Office for Nuclear Regulation

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Plant visits and meetings to establish progress in delivery of site wide and facility specific legionella and asbestos management

Executive summary

Purpose of Intervention

Plant visit and meetings to establish progress in delivery of improvements in two conventional health & safety topic areas - legionella and asbestos risk management.

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 three day visit were meetings and plant visits based around:

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:

Work undertaken by the HALES facility since the start of 2017 has included identification of deadlegs and tests to determine the effectiveness of the water treatment technique currently being applied to the cooling system.

The measures proposed by HALES to improve legionella control in the short term are to be consolidated into a list of prioritised actions to deliver risk reduction. The HALES cooling water system is operating substantially below UK standards for controlling legionella bacteria in evaporative cooling systems. However, further significant reductions in risk from legionella are not feasible in the short term because of conflicting requirements for maintaining nuclear safety. ONR is determining the regulatory approach required to ensure Sellafield progresses the development of longer term options, such as replacing the existing evaporative cooling towers with an alternative means of cooling that does not generate a water aerosol released to atmosphere.

Personnel in the Waste Vitrification Plant (WVP) and Sellafield Ion Exchange Effluent Plant) are demonstrating a greater awareness of the condition of the cooling systems in their respective facilities and greater oversight of the management arrangements and any improvements required is now being provided.

The THORP cooling system currently presents a high risk of legionella proliferation and release. This risk arises from the recent identification of additional deadlegs in the cooling system, weaknesses in the water treatment programme and a risk of aerosol release through gaps in some parts of the cooling tower. The immediate measures proposed by Sellafield to increase the frequency of shot dosing of biocide and circulation around the system were considered to be sufficient to deal with the immediate risk. However, the underlying causes and short/medium term actions require further discussion between ONR and Sellafield.

Calder Hall’s asbestos management arrangements currently appear well embedded and the focus has shifted from remediation and repair of asbestos containing materials to its removal and to the disposal of legacy asbestos waste. Discussions are continuing with regards to disposal of legacy asbestos waste and the presence of asbestos within the reactor pressure vessel area.

Sellafield Ltd. is not currently in a position to identify the overall risk presented by ACMs that are present in a large number of facilities across the site. As a result, ONR questioned Sellafield’s ability to develop a prioritised action plan on a site wide basis - given that the current management arrangements result in each facility/value stream prioritising asbestos related actions autonomously. ONR stated that the risks presented by facilities approaching post operation clean out (POCO) or decommissioning needed to be consistently factored into this process.

Unacceptable work practices were observed to be in use by steeplejacks working on the Combined Heat and Power Plant (CHP) Oxyboiler stack. Two steeplejacks were observed to be disregarding the collective fall protection measures provided by a temporary work platform fitted to the stack approximately 50metres above ground level - as they were standing on the top guardrail of the work platform. Action was taken to secure a cessation of the steeplejack work until a determination could be made as to whether a safe system of work was being (or could be) used.

Conclusion of Intervention

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

The issues identified relating to the HALES and THORP cooling systems are such that there are shortfalls in safety requirements resulting in significant avoidable risks to the public or workers, with at least one contravention that gives rise to a discernible risk gap under the ONR EMM. This in turn indicates that an inspection rating of ‘red – significantly below standard/unacceptable’ should be applied to the HALES and THORP parts of the intervention.

The issues identified relating to the site wide asbestos management arrangements are such that there are inconsistent standards for managing risks to workers. This in turn indicates that an inspection rating of ‘amber – below standard’ should be applied to the site wide asbestos management part of the intervention.

Action taken post visit has concentrated on ensuring Sellafield, and other dutyholders took immediate and short term actions to deal with the risks identified. The ONR EMM is being referred to and enforcement options are being considered for the following aspects of the intervention:

However, an enforcement letter will be sent to Sellafield Ltd. for the legionella and asbestos priority actions identified regardless of any additional enforcement outcome decisions currently being determined. Action progress will be monitored via discussions and plant revisits as appropriate.

ONR regulatory issues 4006 and 4663 on the ONR Regulatory Issues database will be updated to reflect the intervention findings and additional regulatory issues added as required, subject to ONR’s governance procedures.