Questions and Answers on Application of Nuclear Technology

I try to keep questions submitted by groups as the are. Unclear or trivial questions are not replied. Reply has not been proof read.

Q
Be Informed
In spite of decades of development of practical and useful applications of nuclear technology, entire countries are still rejecting these opportunities based largely on the opinion, and fears, of an uninformed public (to which you alluded at the end of lecture 12f). It is not only nuclear technology that suffers this dilemma but other sciences as well, for example, genetics. If it is necessary to take a course like SCI270 to become informed enough to at least enter a debate of the topic. And assuming that the general public as a whole will not be able to learn about the theory and application of Nuclear Science. What must those who understand the technology do if there is to be hope of any country or political system ever being able to make a reasonable choice by relying on public opinion as seems to be the case here and in europe?
A
Glad to hear such an opinion. Often, good scientist are not very vocal and they are overwhelmed by the loud voice of troble makers. I guess we all owe ourselves to dig deeper and know when not to listen. If enough people know how to find truth and solid information, the society will be a nice place to live.

Q
Irradiated food
Would the irradiation of food cause mutation in the food? Is it harmful to eat these food?

What was the controversy behind the use of irradiation for food processing. How is it done, what foods total are being irradiated before consumption? Any dangers of these processes?
A
Mutation refers to the next generation. Irradiated food will not have the next generation, and mutation is not a concern. The process has to go through some form of safety test, and we should dig deeper to see what is involved. It's dangerous to say it one way or another, because not all food are the same. A cautions approach as an individual and as a society is required, but let us do it in a scientific way.

There are irradiated food in the market in Canada, but the percentage is hard to estimate.

Q
4-D images
What is transaxial image? How can computers give 4-D images of wholes?
A
Images through the longest axis of the object are transaxial images. Using computer, we store the 3-D images on computer. By imposing changes, these images can be played back in real time, and thus they are 4-D images.

Q
Radionuclide dating
In this module, there was mention of radionuclide dating using Carbon-14. Isn't there a limit on how far back Carbon-14 dating is useful? What is this limit?

Besides carbon 14, what other radioactive elements naturally occur in our bodies and can they also be used for radioactive dating?
A
The limit is imposed by accuracy of the radioactivity measurements. As the technique improve, the limit extends. Radionuclide dating results for some millions of years have been reported.

Carbon 14 is unique in that it is constantly produced by cosmic rays. Thus, it is used to date the years since the sample becomes inactive. There are other radionuclides such in bodies of animals. For example, potassium has a radioactive isotope, but it cannot be used for dating once-living bodies, because there is no reference point.

Q
Side effect of radiation treatment
Is there any possibility that radioactive cancer treatment introduces new cancer cells because of the treatment dose?
A
Yes, there is a chance for such a side effect. But radioactivity induced cancers usually develop after some years, and extending the life for a few years is a worthwhile risk.

Q
Radiosensitizers and radioprotectors
How does a combination of radiosensitizers and radioprotectors work, in chemo-radiotherapy, so that it only kills the right cells (ex. cancer cells) while not harming other cells?
A
Radiosensitizer is a compound that contains a radioactive nuclide. This compound accumulates in certain type of cells such as cancer cells. Thus, these cells receive a high dose of radiation and die.

Radioprotector is a substance that protects the normal cells from the effects of radiation. This enables a larger dose of radiation to be given. This is an investigational procedure.
Radiation generates many free radicals in the cell. Some radioprotectors are free-radical scavengers. They get rid of the free radicals, and thus reducing the radiation effect. Other chemical principles are also applied to use chemicals as radioprotectors, which is a general name.

Q
Transparency of E-M waves
X-ray consists of high-energy photons. How do these photons pass through human flesh?
A
X-rays may also be considered waves. If the energy is not absorbed, the waves simply pass through, same way as visible light passing through glass.

Q
Promising nuclear technology
What would you consider to be the most promising nuclear technology for the future?
A
Well, I hope I have the ability to predict. I guess nuclear medicine and energy production are some of the fields that will continue to develop.

Q
There did not seem to be anywhere along the course to ask this question, so, although it does not strictly pertain to this section, it does in a general sense. It seems the greatest drawback to current nuclear fission is the disposal of waste fuel. While some fuels can be reprocessed and re-used, a large percentage of the nuclear waste is buried in secure facilities, practically speaking - forever.

In the same why we have discussed the creation of transuraniums and other materials, could we not use high energy neutron radiation to bombard the radioactive nuclei effectively rendering them inert by stabilizing the nucleus? The only drawback I can envision is the energy requirements to generate the high energy neutrons to bombard the target material.
A
This question could have been asked when we talked about nuclear fission and fission reactors.

The problem is that neutron bombardment will not render the radioactive nuclides inactive. In fact, neutron bombardment usually produce radioactive material. So, neutron bombardment makes the material more difficult to handle.