The Chernobyl Disaster
Industrial accidents can occur at anytime, anywhere in the world which may result in loss of lives or injuries to workers and can cause significant damage to the surroundings. Thousands of employees lose their limbs, vision and their lives each day due to the accidents that happen in industries. (Aswathappa, 2005) Industrial accidents cannot be predicted. Most of these happen as a result of human negligence. Accidents occur if the workers are not properly trained to use the industrial equipment or if they are unaware of the safety procedures that have to be followed upon the operation and maintenance of the equipment. Another reason for industrial accidents is due to manufacturing defects in the parts of the equipment or the whole of the equipment. Industrial accidents commonly occur due to irregular maintenance routines or the absence of preventive maintenance activities. Industrial disasters are likely to happen in those industries where hazardous substances are manufactured, stored or handled. Accidents in these industries can trigger explosions.
After effects of these explosions are deadly, causing atmospheric contamination by large quantities of gases, solid debris and radiation. Some examples of such accidents are Bhopal gas disaster, Chernobyl disaster, Fukushima nuclear disaster etc. Some accidents happen due to engineering negligence when shortcuts are employed in engineering design to cut the costs of construction and fabrication. This can lead to unexpected design failures. This report focuses on the Chernobyl nuclear disaster, seeing into its causes and effects in detail. Also role of engineers in predicting and preventing industrial accidents and responsibilities of engineers to build a safe world is discussed.
The Chernobyl Disaster
The Chernobyl accident is a tragic nuclear accident that happened on 26 April 1986 at the nuclear power station at Chernobyl, Ukraine, in the former Soviet Union. The accident released huge amounts of radioactive material into the surroundings. The disaster was a unique industrial accident because of the scale of its social, environmental and economic impacts. The long lived nuclear radiation due to the accident is considered to be over 200 times that of the atomic bombs dropped on Nagasaki and Hiroshima. In Ukraine, Belarus and Russia alone, nearly 9 million people were directly affected. (Nuclear monitor, 2011)
The disaster occurred at 01.23 hour on Saturday, April 26 1986 when the fourth reactor at the Chernobyl power plant, near the city of Pripyat, exploded during a systems test. There was a rapid and unpredicted power surge, and when an emergency shutdown was carried out, it resulted in the rupture of a reactor vessel and caused a chain of steam outbursts due to aggressive rise in the power output. Huge amounts of radioactive substances were dispersed into the atmosphere and the combustible graphite moderator ignited on exposure to air. Since the reactor had not been sheathed by any solid containment vessel, the emission of the nuclear particles amplified. The fire resulted in a cloud of highly radioactive fallout in the atmosphere, which spread over large parts of Ukraine, Russia and Belarus.
The actual number of deaths due to the accident varies extremely; differences arising from the lack of strong scientific evidences and the different approaches to quantify death- the deaths being immediate, short term or long term. 31 deaths are directly associated with the accident, all of them the plant employees and emergency workers. According to an UNESCAR report, as of 2008, 64 deaths were confirmed due to radiation. More than 200,000 emergency workers, 270,000 residents and 116,000 evacuees were exposed to the radiation from the accident. The World Health Organization predicts nearly 4000 future deaths due to cancer and leukemia as a result of radiation exposure. (“Chernobyl Disaster”, n.d) Causes of the disaster
The accident occurred at the 1000MW electric RBMK reactor which apart from electrical power also produced weapons-grade plutonium-239. The main reasons for the accident were
1. Design errors
2. Operator errors and faults of the management
3. Political reasons
The RBMK reactor core becomes unstable when operated at low power i.e. below 700MW the reactor becomes hard to control and any trend towards a runaway chain reaction is spontaneously amplified. This characteristic feature of the RBMK reactor design is very dangerous. This feature is absent in reactors other than RBMK so that any tendency towards a runaway chain reaction is automatically controlled. The accident happened at a low power test, when the reactor was most unstable.
Another design anomaly of the RBMK reactor is that the insertion of control rods is a slow process. It takes nearly one-third of a minute for full insertion of the control rods in the RBMK reactor whereas for other reactors around the world it takes less than 2 seconds. For RBMK reactors, it is difficult to control the runaway of the core when operating in unstable conditions. Besides these reactors do not have fast insertable emergency control rods.
RBMK reactors use boron carbide control rods with graphite tip. On fully insertion, the reactivity increases due to the graphite present. So when the control rods are inserted in the reactor for controlling the reaction rate, the reactivity is further increased as a result of its graphite tip.
Hot graphite gets ignited on exposure to air. The neutron moderator of an RBMK reactor contains approximately 600 tonnes of graphite. Most of the reactors used around the world do not contain graphite or any inflammable material.
Another error in the design of RBMK reactors is that they do not have a filter system for exhaust gases.
