The Office for Nuclear Regulation (ONR) undertakes all regulatory interaction with the Sellafield site licensee (Sellafield Limited (SL)) against a strategy defined by ONR’s Sellafield, Decommissioning Fuel and Waste (SDFW) Directorate. In accordance with that strategy, a System Based Inspection (SBI) of SL’s Package Management Roads and Railways was planned and conducted in June 2017. The purpose of this inspection was for ONR to examine whether safety case claims in respect of this system, that are important to nuclear safety, have been adequately implemented.
My inspection targeted SL’s Package Management Railway system, and in particular the movement of a laden fuel flask around the Sellafield site. The railway system is important to nuclear safety because it is used to provide a safe and secure transportation function between SL’s facilities; moving flasks in a controlled manner so as to minimise collisions and impact, and subsequent loss of containment, identified as the greatest risk to flasks.
The continued safe handling and movement of a radioactive package across the Sellafield site is also important in supporting SL’s overall hazard and risk reduction.
ONR’s SBI process examines evidence to determine compliance against six key Licence Conditions (LCs). These LCs (listed below) have been selected in view of their relevance to ensuring nuclear safety and in providing a structured approach to determining whether the safety case (SC) has been implemented adequately through the system being inspected.
I conducted this SBI of SL’s Package Management - Railways over the course of two days looking at compliance with six LCs. I was assisted by other ONR specialist inspectors with expertise in the field of mechanical engineering. I was also supported on this inspection by SL staff from its internal regulatory organisation.
The inspection comprised discussions with SL staff, physical viewing and inspection of targeted structures, systems and components, on site and a review of SL’s records and other associated safety documentation.
I judged the safety case supporting this system to be adequately implemented. I did however note some areas for improvement as described below.
From the areas I targeted and the evidence I examined during this inspection, I consider that SL has adequately implemented those safety case claims that relate to the Sellafield site railways in particular with respect to locomotive speed control and emergency arrangements.
Through the course of my inspection I did not identify any significant concerns with the adequacy of the licensee’s safety case for the railways system that would necessitate an earlier than planned assessment by ONR.
My inspection identified a number of minor deficiencies and anomalies against LC 10 - Training and LC 34 - Leakage and Escape. However, I consider the significance of these deficiencies to be low and will not be seeking to follow up improvements. As such I awarded inspection ratings of Green (No formal action).
Regarding LC24 - Operating Instructions, I consider SL provided an adequate level of assurance and evidence to demonstrate that operations which may affect safety are carried out in accordance with written instructions.
During the course of my inspection I identified several examples of SL demonstrating good practice. Specific examples include the introduction of System Health Reporting which is driving an improving trend to the management of ageing assets. This is being further progressed by the implementation of railway demand forecasting planning tools as the site moves from operations to decommissioning.
There were however a number of shortfalls observed during the inspection and as a result I, have awarded an Amber inspection rating (seek improvement) against the following LC’s:
I consider SL Package Management Roads and Railways needs to adequately consider and align to the overall Sellafield’s site requirements; relating to minimum safety manning levels and Structures, Systems and Components (SSCs), within its own safety case.
My inspection identified shortfalls in SL’s Package Management Roads and Railways configuration, control and asset condition of a number of its safety mechanisms. I consider SL’s need to demonstrate its safety mechanisms are adequately controlled, configured and are able to deliver their design basis.
I consider SL needs to demonstrate that it is adequately undertaking an intelligent customer role with respect to the delegation of rail vehicle maintenance to its supplier (Direct Rail Services (DRS)), which includes items relied on to deliver nuclear safety; safety mechanisms (SM’s) - i.e. braking systems. A number of recent incidents regarding brake failures underpin this rating.
My inspections findings were shared and accepted by SL, as the licensee, as part of normal inspection feedback.
I consider SL adequately demonstrated ownership and implementation of its Package Management Railways safety case. In addition, it demonstrated an adequate understanding of its arrangements to ensure and maintain the safety of its Railways system for package movements from a nuclear safety perspective.
I have however raised two level 3 Regulatory Issues as a result of the Amber ratings awarded for this inspection, to track SL’s updates to its LC 23, 27 and 28 arrangements to ensure full compliance in a timely manner.
One issue relates to railway minimum manning / equipment levels to support the site (i.e. LC23 - limits and conditions in the interests of safety), and the other to ensure SL has adequate oversight of maintenance activities (i.e. LC28), particular for items relied on for nuclear safety (i.e. LC27).