Last June, IRSN submitted a report on the storage of spent nuclear fuel to the Parliamentary lnquiry Committee on the Safety and Security of Nuclear Facilities. ln the report, which is available on IRSN’s website, the Institute examines the concepts of wet and dry storage existing both in France and abroad.
Based on its assessment of spent nuclear fuel storage in France and on knowledge acquired during services performed abroad, IRSN examined the concepts of wet and dry spent-fuel storage developed both in France and worldwide, along with the associated safety issues.
The two types of spent fuel storage that could be envisaged (wet or dry) do not serve exactly the same needs: storage in a pool is essential for spent fuel with high residual heat and dry storage is suitable for fuel that has cooled down significantly.
The type of spent fuel (natural uranium ENU, reprocessed uranium ERU, or mixed uranium and plutonium oxide MOX) affects any decision about which type of storage to be used, at least for a certain period of time, because MOX fuels have a higher residual heat for longer period.
From a safety point of view, regardless of the type of storage, the decisive parameter is the residual heat of the fuel to be stored. Wet storage, which generally contains hotter fuel, requires more substantial safety measures than dry storage, for which more passive measures can be implemented. In dry storage, cladding (the first containment barrier) is subject to greater thermal stress and is more difficult to inspect.
As a summary, the types of storage do not meet the same requirements. The choice of storage for a given period of time depends on the type of spent fuel (containing natural uranium, reprocessed uranium, or mixed uranium and plutonium oxide). From a safety point of view, the determining factor is the residual heat of the fuel to be stored, whatever the type of storage.
In order to share its work with its foreign counterparts and to continue discussions on the storage of spent nuclear fuel, IRSN has just published an English version of this report on its website.
To find out more and download the report, visit:
www.irsn.fr/spent-nuclear-fuel-storage
Contact
Igor Le Bars, IRSN
igor.lebars@irsn.fr
Источник: eurosafe-forum 6.2019