Office for Nuclear Regulation

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Meetings/plant visits to establish progress in delivery of legionella risk management for the THORP and Evaporator D evaporative cooling systems

Executive summary

Purpose of Intervention

Plant visits and meetings to establish progress in delivery of legionella risk management for the THORP and Evaporator D evaporative cooling systems.

One of the purposes conferred on ONR by the Energy Act 2013 is nuclear site health and safety. The ONR Conventional Health & Safety (CHS) team contributes to this purpose by providing coherent specialist conventional health and safety support and advice to ONR regulatory divisions. This intervention results from a programme of work underway by the ONR CHS team to secure improvements in conventional health and safety management within the nuclear industry. In addition, this work contributes to the ONR Sellafield, Decommissioning, Fuel and Waste (SDFW) Division strategy milestone SC8 ‘Completion of planned corporate inspection schedule'.

Interventions Carried Out by ONR

The key regulatory activities undertaken during the two day visit were meetings and plant visits to establish progress on the management of legionella risks arising from the use of evaporative cooling systems at the Thermal Oxide Reprocessing Plant (THORP) facility and Evaporator D plant within the Highly Active Liquor Evaporation & Storage (HALES) facility.

Regulatory judgement was based on determining compliance with Sections 2 & 3 of the Health & Safety at Work etc. Act 1974 and the relevant statutory provisions/Approved Code of Practices (ACOP) made under the Act, namely:

Technical guidance linked to L8 was also identified as a source of relevant good practice.

Explanation of Judgement if Safety System Not Judged to be Adequate

Not applicable for this intervention.

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

The findings, inspector opinion developed and judgements made during the intervention were made using the relevant legislation, Approved Code of Practices and well-established technical guidance as benchmark standards.

From the plant visits and discussions with relevant personnel ONR identified:

Conclusion of Intervention

Feedback was provided at the end of each meeting and plant visit to the relevant Sellafield personnel.

With regards to the Evaporator D cooling system - ONR welcomed a decision made by Sellafield to maintain the chemical dosing of the system, rather than relying solely on the Sonoxide system as a water treatment method. ONR also commended several of the Evaporator D personnel for their efforts to improve the cooling system from a legionella perspective. However, ONR stated it was also clear that significant work remains to be done to demonstrate effective legionella control measures are fully implemented.

Hence, an inspection rating of ‘amber' is assigned to the Evaporator D part of the visit as the management arrangements yet to be implemented are such that there are inconsistent standards for managing risks to workers. However, ONR emphasised this was due to the deficiencies in the cooling system configuration and should not be seen as reflective of the efforts made by the Evaporator D personnel. One further ONR CHS visit is anticipated to ascertain whether the management arrangements are sufficient - once the cooling system management arrangements are fully developed.

With regards to the THORP cooling system - ONR asked for a formal response from Sellafield setting out the commitments provided during the intervention and indicated that while enforcement notices had been considered, an enforcement letter will be sent to Sellafield Ltd. for the legionella actions identified. Action progress will be monitored via discussions and plant revisits as appropriate.

ONR regulatory issue 5646 in the ONR Regulatory Issues database will be updated to reflect the THORP intervention findings and a level 3 regulatory issue will be created to capture the actions arising from the Evaporator D part of the intervention.