Nuclear Reactor


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Radionuclide production methods--> Nuclear Reactor

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Nuclear Reactor

  1. 1. Radionuclide production methods <ul><li>Cyclotron </li></ul><ul><li>Nuclear reactor </li></ul><ul><li>Radionuclide generator </li></ul>
  2. 2. Nuclear Reactor Pawitra Masa-at 4937092 SIRS/M February 14, 2007
  3. 3. Types of Reactors <ul><li>Power reactor </li></ul><ul><ul><li>Produce commercial electricity. </li></ul></ul><ul><li>Heat production reactor </li></ul><ul><ul><li>Supply heat in some cold countries. </li></ul></ul><ul><li>Research reactor </li></ul><ul><ul><li>Operated to produce high neutron fluxes for experiments. </li></ul></ul><ul><ul><li>Some reactor are designed to produce radioisotope. </li></ul></ul><ul><ul><li>Smaller & simpler than power reactor. </li></ul></ul><ul><ul><li>Operate at lower temperature. </li></ul></ul><ul><ul><li>Less fuel  less fission production build up. </li></ul></ul><ul><ul><li>Components like power reactor. </li></ul></ul>
  4. 5. Isotope Production Reactor <ul><li>Reaction Types </li></ul><ul><ul><li>Fission of U-236 </li></ul></ul><ul><ul><li>Neutron activation </li></ul></ul>
  5. 6. Isotope Production Reactor Heat produced in reactor core is removed by cooling fluids and carried to steam generator (in power reactor) Cd or B, which absorb neutrons. They help to regulate the flux of neutrons. Inserted to slow down the neutrons to make them more easily captured. Samples are stable isotope for radionuclide production from neutron capture reaction. U-235 also can be the target of (n,f) reaction for radionuclide production. *water or D2O can be coolant and moderator at the same time.
  6. 7. Nuclear fission <ul><li>Heavy nuclides (A>230) capture a neutron ; tend to fission. </li></ul><ul><li>Daughter nuclides of ~half the parent mass are produced. </li></ul><ul><li>Possible to purify nuclides carrier free (chemically different) </li></ul><ul><li>Nuclides generally neutron rich and decay by emission. </li></ul>
  7. 8. Neutron interact with target in reactor n n n n n n n n n n n n Fast neutron Thermal neutron sample
  8. 9. Fission of U-236
  9. 10. Fission of U-236
  10. 11. Fission product of U-236 Example
  11. 12. Research reactor for radionuclide production
  12. 13. Fission reaction in fuel core 90 Br 143 Xe
  13. 14. Nuclear Fission Reactor production of 99 Mo <ul><li>Fission products are generated from rods of 235 U inserted into reactor core. </li></ul><ul><li>Chemical seperation of 99 Mo, 131 I, 133 Xe is readily possible from rod material. </li></ul>
  14. 15. Production via Neutron Activation <ul><li>Neutron produced by the fission of Uranium in a nuclear reactor can be used to create radionuclides by bombarding stable target material placed in the reactor. </li></ul><ul><li>Process involves capture of neutrons by stable nuclei. </li></ul><ul><li>Almost all radionuclides produced by neutron activation decay by beta-minus particle emission. </li></ul>
  15. 16. Type of reaction from Neutron activation methods <ul><li>Neutron capture </li></ul><ul><li>Neutron capture with particles ejection </li></ul>For En~ 100 keV Fast neutron For En~ 0.025 eV Thermal neutron.
  16. 17. For production, which is most common, the element does not change, so it is difficult to get carrier-free product. Ex Ex Thermal neutron capture
  17. 18. Fast neutron capture Ex For (n,p) reaction the number of proton (Z) change, the so the radionuclide is carrier-free product.
  18. 19. Some radionuclide used in Nuclear medicine
  19. 20. Calculate Activity of Radionuclide Production t = infinity  saturation factor = 1 So …………………………………………………………………………………………………… . activity Half-life
  20. 21. What’s happening in the surface target ? <ul><li>Cross-section </li></ul><ul><li>Description of the rates at which neutrons interact with the nuclei. </li></ul><ul><li>Microscopic cross-section </li></ul><ul><ul><li>A monoenergetic parallel neutron beam incident normally on a thin target . </li></ul></ul><ul><li>Macroscopic cross-section </li></ul><ul><ul><li>A monoenergetic parallel neutron beam incident normally on a thick target. </li></ul></ul>
  21. 22. Microscopic cross-section <ul><li>Imagine that a monoenergetic neutron beam speed (v) impact on a (very thin) slice of surface area (A) and the thickness (dx) of material </li></ul><ul><li>We shall assume that the target is so thin all nuclei are “visible” to the incident neutrons no nucleus is hidden behind another nucleus </li></ul>
  22. 23. Macroscopic cross-section <ul><li>We have seen that quantitative descriptions of neutron-nuclear interactions involve microscopic cross sections. </li></ul><ul><li>We shall soon find that microscopic cross sections are almost always multiplied by the number density (nuclei/cm3) of the target nuclei. </li></ul><ul><li>It is therefore convenient to define “macroscopic” cross-section. </li></ul><ul><li>For each different type, x = (a,s,f…….)of interaction </li></ul>Note Macroscopic cross-section have unit of inverse length (nuclei/cm 3 )*(cm 2 /nucles)=cm -1
