Nuclear chem dotpoint. (1 Viewer)

[ND]

"describe how commercial radioisotopes are produced"

Is this asking just in general (i.e. fission reactors, particle accelerators), or does it want specific examples (i.e. the production of Tc-99m)?

 

[toknblackguy]

general
although they could most likely tie this into a radioisotope you have studied and it's application in whatever
in general, it is formed in nuclear reactors through neutron bombardment, which can then alpha or beta decay to form different isotopes, some of which are radioactive.

but how is Tc-99m formed/
i know molybdedum 99 beta decays to it, but is that all we have to know?

 

[ND]

I don't know how much we have to know, but this is what i remember (may be a bit dodgy cos i haven't memorised it since trials): Mo is a fission product of uranium. UO2 pelets are placed in a reactor and some is fissioned to Mo. This is put in small glass tubes (can't remember how the Mo is extracted), and delivered to hospitals. It decays to Tc99m along the way. Tc99m is extracted by flowing saline solution through the Mo.

I'm not 100% sure whether the glass tubes are used there or in another stage.

 

[+:: $i[Q]u3 ::+]

it's a pretty general dp.
most are produced in nuclear reactor cores by bombarding suitable target nuclei with neutrons
eg co-60 from neutron-bombardment of co-59.
or as a direct product from fission (insert all the Mo-99 stuff here)

 

[toknblackguy]

anyway...do you know the properties of Tc-99m that makes it useful?
they are:
-short half life of 6 hours
-emits harmful gamma rays that do not damage tissue but are still detectable by special camers
-can be changed to anumber of oxidation states allowing it to be targeted at various biological organs, where it can then collect in the organ being investigated
cheers

 

[Constip8edSkunk]

neutron defficient isotopes are created using cyclotron by bombarding protons or a light positive nucleus,
excess neutron isotopes made in a fission reactor through fission of U-235 though, often neuron irradiation are used as well

 

[MyLuv]

And element with Z>92 produced by particle accelerator

 

[underthesun]

Wouldn't it be bombarding atoms with neutrons or other nucleis, in cyclotron, particle accelerator or reactors?

edit: hmm. looks like the 4u forum...

 

[ND]

I think cyclotrons (which are a type of particle accelerators) bombard with protons. Reactors bombard with neutrons.

 

[Constip8edSkunk]

u cant accelerate neutrons in a cyclotron

 

[toknblackguy]

impossible to accelerate neutrons in cyclotron...yuo need an ion, ie a charge that can be influenced by a magnetic field
but who cares
this is physics!

 

[inasero]

but how is Tc-99m formed/
i know molybdedum 99 beta decays to it, but is that all we have to know?

by neutron bombardment of a molbdenum isotopt in a particle accelerator such as a synchotron
Mo(42 98) + n(0 1) ---->Mo(42 99)
but this is unstable so subsequent beta decays produce:
Mo (42 99)------> Tc (43 99) + e(-1 0)

Tc (43 99) is the isotope you are looking for....it is used in conjunction with scintigraphic counters to study a whole plethora of diseases, but the most common is blood disorders

 

[toknblackguy]

thanks inasero!

 

[eeyore]

I think it's just general
but they could ask you how a specific radioisotope is produced

 

[Constip8edSkunk]

its been asked before ...though cant remember whether it was a trial paper or past HSC paper, or whether it was chem or phys

 

[inasero]

thanks inasero!

eh no worries thats what im here for