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 Site Stakeholder Group and covers activities associated with the regulation of safety at Hinkley Point B Power Station. These reports are distributed quarterly and are also available on the HSE’s web site at http://www.hse.gov.uk/nuclear/llc/index.htm. Site inspectors of HM Nuclear Installations Inspectorate usually attend Site Stakeholder Group meetings and will respond to questions raised there by members of the Site Stakeholder Group. Any other person wishing to enquire about matters covered by this report may contact the HSE’s Nuclear Directorate on 0151-951-3484/3290.
Health and Safety Executive
Nuclear Directorate
Redgrave Court
Merton Road
Bootle
Merseyside
L20 7HS
Routine inspections continued in accordance with our annual plan. The HMNII Site Inspector made the following planned visits during the period:
In addition to the planned visits by the HMNII Site Inspector, an inspection visit was made by NII graphite and fault studies specialists concerning arrangements for monitoring of the graphite core. An inspector from HSE Construction Division also visited to advise on arrangements for asbestos clean-up.
Routine and reactive inspections have continued throughout the period to confirm that the site is operating in compliance with the conditions attached to the Nuclear Site Licence. These included inspections of Licence Conditions 11, 23, 26 and 28. In general the arrangements on site were found to be satisfactory. A particular focus was given to plant maintenance activities during the period. It was found that processes in place for ensuring and monitoring compliance with the station Maintenance Schedule are good, but some weaknesses were identified with the linkage to safety case requirements. Also, more effective strategies to reduce the backlog of relatively minor plant defects are required to be implemented. The level of control and supervision of staff undertaking maintenance activities was found to be adequate, although some shortcomings were noted with the setting to work process. In areas where opportunities for improvement were identified, remedial work has been agreed with station management, with the intention of achieving improvements to current station arrangements in those areas.
The annual review of station performance against emergency arrangements took place on 17th July 2007. The Station demonstrated a thorough process for reviewing the emergency arrangements at Hinkley Point B, an adequate performance in 2006/07 was demonstrated and further improvements were achieved in some areas.
The HMNII Site Inspector attended meetings on 4th July and 28th July 2007 to discuss the compliance of Reactors 3 and 4 with boiler safety case limits. The meetings were held as part of HMNII’s activities to monitor plant condition and safety case compliance. British Energy have subsequently implemented a more formal means of demonstrating compliance with limits derived from the boiler tube failure safety case.
The above meetings with British Energy were conducted in a constructive and positive manner.
The management and recording of some events that occurred on the station during the period were investigated. Most of these were relatively minor and those of concern to the HMNII Site Inspector were discussed with the appropriate company staff. HMNII was generally satisfied with the actions taken.
The HMNII Site Inspector investigated an incident concerning the failure of an 11kV electrical ring main on 06/07/07. An investigation by Station staff found that the cable trench had been significantly waterlogged due to water leakage from an adjacent tank, over an extended period of time. HMNII concluded that there was no threat to nuclear safety.
British Energy has discovered that the effects of irradiation embrittlement on core restraint components are more severe than previously assumed. The properties of the core restraint components may be degraded to the extent there may be a significant number of latent failures, which may affect the function of the support system in normal operation and faults. This new information potentially undermines the existing safety case for the graphite core. The matter has been reported to HMNII and a safety justification made by the Licensee for continued operation in the short-term. A more detailed safety case is being developed to secure the long term position. HMNII will continue to monitor this issue closely.
The HMNII Site Inspector undertook a joint inspection with an inspector from HSE Construction Division of arrangements for clean-up of trace amounts of asbestos fibre found on cable trays and pipework in the gas circulator halls. The arrangements on site for asbestos clean-up were found to be acceptable.
Under Health and Safety legislation the Site Inspector, or other HSE Inspectors, may issue formal notices to secure improvements to safety. No such notices were issued during the reporting period.
The Inspectorate has powers under the Licence to issue Consents, Approvals and Directions. In addition the Inspectorate uses Licence Instruments to issue Specifications and Agreements under the conditions of the Licence. These are all called Licence Instruments. No Licence Instruments were issued during the period.