2009 Report to Government on National Research and

A.50 Information on what is needed in an environmental safety case (ESC) is given in
the Guidance on Requirements for Authorisation (GRA) (EA & NIEA, <strong>2009</strong>). The
GRA states that an ESC should, inter alia:
• demonstrate a clear understanding of the GDF in its geological setting and
how it will evolve over time
• include a clear outline of the key environmental safety arguments and say
how the major lines of reasoning and underpinning evidence support these
arguments
• make use of multiple lines of reasoning, based on a variety of quantitative
and qualitative evidence, leading <strong>to</strong> complementary safety arguments
• explain how uncertainties have been considered
• include quantitative environmental safety assessments for the operational
and post-closure periods
• be updated at each stage in the development of the GDF, at suitable
intervals during its operation, and at closure.
A.51 CoRWM believes that both fundamental and applied research will be needed in
order <strong>to</strong> develop a robust ESC.
A.52 While some international research, particularly that of a more fundamental
nature, will be helpful <strong>to</strong> the UK’s geological disposal programme, much of the
required R&D will be site-specific and hence cannot be conducted until candidate
sites are identified. However, there are a number of underpinning non-site
specific areas, both applied and fundamental, where strategic investment in R&D
is required. Many of these areas are well known and have been the subject of
research programmes worldwide for many years (see e.g. MRS, 2008). Some of
them are highlighted below but CoRWM also emphasises the differing and
complex needs associated with the UK’s diverse wastes and the fact that the
geology in which a UK GDF will be located is not yet known.
A.53 While a range of detailed R&D issues are discussed below, CoRWM considers
that enough is currently known about geological disposal from previous UK and
international R&D programmes <strong>to</strong> engender confidence that it is the right way
forward. The current state of the UK R&D scene in the areas discussed in this
section was highlighted at a meeting supported by CoRWM at the University of
Sheffield in April <strong>2009</strong> (CoRWM doc. 2619). Other issues which came up at the
meeting include: prospects for deep borehole disposal as an alternative <strong>to</strong> mined
reposi<strong>to</strong>ries for HLW; the potential for crossover of knowledge from the oil, gas
and mineral industries, including seismology and geophysics techniques for site
characterisation; testing of modelling predictions; and assessing the
characterisation of geological environments.
Migration (Sorption, Colloids and Water Flow)
A.54 After a GDF has been closed and sealed it will resaturate with groundwater. The
waste containers will slowly corrode and the radioactive species will be released
from the wasteforms. These radionuclides will then interact with their
environment, which will include: in the near field, backfilling materials such as
cement or clay and other minerals and rocks; the engineering and chemically
disturbed zones around the GDF; the host rock; and the groundwater flowing
CoRWM Document 2543, Oc<strong>to</strong>ber <strong>2009</strong> Page 110 of 151