Office for Nuclear Regulation

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System Based Inspection of the solvent/reagent systems

Executive summary

Purpose of Intervention

The Office for Nuclear Regulation (ONR) undertakes all regulatory interaction with the Sellafield site licensee, Sellafield Limited (SL), against a strategy defined by the ONR Sellafield, Decommissioning, Fuel and Waste Division. In accordance with that strategy, a System Based Inspection (SBI) was carried out on the Magnox Reprocessing Facility.

The purpose of this inspection was for ONR to examine whether the licensee’s safety case claims in respect of the solvent and reagent systems have been adequately implemented. The inspection targeted the solvent washing processes within the Magnox Reprocessing Facility (MRF) and comprised discussions with SL staff, a targeted plant walkdown and a review of plant records and other documentation.

Interventions Carried Out by ONR

ONR’s SBI process examines evidence to determine compliance against six licence conditions (LC). These LC’s, listed below, have been selected in view of their relevance to ensuring nuclear safety and provide a structured approach to determining whether the safety case has been implemented adequately through the system being inspected.

LC 10 requires SL to make and implement adequate arrangements for suitable training for all those on site who have responsibility for any operations which may affect safety.

LC23 requires SL to produce an adequate safety case to demonstrate the safety of its operations, and to identify the conditions and limits necessary in the interests of safety.

LC24 requires SL to ensure that all operations which may affect safety are carried out in accordance with written instructions.

LC27 requires SL to ensure that a plant is not operated, inspected, maintained or tested unless suitable safety mechanisms, devices and circuits are properly connected and in good working order.

LC28 requires SL to make and implement adequate arrangements for the regular and systematic examination, inspection, maintenance and testing of all plant which may affect safety.

LC34 requires SL to ensure, so far as is reasonably practicable, that radioactive material and radioactive waste on the site is at all times adequately controlled or contained so that it cannot leak or otherwise escape from such control or containment.

The intervention was performed in line with ONR's guidance requirements (as described in our technical inspection guides) in the areas inspected.

Explanation of Judgement if Safety System Not Judged to be Adequate

Based upon the areas sampled I judge the MRF solvent and reagent systems safety case requirements to have been adequately implemented.

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

From the areas ONR targeted and the evidence I examined during this inspection, I consider that SL has adequately implemented those safety case claims that relate to the MRF solvent and reagent systems. 

For LC10 I sampled the training records of operations and maintenance employees.  From the evidence provided I was satisfied that individuals sampled had completed the minimum training requirements and were deemed suitably qualified and experienced for those tasks.  I therefore judge that an inspection rating of Green (no formal action) is appropriate. 

For LC23 I was content that the limits and conditions were identified by the safety case and that they were transcribed correctly into operational documentation.  The SL operational employees had knowledge of the operating rules associated with the safety case for the solvent and reagent systems. I therefore judge an inspection rating of Green (no formal action) is appropriate. 

For LC24 I was content the operators had access to the relevant operator instructions on the plant and had completed the compliance documentation adequately.  I therefore judge an inspection rating of Green (no formal action) is appropriate. 

For LC27 I was satisfied that the appropriate Safety Mechanisms had been identified within the safety case and had been correctly designated. During the plant visit I was able to visually inspect the preselected safety mechanisms and gained confidence that the safety mechanisms on the plant were in an adequate condition.  I therefore judge that an inspection rating of Green (no formal action) is appropriate. 

For LC28 I sampled the last completed maintenance tasks for a number of safety mechanisms associated with the safety case for MRF solvent washing processes. From the maintenance records sampled I was satisfied that the safety mechanisms selected were being adequately maintained. I therefore judge that an inspection rating of Green (no formal action) is appropriate. 

For LC34 I viewed the recent cell camera inspection survey reports and was content that there is an ongoing programme to monitor the cells and allow visual confirmation that there was no leakage or escape of radioactive material. I therefore judge that an inspection rating of Green (no formal action) is appropriate against LC 34.

Conclusion of Intervention

From the evidence gathered during this intervention, I do not consider there to be any matters that have the potential to impact significantly on nuclear safety. 

I awarded Green (no formal action) inspection ratings to LC’s 10, 23, 24, 27, 28 and 34.