NUCLEAR BOMB OR NUCLEAR ENERGY? RADIATION HAZARDS
International Anti-nuclear day by Dr Srikant Sharma, Dr Nabeela khan
Q1. When was the first nuclear weapon used?
A. On 6th August 1945, an atomic bomb was dropped on Hiroshima by US air forces. This was the first time a nuclear weapon had ever been used; the fireball created by the bomb destroyed 13 square kilometres of the city, and those dead as a result numbered up to 180,000.
Three days later, a second atomic bomb was dropped on the city of Nagasaki, killing between 50,000 and 100,000 people.
Q2. What is the effect of a nuclear weapon?
A. These two events still resonate to this day and serve as the greatest warning of the devastating effects of nuclear weapons.
As well as the high death toll, those that survived the initial detonation and firestorms quickly became ill with radiation poisoning with symptoms ranging from severe burns, hair loss, nausea and bleeding. This was compounded by the fact that 90% of medical staff in both cities were either killed or disabled and what medical supplies existed quickly ran out. Long after the bombings, survivors were still suffering from increased susceptibility to leukaemia, cataracts and malignant tumours with many also being diagnosed with post-traumatic stress disorder later in life. This suffering goes beyond the survivors. Future generations either born to survivors or born to those living in Hiroshima for years to come had increased chances of small brain sizes, delayed development, blindness and increased susceptibility to leukaemia and other cancers. The bombings of both Hiroshima and Nagasaki represent a human tragedy which should never be repeated.
Q3. Are we still paying the price of the nuclear bomb on Hiroshima and Nagasaki as diseases?
A. Most people, including many scientists, are under the impression that the survivors faced debilitating health effects and very high rates of cancer, and that their children had high rates of genetic disease,” says Bertrand Jordan, an author and a molecular biologist in France.
Dr. Jordan’s article contains no new data, but summarizes over 60 years of medical research on the Hiroshima/Nagasaki survivors and their children and discusses reasons for the persistent misconceptions. The studies have demonstrated that radiation exposure increases cancer risk, but also show that the average lifespan of survivors was reduced by only a few months compared to those not exposed to radiation.
Q4. What if you are indoors when a nuclear explosion happens nearby?
A. Plan on staying in your shelter for a minimum of 48 hours (2 days). Under no circumstances leave the shelter in the first forty-eight hours
Q5. What is Nuclear Energy?
A. The energy within the nucleus or core of an atom. Energy holds the dense nucleus together which contains the huge amount of power.
This nuclear energy can be used to create electricity but it must be first released from the atom.
Q6. What are the types of nuclear energy?
A. There are two types : –
- Nuclear fission occurs when a neutron slams into a larger atom, forcing it to excite and split into two smaller atoms—also known as fission products. Additional neutrons are also released that can initiate a chain reaction. When each atom splits, a tremendous amount of energy is released. Uranium and plutonium are most commonly used for fission reactions in nuclear power reactors because they are easy to initiate and control.
- Nuclear fusion occurs when two atoms slam together to form a heavier atom, like when two hydrogen atoms fuse to form one helium atom. This is the same process that powers the sun and creates huge amounts of energy—several times greater than fission. It also doesn’t produce highly radioactive fission products.
Q7. What noble gases released from operations of a nuclear power plant?
A. This is a grave deficit in the study of radiation biology because these gases are so ubiquitous around nuclear reactors and are released with irresponsible impunity. Several of the more dangerous isotopes to which noble gases decay (all of which have different metabolic pathways in the body) include the following:
- Xenon 137, with a half-life of 3.9 minutes, converts almost immediately to the notoriously dangerous caesium 137 with a half-life of thirty years. Xenon 135 decays to caesium 135 with an incredibly long half-life of 3 million years.
- Krypton 90, half-life of 33 seconds, decays to rubidium 90, half-life of 2.9 minutes, then to the medically toxic strontium 90, half-life of twenty-eight years.
- Krypton 85, which has a half-life of 10.4 years, is a powerful gamma emitter.
