1. Site Description
Berkeley nuclear power station is located on the eastern bank of the River Severn in Gloucestershire, England. It was a twin-reactor Magnox station with a net electrical output of approximately 276 MWe (2 x 138 MWe). The station began generating electricity in 1962 and was one of the first commercial nuclear power stations in the UK. It ceased generation in 1989 after 27 years of operation. The site is managed by Magnox Ltd (an NDA subsidiary) as the Site Licence Company.
Berkeley holds historical significance as one of the first Magnox stations to enter the decommissioning phase and has served as a pathfinder for decommissioning approaches applied to the wider Magnox fleet.
2. Decommissioning Method
Berkeley has adopted the Safestore (deferred dismantling) approach, which is consistent with the strategy applied to the wider Magnox fleet:
- Stage 1 (POCO): Completed. All fuel was removed from the reactors and the spent fuel cooling ponds. Operational waste and process materials were removed.
- Stage 2 (Partial dismantling): Substantially complete. All buildings outside the reactor buildings have been demolished or decontaminated. The reactor buildings have been prepared for the Care and Maintenance (Safestore) period.
- Current status: The site is in the Safestore configuration, with the reactor buildings sealed and monitored. The remaining site has been substantially cleared.
- Stage 3 (Final site clearance): Planned for approximately 2074 onwards, when the Safestore period ends and the reactor buildings are dismantled.
- Target end-state: Brownfield/greenfield (to be confirmed based on future land use requirements).
3. Outline Site Characterisation
The main radiological hazards at Berkeley include:
- Activated reactor core components: The graphite moderator and steel components within the biological shield have been activated by neutron irradiation during operation. Key radionuclides include Co-60 (half-life 5.27 years), Fe-55 (2.74 years), Ni-63 (100.1 years) and C-14 (5,730 years, in graphite).
- Contaminated concrete: The biological shield concrete may have activated trace elements and may be contaminated on internal surfaces.
- Residual contamination: Fuel handling areas, cooling pond areas and waste storage areas may have residual surface contamination from operational activities.
- Ground contamination: Historical leakage or spillage may have resulted in localised ground contamination, particularly around liquid waste handling areas.
Key areas requiring detailed characterisation include the reactor buildings (especially the graphite moderator, reactor pressure vessel and biological shield), the former cooling ponds and any former liquid effluent treatment areas.
4. Timescales
| Milestone | Date |
|---|---|
| Start of electricity generation | 1962 |
| Final shutdown | 1989 |
| Defuelling complete | 1992 |
| Stage 1 (POCO) complete | Mid-1990s |
| Stage 2 (external buildings cleared) | 2010s |
| Entry to Safestore (Care & Maintenance) | ~2024 |
| Safestore period | ~2024—2074 (~50 years) |
| Stage 3 (final dismantling) begins | ~2074 |
| Interim End State | ~2024 (Safestore configuration) |
| Final End State (site delicensed) | ~2082 |
| Total programme duration | ~93 years (1989—2082) |
5. Radiological Arisings
| Waste Category | Main Sources | Approximate Volume | Disposal Route |
|---|---|---|---|
| ILW | Graphite moderator blocks; activated steel components; fuel element debris; ion exchange resins; sludges | Several thousand m (packaged) | Geological Disposal Facility (GDF) — interim storage on site or at a centralised facility pending GDF availability |
| LLW | Contaminated concrete rubble; steel from non-core structures; contaminated soil; operational waste (paper, plastic, clothing) | Tens of thousands of m | LLWR Drigg, or other permitted LLW disposal facilities; some may be suitable for controlled landfill after treatment |
| Out of Scope Waste | Lightly contaminated building materials; soil from site clearance | Large volumes | Controlled landfill (under EPR 2016 Schedule 23 thresholds) |
Specific waste challenges at Berkeley:
- Graphite waste: The graphite moderator contains significant quantities of C-14 and H-3 (tritium) and is classified as ILW. The management of irradiated graphite is a UK-wide challenge with no current disposal route, as the GDF is not yet available. Research into graphite treatment options continues.
- Fuel Element Debris (FED): Residual quantities of Magnox fuel cladding material (magnesium alloy) which is reactive and requires careful management.
End of Chapter 6