Editing Integral fast reactor (section)

==Technical overview==

The IFR is cooled by liquid [[sodium]] and fueled by an [[alloy]] of [[uranium]] and [[plutonium]]. The fuel is contained in steel [[Cladding (construction)|cladding]] with liquid sodium filling in the space between the fuel and the cladding. A void above the fuel allows [[helium]] and radioactive [[xenon]] to be collected safely{{Citation needed|date=January 2023}} without significantly increasing pressure inside the fuel element,{{Citation needed|date=January 2023}} and also allows the fuel to expand without breaching the cladding, making metal rather than oxide fuel practical.{{Citation needed|date=January 2023}} The advantages of liquid sodium coolant, as opposed to liquid metal [[lead]], are that liquid sodium is far less dense and far less viscous (reduced pumping costs), is not [[Corrosive substance|corrosive]] (via dissolution) to common steels, and creates essentially no radioactive neutron activation byproducts. The disadvantage of sodium coolant, as opposed to lead coolant, is that sodium is chemically reactive, especially with water or air. Lead may be substituted for the eutectic alloy of lead and [[bismuth]], as used as reactor coolant in Soviet [[Alfa-class submarine]]s.

===Basic design decisions===
{{more citations needed section|date=March 2014}}

====Metallic fuel====
Metal fuel with a sodium-filled void inside the cladding to allow fuel expansion has been demonstrated in EBR-II. Metallic fuel makes [[pyroprocessing]] the reprocessing technology of choice.{{citation needed|date=March 2014}}

Fabrication of metallic fuel is easier and cheaper than ceramic (oxide) fuel, especially under remote handling conditions.<ref name=PE/>

Metallic fuel has better [[heat conductivity]] and lower [[heat capacity]] than oxide, which has safety advantages.<ref name=PE/>

====Sodium coolant====
The use of liquid metal coolant removes the need for a pressure vessel around the reactor. Sodium has excellent nuclear characteristics, a high heat capacity and heat transfer capacity, low density, low [[viscosity]], a reasonably low melting point and a high boiling point, and excellent compatibility with other materials including structural materials and fuel.{{Citation needed|date=January 2023}} The high heat capacity of the coolant and the elimination of water from the [[Nuclear reactor core|reactor core]] increase the inherent safety of the core.<ref name=PE/>

====Pool design rather than loop====
Containing all of the primary coolant in a pool produces several safety and reliability advantages.<ref name=PE/>

====Onsite reprocessing using pyroprocessing====
Reprocessing is essential to achieve most of the benefits of a fast reactor, improving fuel usage and reducing radioactive waste by several orders of magnitude.<ref name=PE/>

Onsite processing is what makes the IFR "integral". This and the use of pyroprocessing both reduce proliferation risk.<ref name=PE/><ref name="youtube.com">{{cite web |url=https://www.youtube.com/watch?v=vuunX3Oc4n4 |title=Roger Blomquist of ANL (Argonne National Lab) on IFR (Integral Fast Reactor) @ TEAC6 . Stated at ~ 19–21 minutes|website=[[YouTube]] |date=12 July 2014 }}</ref>

[[Pyroprocessing]] (using an electrorefiner) has been demonstrated at EBR-II as practical on the scale required. Compared to the [[PUREX]] aqueous process, it is economical in capital cost, and is unsuitable for the production of weapons material, again unlike PUREX which was developed for weapons programs.{{citation needed|date=March 2014}}

Pyroprocessing makes metallic fuel the fuel of choice. The two decisions are complementary.<ref name=PE>{{cite book |title=Plentiful Energy: The Story of the Integral Fast Reactor, the Complex History of a Simple Reactor Technology, with Emphasis on Its Scientific Basis for Non-specialists |first1=Charles |last1=Till |first2=Yoon Il |last2=Chang |year=2011 |isbn=9781466384606 |page=114|publisher=Charles E. Till and Yoon Il Chang }}</ref>