Calder Hall Sellafield Decommissioning Martin Adam Heriot-Watt Edinburgh 2008

History Located in Cumbria, England Worlds First Commercial Nuclear Power Station Construction started 1953, completed 1956 Her Majesty the Queen Opened the Power Station on 17 October 1956 Generated Power Until March 2003 Consisted of 4 Magnox reactors each capable of 50 Mwe of power each. Produced over 70TWh of electricity in its operational life.

History Its early life primary function was to produce weapons grade plutonium From 1964 it was mainly used for commercial fuels Although it was not until 1995 when the UK government announced that all production of plutonium for weapons had ceased

Calder Hall Site Mission: Safely, securely and cost-effectively remove all fuel and buildings from site To processes, treat and dispose of all waste arise To remediate the ground, where necessary and make the land available for reuse.

Current plan Stage 1: Defuelling & Preparations 2003 – 2008 Stage 2: Intermin Decommissioning 2004 – 2011 Stage 3: Care & Maintenance 2011 – 2105 Stage 4: Final Site Clearance

Defuelling & Preparations: Remove all spent fuel and transfer it to Sellafeild Fuel Handling Plant Arrangements must be taken to improve nuclear safety before defuelling can commence Removal of all fuel elements from the reactor core Despatch of all spent fuel from the station Calder Hall has four reactors, with each reactor holding 1696 fuel channels holding either five or six fuel elements Therefore the site had approx 40,000 elements to remove This phase also deals with maintenance issues dealing with both the defuelling process and the ongoing site management.

Intermin Decommissioning: Will begin in parallel with the defuelling process. Reactor 1 and Turbine Hall A, are currently under a request to become listed buildings. Conservation of remaining 3 reactors into safehouses to be used during the care & maintenance phase Hazard reduction activities; Asbestos removal from heat exchangers and from within the turbine halls Removal of redundant facilities (cooling systems, utilities, generators ext.) Cooling towers were demolished on 29 th of September 2007 All Plant not required for industrial Heritage purpose or C&M removed. Reactors 2, 3 & 4 heat exchangers dismantled and removed.

Intermin Decommissioning: Intermediate waste arising will be transported to the low level waste repository in sellafield New construction activities are required Three reactors will require weather proofing and conversion. This will involve re-cladding the roofs which will also have to been replaced/refurbished every 30 years during the care and maintenance phase Modification to existing facilities to maintain services such as water, telecommunication, fire detection and security system A new electrical ring main will be installed, to allow safe termination of existing services Before C&M can start all hazards must be immobilised in a safe and secure way

Care & Maintenance: This stage is designed to ensure that minimal human intervention is needed during the 100-year Care and Maintenance Program Initial phase will last 5 years where the site will remain staffed After this phase, surveillance, safety and security will be of great importance Safehouses will be routinely maintained, inspected regularly and will undergo periodic surveys. The Scope will also include inspections following severe weather conditions to check for any failure of the watertight envelope. Weekly external inspections (e.g. identification of any damage) Monthly ground maintenance on the site Half-yearly external engineering inspections for minor maintenance issues Annual internal engineering inspections for minor maintenance issues External/Internal inspections at 25 year intervals for major maintenance issues

Final Site Clearance: To facilitate this stage a suitable site infrastructure will be installed A waste management facility (WMF) will be constructed to process the waste arising during this phase Wastes will be transferred in a controlled manned to the WMF, monitored and sentenced  Active waste will be packed in a waste disposal boxes, transported off site and disposed off  Clean waste will be used of infilling voids or disposed of off site Reactor 1 and Turbine Hall A are assumed to no longer be listed buildings, therefore will be removed

Final Site Clearance: Entry to safehouse will be gained during early phases of clearance to carry out preliminary structural and radiological surveys In turn a section of each safehouse roof will be removed to allow large items of the plant to be lifted out Once all active plant and any contamination have been removed from the safehouses they will be demolished and any voids below GWL backfilled Near the end of the phase all services, structures installed to support the project will be deplanted, demolished and removed.

Cost: Total overall estimated cost around 1 Billion GBP Cost Distribution by Key Phase (£k)

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