Executive summary
Date(s) of inspection:
January 2026
Aim of inspection
In accordance with the Office for Nuclear Regulation’s (ONR’s) Sellafield Strategy, each year ONR performs a series of planned inspections to seek assurance of compliance against selected licence conditions, targeted at those facilities with significant importance to nuclear safety. One such inspection was undertaken at Special Nuclear Materials Value Stream (SNM) South facilities within the Sellafield site in West Cumbria to sample evidence of implementation of Sellafield Limited's arrangements for compliance with Licence Condition (LC) 28 (Examination, inspection, maintenance and testing) specifically to THORP packages stored in SPRS (Sellafield Product and Residues Store) and THORP Product Store (TPS) within the Special Nuclear Materials (SNM) South (S), in order to inform a regulatory judgement regarding the licensee’s compliance with its legal duties under the nuclear site licence.
Subject(s) of inspection
- LC28 - Examination, inspection, maintenance and testing - Rating: Amber
Key findings, inspector's opinions and reasons for judgement made
The inspection was undertaken on 14 January 2026 by the SNM site inspector and a structural integrity specialist inspector. The inspection targeted compliance against Licence Condition (LC) 28 (Examination, inspection, maintenance and testing) specifically to THORP packages stored in Sellafield Product and Residues Store (SPRS) and THORP Product Store (TPS) within the Special Nuclear Materials (SNM) South (S).
The inspection involved a planning phase and a site visit, which included discussions with relevant Sellafield Limited personnel, review of records, sampling of information contained within electronic databases and other documentation.
Based on the evidence sampled, I concluded the following:
No significant matters were identified that required immediate regulatory attention.
Sellafield Limited continues to implement improvements in response to Regulatory Issue (RI) RI-11185, which will aid further clarity and transparency in demonstrating compliance with the LC28 corporate arrangements.
Sellafield Limited continue to implement improvements in the safety case alignment between the various documentation and had implemented the Technical Basis of Maintenance (TBoM) for THORP welded packages. The TBoM which specifies the target numbers of packages for inspection satisfies the LC28 requirements and informs the Plant Maintenance Schedule (PMS) prompts in MOVEX.
Currently, whilst the required statistical confidence of package inspections has been achieved for TPS, there is a significant shortfall in the statistical confidence achieved for the SPRS due to low number of inspections carried out. Sellafield Limited has identified this as a shortfall and post inspection provided me with a plan to complete the requisite inspections.
I, therefore, rated the LC28 compliance inspection of THORP package inspections at SPRS Amber, and I will seek improvement from the Licensee in this area.
Over the last three years four LC28 inspections were rated Amber. Given the emerging trend of LC28 non-compliance, I will also seek improvement from the Licensee in the implementation of the LC28 arrangements across SNM portfolio.
Conclusion
On the basis of the evidence sampled at the time of the inspection, I found that the requisite THORP package inspections in SPRS, as stated in the TBoM, have not been delivered and no justification is currently available.
Taking all of the above into account, and noting the ONR guidance on inspection ratings, it is my opinion that an inspection rating of AMBER for Licence Condition 28 is merited here.
For the Amber rating in this inspection, I will seek improvement in this area. One L3 Regulatory Issue raised (RI-12900).
In addition, I raised another L3 Regulatory Issue to address the emerging trend of LC28 non-compliance across SNM North and South (RI-12905).
I also raised one L4 Regulatory Issue to allow ONR to monitor progress in addressing the identified minor shortfall on the development of a Maintenance Instruction, update the MOVEX with the correct Operating Instruction, and undertake assurance activities specific to MOVEX package inspections (RI-12901).