The "Nuclear" in "Nuclear Radiation"

­L­e­t's start at the beginning and understand where the word "nuclear" in "nuclear radiation" comes from. Here is something you should already feel comfortable with. Everything is made of atoms. Atoms bind together into molecules. So a water molecule is made from two hydrogen atoms and one oxygen atom bound together into a single unit. Because we learn about atoms and molecules in elementary school, we understand and feel comfortable with them. In nature, any atom you find will be one of 92 types of atoms, also known as elements. So every substance on Earth, metal, plastics, hair, clothing, leaves, glass is made up of combinations of the 92 atoms that are found in nature. The Periodic Table of Elements you see in chemistry class is a list of the elements found in nature plus a number of man-made elements.

Inside every atom are three subatomic particles: protons, neutrons and electrons. Protons and neutrons bind together to form the nucleus of the atom, while the electrons surround and orbit the nucleus. Protons and electrons have opposite charges and therefore attract one another (electrons are negative and protons are positive, and opposite charges attract), and in most cases the number of electrons and protons are the same for an atom (making the atom neutral in charge). The neutrons are neutral. Their purpose in the nucleus is to bind protons together. Because the protons all have the same charge and would naturally repel one another, the neutrons act as "glue" to hold the protons tightly together in the nucleus.

The number of protons in the nucleus determines the behavior of an atom. For example, if you combine 13 protons with 14 neutrons to create a nucleus and then spin 13 electrons around that nucleus, what you have is an aluminum atom. If you group millions of aluminum atoms together you get a substance that is aluminum -- you can form aluminum cans, aluminum foil and aluminum siding out of it. All aluminum that you find in nature is called aluminum-27. The "27" is the atomic mass number -- the sum of the number of neutrons and protons in the nucleus. If you take an atom of aluminum and put it in a bottle and come back in several million years, it will still be an atom of aluminum. Aluminum-27 is therefore called a stable atom. Up to about 100 years ago, it was thought that all atoms were stable like this.

Many atoms come in different forms. For example, copper has two stable forms: copper-63 (making up about 70 percent of all natural copper) and copper-65 (making up about 30 percent). The two forms are called isotopes. Atoms of both isotopes of copper have 29 protons, but a copper-63 atom has 34 neutrons while a copper-65 atom has 36 neutrons. Both isotopes act and look the same, and both are stable.

The part that was not understood until about 100 years ago is that certain elements have isotopes that are radioactive. In some elements, all of the isotopes are radioactive. Hydrogen is a good example of an element with multiple isotopes, one of which is radioactive. Normal hydrogen, or hydrogen-1, has one proton and no neutrons (because there is only one proton in the nucleus, there is no need for the binding effects of neutrons). There is another isotope, hydrogen-2 (also known as deuterium), that has one proton and one neutron. Deuterium is very rare in nature (making up about 0.015 percent of all hydrogen), and although it acts like hydrogen-1 (for example, you can make water out of it) it turns out it is different enough from hydrogen-1 in that it is toxic in high concentrations. The deuterium isotope of hydrogen is stable. A third isotope, hydrogen-3 (also known as tritium), has one proton and two neutrons. It turns out this isotope is unstable. That is, if you have a container full of tritium and come back in a million years, you will find that it has all turned into helium-3 (two protons, one neutron), which is stable. The process by which it turns into helium is called radioactive decay.

Certain elements are naturally radioactive in all of their isotopes. Uranium is the best example of such an element and is the heaviest naturally occurring radioactive element. There are eight other naturally radioactive elements: polonium, astatine, radon, francium, radium, actinium, thorium and protactinium. All other man-made elements heavier than uranium are radioactive as well.

In this figure, the yellow particles are orbital electrons, the blue particles are neutrons and the red particles are protons.

How Nuclear Medicine Works

In hos­pitals or on TV, you've probably seen patients undergoing radiation therapy for cancer, and doctors ordering PET scans to diagnose patients. These are part of the medical specialty called nuclear medicine. Nuclear medicine uses radioactive substances to image the body and treat disease. It looks at both the physiology functioning and the anatomy of the body in establishing diagnosis and treatment.

In this post, we will explain some of the techniques and terms used in nuclear medicine. You'll learn how radiation helps doctors see deeper inside the human body than they ever could.

Imaging in Nuclear Medicine

One problem with the human body is that it is opaque, and looking inside is generally painful. In the past, exploratory surgery was one common way to look inside the body, but today doctors can use a huge array of non-invasive techniques. Some of these techniques include things like X-rays, MRI scanners, CAT scans, ultrasound and so on. Each of these techniques has advantages and disadvantages that make them useful for different conditions and different parts of the body.

Nuclear medicine imaging techniques give doctors another way to look inside the human body. The techniques combine the use of computers, detectors, and radioactive substances. These techniques include:

• Positron emission tomography (PET)
• Single photon emission computed tomography (SPECT)
• Cardiovascular imaging
• Bone scanning

All of these techniques use different properties of radioactive elements to create an image.

