Introduction
The development of the geological disposal facility is a long term project and there needs to be confidence that what is planned is appropriate and meets the various stakeholder requirements.
What is a safety case?
The safety case developed by the Nuclear Decommissioning Authority’s delivery organisation will provide evidence to demonstrate that the geological disposal system meets all applicable regulatory criteria and will be safe. A safety case will typically include a statement about the approach to safety and the safety assessment that has been undertaken, along with supporting information.
The elements of a safety case
A safety case will usually contain the following five main elements:
- Purpose and context – an outline of the programme and the current step or decision point within the programme against which the safety case is presented.
- The safety strategy – a statement of the high-level approach to ensuring safety.
- The assessment basis – the collection of information and analysis tools supporting the safety assessment.
- Evidence, analyses and arguments – a demonstration of compliance with safety criteria, using multiple lines of evidence, including both quantitative and qualitative arguments.
- Synthesis – a statement of confidence, identification of uncertainties, and a forward programme to investigate significant uncertainties.
The Disposal System Safety Case
The Disposal System Safety Case has an overview and three key documents, one for each of the three components of the overall safety case – transport safety, operational safety, and post-closure safety.
In turn, these three documents are supplemented by numerous specifically commissioned reports, and a great deal of wider scientific literature.
Fig 1: Disposal system safety case document structure (courtesy NDA)
The Disposal System Safety Case considers the safety of waste transport, the safety of the construction and operation of the geological disposal facility, and the safety of the geological disposal facility in the very long term, after it has been closed. Everyone needs to be sure that each of the transport, construction, operation and post-closure stages is safe. Each of these stages is subject to separate regulatory control and requires approval. In addition, the development of a geological disposal facility will require planning approval as part of the local planning process.
Safety cases have been developed by waste producers for packaging and transport of some radioactive wastes and other radioactive materials, as these activities have been taking place for a long time.
For a geological disposal facility, the safety case will relate to a given stage of development, and should acknowledge the existence of any unresolved issues and provide guidance for work to resolve these issues in future development stages. The safety case for a geological disposal facility will be developed by the implementing organisation.
Work to date builds on more than 25 years of site-specific and generic experience studying geological disposal and undertaking safety assessments in the UK, and 20-30 years of such experience in other countries with major nuclear programmes worldwide.
The safety case will be updated periodically in line with major programme stages: site selection, site characterisation, planning approval, disposal facility construction, disposal facility operation, disposal facility sealing and closure, and eventual withdrawal of control. The period from the start of the building of the geological disposal until closure, may extend up to 100 years or even more. This allows time for the implementing organisation to improve the design of safety barriers, if necessary, as new information becomes available.
Regulating the geological disposal facility
The safety case will undergo regulatory scrutiny throughout the various phases of implementing the geological disposal facility. Regulators will consider applications for permissions, licences and authorisations at appropriate stages. The main regulators are listed below.
Regulation of Nuclear Industry
On 8 February 2011, a written ministerial statement by the Rt. Hon. Chris Grayling MP announced the Government’s intention to bring forward legislation to create a new independent statutory body outside of the HSE to regulate the nuclear power industry.
Organisation and responsibilities of the Office for Nuclear Regulation
The new statutory corporation, known as the Office for Nuclear Regulation (ONR), will take on the relevant functions that were carried out by the Health and Safety Executive and the Department for Transport. Formerly part of the Department for Transport, Radioactive Materials Transport Team (RMTT) regulates the transport of radioactive material by road and rail in Great Britain. They also advise on its transport by sea and air within the United Kingdom. This includes to and from licensed nuclear sites and non-nuclear sectors such as hospitals and education establishments. RMTT’s transfer to ONR represents another step in the transformation to a single, integrated regulator.
The ONR will be a new independent regulator, formally responsible in law for delivering its regulatory functions. The creation of the ONR will consolidate civil nuclear and radioactive transport safety and security regulation in one place. Pending the legislation, and in the interim, the Health and Safety Executive has taken steps to establish the ONR as a non-statutory body from 1 April 2011, signalling the commitment to securing an appropriately resourced and responsive regulator for the future challenges of the nuclear sector. The Government will review the functions and processes of the interim body in order to inform its planned legislation.
Security Regulation – Office for Civil Nuclear Security (OCNS)
This division within HSE’s Nuclear Directorate regulates security arrangements in the civil nuclear industry, including security of nuclear material in transit.
Security
All nuclear installations must have a site-specific security plan approved by the OCNS and any proposed changes to security plans must also be approved in advance by OCNS. The security plan must provide details on site security management, policing and guarding and describe in detail the site security measures and arrangements for managing and reporting incidents. OCNS approval of carriers and transport plans will also be required where movement of nuclear material to the facility is involved.
These security measures will ensure that any material that could present a terrorist target is protected, both during transport to the geological disposal facility and during operations at the disposal facility. Once the disposal facility is sealed, the depth of the facility ensures that the nuclear materials remain inaccessible.
Other stakeholder input
As well as having regulatory input to the safety case, it will be important to ensure other key stakeholders are confident with the proposals set out in these documents.
An important way of building confidence in the assessments is by ensuring that the work is subject to independent review. This review could be of the following types:
- Peer review by independent experts and advisory committees.
- Peer review by international organisations, such as the IAEA or the OECD/NEA.
- Peer review by the scientific establishment.
- Regulatory review as part of the normal implementing organisations engagement with regulators and planners.
- Review by the Committee on Radioactive Waste Management or other committees established by local or national government.
- The involvement of local communities and other interested parties in reviewing and commenting on the proposals.
Further information:
For further information please see: