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Key Issues Influencing the Performance of Near-Field Barriers

Published online by Cambridge University Press:  01 January 1992

P.W. Tasker ,
S.J. Wisbey  and
C.B. Boyle
P.W. Tasker
Affiliation:
AEA Decommissioning & Radwaste, Harwell Laboratory, Didcot, Oxon., OXI1 ORA, UK
S.J. Wisbey
Affiliation:
AEA Decommissioning & Radwaste, Harwell Laboratory, Didcot, Oxon., OXI1 ORA, UK
C.B. Boyle
Affiliation:
AEA Decommissioning & Radwaste, Harwell Laboratory, Didcot, Oxon., OXI1 ORA, UK
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Abstract

In developing a national strategy for the disposal of radioactive wastes, each country will consider isolation options that are appropriate to the types of waste that are produced. The options are developed in response to specific national regulatory requirements, and thus will focus on different aspects of performance. However, there are a number of technical concerns that are common to all programmes. The major issues concerning the behaviour of the chemical and physical barriers in the near field of a radioactive waste repository are discussed in this paper.

The description of key issues has been divided into the following categories: barrier design, barrier evolution, scientific understanding through modelling, and validation of performance. The near-field barriers are selected and designed to provide appropriate radionuclide containment and control. Factors affecting the evolution of these barriers, such as container degradation and gas generation, determine the subsequent release of radionuclides to the human environment. Modelling repository evolution is therefore an integral feature of performance assessments, and issues such as the treatment of inhomogeneities and non-equilibrium chemistry may need to be addressed. However, the use of mathematical and computer models implies a requirement for validation. The use of demonstration experiments and natural analogues builds confidence in the predictions of repository performance models, and provides a degree of validation for otherwise inaccessible timescales.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 294: Symposium V – Scientific Basis for Nuclear Waste Management XVI , 1992 , 697
Copyright
Copyright © Materials Research Society 1993

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References

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