ONDRAF/NIRAS FEP List…t)) - Version 1.1
FEP 2.1.9.1 Chemical gradient

Records the decision as to whether or not the FEP is relevant for consideration in the assessment. If not, a brief justification is given. If so, it is indicated to which compartments the FEP may a priori be relevant (near field, geosphere, biosphere, direct exposure).

Briefly records whether and in what way the FEP is considered in the near field part of the scenarios and models. These include the gradual release/leaching scenarios, i.e. the expected evolution, alternative evolutions and human intrusions in terms of effect on the containment capacity of the disposal system.

Briefly records whether and in what way the FEP is considered in the geosphere (hydrogeology) assessment basis and models for leaching scenarios.

Briefly records whether and in what way the FEP is considered in the biosphere models associated with gradual release/leaching scenarios. In summary, a biosphere model is described for three biosphere receptors: a hypothetical well at the foot of the eastern tumulus, the river north of the site, and wetland zones between the disposal site and the rivers. The well yields the highest impact, and compliance with the equivalent skin dose limit needs to be demonstrated as well. The impact to non-human biota belonging to ecosystems associated with all three receptors is also assessed by means of an ERICA assessment.

Briefly records whether and in what way the FEP is considered in the direct exposure scenarios and models. These include human intrusion scenarios as used in impact calculations, human intrusion scenarios considered in performance analysis to assess the potential contribution of intrusion barriers, alternative evolutions in which direct exposure could occur (crater formation following a large passenger plane crash), penalising conditions beyond 2000 years.