The lecture provides a comprehensive background on the fundamentals of nuclear and radiochemistry. The chart of nuclides are introduce. The structure of the chart and the provided data are discussed. The modes of nuclear transformations are presented. The decay modes are related to nuclear stability and energetics. Radioactive decay rate equations are given. The utility of these equations in nuclear and radiochemistry are discussed. Nuclear reaction are presented, with an emphasis on neutron interactions. Nuclear fission is introduced, primarily through neutron induced reactions. Fission products are discussed, with yields and basic chemistry given. The lecture ends with an overview of the production of 99mTc production.
Readings and Web Links
Lecture 5: Fundamentals of Nuclear and Radiochemistry
- It was stated that 1 kg of 238U contained about 70 (spontaneous) fissions per second. Calculate the spontaneous fission half-life of 238U in years? Does the Chart of the Nuclides give a spontaneous fission half-life for 238U. If so, what is value and how does it compare to the value you calculated.
- It was also stated that the 1 kg of 238U contained about 145 billion alpha disintegrations per second. Calculate the alpha particle decay rate for 238U. How does this compare to the value listed on the Chart of the Nuclides?
- A patient was injected with 15 milliCuries of 99mTc for a heart imaging test. How many milliCuries of 99Tc will there be in the patient if all of the 99mTc decays and remains in the patient.
- It is stated that the radioactive decay process is essentially independent of temperature, pressure, or chemical environment. However, which of the three uranium isotopes listed below would be most susceptible to a change in its half-life if the environmental chemical conditions where changed. 238U, 237U,235mU. Speculate on what might be the reason(s) why there would be a change.
- A certain radioactive nuclide which has no radioactive parent has a half-life of 10.1 days. What is the fraction of the initial amount that will be left in (a) 10.1 days, (b) 30.3 days, and (c) 111.9 days?
- In a uranium ore, there are a certain amount of neutrons present from cosmic ray product, (α,n) reactions on light elements, and spontaneous fission of 238U. Write the equations showing the nuclear reactions/transformations that could lead to the production of 239Pu in the ore.
- Calculate the binding energy per nucleon in MeV/nucleon for 63Cu assuming the atomic mass for 63Cu is 62.929601 atomic mass units (amu or Daltons). The atomic mass for a neutron is 1.008664924 and the atomic mass for 1H is 1.007825032. 1 amu = 931.5 MeV.
- A radioactive sample is shipped from South Carolina to California. The container on the outside is swiped at the receiving site and found to indicate some radioactivity. The shipper insists that the activity is “natural” and is from the uranium-238 radioactive decay series. What question(s) would you ask and what test(s) would you perform to prove or disprove the shippers claim?
- An unknown fissile material is irradiated for a short period of time (assume no decay of the fission products during irradiation) and is analyzed for 99Mo and 111Ag. At precisely 5 days after the end of the irradiation the atom/atom ratio of 99Mo/111Ag is 156.3. Is the fissile material 239Pu or 235U.
- On the chart of the nuclides the fission yield is given for 233U, 235U and 239Pu. Why is 233U included? It is not a naturally occurring nuclide.
Saturday 29 May, 2010