Description

Dissolution is a process whereby solid substances dissolve into solution. Precipitation and crystallisation are processes by which solids are formed out of liquids: precipitation occurs when a dissolved substance separates from solution as a fine suspension of solid particles; crystallisation is the process of producing pure crystals of an element, molecule or mineral from a fluid or solution undergoing a cooling process.

Category

Category of FEP

Supercontainer EBS

Sub-category

Sub-category of FEP

Chemical processes

Ondraf Niras FEP Number

Ondraf Niras FEP Number

17

FEP Effects

Description of FEP Effects

A change to a more reducing environment away from the waste could cause precipitation of uranium and other redox-sensitive elements that have a lower solubility under reducing conditions. Subsequent dissolution of the precipitated elements may occur if the redox conditions shift from reducing to oxidising. Other factors that may cause precipitation and dissolution away from the waste are changes in temperature or in the concentration of ions and complexes that affect the speciation of the elements.

NEA TN2 IFEP Reference(s)

Related IFEPs from the NEA TN2 List of Proposed IFEP Revisions [NEA/RWM/R(2013)8]

2.3.4.6 Dissolution (waste package). 2.3.4.7 Mineralisation (waste package). 2.3.4.8 Precipitation reactions (waste package). 2.4.1.2 Dissolution (waste form). 2.5.2.4 Dissolution, precipitation and mineralisation (waste package). 3.2.4.5 Dissolution (GDF). 3.2.4.6 Mineralisation (GDF). 3.2.4.7 Precipitation reactions (GDF). 3.3.2.4 Dissolution, precipitation and mineralisation (GDF).