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Application of nuclear and subnuclear physics

Application of nuclear and subnuclear physics. Energetic application. 1) Radionuclide sources 2) Classical nuclear reactors 3) Fast (breeder) reactors 4) Accelerator driven transmutors? 5) Thermonuclear reactors?. Medical application

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Application of nuclear and subnuclear physics

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  1. Application of nuclear and subnuclear physics Energetic application 1) Radionuclide sources 2) Classical nuclear reactors 3) Fast (breeder) reactors 4) Accelerator driven transmutors? 5) Thermonuclear reactors? Medical application 1) Diagnostics – using of signed atom method 2) Positron emission tomography 3) Radiation therapy 4) Irradiation using particles or nuclei Nuclear power station Darlington Industrial application and application in other science disciplines 1) Activation analysis 2) Surface studies 3) Implantation atoms 4) Radioactive dating 5) Conservation by irradiation Radiation safety 1) Natural and artificial radiation sources 2) Radioactive waste handling Radiation department of clinic at Heidelberg

  2. Radionuclide sources Principle: Decay of radioactive nuclei  heat is produced (for example isotopes with suitable decay times 90Sr – 28.8 y, 137Cs – 30.1 y, 210Po – 0.38 y and 238Pu – 87.7 y) Thermoelectric cell transforms heat to electricity ( Sebeck phenomena - U T, efficiency 5 – 10%) Pioneer 10 Advantages: Independent on sun light – possibility to use in every place Long and stable function also in hard conditions of vacuum and strong electric and magnetic fields Simplicity  reliability Disadvantage: Possibility of ecology danger during probe accident Casini probe working near Saturn is supplied by radionuclide sources

  3. Radionuclide cells of Nimbus B-1 probe on see ground after accident of booster rocket (1968) Probe accidents (without danger): up to year 1964 – construction ensure of source burning down at atmosphere after year 1964 – construction ensure of source impact in compact form (PuO2 – ceramic material, graphite and iridium cover) Nimbus B-1, SNAP-27 Apollo 13, Mars 8 (1996) Installation of SNAP-27 Used by outer planet probes, landing modules working long time without sun light Launch of Ulysses probe from space shuttle deck

  4. Classical nuclear reactors Fission reactions – nuclear fission spontaneous or after energy obtaining - usually energy of neutron capture is delivered - accompanied by production of neutrons with energy in MeV range ( 2 - 3 neutrons per fission) Fission chain reaction: Fission of 235U and 239Pu nuclides by neutron capture 235U: 85 % - fission 15 % - photon emission Nuclear power station Indian point (USA) Very high values of cross sections of small neutron energies (10-2 eV) Necessity of neutron moderation - moderator Fission – creation of fission productsCapture  photon emission  beta decay – transuranium production Delayed neutrons – emitted by fission products (neutron excess) - mean lifetime 8.8 s Multiplication factor k – number of neutrons of future generation produced per one neutron of present generation k < 1 subcritical system k = 1 critical system k > 1 supercritical system

  5. Nuclear reactor Reactor insideduring fuel exchange Power station Diablo Canyon USA Reactor regulation: Compensation rods - worsening of neutron balance during operation is compensated by their gradual removal Control rods – regulation of immediate changes of output Safety shut-down rods - fast reactor stopping Fuel: 1) natural uranium – consisted of 238U and only 0.72 % of 235U 2) enriched uranium – increasing of 235U content on 3-4% (clas.reactor) mostly in the form of UO2 Important is heat removal (water) Year 2006 (MAAE source): 435 energetic reactors, power 370 GWe→ production of 16 % of electricity total operating experience:> 10 000 reactoryears

  6. Fast (breeder) reactors Nonmoderated neutrons → necessity of high enrichment of uranium 20 - 50 % of 235U (or 239Pu) Production of 239Pu: 238U + n → 239U(β-) + γ → 239Ne (β-)→239Pu More neutrons from 239Pu (3 per one fission) → production of more plutonium than is burned up (breeding zone) High enrichment → high heat production → necessity of powerful cooling → molten natrium (temperature of 550 oC) Lifetime of fast neutron generation is very short → bigger role of delayed neutrons during regulation Fast breeder reactor at Monju (Japan) - 280 MWe Power stations Phenix - 250 MWe and Superphenix 1200 MWe (France)