- Argon 39 has a 265-year half-life
Other dangerous noble gases include xenon 141, 143, and 144, which decay to cerium 141, 143, and 144. According to the National Council on Radiation Protection (NCRP Report No. 60) these three cerium isotopes, which are beta emitters, are abundant products of nuclear fission reactions and have moderately long halflives. They bio-concentrate in the food chain, and they irradiate the lung, liver, skeleton, and gastrointestinal tract, where they act as potent carcinogens
Q8. What are the types of contamination due to nuclear energy?
Internal contamination occurs when people swallow or breathe in radioactive materials, or when radioactive materials enter the body through an open wound or are absorbed through the skin. Some types of radioactive materials stay in the body and are deposited in different body organs. Other types are eliminated from the body in blood, sweat, urine, and faeces.
External contamination occurs when radioactive material, in the form of dust, powder, or liquid, comes into contact with a person’s skin, hair, or clothing. In other words, the contact is external to a person’s body.
Q9. What is Radiation exposure?
A. Radioactive materials give off a form of energy that travels in waves or particles. This energy is called radiation. When a person is exposed to radiation, the energy penetrates the body.
Q10. How can one block these radiations?
A. Radiation can be absorbed by substances in its path. For example, alpha radiation travels only a few centimetres in air, beta radiation travels tens of centimetres in air, while gamma radiation travels many metres. All types of radiation become less intense the further the distance from the radioactive material.
The thicker the substance, the more the radiation is absorbed. The three types of radiation penetrate materials in different ways.
Alpha radiation is the least penetrating. It can be stopped (or absorbed) by a sheet of paper.
Beta radiation can penetrate air and paper. It can be stopped by a thin sheet of aluminium.
Gamma radiation is the most penetrating. Even small levels can penetrate air, paper or thin metal. Higher levels can only be stopped by many centimetres of lead, or many metres of concrete.
Q11. What are the health effects of radiation exposure?
A. The long-term recovery process after a radiation emergency can lead to increased emotion and psychological distress. In addition, people who receive high doses of radiation could have a greater risk of developing cancer later in life, depending on the level of radiation exposure. For people who receive low doses of radiation, the risk of cancer from radiation exposure is so small that it cannot be separated from exposure to chemicals, genetics, smoking or diet.
|Exposure in mSv||10,000 single dose, fatal within weeks.||5000 single dose, would kill half of those exposed within a month.||1000 single dose could cause radiation sickness, nausea but not death||100 recommended a limit for radiation workers every five years.|
|Immediate effects||Cell damage, especially fast growing cells||Brain – fatigue, nausea||Hair follicles – hair loss||Intestinal lining – Diarrhea, malnutrition.||Skin cells – sore, peeling.||WBC and bone marrow – immune system failure|
|Late effects||DNA damage in cell nucleus||Egg and Sperm cells with damaged DNA can produce babies with birth defects.||Body cells develop tumors or abnormal growth, blood cell damage can lead to leukemia.|
Q12. What is Acute Radiation Syndrome?
A. The radiation dose must be large (i.e., greater than 0.7 Gray. Mild symptoms may be observed with doses as low as 0.3 Gy or 30 rads. The dose usually must be external (i.e.outside of the patient’s body). The radiation must be penetrating (i.e., able to reach the internal organs). High energy X-rays, gamma rays, and neutrons are penetrating radiations. Most radiation injuries are local, frequently involving the hands, and these local injuries seldom cause classical signs of ARS. The dose must have been delivered in a short time (usually a matter of minutes). Fractionated doses are often used in radiation therapy. These large total doses are delivered in small daily amounts over a period of time.
Q13. How does radiation affect pregnancy?
A. The health effects, of 2 weeks gestation, the concern from an exposure of > 0.1 grey or 10 rads, is the death of the embryo. If the embryo survives, however, radiation-induced noncancer health effects are unlikely, no matter what the radiation dose.
In all stages of gestation, radiation-induced noncancer health effects are not detectable for fetal doses below 0.05 Gy (5 rads)
From about 16 weeks’ gestation to birth, radiation-induced noncancer health effects are unlikely below about 0.50 Gy (50 rads). Fetal sensitivity to radiation-induced health effects is highly dependent on fetal dose, and the mother’s abdomen provides some protection from external sources of ionizing radiation.
Q14. How does the radiation affect the body based on the amount of radiation exposed?
