Editing Nuclear reprocessing (section)

===Volatilization in isolation===
Simply heating spent oxide fuel in an inert atmosphere or vacuum at a temperature between {{convert|700|°C}} and {{convert|1000|°C}} as a first reprocessing step can remove several volatile elements, including caesium whose isotope [[caesium-137]] emits about half of the heat produced by the spent fuel over the following 100 years of cooling (however, most of the other half is from [[strontium-90]], which has a similar half-life).
The estimated overall mass balance for 20,000&nbsp;g of processed fuel with 2,000&nbsp;g of cladding is:<ref>{{cite web |url=http://web.mac.com/mosb1000/iWeb/Bob's%20Site/Examples_files/Sr_Design_Rpt.pdf |title=Removal of caesium from spent nuclear fuel destined for the electrorefiner fuel treatment process |author=Wolverton, Daren |publisher=University of Idaho (dissertation?) |date=11 May 2005 |display-authors=etal |url-status=dead |archive-url=https://web.archive.org/web/20071129121201/http://web.mac.com/mosb1000/iWeb/Bob%27s%20Site/Examples_files/Sr_Design_Rpt.pdf |archive-date=29 November 2007}}</ref>

{| class="wikitable"
|-
! !!Input !!Residue !![[Zeolite]]<br />filter!!Carbon<br />filter!!Particle<br />filters
|-
|[[Palladium]]||28||14||14|| ||
|-
|[[Tellurium]]||10||5||5|| ||
|-
|[[Molybdenum]]||70|| ||70|| ||
|-
|[[Caesium]]||46|| ||46|| ||
|-
|[[Rubidium]]||8|| ||8|| ||
|-
|Silver||2|| ||2|| ||
|-
|[[Iodine]]||4|| || ||4||
|-
|Cladding||2000||2000|| || ||
|-
|[[Uranium]]||19218||19218|| || ||?
|-
|Others||614||614|| || ||?
|-
|Total||22000||21851||145||4||0
|}

====Advantages====
* Requires no chemical processes at all
* Can in theory be done "self heating" via the [[decay heat]] of sufficiently "fresh" spent fuel
* [[Caesium-137]] has uses in [[food irradiation]] and can be used to power [[radioisotope thermoelectric generator]]s. However, its contamination with stable {{chem|133|Cs}} and long lived {{chem|135|Cs}} reduces efficiency of such uses while contamination with {{chem|134|Cs}} in relatively fresh spent fuel makes the curve of overall radiation and heat output much steeper until most of the {{chem|134|Cs}} has decayed
* Can potentially recover elements like [[ruthenium]] whose ruthenate ion is particularly troublesome in PUREX and which has no isotopes significantly longer lived than a year, allowing possible recovery of the metal for use
* A "third phase recovery" can be added to the process if substances that melt but don't vaporize at the temperatures involved are drained to a container for liquid effluents and allowed to re-solidify. To avoid contamination with low-boiling products which melt at low temperatures, a melt plug could be used to open the container for liquid effluents only once a certain temperature is reached by the liquid phase.
* Strontium, which is present in the form of the particularly troublesome mid-lived fission product {{chem|90|Sr}} is liquid above {{convert|1050|K}}. However, [[Strontium oxide]] remains solid below {{convert|2804|K}} and if strontium oxide is to be recovered with other liquid effluents, it has to be [[reduction (chemistry)|reduced]] to the native metal before the heating step. Both Strontium and Strontium oxide form soluble [[Strontium hydroxide]] and hydrogen upon contact with water, which can be used to separate them from non-soluble parts of the spent fuel.
* As there are little to no chemical changes in the spent fuel, any chemical reprocessing methods can be used following this process

====Disadvantages====
* At temperatures above {{convert|1000|K}} the native metal form of several [[actinide]]s, including [[neptunium]] (melting point: {{convert|912|K}}) and [[plutonium]] (melting point: {{convert|912.5|K}}), are molten. This could be used to recover a liquid phase, raising proliferation concerns, given that uranium metal remains a solid until {{convert|1405.3|K}}. While neptunium and plutonium cannot be easily separated from each other by different melting points, their differing solubility in water can be used to separate them.
* If "nuclear self heating" is employed, the spent fuel with have much higher [[specific activity]], heat production and radiation release. If an external heat source is used, significant amounts of external power are needed, which mostly go to heat the uranium.
* Heating and cooling the vacuum chamber and/or the piping and vessels to collect volatile effluents induces [[thermal stress]]. This combines with radiation damage to material and possibly [[neutron embrittlement]] if [[neutron source]]s such as [[californium-252]] are present to a significant extent.
* In the commonly used oxide fuel, some elements will be present both as oxides and as native elements. Depending on their chemical state, they may end up in either the volatalized stream or in the residue stream. If an element is present in both states to a significant degree, separation of that element may be impossible without converting it all to one chemical state or the other
* The temperatures involved are much higher than the melting point of lead ({{convert|600.61|K}}) which can present issues with radiation shielding if lead is employed as a shielding material
* If filters are used to recover volatile fission products, those become [[low level waste|low-]] to intermediate level waste.