1:45 PM - 3:15 PM
[O11-P70] Monazite-derived radiation measurement and its application to electric power
Keywords:Monazite, gamma rays, radioactive decay
Monazite-derived radiation measurement and its application to electric power
1.Background and Purpose
In recent years, the energy demand has been increasing. Thermal power generation, with stable supply and efficiency, has long met rising energy demand. On the other hand, thermal power generation has some problems, such as the finite nature of fossil fuels and its environmental impact. Therefore, cleaner energy sources, such as nuclear and renewable energy generation, are being developed. However, nuclear power generation has been discouraged in Japan due to the nuclear accident. Renewable energy is also limited by location because of its source. Therefore, in this study, I considered using nuclear batteries as a model for power generation. By using it for power generation, power can be generated in various locations, including space, without site limitations. However, the plutonium used in nuclear batteries is highly radioactive and affects the human body.Therefore, I decided to eliminate the limitation of the nuclear battery by using a material with low radiation dose instead of plutonium.
2.Experiment
Equipment used
Monazite [fig.1], an inexpensive material, was used as a low radiation dose material in the experiment. A γ-ray detector [fig.2] was used to measure the radiation emitted from the monazite.In a γ-ray detector, radiation excites the scintillator molecules, and the energy released when they return to their original state is recorded.
Experiment Summary
First, the measurements were performed with the monazite and the γ-ray detector fixed. Next, because the former condition contained natural radiation, the monazite was removed and only natural radiation was measured. The monazite energy was then determined from the difference between the two measurements. The monazite needed for 1 W of power was estimated from the energy obtained.
Step 1
The γ-ray detector and monazite were taped together and installed on the 5th floor of Building 63, Nishi-Waseda Campus, Waseda University. Since the detector could also detect natural radiation, measurements were also taken with the monazite removed. Measurements were taken several times.
Step 2
The total energy amount was obtained by excluding measurement noise from the value obtained in step 1. The total energy amount was divided by the measurement time to obtain the amount of γ-ray energy detected by the detector in a day.
Step 3
Since the detector uses [keV] as the energy unit, it was converted to [J]. And since the monazite and the gamma detector were in contact, it is possible that radiation emitted from a direction where there was no detector was not measured. Therefore, the measured energy was doubled to estimate the monazite needed for 1 W of power.
3.Result
[fig.3] and [fig.4] show monazite with natural radiation and natural radiation alone. The energies of each measured data are also shown in [Table 1]. The daily average energy from monazite was 7.603 x 105 keV (1.180 x 10-10 J), doubled to 2.359 x 10-10J to account for all radiation emitted from monazite. Thus, about 3.662 x 1014 monazite units are needed for 1 W of power.
4.Consideration
From the results, I considered that monazite is not suitable for power generation. However, although only γ-rays were measured in this experiment, monazite also emits other types of radiation such as α- and β-rays. Therefore, I thought that more energy could be expected to be obtained from monazite than the energy obtained in this experiment.
5.Conclusion
Generating electricity from monazite's γ-ray energy is unrealistic. Considering the radiation energy from monazite, electricity could be generated with less monazite than used in the experiment.In addition, there are some materials with low radiation dose as well as monazite. Therefore, I thought it is important to measure radiation levels other than monazite and compare the results.
1.Background and Purpose
In recent years, the energy demand has been increasing. Thermal power generation, with stable supply and efficiency, has long met rising energy demand. On the other hand, thermal power generation has some problems, such as the finite nature of fossil fuels and its environmental impact. Therefore, cleaner energy sources, such as nuclear and renewable energy generation, are being developed. However, nuclear power generation has been discouraged in Japan due to the nuclear accident. Renewable energy is also limited by location because of its source. Therefore, in this study, I considered using nuclear batteries as a model for power generation. By using it for power generation, power can be generated in various locations, including space, without site limitations. However, the plutonium used in nuclear batteries is highly radioactive and affects the human body.Therefore, I decided to eliminate the limitation of the nuclear battery by using a material with low radiation dose instead of plutonium.
2.Experiment
Equipment used
Monazite [fig.1], an inexpensive material, was used as a low radiation dose material in the experiment. A γ-ray detector [fig.2] was used to measure the radiation emitted from the monazite.In a γ-ray detector, radiation excites the scintillator molecules, and the energy released when they return to their original state is recorded.
Experiment Summary
First, the measurements were performed with the monazite and the γ-ray detector fixed. Next, because the former condition contained natural radiation, the monazite was removed and only natural radiation was measured. The monazite energy was then determined from the difference between the two measurements. The monazite needed for 1 W of power was estimated from the energy obtained.
Step 1
The γ-ray detector and monazite were taped together and installed on the 5th floor of Building 63, Nishi-Waseda Campus, Waseda University. Since the detector could also detect natural radiation, measurements were also taken with the monazite removed. Measurements were taken several times.
Step 2
The total energy amount was obtained by excluding measurement noise from the value obtained in step 1. The total energy amount was divided by the measurement time to obtain the amount of γ-ray energy detected by the detector in a day.
Step 3
Since the detector uses [keV] as the energy unit, it was converted to [J]. And since the monazite and the gamma detector were in contact, it is possible that radiation emitted from a direction where there was no detector was not measured. Therefore, the measured energy was doubled to estimate the monazite needed for 1 W of power.
3.Result
[fig.3] and [fig.4] show monazite with natural radiation and natural radiation alone. The energies of each measured data are also shown in [Table 1]. The daily average energy from monazite was 7.603 x 105 keV (1.180 x 10-10 J), doubled to 2.359 x 10-10J to account for all radiation emitted from monazite. Thus, about 3.662 x 1014 monazite units are needed for 1 W of power.
4.Consideration
From the results, I considered that monazite is not suitable for power generation. However, although only γ-rays were measured in this experiment, monazite also emits other types of radiation such as α- and β-rays. Therefore, I thought that more energy could be expected to be obtained from monazite than the energy obtained in this experiment.
5.Conclusion
Generating electricity from monazite's γ-ray energy is unrealistic. Considering the radiation energy from monazite, electricity could be generated with less monazite than used in the experiment.In addition, there are some materials with low radiation dose as well as monazite. Therefore, I thought it is important to measure radiation levels other than monazite and compare the results.