONR began to carry out enquiries about the incident.

Dutyholder’s response

Sellafield Ltd suspended plutonium oxide movements from the facility, introduced enhanced interim transport controls, reviewed whether similar issues could happen elsewhere across its operations and initiated an investigation.

ONR’s actions

ONR judged that Sellafield Ltd’s initial steps to control risks were satisfactory while the dutyholder’s investigation took place, and asked Sellafield Ltd for information about the event circumstances, ongoing risks and controls, and proposed actions to prevent recurrence. ONR maintained regulatory oversight of emerging developments and issues that could influence our regulatory approach. Sellafield Ltd submitted their investigation on 14 July 2026 with a final INES rating of level 1. ONR subsequently identified shortcomings in Sellafield Ltd’s internal investigation, particularly in respect of their assessment of consequences, risks, causes and corrective actions. Their investigation also highlighted weaknesses in Sellafield Ltd’s organisational learning from previous transport-related events. ONR is taking such shortfalls seriously and is carefully considering whether further regulatory action is needed.

Note

ONR was not in a position to publish a summary of Incident ID 6045/6, which occurred in Quarter 1, within the corresponding ministerial statement of civil incidents. With a full understanding of the circumstances having been acquired in Quarter 2, the corresponding summary is provided in this statement.