The purpose of this Intervention was to permit detailed technical discussions, between the Office for Nuclear Regulation (ONR) fuel performance Inspector and key Licensee representatives, on the Cycle 13 re-load safety case for Sizewell B (SZB). Whilst ONR does not formally permission this Category 2 safety case, nevertheless ONR has traditionally always produced an Assessment Report (AR) reporting the results of its sampling of re-load safety cases. This AR in turn forms one of the inputs into ONR’s decision making in the granting of Consent (under Licence Condition 30, LC 30) for the reactor to return to power after its statutory outage.
The opportunity was also taken for the Licensee to provide a briefing to ONR on the forthcoming high burn-up safety case for SZB and to have a meeting with Licensee staff on the Criticality Incident Detection and Alarm System (CIDAS) omission safety case for SZB.
The Intervention was performed under LC 23 (i.e. Operating Rules), in determining that the Licensee has produced an adequate safety case for its proposed Cycle 13 reactor core design and that it is likely that an adequate safety case will be provided for increasing fuel burn-up values at the Station. Discussions were also held around an outstanding ONR query on the Licensee’s CIDAS omission safety case for SZB. The Intervention as a whole consisted of a number of presentations, by the Licensee’s key technical experts, to the ONR fuel performance inspector and the opportunity for discussions around these presentations.
The Licensee’s presentations I judged to be of a good quality and I was impressed by the depth of knowledge apparent in the Licensee’s SZB fuel and core safety case team (it was apparent that many of the team had worked on several Cycle re-load safety cases before and that collectively there was a great deal of experience within the team on SZB fuel matters generally). All my detailed questioning on the Cycle 13 re-load safety case was satisfactorily answered and all documentation I had requested, to assist in my sampling of the safety case, was duly provided (together with some other documentation that the Licensee considered would be useful). The meetings were conducted by the Licensee in a very constructive, open and transparent manner and it was clear that the Licensee had put a lot of preparation into the meetings.
In addition the Licensee provided a helpful ‘up-date’ presentation on the forthcoming high burn-up safety case for SZB and discussions with the Licensee enabled successful resolution of an outstanding ONR question on the CIDAS omission safety case for SZB.
The Intervention provided for a very detailed and useful exchange of information on the safety cases discussed and has increased my confidence in the Cycle 13 re-load safety case presented. I now need only sample some of the key supporting references in order to start the writing of my AR.
The information provided on the forthcoming high burn-up safety case was also of value and discussions with the Licensee allowed successful resolution of an outstanding ONR question on the Licensee’s CIDAS omission safety case for SZB.
N/A.