Halcrow provided multidisciplinary engineering design services to UKAEA Dounreay between 2004 and 2006 for the design of the D1209 replacement ventilation system.
The design services provided by Halcrow included: active ventilation; structural engineering; electrical control and instrumentation (including power supplies and back-up generation); design of a new stack and the modelling of the dispersion of the stack discharges; preparation of nuclear safety case documentation and installing care and maintenance provisions for the existing D1209 ducts, which incorporate active and inactive elements.
The existing approximately 300m long D1209 spine duct provides safety critical ventilation for the Fuel Cycle Area (FCA). This was required to be maintained in an operational state whilst the replacement system is installed and commissioned prior to changeover.
The replacement system must then operate continuously for a design lifetime of 40 years and accommodate progressive shutdown of the facilities served by the duct. Mechanical and electrical systems covered by Halcrow’s commission also included fan selection, acoustic assessment, and discharge monitoring and sampling systems.
Halcrow also provided assessment and justification for design decisions to provide an auditable trail demonstrating best practicable means, whole life costs and substantiated safety case. Additionally the systems proposed were designed by Halcrow for availability, reliability and maintainability (ARM) targets.