Nuclear medicine imaging is useful for detecting:

• tumors
• aneurysms (weak spots in blood vessel walls)
• irregular or inadequate blood flow to various tissues
• blood cell disorders and inadequate functioning of organs, such as thyroid and pulmonary function deficiencies.

The use of any specific test, or combination of tests, depends upon the patient's symptoms and the disease being diagnosed.

Nuclear medicine red blood cell (bleeding) scan

 Red blood cells of the patient have been marked with a radioactive substance that the camera can see. When the tagged cells are injected into the patient's blood stream, they get carried away. If there is a spot of active bleeding inside the patient, the cells will leak out and collect at the point of leakage. 9 images of a patient's belly were taken, with about 10 minutes time between each image. The increasing vertical black line in the left lower part of the image (arrow), which gets denser over time, represents active bleeding at the beginning of the large bowel. 

SHOULD WE GO NUCLEAR?

Should Malaysia Go For Nuclear

Why should Malaysia opt the the sixth fuel-NUCLEAR??That question has been the focus of heated political debate in Malaysia for the past eight years. Mahathir Mohamad, who served as prime minister from 1981 to 2003, was firmly committed to a non-nuclear Malaysia. But since his departure, his successors have made some moves toward nuclear energy production. In December 2010, for example, Peter Chin, the country's energy minister, announced plans to build two 1,000-megawatt nuclear power plants by 2022. A month later, Prime Minister Najib Razak announced the establishment of the Malaysian Nuclear Power Corporation, which will lead the planning process.

The Fukushima nuclear accident, however, has raised new doubts about whether Malaysia is ready for nuclear power. Malaysian experts disagree over the need for nuclear power plants, and their potential impact on public safety and the environment. There is little doubt that Malaysia must develop new energy sources to meet its future energy demands without relying on costly foreign imports. But these demands can be met with renewable energy instead.

 In any debate over Malaysian energy policies, three important documents are always used as points of reference. The first was Malaysia's 1979 National Energy Policy, the objective of which was to ensure an adequate, secure, and cost-effective supply of energy -- as well as to promote energy efficiency while discouraging wasteful and unproductive patterns of energy consumption. The second key document was the 1981 four-fuel diversification policy, which was formulated to reduce over-dependence on a single fuel source by developing four types of energy: hydropower, oil, natural gas, and coal. Finally, the third reference point was the five-fuel diversification policy introduced in 2000, which included renewable energy (except hydropower) as a fifth energy source.

These three policies have worked well to fulfill the energy demands of the country, and have received widespread support. But now that nuclear power is being considered as Malaysia's sixth fuel, there is no longer general agreement on energy policy. Three main groups have emerged: one that strongly favors the development of nuclear energy, another that supports nuclear energy but is concerned about safety and environmental effects, and a third group that rejects any moves toward nuclear power in Malaysia.

WE NEED NUCLEAR. Proponents of nuclear power point to the current energy situation in Malaysia as evidence that new energy sources must be developed. Government officials believe that Malaysia's current energy sources will not be sustainable beyond 2020, and that the depletion of the nation's fossil-fuel resources is a threat to national security.

Analysts predict that escalating global oil prices will force Malaysia to become a net oil importer in the years to come. Malaysia uses oil mainly in the transportation sector, and relies on natural gas and coal (along with hydropower) to generate electricity. However, government officials have expressed concern that the cost of coal and gas is likely to soar in the coming decades, as supply fails to keep up with demand. Malaysia's coal imports, which held steady for many years, have grown rapidly in the past two years. Natural gas is currently the largest energy source for the country, but national gas fields may be depleted by 2027, which would leave the country unable to meet petrochemical industry demand and commitments for exports of liquefied natural gas.

Because of these gathering storms, there is no doubt that Malaysia urgently needs new sources of energy to assuage its future energy demands, and nuclear energy seems a very attractive alternative -- particularly since the neighboring countries of Vietnam and Thailand have already announced plans to bring their first nuclear plants online by 2020, and Indonesia intends to construct a plant on Java Island by 2015. Nevertheless, for Malaysia, the prudent management of current energy resources -- to ensure that they are sustainable over the long term -- deserves serious consideration as an alternative to nuclear energy.

Nuclear and Conventional Power Plants Difference

 

 

 

Nuclear power plant technology is created by humans, not by some creatures from Mars =P
Most of people think that nuclear power plant is definitely a different thing compare to conventional power plant. They believe that the concept and design of a nuclear power plant is very complex especially on how the power plants generate electricity.

 

Both of the power plant types do have almost similar concept on how they produce electricity. Steam is produced then it will turn the turbine. The energy from the turbine will be converted to electricity by the generator.

Next, the steam is being cooled by the condenser and the whole process will start again. Maybe the diagrams below will help you to imagine about the concepts.

Schematic of a Nuclear Power Plant

These are the similarities:

· Steam Generator: Both generate steam. (Red Circle)
· Turbine: Both plants have turbines. (Yellow Circle)
· Generator: Both plants need generators to produce electricity. (Green Circle)
· Condenser: Both plants need to remove excess heat. (Brown Circle)

The big difference between a conventional power plant and a nuclear power plant is that the nuclear power plant generates heat through the nuclear reactor while the conventional power plant burns fossil fuel (coal/oil/gas) at the boiler in order to get heat to produce steam. (Orange Circle).