A. Radiation includes ionizing (X-rays, Gamma Rays, or consist of subatomic particles such as alpha and beta particles and neutrons) and non-ionizing radiation(UV, visible light, laser, infrared and microwaves). The clinical effect depends upon their range of air and tissue penetration.
Gray(Gy)= 1joule/kg (energy absorbed per unit mass of tissue). However, to take account of differences between the behaviour of different radiations and the differences in sensitivity of various tissues, sieverts(Sv) are used as a unit of the damaging effect of radiation. 1Sv = 100 REM (Roentgen equivalent man). Radioactivity of naturally occurring substances on earth (radon gas, cosmic radiation) produces an average individual dose of radiation is approximately 2.4 mSv per year.
- Less than 0.05 Gy: No visible symptoms.
- 0.05-0.5 Gy: Temporarily decreased red blood cell count.
- 0.5-1 Gy: Decreased production of immunity cells; susceptible to infection.
- 5-3 Gy: 35% percent of exposed die within 30 days(LD 35/30). Nausea, vomiting, and loss of hair all over the body.
- 3-4 Gy: Severe radiation poisoning, 50% fatality after 30 days (LD 50/30). Other symptoms are similar to the 2–3 Sv dose, with uncontrollable bleeding in the mouth, under the skin and in the kidneys (50% probability at 4 Sv) after the latent phase.
- 4-6 Gy: Acute radiation poisoning, 60% fatality after 30 days (LD 60/30). Fatality increases from 60% at 4.5 Sv to 90% at 6 Sv (unless there is intense medical care). Female sterility is common at this point. Convalescence takes several months to a year. The primary causes of death (in general 2 to 12 weeks after irradiation) are infections and internal bleeding.
- 6-10 Gy: Acute radiation poisoning, near 100% fatality after 14 days (LD 100/14). Survival depends on intense medical care. Bone marrow is nearly or completely destroyed, so a bone marrow transplant is required. Gastric and intestinal tissue are severely damaged.
Q15. What about the radioactive waste produced by these nuclear power plants?
A. Each regular 1,000-megawatt nuclear power plant generates 30 tons of extremely potent radioactive waste annually. And even though nuclear power has been operational for nearly fifty years, the nuclear industry has yet to determine how safely to dispose of this deadly material, which remains radioactive for tens of thousands of years. Most nuclear waste is confined in huge cooling pools, euphemistically called “swimming pools” at reactor sites, or in dry storage casks beside the reactor. But there are many other locations in the United States and other countries where huge quantities of reprocessed toxic material and other radioactive waste from nuclear power plants are left unconfined, leaching, leaking, and seeping through soils into aquifers, rivers, lakes, and seas, where it enters and concentrates in the food chains of plants, fish, animals, and humans.
Q16. What are spent fuel pool?
A. Spent fuel pools (SFP) are storage pools for spent fuel from nuclear reactors. They are typically 40 or more feet (12 m) deep, with the bottom 14 feet (4.3 m) equipped with storage racks designed to hold fuel assemblies removed from the reactor. While only about 20 feet (6.1 m) of water is needed to keep radiation levels below acceptable levels, the extra depth provides a safety margin and allows fuel assemblies to be manipulated without special shielding to protect the operators.
Q17. How can a common man dispose of nuclear waste?
A. Low-level radioactive waste, such as contaminated gloves, can be disposed of in landfill sites. Higher level waste, which may be dangerously radioactive, is more difficult to dispose of. It can be reprocessed to extract nuclear fuel or encased in glass and left deep underground.
Q18. Does solar or lunar eclipse affect pregnancy?
A. In many cultures, including in India, a solar or lunar eclipse is considered a bad omen and harmful for a pregnant woman. The eclipse is believed to affect the developing baby by causing a physical deformity, cleft lip or birthmarks. There is no scientific proof to back this opinion.
Q19. How much radiation is one exposed to while air travel?
A. We are exposed to low levels of radiation when we fly. You would be exposed to about 0.035 mSv (3.5 mrem)of cosmic radiation if you were to fly within the United States from the east coast to the west coast. This amount of radiation is less than the amount of radiation we receive from one chest x-ray.
