NUCLEAR RADIATION LEAK:HOW DANGEROUS IT COULD BE FOR MANKIND?

Dr. BHASKAR CHAKRABORTY Professor of Chemistry Sikkim Government College (NBBGC) An Extension Centr

What is nuclear radiation?

Nuclear radiation is the energy emitted from the nucleus of an atom, either in the form of particles (like alpha and beta particles) or as electromagnetic waves (like gamma rays). This emission occurs when unstable atoms, called radioactive atoms, decay and release energy to achieve a more stable state.Nuclear radiation can manifest in several forms which includes a) Alpha particles (Helium nuclei having 2 protons and 2 neutrons) b) Beta particles (High-energy electrons or positrons) c) Gamma rays (Electromagnetic radiation with high energy).When a radioactive nucleus decays, it releases energy in the form of nuclear radiation, transforming into a different element or isotope.Nuclear radiation is often referred to as ionizing radiation because it has enough energy to remove electrons from atoms, which can damage living tissue.Nuclear radiation can originate from natural sources like Plutonium, uranium and thorium in the Earth's crust, as well as from cosmic rays and it can also be produced by human activities such as nuclear reactors.In a nuclear reactor, a controlled nuclear fission chain reaction generates heat, which is then used to produce steam, driving turbines to generate electricity. Normal operation involves carefully managing the reaction rate with various parameters, including temperature, pressure, and radiation levels.During a nuclear war, the operation of a nuclear reactor would be significantly impacted, potentially leading to a shutdown and the reactor's safety systems would be activated to prevent a meltdown or radioactive release. Nuclear reactors are designed to operate in a controlled manner but a nuclear blast would overwhelm these systems.

What happens if there is leakage in a nuclear reactor?

A leak of one gram of plutonium from a nuclear reactor would pose a significant health risk, particularly if inhaled. While immediate death from a single gram of plutonium is unlikely, it can lead to long-term health problems like cancer including lung cancer. The primary danger lies in the radioactive alpha particles emitted by plutonium which can damage lung cells and increase the risk of cancer if inhaled. Plutonium is most dangerous when inhaled, as the alpha particles can directly damage the respiratory system.  Inhaling even small amounts of plutonium can increase the risk of developing lung cancer and other cancers. Unlike some other toxins, plutonium's effects are primarily delayed, with cancer developing years after exposure. Plutonium is also a heavy metal and has chemical toxicity, similar to lead and mercury.

While the immediate dangers of a leak may be manageable, the potential for long-term health problems and environmental contamination are significant. Even a leak of one gram of plutonium would be a serious health concern, primarily due to the risk of lung cancer and other cancers from inhaling the radioactive particles, even though immediate death is unlikely.Plutonium-239, used in nuclear warheads, remains dangerous for over 24,000 years. Just one gram released into the air could impact millions. Other radioactive elements like Iodine-131, Caesium-137, Strontium-90 and Uranium-235 are equally worrying. Iodine-131 can trigger thyroid cancer. Caesium-137 affects muscle tissue. Strontium-90 targets bones and teeth, while uranium-235 may damage the lungs, liver and bones.

Radioactivity of Plutonium and its isotopes

Like all other heavy elements, plutonium has a number of isotopes, differing in the number of neutrons in the nucleus. All 22 plutonium isotopes are radioactive, because they are to some degree unstable and therefore decay, emitting particles and some gamma radiation as they do so.Twenty-two radioisotopes of plutonium have been characterized, from ²²⁶Pu to ²⁴⁷Pu. The longest-lived are ²⁴⁴Pu with a half-life of 80.8 million years,²⁴²Pu with a half-life of 373,300 years and ²³⁹Pu with a half-life of 24,110 years respectively. All other isotopes have half-lives of less than 7,000 years. The destructive power of the Plutonium bomb in war was first demonstrated on Nagasaki, Japan. The bomb consisted of 10 kg of Pu²³⁹ at its core. All plutonium isotopes are fissionable with fast neutrons, though only two are fissile (with slow neutrons). For this reason all are significant in a fast neutron reactor (FNR). Unlike Uranium, virtually any combination of Plutonium isotopes can be used to make a new clear weapon.The global stockpile of separated plutonium is estimated to be around 565 metric tons. Of this, about 140 metric tons are estimated to be in weapons or available for use in weapon programs, while the remaining 425 metric tons are either produced outside of weapon programs or not directly suitable for weapons.

Natural availability of radioactive plutonium in the world

Plutonium is a very expensive element, with prices ranging from a few thousand dollars per gram to potentially hundreds of thousands, depending on the specific application and isotopic composition.

The country with the highest inventory of separated plutonium is the United Kingdom, holding 140.6 metric tons of civilian-grade plutonium. Russia is second with about 63 metric tons of separated civil plutonium.Not all radioactive elements glow, but plutonium is one of the radioactive materials that does glow. The element reacts with oxygen in the air, causing it to glow a deep red, like a burning ember. Plutonium doesn't glow because of the radiation it gives off, but because the metal essentially burns in the air.Plutonium readily reacts with oxygen in air, spontaneously oxidizing to form plutonium dioxide (PuO₂). This reaction is further complicated by the presence of moisture, leading to the formation of plutonium hydrides and oxides, which can expand the plutonium sample and form a pyrophoric powder.

Harmful and health hazardous effects of plutonium during nuclear reactor leakage

Most forms of plutonium emit alpha particles, which are not very harmful outside the body, but can be very damaging when inhaled. When plutonium particles are inhaled, they lodge in the lung tissue. The alpha particles can kill lung cells, which causes scarring of the lungs, leading to further lung disease and various carcinogenic growths including bone cancer.Plutonium leaks from nuclear reactors pose serious health risks, primarily due to its radioactive nature. In addition to cancers, plutonium exposure can cause various other health problems, including leukemia and damage to the kidneys and blood. Other health effects include radiation pneumonitis, interstitial fibrosis, and tumors in various organs. While plutonium is toxic, the main hazard is the alpha radiation it emits, which can damage DNA and cause mutations.Proper handling and safety precautions are crucial to minimize the risks associated with plutonium exposure.

Courtesy: Bhabha Atomic Research Centre (BARC) E-Journals (2022-2024)