  7. Accelerator driven nuclear transmutor It consists of: 1) Proton accelerator - energies in the range 100 - 1000 MeV 2) Target - lead, tungsten … 3) Vessel containing system of nuclear waste, moderator Necessity of separation of stable and shortlived isotopes Basic properties: • Usage of spallation reactions • Very high neutron density → effective transmutation • Subcritical behavior • 4) Production of neutrons with very wide energy range Conception scheme of accelerator driven nuclear transmutor

  8. Concrete proposition of nuclear transmutor Proton accelerator: E = 100 MeV - 2 GeV I = 20 - 100 mA Problems: necessity of stable trouble-free operation during very long time. Target: tungsten? liquid lead? uranium and transuranium? Neutron density: ~1020 m-2s-1 (reactor ~1017 - 1018 m-2s-1) Problems: removal of great amount of heat Subcritical blanket: Problems: necessity of continuous separation, efficient transport and neutron moderation Scheme of concrete accelerator driven transmutation system: Energy production as at classical nuclear power station, its part supplies accelerator

  9. Thermonuclear reactors? Fusion of light nuclei  energy production Practical use: 2H + 3H 4He + n + 17.58 MeV High temperature (107 - 109 K)nuclear reactions thermonuclear reactions Lawson criterion – necessary condition for production of more thermonuclear energy than it is consumed for fuel heating: For DT reaction: τρ ≥ 3∙1020 s∙m-3 Temperature 108 - 109 K τ – time of hot plasma maintenance,ρ – density of plasma nuclei Experimental "thermonuclear reactors" of Tokamak type: Ring chamber - ring magnetic field (chamber height 2 - 4 m, B = 2 - 5 T, currents 2∙106 A): Important - high vacuum and strong magnetic field  plasma maintenance TFTR (Tokamak Fusion Test Reactor), Princeton (USA): TFTR at Princeton worked between years 1987 -97, maximal power was 10 MW, general view and insideview on ring

  10. JET (Joint European Torus), Culham near Oxford, Great Britain Up to 16 MW in pulls and 4 MW during 5 s, 65% usage of delivered energy Experimental device JET at Culhamu (height 12 m, diameter 15 m) JT-60 (JAERI Tokamak 60), Naka, Japan ITER - international thermonuclear experimental reactor: Neutron and gamma ray shielding, created helium offtake Lithium envelope – tritium production: 6Li(n,)3H 7Li(n,n)3H Precursor of JT-60 device was JTF-2M device Goal: Building of future thermonuclear reactor prototype

  11. Diagnostics – usage of labeled atom method Stable isotopes in compounds should be changed by radioactive ones: ( 197Au 198Au, 12C 11C, 127I 123I) Advantage is very short lifetime → radioactivity quickly vanishes 1) Investigation of function and states of different organs and tissues 2) Localization of malignancies Radiopharmaceutics – labeled compounds at medicine – wide assortment of compounds for different organs investigation is very important Preparation of radiopharmaceutics, lead glass protection (company Radiopharmacy, Inc. – Indiana, USA) Record of radioactivity distribution in investigated organs - scintigrams 32P, 57Co, 58Co, 51Cr, 18F, 67Ga, 75Se, 89Sr, 99mTc, 111In, 133Xe, 153Sm, 197Hg, 201Th, 203Hg Examples of other used radionuclides: Detection of radiation by system of gamma detectors (NaI(Tl) is mainly used) ↔ organ scintigrams Metabolism of different elements and compounds is studied Labeled compounds are used in many further fields: ecology, hydrology, chemistry, biology, and industry

  12. Positron emission tomography Radioactive isotopes with positron decay → positron annihilation in rest → creation of two photons (gamma ray quanta) flying in opposite directions → their detection and annihilation position determination Used radioisotopes:11C, 13N, 15O, 18F Insertion of radioactive isotope to compound subsides at studied organ (accurate diagnostics and medical research): 1) Determination of position and sizes of cancer tumor 2) Efficiency of irradiation using heavy ions (10C, 11C) 3) Identification well and bad perfused parts 4) Identification of intensively working brain parts Heart damaged by heart attack Healthy heart Very good spatial resolution ( 2 mm ), still new chemical compounds for PET chambers (systems of Positron Emission Tomography) Typical PET chamber and commercial cyclotron IBA cyklone 10/3

