Nuclear Decommissioning and Site Restoration

From Data to Decisions

Quintessa's capabilities and experience of providing environmental and radioactive waste decision support services from data to decisions is the foundation for providing support to the Nuclear Decommissioning Authority and nuclear site licensees in the management of the UK's nuclear legacy through: Decision-making, BPEO and BPM Site end point development Data interpretation and visualisation Geology and hydrogeology Environmental risk assessments Mathematical Modelling

NDA and overseas sites

Quintessa staff have a wide range of knowledge and experience of many of the issues affecting NDA and international sites. This experience ranges from data interpretation and site conceptualisation, environmental modelling and post-closure safety cases, to life cycle base line and site end point development.

In particular, UK staff site expertise includes: Sellafield Drigg Dounreay Harwell Magnox stations Springfields

Comprehensive modelling capability

Quintessa's unique blend of site knowledge, problem understanding and assessment techniques is underlain by a comprehensive modelling capability ranging from conceptual and mathematical model formulation to the development and application of state-of-the-art software.

Quintessa has a modelling capability covering all scales of processes relevant to NDA sites from the present through to decommissioning, cleanup and site end points, including:

• Performance assessment/screening level using AMBER and GoldSim
• Geochemical analysis using RAIDEN
• Groundwater and contaminant transport
• Remediation technique performance prediction and·assessment
• Waste form evolution

Also, Quintessa has signed a partnership agreement with GoldSim Technology Group. Under this agreement, Quintessa offers training and other GoldSim support, including:

Environmental risk assessments for contaminated land/waste disposal Process and financial modelling Quantitative input into decision making Provision of models in controlled distributable form to clients· through freely available 'player' format.

Some recent examples of nuclear decommissioning and site restoration projects at Quintessa include:

• The development and maintenance of the SimER Code;
• Strategic Issues in Radioactive Waste Management and Decommissioning;
• Outline Post-Closure Safety Case for the Dounreay Site;
• Updating the Dounreay Site Restoration Plan for Developments in the Regulatory Approach to Site Closure;
• Sensitivity Analysis for Contaminated Land Safety Assessment;
• Post-Closure Safety Case for the Dounreay Shaft;
• Dourneay Hydrogeological Strategy;
• Development of 'RCLEA' model for radioactively contaminated land;
• Understanding Groundwater Flow and Radionuclide Transport at the Dounreay Shaft;
• Best Practicable Environmental Option (BPEO) Studies in Support of the Dounreay Site Restoration Plan;
• Summary of SAFEGROUNDS guidance document;
• Best Practicable Environmental Option for Low Level Waste at Dounreay;

For more information, please contact David Hodgkinson.