Near surface disposal of low-level radioactive waste

Project summary

ONDRAF/NIRAS is entrusted by law with developing a coherent policy for the safe management of all radioactive waste that exists on Belgian territory and, subject to parliamentary and government review, implementing that policy consistent with Royal Decrees, government decisions and decisions from the regulatory body. Consistent with its mission, ONDRAF/NIRAS must implement plans for the development of waste management facilities, including facilities for the final disposal of radioactive waste.

To deal with the short-lived low and intermediate level radioactive waste (category A waste), originating from the operation and decommissioning of past and future nuclear facilities, and from industrial, medical and research applications, a near surface disposal facility will be developed.

Figure 1. Proposed location for the Belgian near surface disposal facility for category A waste (source: ONDRAF/NIRAS).

On June 23rd 2006, the Belgian government decided in favour of a near surface disposal facility for the category A waste that will be located in the municipality of Dessel (near Belgoprocess where part of the waste is already temporarily stored) (Figure 1). Between 2006 and 2011, different detailed technical studies will be carried out to prepare different license applications with a view to enter the construction phase. The current roadmap foresees start of the construction around 2011, such that the first disposal vaults will be ready not later than 2016 (Figure 2).

During the current project phase, ONDRAF/NIRAS must develop a near surface disposal facility in Dessel, that is based on the design developed within the previous preliminary project phase by the STORA-Dessel partnership. SCK•CEN is one of ONDRAF/NIRAS’ partners in evaluating the long-term safety of the planned near surface disposal facility.

Objectives

The long-term safety of radioactive waste disposal facilities is usually demonstrated with the support of a safety assessment. This normally includes modelling of radionuclide release from a multi-barrier near-surface or deep disposal facility to the geosphere and biosphere. The main objective of the overall work is to support ONDRAF/NIRAS in ensuring a safe, permanent and sustainable solution for the management of short-lived low and intermediate level radioactive waste (LILW-SL, or category A waste) in Belgium.

The approach to post-closure safety assessment implemented by SCK•CEN was based on the internationally recognised ISAM methodology, which was developed for near surface disposal of LILW-SL by the IAEA. The methodology considers three main components of the disposal system, i.e. the near field, geosphere and biosphere.

  • The near field comprises the waste and the engineered barriers.
  • The geosphere comprises the geology and hydrogeology of the site.
  • The biosphere incorporates all relevant exposure pathways through which men can be exposed such as inhalation of gaseous radionuclides (e.g. radon) and resuspended dust, direct radiation from contaminated sediments and soils, and ingestion of contaminated water and food cultivated on contaminated soil or contaminated by irrigating with contaminated water.

Contact: Diederick Jacques