  13. Radiation therapy Cancer cells are more sensitive to radiation → radiation is used for destruction of cancer cells and elimination of tumors External radiation therapy: Irradiation by external radiation source – mostly X or gamma rays - cobalt or cesium emitters use 60Co and 137Cs Internal radiation therapy: 1) Small capsule with emitter (for example iridium thin wires for treatment of skin cancer) is transported to proximity of tumor inside body 2) Radioactive compound is injected inside body and it is concentrated in organ affected by tumor Cobalt emitter of Faculty Hospital at Ostrava Boron neutron capture therapy Compound containing 10B is injected to body → it is cumulated in cancer cells, healthy cells do not drop boron inside → irradiation by thermal and epithermal neutrons from reactor → energy from reaction 10B(n,α)7Li destroys cancer cells

  14. Heavy ion irradiation Usage of ionization energy losses dependency on charged particle velocity. Larger charge (heavier ion) → larger part of energy is deposited on the end of trajectory Possibility to place destructive energy to tumor without damages of neighboring tissue Heavy ion accelerator Test system uses accelerator SIS at GSI Darmstadt (100 MeV - 1 GeV) Part of heavy ion accelerator SIS at GSI Darmstadt

  15. Possibility of accurate setting of position (given by beam direction) and depth (ion energy) Three-dimensional irradiation: 1) Models in water 2) Plan of irradiation and result is controlled by positron emission tomography (PET) (radioactive ions are accelerated – positron emitter) Suitable for brain tumor or spine tumor (incoparable smaller damage of neighboring tissue than for surgical operation).

  16. Higher sensitivity of cancer cells against radiation damage Some dozens of patients were successfullyirradiated at GSI from 1997 year Radiation table at GSI Darmstadt (perfect fixation of patient is important) Model of specially projected device for hospital at Heidelberg

  17. Activation analysis X-ray-fluorescence activation analysis – irradiation by X-ray or gamma ray source → photoeffect → characteristic X-rays Neutron activation analysis – sample is irradiated by known neutron flux with known energy spectrum mostly from reactor. Radionuclides are created during irradiation → characteristic gamma lines → their intensities are given by amount of original isotope Advantages: 1) Very small sample is necessary 2) Very small element contents should be determined (10-12 g of element in 1g of sample) 3) Sample is not damaged – very advantageous for archeology Wide use in ecology, biology, archeology, historiography, geology, astrophysics … Particle flux can be determined using known material of used foils by activation analysis (determination of neutron flux in reactor or accelerator proton flux) Semiconductor HPGe detectors are mainly used for gamma ray measurements (example of detector at JINR Dubna and obtained spectra)

  18. Surface studies Studies of composition and structure of surface layers A) Using of neutrons (mainly from reactor): Neutron scattering - neutron diffraction (diffraction and interferometry): Difractometer SPN-100 NPI ASCR Neutron interferometer B) Using of accelerated light ion – nuclear analytical methods: • Rutheford backscattering (RBS): • X-ray emission induced by particles (PIXE) • Gamma ray emission induced by particles (PIGE) Radiation defectoscopy: Mostly using gamma rays but also neutrons or charged particles(many imaging methods) Example of RBS method use for study of surface with lubricated layer of aluminum oxide (NPI of ASCR)

  19. Ion implantation Use of ions accelerated on energies within the keV – MeV range implanted to materials Modification of surface properties of different materials (metals, semiconductors) Use mainly but not only at electronic industry – production of microchips and others semiconductor components Industry: surface modification – harder materials resisting against corrosion. Crystal modification – change of atoms Enrichment of surface by impurity in the amount of only single atoms Nuclear filters– ionizing traces after passage of ionizing particle through material → chemical etching → very small holes → very fine filters Implantator TECVAC 221

