Office for Nuclear Regulation

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IRR99 inspection - THORP; on Sellafield Ltd.'s nuclear licensed site at Sellafield

Executive summary

Purpose of intervention

This report presents the findings of a planned intervention that was undertaken at the at the Sellafield nuclear licensed site in order to assess Sellafield Limited's (SL) compliance with the Ionising Radiations Regulations 1999 (IRR99) within the Thermal Oxide Reprocessing Plant (THORP).

Interventions Carried Out by ONR

The licensee provided a summary of the activities undertaken at the facility and its arrangements for ensuring compliance with IRR99.  Matters discussed included the application of the hierarchy of control measures for restricting exposure to radiation, dose management, control of work, training and supervision of personnel, and contingency arrangements. A range of documentation, including risk assessments, local rules, a pre-job ALARP study and post-job review, the radiological survey schedule, and survey records was also examined during the intervention. I also conducted a plant visit to identify whether the licensee's arrangements were being effectively applied at the point of work.

IRR99 is primarily concerned with ensuring that work with ionising radiations is conducted safely.  I assessed the adequacy of SL's arrangements for the control of work with ionising radiations, focussing on compliance at THORP with the following aspects of IRR99:

Explanation of Judgement if Safety System Not Judged to be Adequate

This intervention was not a system based inspection.

Key Findings, Inspector's Opinions and Reasons for Judgements Made

From what I observed and examined, the arrangements for the control of work with ionising radiations and their implementation indicate that there are no significant shortfalls of compliance with the Ionising Radiations Regulations 1999 (IRR99) within the Thermal Oxide Reprocessing Plant (THORP).

However, I noted the following areas for improvement:

Whilst I am satisfied that the radiological hazards during the work were adequately controlled and that doses remained ALARP, it is not clear that there was a reassessment of the conclusions of an ALARP study once it became clear that conditions were different and that the doses received on the project would be higher than originally thought. I advised the licensee that a robust review, identifying appropriate learning, would be beneficial to identifying how future work planning and review could be improved to ensure that doses are kept ALARP. I intend to raise a level 4 Regulatory Issue to enable ONR to track the progress of this review process.

I noted a recent trend of shortfalls in radiological protection behaviours which has been identified. While it is of concern that day-to-day radiological protection standards may be slipping on the plant, I am reassured that the issue has been identified and is being treated with the appropriate seriousness by the licensee and that some recent improvement has been noted. For these reasons I do not propose any further action is required by ONR at this time beyond normal regulatory surveillance.

It is unclear to me how assurance is gained that self-monitoring standards are being maintained and how any new relevant information is being communicated to those who are approved to self-monitor. I stated that I intended to raise this matter as a level 4 regulatory issue and I will discuss this with the Corporate Radiation Protection Advisor (RPA) during the next meeting with SL's EHSQ central function.

In addition, I have noted the following areas of good practice:

The licensee's drive to only designate those who satisfy the requirements as Classified Workers, as opposed to it being a standard for access to the work areas, is a positive step. It shows consideration of the actual potential for radiation exposure, helps drive appropriate behaviours and re-enforces that day-to-day radiation exposure should be kept ALARP rather than just focusing on the ‘high dose' tasks.

The close supervision by the Radiation Protection Advisor of the reassessment of Radiation Protection Supervisors ensures consistency and upkeep of knowledge and ensures that the reassessment process is not just an administrative requirement, but adds value to the radiation protection standards in the facility.

Conclusion of Intervention

From what I observed and examined, the arrangements for the control of work with ionising radiations and their implementation indicate that there are no significant shortfalls of compliance with the Ionising Radiations Regulations 1999 (IRR99) within the Thermal Oxide Reprocessing Plant (THORP).  Consequently, I rated the intervention as Green (No Formal Action).