  23. 24. Target cross-section
  24. 25. Concept of neutron flux <ul><li>Imagine all neutron in unit volume. </li></ul><ul><li>The flux is the product of the density (n) of the neutron population and the speed (v) </li></ul>
  25. 26. Neutron Flux density in Reactor graphite *For Neutron source (isotope type) Fuel rod control rod sample
  26. 27. Calculate Activity of Radionuclide Production For a mass (w) of the element The total number of target nuclei , for isotopic abundance.
  27. 28. Reactor Radioisotopes used in medicine <ul><li>Technetium-99m ( 6 h ): Used in to image the skeleton and heart muscle in particular, but also for brain, thyroid, lungs ( perfusion and ventilation ) , liver, spleen, kidney ( structure and filtration rate ) , gall bladder, bone marrow, salivary and lacrimal glands, heart blood pool, infection and numerous specialised medical studies . </li></ul><ul><li>Iodine-131 ( 8 d ): Widely used in treating thyroid cancer and in imaging the thyroid; also in diagnosis of abnormal liver function, renal ( kidney ) blood flow and urinary tract obstruction . A strong gamma emitter, but used for beta therapy . </li></ul><ul><li>Phosphorus-32 ( 14 d ): Used in the treatment of polycythemia vera ( excess red blood cells ). Beta emitter . </li></ul><ul><li>Samarium-153 ( 47 h ): Sm-153 is very effective in relieving the pain of secondary cancers lodged in the bone, sold as Quadramet . Also very effective for prostate and breast cancer . Beta emitter . </li></ul>
  28. 29. Reactor Radioisotopes used in medicine <ul><li>Molybdenum-99 ( 66 h ): Used as the 'parent' in a generator to produce technetium-99m . </li></ul><ul><li>Cobalt-60 ( 10.5 mth ): Formerly used for external beam radiotherapy . </li></ul><ul><li>Iodine-125 ( 60 d ): Used in cancer brachytherapy ( prostate and brain ) , also diagnostically to evaluate the filtration rate of kidneys and to diagnose deep vein thrombosis in the leg . It is also widely used in radioimmuno - assays to show the presence of hormones in tiny quantities . </li></ul><ul><li>Bismuth-213 ( 46 min ): Used for TAT . </li></ul><ul><li>Chromium-51 ( 28 d ): Used to label red blood cells and quantify gastro - intestinal protein loss . </li></ul>
  29. 30. Reactor Radioisotopes used in medicine <ul><li>Copper-64 ( 13 h ): Used to study genetic diseases affecting copper metabolism, such as Wilson's and Menke's diseases . </li></ul><ul><li>Dysprosium-165 ( 2 h ): Used as an aggregated hydroxide for synovectomy treatment of arthritis . </li></ul><ul><li>Erbium-169 ( 9.4 d ): Use for relieving arthritis pain in synovial joints . </li></ul><ul><li>Holmium-166 ( 26 h ): Being developed for diagnosis and treatment of liver tumours . </li></ul><ul><li>Iridium-192 ( 74 d ): Supplied in wire form for use as an internal radiotherapy source for cancer treatment ( used then removed ). </li></ul><ul><li>Iron-59 ( 46 d ): Used in studies of iron metabolism in the spleen . </li></ul>
  30. 31. Reactor Radioisotopes used in medicine <ul><li>Lutetium-177 ( 6.7 d ): Lu-177 is increasingly important as it emits just enough gamma for imaging while the beta radiation does the therapy on small ( eg endocrine ) tumours . Its half - life is long enough to allow sophisticated preparation for use . </li></ul><ul><li>Palladium-103 ( 17 d ): Used to make brachytherapy permanent implant seeds for early stage prostate cancer . </li></ul><ul><li>Potassium-42 ( 12 h ): Used for the determination of exchangeable potassium in coronary blood flow . </li></ul><ul><li>Rhenium-186 ( 3.8 d ): Used for pain relief in bone cancer . Beta emitter with weak gamma for imaging . </li></ul><ul><li>Rhenium-188 ( 17 h ): Used to beta irradiate coronary arteries from an angioplasty balloon . </li></ul>
  31. 32. Reactor Radioisotopes used in medicine <ul><li>Selenium-75 ( 120 d ): Used in the form of seleno - methionine to study the production of digestive enzymes . </li></ul><ul><li>Sodium-24 ( 15 h ): For studies of electrolytes within the body . </li></ul><ul><li>Strontium-89 ( 50 d ): Very effective in reducing the pain of prostate and bone cancer . Beta emitter . </li></ul><ul><li>Xenon-133 ( 5 d ): Used for pulmonary ( lung ) ventilation studies . </li></ul><ul><li>Ytterbium-169 ( 32 d ): Used for cerebrospinal fluid studies in the brain . </li></ul><ul><li>Ytterbium-177 ( 1.9 h ): Progenitor of Lu-177 . </li></ul><ul><li>Yttrium-90 ( 64 h ): Used for cancer brachytherapy and as silicate colloid for the relieving the pain of arthritis in larger synovial joints . Pure beta emitter . </li></ul><ul><li>Radioisotopes of caesium, gold and ruthenium are also used in brachytherapy . </li></ul>
  32. 33. Conclusion -Product atom has same charge -Low specific activity -Short half-life -expensive Disadvantage -Less expensive -Product atom has different charge -High specific activity Advantage -Target bombarded with neutron. -Target bombarded with charged particles (proton, deuteron). Definition of the method Nuclear reactor Accelerators
  33. 34. Thank You  นางสาวปวิตรา หมะสะอะ 4937092 SIRS/M