• PROJECT • DUNGENESS B, KENT
Dungeness B
Reactor Building & Switch House H&V Upgrades
Full H&V upgrades across two building scopes at Dungeness B nuclear power station. Bespoke AHU design and installation, control panel replacement, EC&I, and complex lifting operations on a live site.
SITE
Dungeness B
LOCATION
Dungeness, Kent
CLIENT
SCOPE
Reactor Building · Switch House
TIMELINE
2025-2026
Energy Consultancy delivered a comprehensive H&V upgrades programme across two building scopes at Dungeness B nuclear power station, the Reactor Building and the Switch House, for EDF Energy.
The scope covered bespoke AHU design and installation, non-return damper replacement, control panel engineering and replacement, fan anti-vibration mount renewal, pre-filter upgrades, ductwork and instrumentation modifications, and a full EC&I package throughout.
Both scopes were delivered on a live station, with all works managed to nuclear compliance standards and a full documentation package produced from design through to commissioning sign-off.
STANDARDS APPLIED
SAFE SYSTEMS OF WORK
Safety Documents — live plant isolation
DOCUMENTATION
ITP · QP · LTRP · RAMS · Lift Plans
DESIGN
Design of Operations · CAD drawings
TESTING
Full system testing · Site Acceptance
LIFTING
Lift Plans · Scaffold · Telehandler
Background & Context
Dungeness B is an Advanced Gas-cooled Reactor (AGR) station on the Kent coast, operated by EDF Energy. The Reactor Building and Switch House H&V Upgrades programme was commissioned to address ageing heating and ventilation infrastructure across two critical areas of the station, replacing existing plant with modern equivalents and bringing the systems up to current operational and compliance standards.
The programme required Energy Consultancy to design, procure, and install bespoke plant to suit the specific conditions of each building, rather than specifying off-the-shelf equipment, a common requirement in nuclear environments where existing geometry, load conditions, and safety requirements rarely align with standard commercial plant.
Project Scope – Two Buildings
SCOPE 01
Reactor Building
- AHU design & installation (2 units, 204 kg each, ceiling height)
- Non-return damper removal and replacement
- Control panel design, removal, replacement and commissioning
- Fan anti-vibration mount replacement
- Pre-filter frame upgrades and filter replacement
- Ductwork modifications
- Instrumentation modifications
- Full system decommissioning, installation and testing
SCOPE 02
Switch House
- Full H&V design across the Switch House
- Control panel design, removal, replacement and commissioning
- Plant decommissioning and removal
- New plant installation
- Full EC&I package
- System commissioning and full testing
- Complete documentation handover
The Challenge
Delivering H&V upgrades within a live nuclear power station brings challenges that go beyond standard building services replacement. At Dungeness B, the specific conditions of this programme added several layers of complexity:
Station live throughout
All works were carried out under formal Safety Document controls, ensuring affected plant was confirmed “not live” before any works proceeded. This added a procedural layer to every task on site and required close coordination with the station’s operational teams at every stage.
Bespoke AHU design
The replacement AHUs could not be sourced off the shelf. The geometry and load requirements of the Reactor Building meant Energy Consultancy designed the replacement units to specification, then procured and installed them. Getting this right in the design phase is what makes the installation straightforward; getting it wrong would have meant returning to site.
High-level lifting and rigging
The Reactor Building scope involved some of the most technically demanding lifting operations on the project. Two replacement AHUs, each weighing 204 kg, were installed at height, requiring scaffold erections and a carefully planned rigging operation. The control panel replacement also required a telehandler for high-level positioning.
Fan suspension for anti-vibration mount replacement
Replacing the anti-vibration mounts beneath the existing fans required each fan to be suspended in position while the mounts were removed and replaced underneath, a task that looks simple on a drawing and requires careful planning in practice.
Specialised panel and materials procurement
Control panels and specific materials were procured to Energy Consultancy’s own design and specification, rather than to a client-issued specification, placing the full design responsibility, and the accountability for fit and function, with our team.
Our Approach
Energy Consultancy led the full design process for both scopes, producing Design of Operations documentation, CAD drawings, and all technical specifications required to define the replacement plant. The bespoke AHU design for the Reactor Building was a critical early-programme task: the units had to be designed specifically for the geometry and operating conditions of their final installation position, then procured to that specification before any physical works could begin. Control panels were also designed and procured to Energy Consultancy’s own specification, with the full panel design forming part of the documentation package handed over to the client on completion.
Prior to any physical works on either scope, formal Safety Documents were raised to isolate and confirm “not live” the affected plant. This is a specific nuclear site requirement, not a generic risk assessment, but a documented, station-sanctioned process that defines the exact conditions under which each element of work can proceed. Scaffold erections were completed before high-level work commenced, and individual Lift Plans were produced for all significant lifting operations.
Existing plant across both scopes, AHUs, non-return dampers, control panels, fans, and associated instrumentation, was systematically decommissioned and removed before new plant was installed. The anti-vibration mount replacement on the Reactor Building fans required each fan to be suspended in position while mounts were changed out below, maintaining the fan’s alignment throughout. AHU installation at height in the Reactor Building was the programme’s most demanding physical operation, two 204 kg bespoke units lifted and positioned using carefully sequenced rigging, with no room for error given the installed position and the surrounding plant.
Both scopes included a full EC&I package alongside the mechanical works — control panel installation, instrumentation modification and replacement, and full controls commissioning across every system. All works concluded with formal system testing before sign-off, confirming correct operation of every installed component before handover.
Outcomes & Deliverables
EDF Energy received fully upgraded H&V systems across both the Reactor Building and Switch House, alongside a complete documentation package:
- Bespoke AHU design, supply & installation
- Control panel design, supply & installation
- Pre-filter frame upgrades & filter replacement
- Full EC&I package — both scopes
- Design of Operations documentation
- Risk & Method Statements (RAMS)
- Quality Plans (QP)
- Control panel design documentation
- Non-return damper replacement
- Fan anti-vibration mount replacement
- Ductwork & instrumentation modifications
- Scaffold erections & rigging — Lift Plans produced
- CAD drawings — both scopes
- Inspection & Test Plans (ITP)
- Site Acceptance Test records
- Lifetime Record Pack (LTRP)
Services Delivered on This Project
BUILDING SERVICES & HVAC DESIGN
Bespoke AHU design and full H&V design to suit nuclear environments and specific site conditions.
EC&I DESIGN
Control panel design, instrumentation modification and EC&I throughout both building scopes.
INSTALLATION & COMMISSIONING
Plant installation and commissioning in a live nuclear environment, including complex high-level lifting operations.