Health and Safety
Executive / Commission
Nuclear
LLC reports
This report is issued as part of the Health and Safety Executive's commitment to make information about inspection and regulatory activities relating to the above site available to the public. It is for distribution to members of the Dungeness Local Community Liaison Council and covers activities associated with the regulation of safety at Dungeness B Nuclear Power Station. These reports are distributed quar-terly and are available on the HSE web site (hse.gov.uk/nuclear/llc/2003/index.htm). Site Inspectors of HM Nuclear Installations Inspectorate (part of the Health and Safety Executive's Nuclear Directorate) attend LCLC meetings and will be happy to respond to any questions raised there by members of the LCLC. Any other person wishing to inquire about matters covered by this report should contact the HSE's Nuclear Directorate Information Centre on 0151 951 4103.
1. The Nuclear Installations Inspectorate (NII) Site Inspector and/or his assistant visited Dungeness 'B' on the following dates during the quarter covered by this report:
7-10 and 23-26 July, 11-14 August, and 1-3 and 16-18 September.
2. Other NII inspectors with specialist technical expertise also visited site during the period so as to support the Site Inspector by performing inspections on licence condition compliance and compliance with the power station's nuclear safety case.
During the visits listed above the Site Inspector, and assistants, carried out planned inspections of the licensee's compliance with: (i) the conditions attached to the Site Licence; (ii) the Ionising Radiations Regula-tions; and (iii) other relevant health and safety legislation.
A team of NII inspectors supported the Site Inspector when witnessing a partial repeat Level 1 Emergency Exercise on 3 September, following the shortfall noted at the Level 1 Emergency Exercise on 21 May 2003. Unfortunately the NII team could not see the desired improvement. As a consequence the station has produced a recovery plan that the station director presented to the regulator at the NII HQ, Bootle on 9 October, one individual has had his authorisation removed and a group of people have been retrained. Another partial repeat exercise will now be witnessed by NII in February 2004. In the meantime NII is content that the Dungeness B emergency arrangements are adequate and that a problem has been identified relating to the way that arrangements are demonstrated that the company is addressing so as to fully achieve the high standards that NII demands of nuclear licensees.
The Site Inspector attended the EPCC meeting at Dungeness on 25 July 2003.
As part of routine, planned inspections the Site Inspector examined the licensee's arrangements for the recording and investigation of incidents at the power station and, where appropriate, undertook independent investigations to the extent that was warranted by the significance of the incident.
7. On 11 July the site experienced an event that resulted in an Operating Rule breach. BE deciding to rate the event as an INES 2 event. This was investigated by the site inspector. It was found that the main boiler feed pump had spuriously tripped on Reactor 21, the reactor tripped automatically but there were subsequent problems establishing post trip cooling as the start-up boiler feed pump caught fire and the emergency boiler feed pumps were unavailable. Defence in depth was compromised but post trip cooling was established with the shutdown boiler feed pump. Back-up feed and AFS systems were available at all times but they were not called upon. During the transient an Operating Rule temperature limit was just breached for a few seconds. A number of improvements have arisen from the event. NII will take no further action.
8. Reactor 21 was manually tripped on 26 August so as to stop a power transient that had been initiated by the spurious closure of bled steam valves following a control circuit relay failure. NII investigated the event as Operating Rule power limits had been exceeded for an unacceptable time, during the reactor power transient that followed the closure of the steam valves, before operators took appropriate action. NII have identified areas for improvement. A formal, regulatory letter had been sent to the station director requiring him to produce an improvement programme by the end of November, and to report progress against that programme in spring 2004.
9. The NII has powers within the standard Nuclear Site Licence Conditions to issue Consents, Approvals and Directions. In addition NII uses Licence Instruments to issue Specifications and Agreements under the conditions attached to the Licence. In accordance with formal regulatory procedures under Site Licence No. 61 the NII issued the following:
Licence Instrument No 55 was issued on 26 August giving HSE agreement to continued operation of the Dungeness B reactors on the basis of the revised Hazards Safety Case.
Published on the HSE web site 26.09.2004