Q20. How much radiation harm do the diagnostic procedure have?
|Diagnostic Procedure||Typical Effective Dose (mSv)1||Number of Chest X-rays (PA film) for Equivalent Effective Dose2||Time Period for Equivalent Effective Dose from Natural Background Radiation3|
|Chest x-ray (PA film)||0.02||1||2.4 days|
|Skull x-ray||0.1||5||12 days|
|Lumbar Spine||1.5||75||182 days|
|I.V. urogram||3||150||1.0 year|
|Upper G.I. exam||6||300||2.0 years|
|Barium enema||8||400||2.7 years|
|CT head||2||100||243 days|
|CT abdomen||8||400||2.7 years|
Q21. What is personal radiation monitoring?
A. Personal radiation monitoring devices or dosimeters (PMDs) are badges that detect various forms of radiation a worker may be exposed to. The dosimeter or badge detects the exposure of a person to x-rays, gamma radiation, neutron and beta particles. Workers are required to wear the dosimeters for periods of up to three months. The accumulated dose from the various types of radiation is measured by the dosimetry service provider and reported to the employer.
Q22. How significant are the risks from occupational exposure to ionizing radiation?
A. The corresponding doses for therapeutic radiologists and those practising special procedures (and cardiac catheterization)were 110 mrems and 550 mrems respectively. The estimated excess cancer deaths for general radiologists would be between 0.97 and 1.63 per 1,000 people at risk.
Q23. What should one do if exposed to radiation?
A. Take off all clothes (shirts, shoes, underwear etc.,) and place them in secure plastic bags. Removing these items eliminates roughly 90% of external contamination. Shower with soap and water, scrubbing hard to remove any possible radiation.
Q24. What medical treatment are available for radiation emergencies?
A. Some medical treatments are available as below:
Potassium Iodide- This is a nonradioactive form of iodine. In humans, the thyroid gland is prone to absorbing radioactive iodine. But when Potassium Iodide is taken orally, it saturates the thyroid with non-radioactive iodine, reducing the amount of radiation the thyroid would take in. Hence Potassium iodide is most effective if taken within a day of exposure.
Prussian Blue – This type of dye binds to particles of radioactive elements known as cesium and thallium. The radioactive particles are then excreted in feces. This treatment speeds up the elimination of the radioactive particles and reduces the amount of radiation cells may absorb.
DTPA (Diethylenetriamine pentaacetate) – This substance binds to metals. DTPA binds to particles of the radioactive elements plutonium, americium and curium. The radioactive particles pass out of the body in urine, thereby reducing the amount of radiation absorbed.
Neupogen – A protein called granulocyte colony-stimulating factor, which promotes the growth of white blood cells, may counter the effect of radiation sickness on bone marrow. Treatment with this protein-based medication, may increase white blood cell production and help prevent subsequent infections. If there is severe damage to bone marrow, transfusions of red blood cells or platelets may be needed.
Sodium calcium edetate or other equivalent chelating agents and high dose of oral calcium may be used.
Supportive treatment for bacterial infections, headache, fever, diarrhea, nausea and vomiting, dehydration, burns may also be required.
Q25. What are the benefits of nuclear energy?
A. Nuclear energy by far has the lowest impact on the environment since it does not release any gases like carbon dioxide or methane, which are largely responsible for the greenhouse effect. As a result, this differentiates nuclear energy from fossil fuels in that it does not produce negative carbon externalities as a byproduct. There are roughly 5.5 million tonnes of uranium in the known reserves that could be mined at $130 USD per kilogram. Currently, with the world’s consumption of around 66,500 tonnes per year, there is about 80 years worth of fuel. The main advantage to nuclear energy is that is it relatively low-cost and consistently runs on its full potential, making it the ideal source to power national grids.
Q26. How is irradiation used for food?
A. The effects of irradiation on the food and on animals and people eating irradiated food have been studied extensively for more than 40 years. These studies show clearly that when irradiation is used as approved on foods: Disease-causing microorganisms are reduced or eliminated, the nutritional value is essentially unchanged, the food does not become radioactive. The process involves exposing the food, either packaged or in bulk, to carefully controlled amounts of ionizing radiation for a specific time to achieve certain desirable objectives.
This article has been written by Dr Srikant Sharma, senior consultant physician, along with Dr Nabeela khan: Moolchand Medcity, New Delhi.
Dr. Srikant Sharma is a Senior consultant in internal medicine, Moolchand Medcity, New Delhi.