Office for Nuclear Regulation

This website uses non-intrusive cookies to improve your user experience. You can visit our cookie privacy page for more information.

Nuclear Generation Ltd. (NGL) - review of case for Dungeness B continued operation

Information requested

I refer to the April June 2013 Quarterly Site Report for Dungeness B, particularly to Section 2.2 Non-routine Matters and specifically to the 1st bullet point of page relating to the graphite weight.

The item refers to a multidisciplinary team of ONR specialist inspectors reviewed NGLs case for continued operation. . and, relating to this, please provide the following:

  1. a comprehensive list of the documents, data and information available to and reviewed by the ONR team;
  2. a copy of each of the documents (etc) identified in  item 1) above; including
  3. a copy of the IJCO submitted by NGL;
  4. if not included in item 2) above, provide copies of a)  ONR Assessment Report ONR-CNRP-AR-13-039 Dungeness B Interim Justification for Continued Operation with Revised Predictions of Graphite Weight Loss EC 349955 Rev001. (TRIM 2013/242264); b) ONR Assessment Report ONR-CNRP-AR-13-042. Structural Integrity Assessment of the Dungeness B Request to Extend the Operating Interval of Reactor 21. (TRIM 2013/209223);
  5. if not March 2014, please identify the month and year that relates to the statement adequate to support operation for about a year;
  6. the date and a copy of the written communication to (the) Dungeness B site in relation to securing a longer term safety case; and
  7. if, as it is stated, the graphite weight loss incident is not to be discussed in future Dungeness SSG reports, please identify the means and venue[s] at which it is intended to further report to the public this acknowledged nuclear safety case anomaly?

    Now I refer to the Level 4 - Presentation and discussion of aspects of the Dungeness B graphite average core weight loss Interim Justification for Continued Operation, please provide
  8. the date of this Level 4 meeting.

Information released and exemptions applied

We consider that this request is manifestly unreasonable under Regulation 12(4)(b) of the Environmental Information Regulations, because the resource required to answer it would require an unreasonable diversion of resources from the provision of the public services for which ONR is mandated.

I can confirm that the Office for Nuclear Regulation (ONR) holds the information you requested. However, we have identified 431 pages of documents that may be within scope. The bulk and the complexity of the material means that a very considerable amount of specialist inspector time would be needed to examine material, consider whether any of the exceptions under the Environmental Information Regulations apply e.g. for personal information, commercial sensitivity and for national security matters, and if appropriate, redact that material. The estimate of the amount of time which this would take is in excess of 35 hours.

However in the spirit of being helpful, we have/will provide information on questions 4 to 8, please see these responses below:

Q 4 ONR, will provide these documents after 3rd party consultation has taken place.

Q 5 - In relation to your question concerning the date that relates to the statement, adequate to support operation for about a year, ONR anticipates that NGL's safety case could be strengthened within a year from the date of our assessment report i.e. by about July 2014. The improvements that ONR has requested NGL makes in our letter of 11 July 2013 will mainly be completed within a year and will be reviewed at a number of meetings during that time. NGL has undertaken to keep ONR informed as the results become available.

Q 6 - please see document attached, which has had redactions made under exception Regulation 13 - Personal Data.

Q 7 - It is not unusual for time limited safety cases to be made by licensees for operations at their sites.When this occurs, the licensees processes ensure that before the time limit of the safety case is reached either a new safety case is in place for the operation concerned that extend or removes the time limit, or the operation much cease when the time limit is reached.

Due to the fact that graphite weight loss increases during power operations the particular safety case of relevance here was predicted to expire on 27 July 2013. The licensee was preparing to update this safety case to extend the time limit to 31 July 2014 and indeed this new safety case is now in place. There are also plans to produce a safety case that extends this limit out to 2018 and ONR is also aware that the licensee is engaged in work to support plant life extension at Dungeness B beyond 2018. These matters are routine business and ONR inspectors would not discuss such matters in the Site Stakeholder Group (SSG) reports unless it looked possible that a time limit would be reached before a new safety case was in place to extend it.

The reason this matter features in the non-routine section of the SSG report was due to the licensee discovering an error in their forward prediction of graphite weight loss, i.e. a safety case anomaly. This matter was reported to ONR as an incident.ONR judged that, taking into account this safety case anomaly, the licensees safety case for continued operation for about a year was adequate.ONR provided the licensee with its expectations relating to securing a long term safety case in a letter.

The safety case anomaly was appropriately reported in the non-routine matters section of ONR's SSG report and has been dealt with using the licensees processes to the satisfaction of ONR. There is therefore nothing further to report on this safety case anomaly.

If normal business to extend the current safety case beyond 31 July 2014 leads to significant problems, so that operations beyond that date might not be supported, ONR would include this in a future SSG report.Similarly ONR's view of the plant life extension, which is a major project, would also be reported in a future SSG report. Future ONR work could also be reported via its Project Assessment Report and Interventions Report publications.

Q 8 18 June 2013.

PIT (Public Interest Test) if applicable

Not applicable.