Halcrow provides a complete service to manage and expedite the research, planning and methodology required to successfully demolish or deconstruct nuclear facilities. Halcrow is currently working with UKAEA on what is widely regarded as the UK's most challenging remediation project, the Dounreay shaft.

Halcrow has considerable experience of managing the processes leading to demolition of nuclear / industrial facilities.  Our experience of demolition on nuclear sites includes work on the Dounreay Solid Intermediate Level Waste project, Dounreay Fastbreeder Reactor – Primary Circuit Decommissioning Project and shaft remediation.  Those projects required work on Buildings D1111 (former generator house), D1118 (former battery house), D1110 (former heat exchanger building), D1112 (workshops), D8542 (former workshops and offices), DN041 (offices) and D1499 (offices) at UKAEAs Dounreay Nuclear Establishment.  Work on these structures included preparation of building histories, preparation of contamination histories, review of existing asbestos surveys and arrangement of

additional surveys, arrangement of radiological and chemical contamination surveys, summary demolition drawings, derivation of estimated arisings, agreement of waste routes, contract documentation, excavation and radiological monitoring protocols and the design of associated services diversions.  HAZOP studies were also undertaken in support of these activities with eventual production of Safety Approved Modification documentation to obtain approval to undertake the work.

At Rosyth Naval Base, Halcrow acted as Independent Technical Assessor for the information gathering, option review and development of preferred options for the decontamination, decommissioning and demolition of five facilities.  Halcrow also peer reviewed the preliminary safety report.

Halcrow also has extensive experience of the demolition of numerous hazardous, non-nuclear, structures, providing a source of valuable, transferable, knowledge. Demolition commissions include:

	ICI Research Chemical Plant and Small Scale Radioactive Testing Facility in the Catalyst Industrial Estate Project.
	Derelict industrial units with severe asbestos problems at Friars Terrace, Stafford.
	Britannia Zinc Smelting Plant, Avonmouth, Bristol and associated structures, including contaminated waste.
	Marconi site, Broughton Road, Rugby.
	Royal Navy vehicle maintenance shed.
	Redundant buildings at former RAF Pershore.
	HH Robertson Site, Cranwell Road, Ellesmere Port.

Halcrow's knowledge and experience of demolition techniques has developed from producing demolition works documentation and has benefited from the experience of working in conjunction with contractors. Halcrow's involvement in many projects, as planning supervisor, has added to this substantial level of corporate knowledge.

On nuclear sites in general, the techniques required to demolish structures require thorough preparation including researching buildings operational and contamination histories, conducting asbestos, chemical and radiological surveys, preparation of summary demolition drawings and estimates of quantities, agreement of waste routes and protocols for waste monitoring. Definition of particular orders of demolition is also common, including the requirements for advance soft strip, separate removal of contaminated material (whether radiological, asbestos or chemical) and structural demolition in safe stages.

Selection of particular techniques / plant to be used is generally undertaken by a specialist demolition contractor to safely meet the requirements derived above and remove contaminated equipment.

On nuclear sites with general structures, techniques often include cleaning of structures to remove substances hazardous to health, cold cutting to avoid ingestion of lead paint fumes, use of high strength clippers on booms to reduce, to an absolute minimum, the amount of working at height, use of crane access and working platforms, piece by piece dismantling of structures (particularly in confined spaces).  Halcrow has experience in developing the use of all these techniques on projects at UKAEA Dounreay, and on other, non-nuclear, projects.

Projects
	Dounreay Solid Intermediate Level Waste project
	Dounreay Fastbreeder Reactor - Primary Coolant Decommissioning Project
	Dounreay Shaft Isolation Project

Survey / planning and protocols for
	Usage / radiological history		waste routes
	asbestos		excavation
	radiological contamination		radiological monitoring
	chemical contamination		contract documentation
	demolition drawings		services diversions
	estimated arisings		SAM and HAZOP

Case Study
Dounreay Solid Intermediate Level Waste Project Enabling Works

The enabling works for UKAEA's Solid Intermediate Level Waste project at Dounreay (2000 - 2003) involved the demolition of non-process buildings constructed in the 1950s. The buildings were constructed of some materials now considered to be hazardous. The final use of the buildings was generally as offices or stores, but some had been used for other purposes in the past. Such buildings had not been previously demolished at Dounreay and Halcrow assisted UKAEA to map and co-ordinate the processes required to achieve demolition.

Halcrow reviewed and summarized the available documentation on the buildings and interviewed UKAEA past and present staff to obtain a comprehensive record of the construction and usage history of each building. Halcrow managed the review, summary and interpretation of the radiological records of each building by specialist radiological protection advisors and radiological re-assurance surveys by UKAEA's in-house radiological protection section. The surveys confirmed that the only radiological hazards in the buildings were minor ones. These hazards were anticipated, as a result of the earlier work on the buildings history, and required the removal of small amounts of low level contaminated material from one building. Halcrow investigated the required means of removal and disposal of both active and inactive materials from the buildings, conducted outline surveys of the buildings and produced summary demolition drawings. Halcrow completed the demolition warrant application, on behalf of UKAEA, using the summary demolition drawings and waste disposal requirements that had been researched.

As the requirements of the SILW project evolved, only one building was finally scheduled for demolition, the demolition of others being held in abeyance for programming reasons or cancelled because of changed layouts of proposed facilities. Halcrow prepared the ECC contract documentation to ensure that the demolition of the building was performed in accordance with the requirements of the demolition warrant to achieve safe, environmentally satisfactory, removal of all material.