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METHODS USED TO PRODUCE Mo-99 - Coggle Diagram
METHODS USED TO PRODUCE Mo-99
Neutron capture of molybdenum-98 (Mo-98)
ACCELERATOR BASED PRODUCTION
Acceleration of electron beams
i. Requires a high energy electron accelerator
ii. The electrons are accelerated in the LINAC machine
iii. High energy photons are produced when electrons bombard the target
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participation of high flux
bremsstrahlung photons in (γ,n) reaction in heavy water
Proper neutron flux with 2.2 MeV is produced
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Production of Mo-99 neutron capture reaction Mo-98(n,γ)Mo-99
The neutron flux produced bombards the Mo-98 target and produce Mo-99
Fission of uranium-235 (U-235)
Fabrication of uranium targets
i.Target designed to be irradiated in a reactor
ii. Properly sized to fit into the irradiation position
iii.Contain a sufficient amount of U-235 to produce the required amount of Mo-99 when irradiated
iv. Good heat transfer properties to prevent overheating
v. Compositions include uranium metal, uranium oxides, and alloys of uranium
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Irradiation of targets in a nuclear reactor
i. Irradiation of U-235 with thermal neutrons
ii. SomeU-235 nuclei absorb these neutrons, which can cause them to fission.
iii. Nuclear reactors provide an efficient source of thermal neutrons for Mo-99 production
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Dissolution of the uranium target and recovery and purification of Mo-99
iv. Targets are removed from the reactor and cooled in water typically for half a day before being processed
v. The targets are placed into hot cells for chemical processing.
vi. Processing is carried out quickly to recover the Mo-99
to minimize further losses from radioactive decay.
vii. The apparatus in the hot cell used to process the targets and recover the Mo-99 consists of a container for dissolving the targets
connected to tubing and columns for subsequent chemical separations to isolate Mo-99.
REACTOR BASED REACTION
COMPARISON BETWEEN TWO METHODS
Neutron capture of Mo-98
Specific activity
Produce low specific activity of Mo-99
Target required
Requires enriched Mo-98 target
chemical processing
Facility requirement
Amount of waste
minimal waste
High-level radioactive waste
Requires high flux neutron source
Requires dedicated processing facility
Simple chemical process
Complex chemical processing
requires enriched U-235 target
Produce high specific activity of Mo-99
Fission of U-235
