RD&D-Programme 2004 - SKB

The requirements on safeguards issued by both Swedish and international inspection authorities
must be met in the encapsulation plant. This is provided for during the engineering phase by
setting aside space in the layout for apparatus rooms, fuel measurement equipment, cameras
and surveillance instruments. The plant will be designed so that several Key Measuring Points
(KMPs) can be established, for example at the fuel handling pool, in the handling cell after the
fuel has been placed in the canister before the lid is put on, and in the transport air lock before
the canister is dispatched from the plant. The canister components are individually marked and
can be followed through the various handling steps. In designing the plant’s layout, steps are
also taken to prevent “diversion routes” for nuclear materials in order to facilitate surveillance.
The smallest unit that will be able to be handled is a fuel assembly.
Information on the fuel’s nuclear material content and other safeguards-related information
is that which is available for the fuel stored in Clab. The fuel’s decay heat will be verified by
means of gamma measurements, which are planned to be performed in the encapsulation plant.
This measurement position can also be used by the supervisory bodies for their own measurements.
It is also possible to “share” the signal from the measurement probes.
Each canister will have a unique identity that can be checked visually. The administrative
safeguards system keeps track of which fuel assemblies are contained in each canister. Visual
verification of the fuel’s identify can be performed before the canisters are sealed. This information
can be recorded by a TV camera and stored in digital form. After sealing and inspection,
the canisters are placed in transport casks. The casks also have a unique identity which is
administratively linked to the contents and permits verification. The transport casks are placed
in a supervised store and kept under surveillance awaiting transport to the deep repository. The
total number of casks needed for spent fuel transport depends on the geographic location of the
repository. The transport casks will be handled in keeping with the same principles as those that
apply to transport of spent fuel from the nuclear power plants to Clab.
In the event the encapsulation plant is built connected to Clab, it will belong to the same
Material Balance Area (MBA) as Clab. This facilitates administration for both the operator
and the supervisory bodies.
Through SKB’s participation in international working groups in the area of safeguards for final
disposal, where encapsulation is one aspect, groups from the EU (Esarda) and the IAEA have
studied the Canister Laboratory and deposition of canisters at Äspö. This has led to a greater
understanding of the whole process of handling of spent fuel from Clab to the deep repository.
Both Euratom and the IAEA share the view that SKB should have an MBA for the encapsulation
plant and Clab in the event the encapsulation plant is built connected to Clab. In the event
of a standalone encapsulation plant, this will comprise its own MBA.
The trend within safeguards to supplement or partially replace traditional safeguards (seal,
camera inspections, etc) with indirect controls such as measurements in the surrounding
environment and gathering of open information, unannounced inspections etc, will naturally
affect the design of the safeguards system at the time of the permit application /8-4/.
102 RD&D-Programme 2004