RD&D-Programme 2004 - SKB

The international and Swedish regulatory frameworks recommend monitoring during all steps of
the implementation of the deep repository, with the limitation that the safety of the post-closure
repository shall not be dependent on monitoring or future maintenance. The steps and measures
that are adopted to carry out monitoring should have a minor or negligible impact on the safety
of the repository, or should result in improved safety.
Over a number of years – not least during ongoing site investigations, ongoing activities and
construction of the Äspö HRL, as well as the recently completed expansion of Clab – SKB has
accumulated considerable experience from monitoring of nuclear and non-nuclear installations.
The observations have, for example, concerned mechanical, geochemical and geohydrological
conditions in the rock before and during construction as well as during operation of the facilities.
The results of the observations have been utilized in the construction phase for detailed
adaption of the facilities and to achieve high safety in construction and operation. Experience
can also be gained from the monitoring of groundwater and barrier performance performed
at the final repository for low- and intermediate-level waste (SFR) and at the Äspö HRL.
Experience gained from monitoring concerns all aspects from design, installation, operation
and maintenance to decommissioning of measurement systems.
Programme
The ongoing site investigations are an important part of the monitoring programme that will be
prepared during the RD&D period.
During the site investigation phase, a primary baseline is established with data from the ground
surface investigations. The purpose of the primary baseline is to create a reference so that
changes caused by construction, operation and closure of the deep repository can be identified
and distinguished from natural variations and variations caused by other human activities.
Identified changes will also be compared with predictions of the changes obtained with the aid
of models of the rock and the repository. The changes can also be used to adapt the repository to
the geological conditions on the site. During the site investigations, information is gathered on
e.g. land use, surface ecosystems, geology, hydrogeology, rock mechanics and hydrochemistry.
Collection of primary baseline data takes place over a relatively long period of time and the
measurement frequency is adjusted so that seasonal and annual variations are included.
An overview of possible features, processes and parameters included in primary baseline data
for monitoring is published in /12-1/. The monitoring carried out during the site investigation
phase largely follows the general execution programme /12-3/, where the investigation methods
have been described, and the site-adapted programmes /12-4, 12-5/.
During the construction phase, detailed investigations of the rock from the surface will continue
while the underground part is being built and the rock is being investigated. The monitoring
performed during this phase focuses on an understanding of geohydrological, geochemical and
rock mechanical processes and their impact on the long-term performance of the repository, but
also includes documentation of the disturbances caused by repository construction and monitoring
of environmental impact.
Planning for monitoring during the construction phase is under way, and it is predicted that the
details will be presented in the overall programme for the construction phase, see section 11.3.
The monitoring programme should describe the following /12-1/:
• The goals of the monitoring programme.
• Criteria for selection of what is to be monitored.
• Identification of properties, processes, features and observable quantities to be monitored.
• Which methods are to be used.
• The duration and frequency of monitoring, including criteria for how monitoring can be
terminated.
• Procedures for quality control and reporting of results.
140 RD&D-Programme 2004