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textbook:nrctextbook:chapter4 [2025-03-13 15:28]
Merja Herzig 		textbook:nrctextbook:chapter4 [2025-08-28 14:18] (current)
Merja Herzig
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 ====== 4. Radionuclides ====== ====== 4. Radionuclides ======
 Chapter 4 from //BASICS OF NUCLEAR PHYSICS AND OF RADIATION DETECTION AND MEASUREMENT – An open-access textbook for nuclear and radiochemistry students// by Jukka Lehto Chapter 4 from //BASICS OF NUCLEAR PHYSICS AND OF RADIATION DETECTION AND MEASUREMENT – An open-access textbook for nuclear and radiochemistry students// by Jukka Lehto
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 +{{anchor:primordial_radionuclides}}
 ===== 4.1. Primordial radionuclides ===== ===== 4.1. Primordial radionuclides =====
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 Primordial (primary) radionuclides, as well as other elements, were formed in the nuclear reactions following the creation of the universe and they have been present in the earth ever since of its birth some 4.5 billion years ago. Due to the high flux of energetic protons and alpha particles, a great number of heavy elements were created in these nuclear reactions. Those elements and nuclides with considerably shorter half-life than the age of the Earth have already decayed away and only those with half-lives comparable with the age of the Earth still exist. These primordial radionuclides can be classified into two cathegories: Primordial (primary) radionuclides, as well as other elements, were formed in the nuclear reactions following the creation of the universe and they have been present in the earth ever since of its birth some 4.5 billion years ago. Due to the high flux of energetic protons and alpha particles, a great number of heavy elements were created in these nuclear reactions. Those elements and nuclides with considerably shorter half-life than the age of the Earth have already decayed away and only those with half-lives comparable with the age of the Earth still exist. These primordial radionuclides can be classified into two cathegories:
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 +{{anchor:long_lived_radionuclides}}
  
   * Parent nuclides of natural [[textbook:nrctextbook:chapter4#decay_chains2|decay chains]], <sup>238</sup>U, <sup>235</sup>U and <sup>232</sup>Th   * Parent nuclides of natural [[textbook:nrctextbook:chapter4#decay_chains2|decay chains]], <sup>238</sup>U, <sup>235</sup>U and <sup>232</sup>Th
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 The three [[textbook:nrctextbook:chapter4#table_41|primordial radionuclides]] <sup>238</sup>U, <sup>235</sup>U and <sup>232</sup>Th are parent nuclides in decay chains, which end up through several [[textbook:nrctextbook:chapter5#alpha|alpha]] and [[textbook:nrctextbook:chapter5#beta|beta]] decays to stable lead isotopes. In between there are a number of radionuclides of twelve elements. The [[textbook:nrctextbook:chapter6#half_life|half-life]] of <sup>238</sup>U is 4.5·10<sup>9</sup> y and it starts a series with 17 radionuclides and the <sup>206</sup>Pb [[textbook:nrctextbook:chapter2#isotope|isotope]] is the terminal product (Figure IV.1.) This decay chain is called uranium series and as the [[textbook:nrctextbook:chapter2#mass_number|mass numbers]] of the product are divided by four the balance is two. The three [[textbook:nrctextbook:chapter4#table_41|primordial radionuclides]] <sup>238</sup>U, <sup>235</sup>U and <sup>232</sup>Th are parent nuclides in decay chains, which end up through several [[textbook:nrctextbook:chapter5#alpha|alpha]] and [[textbook:nrctextbook:chapter5#beta|beta]] decays to stable lead isotopes. In between there are a number of radionuclides of twelve elements. The [[textbook:nrctextbook:chapter6#half_life|half-life]] of <sup>238</sup>U is 4.5·10<sup>9</sup> y and it starts a series with 17 radionuclides and the <sup>206</sup>Pb [[textbook:nrctextbook:chapter2#isotope|isotope]] is the terminal product (Figure IV.1.) This decay chain is called uranium series and as the [[textbook:nrctextbook:chapter2#mass_number|mass numbers]] of the product are divided by four the balance is two.
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 +{{anchor:uranium_chain}}
  
 +{{:textbook:nrctextbook:u_238_decay_series_n3.png?400|}}
  
-{{:textbook:nrctextbook:uranium_decay_chain_fig_4_1.png?400|}} +Figure IV.1. The uranium decay chain, A = 4n+2. 
- +
-Figure IV.1. The uranium decay chain, A = 4n+2 (http://www2.ocean.washington.edu/oc540/lec01-17/).+
  
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 +{{anchor:actinium_chain}}
 +{{:textbook:nrctextbook:u_235_decay_chain_n3.png?400|}}
  
-{{:textbook:nrctextbook:actinium_decay_chain_fig_4_2.png?400|}}+Figure IV.2. The actinium decay chain, A = 4n+3. 
  