From the diagram below, you will understand the difference. It is just the different way of producing heat to generate steam, either from nuclear reactor or fossil-fueled boiler.

 

 

 

 

 

 

Chernobyl life in the dead zone

This video shows the current situation in Chernobyl and its wild life. It has the radioactive level of 400 "hiroshima" incident and it is not a safe place to stay for another few hundred years.Nuclear plant incident can be very dangerous and incurable,but what are the chances for it to happen?Discuss and leave your opinion in the comment section below!

REPROCESSING AND NUCLEAR WASTE

The Composition of Spent Fuel Rods

When questions about safety and cost are put to rest, the question always remains what are you goin to do with the waste. Yet the whle question is premised wrong. More than 97% of the material in spent fuel rod can be successfully recycled. After sitting in a reactor for five years, only 3% of a fuel rod's potential energy has been tapped. It is important to remember the incredible density of nuclear energy. Recycling procedures generally reduce the volume of material by 70% and that includes the disposal container.

96% of a fuel rod is uranium-238, the non-fissionable isotope. Basically it is there for packing material. It serves no purpose except to hold the fissionable isotope, U-235. The natural uranium is only mildly radioactive and poses no danger. It can be handled safely with gloves. For regulatory purposes, however it has been classified as low level waste. This means it can be safely disposed by burning it in the ground.

Enriched uranium is 4 percent U-235, as opposed to 0.7 percent in the natural ore. After five years in a reactor, U-235 is back down to approximately 1%. This 1% can be recycled. Meanwhile about 1% of the U-238 has been transmuted into plutonium, which is also fissionable. But plutonium can be blended with U-235 to form MOX fuel, which can be used as fuel in most reactors. This means both the uranium and plutonium waste can be recycled for energy.

The remaining 3% is fission products and actinides that are produces in the reactor. These are highly radioactive and must be handled remotely. But many are also valuable medical and industrial isotopes. Nuclear medicine is an $8 billion industry. It is a prime technology in treating cancer. The problem in dealing with spent fuel rods of course is their intense radioactivity. However six feet of water or four feet of lead can block all radiation. There has bee no incident anywhere in the world where a person has been injured or killed by exposure to spent fuel.

Nuclear waste is not a flaw in nuclear technology. The real problem is reprocessing is not being done with used nuclear fuel.

Nuclear proliferation

Reprocessing is not done was due to the driven concern that isolating plutonium would lead to the proliferation of nuclear weapons. However reprocessing and proliferation were 2 sides of the same coin. At the same time history has shown that if nuclear weapons are going to proliferate, stealing plutonium from reprocessing operations will not be the likely route. Nuclear technology is no longer a secret and most countries have their own scientists.

 

Why Radiation Fears Are Often Exaggerated??

What is it about nuclear energy that makes people particularly fearful?

There has been a lot of research on this. Nuclear radiation ticks all the boxes for increasing the fear factor. It is invisible, an unknowable quantity. People don't feel in control of it, and they don't understand it. They feel it is imposed upon them and that it is unnatural. It has the dread quality of causing cancer and birth defects.

Nuclear power has been staggeringly safe, but that doesn't stop people being anxious about it, just as airplanes and trains are an amazingly safe way to travel but people still worry far more about plane crashes than car crashes.

People are calling the release of radiation from the Fukushima nuclear power station in Japan a "catastrophe". Is this justified?

This is indeed a really serious event, but it has to be put in the context of the earthquake and tsunami which led to it and which has been the direct cause of massive suffering, which is still continuing. Obviously there are threats from the nuclear power station, but they are limited and they are quantifiable.

It's not a Chernobyl. Though the 1986 explosion at Chernobyl was a terrible event for many people, the lasting effects were nothing like as bad as expected.

Many governments are suspending their nuclear power projects in response to the events in Japan. Is it sensible to make these decisions in the aftermath of a disaster?

This is a tricky one. The Fukushima power station was hit by an unimaginable force. One is always surprised by these events, but one of the things you learn when you study risk is that surprising things happen. We have to expect the unexpected.

Of course, political decisions are made on the basis of how people feel. That's a politician's job perhaps, not just to respond to objective measurements of risk but to what people want. But it's good to try and keep a perspective on what the risks are for all viable alternatives, including the risk of relying on unsavoury regimes for our sources of energy.

Does this mean that fear itself is part of the problem?

One of the biggest risks from radiation is the psychological damage it causes. After events like the 1979 partial meltdown at Three Mile Island, Pennsylvania, and the Chernobyl accident, there was substantial psychological trauma, even among people who were not affected, because there is such a fear of radiation and its long-term consequences.

Would you be happy to live next to a nuclear power station?

I have been trying to think how I would feel if I were in Japan right now. Would I be rushing out of Tokyo or not? I would love to say that I would be a plucky Brit and sit there with my stiff upper lip. But it is very difficult to know how you would react, especially as people respond to the feelings of those around them. But yes, I would be happy to live next to a nuclear power station, if only they weren't such big ugly things.