The intervention was intended to (a) allow ONR to form a view on the effectiveness of the licensee’s system of measures in place to provide the safety function of radiation protection for its Materials Handling Centre (MHC) waste drum inspection X-ray unit; and (b) provide an opportunity for the licensee to update ONR on the ongoing preparations for its intended application to de-license the Maynard Centre and re-license the MHC and associated buildings as the Cardiff Nuclear Licensed Site (CNLS).
The intervention was an inspection on day 1 of the licensee’s compliance with a set of licence conditions (appointments, training, operating rules & instructions, safety mechanisms, examination & maintenance and leakage & escape) focusing on the safety function of radiation protection for its Materials Handling Centre (MHC) waste drum inspection X-ray unit. On day 2 the licensee gave a presentation and we held a discussion on the licensee’s de-/re-licensing progress followed by a tour of the relevant parts of the site.
We inspected a selection of training records for relevant staff and found them to be comprehensive and largely in order.
We inspected the licensees’ duly authorised person (DAP) appointments for the X-ray unit which appeared to be in order. I considered the arrangements for ensuring duties were performed by SQEP individuals were adequate, although a little over-reliant on knowledge of the expertise and experience of individual members of staff rather than a more formal documentation of the specific competencies required for the post.
We considered the safety case within the X-ray unit operational safety report and the single operating rule contained therein for the operation of the X-ray unit (safety interlock systems on the X-ray cabinet door to be operational during routine operations of the X-ray generator), and judged them to be adequate for their purpose. We judged the operating instructions to be appropriate to ensure conformance with the operating rule. Operating instructions were not readily available at the X-ray unit, being held in office buildings instead. The X-ray unit operator explained that the high levels of training and experience of the current staff meant that operating instructions were well-known and it was not necessary to have hard copies available within the MHC. I followed this up with the licensee, suggesting that this would not be a good arrangement in the event that new staff were employed, and the licensee agreed to consider improvements to operating instruction availability at the X-ray unit.
We inspected the safety important equipment for the MHC waste drum inspection X-ray unit, including key interlocks and switches, emergency stops, emergency pull cords, visual warning lights and warning sounders. The interlock system appeared to have been well designed and maintained. Discussion with an X-ray unit operator revealed minor difficulties with the operation of cage door interlock switches. I asked the licensee to consider whether improvements could be made, and it agreed to do so in conjunction with a review of the safety interlock system identified in its forward action plan.
We inspected the licensee’s maintenance arrangements and extracts from its electronic maintenance system, and found them to be satisfactory.
We conducted a site tour of the Materials Handling Centre. Waste storage arrangements appeared to us to be very tidy and being operated within a well-organised system, with generally very high standards of housekeeping.
The licensee took us through an overview of the current status of the de-/re-licensing project, providing comprehensive information on sample collection and analysis, decommissioning, demolition and remediation activities, and the clearance-in-principle approach. We noted that progress had been a little slower in recent weeks than originally planned, but that the work continued to be carried out very carefully and thoroughly. ONR and the licensee agreed that the process leading up to de- & re-licensing appeared to be well planned out, and neither party was aware of any significant problematic issues. A tour of the site for de-licensing demonstrated to us that, other than locked-off construction/demolition areas, it was very tidy and clear of decommissioned and demolition materials.