-Figure IV.2. The actinium decay chain, A = 4n+3  
-(http://eesc.columbia.edu/courses/ees/lithosphere/labs/lab12/U_decay.gif). 
  
 {{anchor:thorium}} {{anchor:thorium}}
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 +{{anchor:thorium_chain}}
 +{{:textbook:nrctextbook:th_232_decay_chain_n3.png?400|}}
  
-{{:textbook:nrctextbook:thorium_decay_chain_fig_4_3.png?400|}} +Figure IV.3. The thorium decay chain, A = 4n.
- +
-Figure IV.3. The thorium decay chain, A = 4n (http://www2.ocean.washington.edu/oc540/lec01-17/).+
  
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 {{anchor:nuclear_weapon_production}} {{anchor:nuclear_weapon_production}}
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-//**In nuclear weapon production**//, a source of radionuclides is plutonium production, which is done by irradiating <sup>235</sup>U-enriched uranium in a nuclear reactor. In uranium weapon material production no new radionuclides are formed since only <sup>235</sup>U is enriched with respect to <sup>238</sup>U. The radionuclides +In **//nuclear weapon production//**, a source of radionuclides is plutonium production, which is done by irradiating <sup>235</sup>U-enriched uranium in a nuclear reactor. In uranium weapon material production no new radionuclides are formed since only <sup>235</sup>U is enriched with respect to <sup>238</sup>U. The radionuclides 
 formed in plutonium production are essentially the same as in nuclear explosions and in nuclear power reactors. After radiochemical separation of plutonium for weapons material the rest, the high-active waste solution, contains the fission products and other radionuclides than Pu and U. These waste solutions are stored in tanks in the USA and they still wait to be treated before final disposal. In the former Soviet Union, only part of the waste solutions are in tanks while a large fraction was discharged into the environment at the Majak site, first to Techa river and later to Karachai lake. This has resulted in a huge contamination of the area. In nuclear weapons production, there has been two major accidents leading to large environmental contamination. The first occurred in 1957 in Sellafield in the UK where a plutonium production reactor caught fire and released large amounts of radioactivity, especially radioactive iodine. In the same year, a high-active waste tank exploded at the Majak site in Russia and large areas, fortunately mostly inhabited, were contaminated with  formed in plutonium production are essentially the same as in nuclear explosions and in nuclear power reactors. After radiochemical separation of plutonium for weapons material the rest, the high-active waste solution, contains the fission products and other radionuclides than Pu and U. These waste solutions are stored in tanks in the USA and they still wait to be treated before final disposal. In the former Soviet Union, only part of the waste solutions are in tanks while a large fraction was discharged into the environment at the Majak site, first to Techa river and later to Karachai lake. This has resulted in a huge contamination of the area. In nuclear weapons production, there has been two major accidents leading to large environmental contamination. The first occurred in 1957 in Sellafield in the UK where a plutonium production reactor caught fire and released large amounts of radioactivity, especially radioactive iodine. In the same year, a high-active waste tank exploded at the Majak site in Russia and large areas, fortunately mostly inhabited, were contaminated with 
 radionuclides. radionuclides.
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 +{{anchor:nuclear_power_accidents}}
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 There have been, however, three major accidents in nuclear power plants resulting in a large release of radionuclides into the environment. The first one occurred in 1979 in Harrisburg, USA, but only noble gases and other gaseous radionuclides were released from the damaged reactor and no long-term contamination of the surrounding area took place. The second and the largest accident took place in Chernobyl, Ukraine, where a power reactor exploded and caught fire in 1986. This accident caused a severe environmental contamination, not only in Ukraine, Belorussia and Russia,  There have been, however, three major accidents in nuclear power plants resulting in a large release of radionuclides into the environment. The first one occurred in 1979 in Harrisburg, USA, but only noble gases and other gaseous radionuclides were released from the damaged reactor and no long-term contamination of the surrounding area took place. The second and the largest accident took place in Chernobyl, Ukraine, where a power reactor exploded and caught fire in 1986. This accident caused a severe environmental contamination, not only in Ukraine, Belorussia and Russia, 
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-A wide range of radionuclides for research and medical use are being produced in reactors and accelerators. After use, they are mainly either aged or released into the environment. Some of the most important radionuclides used in medical and biosciences and in clinical use are listed in Table IV.III.+A wide range of radionuclides for research and medical use are being produced in [[textbook:nrctextbook:chapter16#radionuclide_production_reactors|reactors]] and [[textbook:nrctextbook:chapter16|accelerators]]. After use, they are mainly either aged or released into the environment. Some of the most important radionuclides used in medical and biosciences and in clinical use are listed in Table IV.III.
  
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textbook/nrctextbook/chapter4.1741876124.txt.gz · Last modified: 2025-03-13 15:28 by Merja Herzig

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