This intervention was carried out as part of the periodic safety assessment (PSR) of Wylfa reactor 1. The purpose of this intervention was to identify the extent to which control and instrumentation (C&I) equipment is used in the fuel route, the continued maintainability of the C&I equipment, and whether this will be adequate to maintain safety throughout the period of the PSR. This intervention was also used to assess the competence of the Wylfa C&I personnel.
My intervention consisted of a walkdown of the C&I aspects of the fuel route, discussions relating to the equipment viewed, and inspection of related documentation.
I found that the fuel route C&I equipment is relied upon for control and protection functions, and that inability to maintain this C&I equipment in an operable state could potentially result in a loss of ability to move fuel between reactors, store and retrieve fuel within the dry storage cells, and to export fuel from the site.
The more complex equipment, including the programmable logic controllers for the flask handling crane and the stand-alone equipment for the torqueing of the flask bolts and pressure testing, either has a replacement designed and manufactured, or is a modern design that can be supported by existing manufacturers or repaired by C&I engineers with appropriate industrial knowledge.
I found a deficiency in the procedure to test the correct operation of the computerised flask bolt torqueing equipment and noted that operational experience did not appear to be being applied to the fuel handling crane. I raised actions for these points to be corrected.
I found there to be an acceptable level of competence within the fuel route C&I staff who were able to demonstrate a good understanding of the fuel route C&I systems and the challenges posed by obsolescence, and ongoing maintenance.
The deficiencies identified during the intervention are relatively minor in nature, and will not immediately adversely affect nuclear safety. Accordingly, I am of the opinion that the fuel route C&I equipment is fit for continued operation.