Oxygen injection systems at Heysham 2

British Energy has requested permission from HSE Nuclear Directorate to enter the oxygen injection systems installed at Heysham 2 from commissioning into routine operations under a consolidated safety case.

This request is in line with the licensee’s responsibility as set out in its nuclear site licence (licence condition 21(8)).

Background

Carbon deposition can accumulate on boiler surfaces of Advanced Gas Cooled Reactors during routine operation leading to a significant reduction in thermal efficiency.  In 1996, an oxygen injection system was proposed for each reactor at Heysham 2 Power Station to recover the thermal performance of the boilers by removing (oxidising) the carbon deposit layer.  Due to operational issues, the oxygen injection systems have been under commissioning control ever since.  British Energy has now completed a series of improvements to the oxygen injection systems and produced a consolidated safety case to justify routine operation.

Assessment and inspection work carried out by ND in consideration of this request

HSE Nuclear Directorate consideration of British Energy’s request has been based on the following key activities:

  • Assessments by HSE Nuclear Directorate Fuel Behaviour and Control and Instrumentation Specialists
  • Inspections by the HSE Nuclear Directorate Fuel Behaviour Specialist and Site Inspector on matters arising from assessment of the Consolidated Safety Case and the licensee’s readiness to enter the oxygen injection systems into routine carbon removal operations.
  • Consideration of the surveillance work undertaken by the licensee’s internal regulator.

Matters arising from ND’s work

There are no regulatory issues that would prevent HSE granting British Energy permission to enter the oxygen injection systems at Heysham 2 into routine operations.

Conclusions

British Energy has provided a consolidated safety case to support entering the oxygen injection systems installed at Heysham 2 from commissioning into routine carbon removal operations.  NII specialist inspectors have concluded that the Consolidated Safety Case is of an adequate standard to support entry of the oxygen injection systems into routine operations.  There are no outstanding matters from NII inspections of matters arising from NII assessment of the Consolidated Safety Case, or of British Energy’s readiness to enter routine operations that would prevent HSE granting British Energy permission to enter the oxygen injection systems at Heysham 2 into routine operations.

Recommendation

HSE permission to enter the oxygen injection systems installed at Heysham 2 into routine carbon removal operations should be given through issue of the following Licence Instruments:

LI 563 – Health and Safety Executive (HSE) Notification to submit to the Executive the Consolidated Safety Case for the oxygen injection systems installed at Heysham 2 and not to commence routine carbon removal operations without the Consent of the Executive.

LI 564 – Health and Safety Executive (HSE) Consent to the oxygen injection systems installed at Heysham 2, as described in the Consolidated Safety Case, entering routine carbon removal operations.

View the full Project Assessment Report here.