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Title:
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A repository design for the retrievable disposal of radioactive waste in rock salt
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Author(s):
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Published by:
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Publication date:
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ECN
NUCLEAIR
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1997
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ECN report number:
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Document type:
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ECN-RX--97-054
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Article (scientific)
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Number of pages:
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18
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Published in: Paper presented at the "4th International workshop on the design and construction of final repositories", 6-8 October 1997, Luce (), , , Vol., p.-.
Abstract:
A new design for a repository for high level radioactive wastes in rocksalt has been developed at the Netherlands Energy Research Foundation. This
design and the work being done to evaluate this design is presented in this
paper. It is emphasised that this evaluation is not yet completed and that
the design is still a draft and is subject to discussion within the Dutch
waste management research programme. The basic philosophy underlying the new
design is that it should facilitate the retrieval of the waste whilst at the
same time passive safety design principles are taken into account. The
disposal of the radioactive waste is conceived as an extended and phased
operation consisting of the following steps: facility construction; the
placement of the wastes in the repository; the operation of the repository as
an underground waste storage facility - during this period the waste can be
retrieved in accordance with a procedure which has been developed based upon
present-day technology; regular (for example, every 20 to 30 years) decisions
as to whether the repository should remain 'open' or be 'closed'; closure of
the repository. The repository consists of two main galleries joined by a
number of cross galleries. In each cross gallery 40 shallow horizontal
boreholes are constructed; one waste container is placed in each horizontal
borehole. Each borehole is then 'back-filled' with salt plugs as soon as the
waste canister is placed in the borehole. The cross galleries and main
galleries are kept open during the period of interim storage. These galleries
are back- filled once the decision has been made to close the mine.
Calculations have been carried out in order to evaluate the design with
respect to the dose rate and temperature conditions in the cross galleries
(to which access will be needed for maintenance purposes). A performance
assessment for the design is currently being carried out: in addition to the
scenarios considered for the previous repository designs - e.g. the
subrosion, ground water intrusion and human intrusion scenarios - attention
is also being given to scenarios during the operational period (for example,
flooding of the repository during this period). 3 figs., 8 refs.
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