Quintessa Update
Autumn 2003.

Welcome to the Autumn 2003 edition of Quintessa Update, the electronic newsletter of Quintessa Limited.

Best Practicable Environmental Option for LLW at Dounreay

The Dounreay site
Reproduced by kind permission of UKAEA
UKAEA Dounreay has recently embarked on a programme of public consultation on options for the long-term management of low-level radioactive waste arising from the restoration of the site with the aim of identifying the 'Best Practicable Environmental Option' (BPEO). The project is breaking new ground in development of strategy for the long-term management of large quantities of solid radioactive waste in the UK. Quintessa staff have been involved in this project over a period of several years. This has included assistance in developing the BPEO methodology, and contributing to a range of technical studies that support the BPEO project. These technical studies have given particular consideration to the potential impact of long-term waste management options on human health and the environment.

Wham! (Web-Hosted AMBER Model)

The Wham! Basic User graphical interface The Wham! Advanced User graphical interface Quintessa is committed to providing online modelling tools that allow stakeholders to draw their own conclusions about environmental impacts. The latest of these (Wham!) is based upon the hypothetical Vault Test Case developed as part of the IAEA's Co-ordinated Research Project (CRP) on Improvement of Safety Assessment Methodologies for Near Surface Disposal Facilities (ISAM). The model represents a near-surface radioactive waste repository (vault) and simulates the fate of the contaminants released due to the infiltration of water. Contaminants are leached from the vault into the unsaturated zone and then into an underlying aquifer. They are then transported through the aquifer to a well from which water is abstracted for human use. Wham! has been designed with two graphical user interfaces, intended to make the model understandable and useable by both people with little experience of this kind of modelling and by advanced users, and is capable of automatically generating both web-based and PDF reports.

Development of Waste Package Evolution Scenarios

Quintessa has assisted Nirex in developing waste package evolution scenarios for the geological disposal of low-level and intermediate-level wastes, as input to investigating the importance of time-dependency and heterogeneity effects on post-closure repository performance*. In addition to a base scenario, seven variant scenario classes have been defined representing combinations of enhanced water flux, altered water chemistry and physical disruption, and scenarios were presented as combined storyboards and timelines.
* L.E.F. Bailey and D.P. Hodgkinson. Development of Waste Package Evolution Scenarios for the Nirex Phased Disposal Concept. Nirex Report N/062, November 2002.


Reproduced by kind permission of CIRIA
The SAFEGROUNDS project, managed by CIRIA , is a forum for developing and making available good practice guidance on the management of radioactively and chemically contaminated land on nuclear and defence sites in the UK. It is open to all stakeholders and encourages discussion and feedback on all the key issues. A short summary of the SAFEGROUNDS guidance document "Good practice guidance for the management of contaminated land on nuclear and defence sites", has just been issued. This is intended to promote awareness and the use of the guidance. The summary has been prepared by James Penfold at Quintessa and Marion Hill, both of whom also collaborated on the development of the detailed guidance document. The summary, guidance, and other useful information is available at the SAFEGROUNDS website: www.safegrounds.com.