  20. Radioactive dating Use of different radioactive nucleus decay time. We study ratio between stable and radioactive isotopes, mother and daughter nuclei. Archeology: radioactive carbon 14C (T1/2 = 5730 years) produced by cosmic ray interaction at atmosphere, organism absorbed it by breathing – death → isotope 14C is decaying. The ratio 14C/13C/12C determines age of remnants. Problem – background, small activities, change of production of 14C and 12C (burning of fossil carbon and nuclear tests) Range: 20 000 – 25 000 years ! only for organic materials ! Wider range thanks accelerator mass spectroscopy ~50000 years Mass spectrometer for 14C dating on University at Aarhus (Sweden) Geology and cosmogony: Accelerator mass spectrometer Measurement of exposing time of meteorites: Isotope 39Ar 26Al 10Be 53Mn T1/2 [year] 269 7,4·105 1,51·106 3,74·106 Morávka meteorit Potassium-argon method 40K (T1/2 = 1.28 billion years). After freezing, created 40Ar can not escape → age can be determined. Dating of rocks, minerals and objects created from melted material. Cosmology: Very long-life isotopes, ratio between radioactive and stable – creation time of elements in different space regions – use of spectroscopy

  21. Conservation by irradiation Conservation of historical artifacts: Use of biological effects of ionizing radiation on insect and microorganisms. Mostly gamma rays are used, mainly 60Co source Genesis – emitter for food conservation Gray Star Company, uses 60Co radioactive source Radiation preservative workplace at Central Bohemia museum at Roztoky Food conservation: Elimination of danger pathogens – more healthy and durable food store Sterilization of medical material: Surgical and other medical material, implantats (joint substitutes …). Changes of some polymer features are used Advantages: 1) High efficiency 2) It does not damage and change features of conserved material 3) It can change features of some polymers positively 4) It does not leave harmful or toxic remains

  22. Natural and artificial radiation sources Quantities describing ionizing radiation and its biological effect: ActivityA [Bq = s-1] – number of decaysRate [Bq = s-1] – number of detected particles Imparted energy: Dose D [Gy = Jkg-1] - total energy imparted to tissue or organ Dose rate [Gy s-1] Radiation biological effect depends on type of tissue and radiation: Dose equivalentH = QD [Sv], Q - quality factor - relative biological effect of given radiation on tissue Equivalent dose HT = wRDT[Sv]DT – dose absorbed by tissue Radiation weighting factor wRquality factor estimating biological risk of radiation Every organ or tissue are differently sensitive: Effective dose –sum of equivalent doses weighted with the respect to radiation sensitivity of organs and tissues of whole human body Biological effects of ionizing radiation: Non-stochastic – are threshold, dose is sufficient to create observable damage during relatively short time Stochastic effects - dose does not create observable damage during short time but it is some probability of its later appearance

  23. Radiation sources to which population is exposed: Ĥ -annual average equivalent dose External irradiation – external radioactivity sources Internal irradiation – radionuclides inside body Radiotoxicity – degree of radionuclide harmful effects: Five classes of radionuclide recklessness – the most danger is first: (60Co, 134Cs, 137Cs, 210Pb, 226Ra, 239Pu, 241Am) Basic limits: ordinary man 1 mSv/year worker with radiation 50 mSv/year

  24. Nuclear waste – spent fuel Composition: 96 % uranium (~1% 235U) 1 % transuranium 3 % fission products (stable, short-live, long-live) Some long-life radioactive fission products: 99Tc (2.1105 years), 129I (1.57107 years), 135Cs (2.3106 years) Long-life transurans: 237Np (2.3106 years), 239Pu (2.3106 years), 240Pu (6.6103 years), 244Pu (7.6107 years), 243Am (7.95103 years) Tests of spent fuel (Monju) Reactor inside and fuel exchange in one from USA reactor Year production of nuclear waste at France (75% energy): High activity (1000 Mbq/g) : 100 m3Mean activity (1 Mbq/g) : 10000 m3 Temporary reposition – heat removal is very important during starting stage (water tank) Reprocessing of spent fuel Processing and imposition of nuclear waste

  25. Cementation - mixing with cement mixture • Bitumenation - mixing with molten asphalt bitumen • c) Vitrification - mixing with molten glass Modification and processing of nuclear waste: Pictures mainly from Sweden program of radioactive waste handling Manipulation with high activity waste Vitrification Different types of radioactive waste transport

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