RBMK reactors do not possess a containment vessel. They would have controlled the escape of nuclear substances into the surrounding. ( Frot, n.d) Operator errors and faults of the management:
In addition to design errors, many human errors were also identified. The operating rules restrict the reactor functioning at low power level for any length of time. It also states not to have less than 30 control rods fully inserted into the core of the reactor. Both these operating rules were breached. Moreover the test procedure was not properly followed. The safety mechanisms for emergency water injection and shutdown were knowingly avoided. It is apparent that the operators did not have sufficient training and appropriate experience for operating the reactor. They were not aware of the consequences of their actions. The management failed to provide adequate training to their employees. Moreover the instructions given for the test were vague and incomplete. (Frot, n.d)
The political and military tension between the USSR and the US forced both sides to be heavily armed in preparation of an all-out nuclear World War III. The scientists and engineers under the USSR had only one guideline: to produce maximum amount of weapons grade plutonium in the shortest time. As a result the design, construction and operation of the RBMK reactor were rushed. The entire budget allocated was used to produce maximum amount of plutonium. No attention was given for improvements or for safe operation of the reactor.
Effects of the Chernobyl accident
Spread of radioactive substances across many countries:
The radioactive substances released as a result of the Chernobyl disaster is estimated to be 200 times than that by the atomic bombings in Japan. Nearly 0.1 million km² of land was polluted with nuclear fallout, with most affected regions being in Belarus, Ukraine and Russia. Trace amounts of radioactive contamination were detected all across Europe. Isotopes of Iodine, Strontium and Caesium have very high nuclear decay rates and they accumulate in the food chain. Most of the radiation exposures suffered by the people were caused by Iodine-131 and caesium-137. (“Chernobyl Disaster”, n.d)
Plant employees and local inhabitants:
The aftereffects of the accident were devastating. Around 237 people were diagnosed with acute radiation sickness or ARS, of which thirty one people died within first 3 months. Almost all of the victims were plant employees and emergency workers who were unaware of the dangers of radiation exposure. About 135,000 people were evacuated from the accident site, including fifty thousand people from the city of Pripyat. (“Chernobyl Disaster”, n.d)
Radioactivity in the surroundings:
The nuclear contamination of the water systems became a major complication in the direct aftermath of the disaster. In the worst hit areas of Ukraine and Belarus, levels of radioactivity in potable water caused concern for even months after the disaster. After the accident, 4 square kilometers of pine forest close to the reactor became reddish-brown and died, since then known as “Red Forest”. Many animals in the accident affected regions also died or stopped reproducing. Many deformed animals were born. Due to the residual radioactivity from the accident in the plants, on which the sheep graze on, many sheep had to be given uncontaminated feed before slaughtering even 20 years after the accident.
Human Impacts of the Accident
One of the major health impacts from the accident is thyroid cancer among children. More than 4000 such cases were reported. Of these 4000 cases, the cancer led to the death of nine people. Another health disorder associated with the accident is the psychological problems. Exaggerated fears about the effects of radiation have led to mental disorders for many survivors. The actual number of deaths due to the accident varies extremely; differences arising from the lack of strong scientific evidences and the different approaches to quantify death- the deaths being immediate, short term or long term. 31 deaths are directly associated with the accident, all of them the plant employees and emergency workers.
According to an UNESCAR report, as of 2008, 64 deaths were confirmed due to radiation. More than 200,000 emergency workers, 270,000 residents and 116,000 evacuees were exposed to the radiation from the accident. The World Health Organization predicts nearly 4000 future deaths due to cancer and leukemia as a result of radiation exposure. Another impact of the accident was an increase in abortion requests across Europe. Although abortion is legal in most of the European countries, there were many requests for induced abortions due to fears of radiation. The fear of embryonic abnormalities forced pregnant women to terminate normal pregnancies in many European countries. (“Chernobyl Disaster”, n.d)
Why and how do industrial accidents happen?
Industrial accidents cannot be predicted. Most of these occur as a result of human negligence. When an employee violates the safety procedures or tries to perform a task without the proper tool, he can damage that industrial equipment and can pose a threat to the safety of other employees. Accidents can also occur if the workers are not properly trained to use the industrial equipment or if they are unaware of the safety procedures that have to be followed upon the operation and maintenance of the equipment. All industrial equipment should be operated by trained and qualified personnel only, such that in the event of equipment malfunction the operator has suitable knowledge to tackle the situation. Another reason for industrial accidents is due to manufacturing defects in the parts of the equipment or the whole of the equipment. Numerous quality control checks are followed during the manufacture of an equipment to make sure the equipment is safe to use.
Since most of these checks are done manually, it is likely that a faulty piece of equipment is missed during the process. If this equipment is installed and operated in an industry, it can cause an industrial accident which can injure or even kill an employee. Industrial accidents commonly occur due to irregular maintenance routines or the absence of preventive maintenance activities. Without proper maintenance done on a pre-planned routine, the chances for equipment failure are high. It is the responsibility of maintenance personnel to carry out these activities. Failure of equipment in the midst of its operation can have serious consequences. Some accidents happen due to engineering negligence when shortcuts are employed in engineering design to cut the costs of construction and fabrication. This can lead to unexpected design failures. .
How can accidents be minimized?
Employee training: For employees working in hazardous situations, proper training should be provided for handling certain equipment and dangerous substances.
Proper handling of hazardous waste material: Employees should be directed on the proper handling and disposal of these substances to avoid unfortunate happenings.
Quality check of equipment: All the equipment in an industry should be checked for its quality periodically. It must pass the established standards in order for it to be used.
Health and safety inspection checks: Certain non-profit organizations organize health and safety inspection checks in different industrial workplaces. In addition to the inspection of these workplaces, they deliver industrial training to the employees, consulting for development and information regarding industrial health and safety.
Danger zone warning: In most industries, there are places that have industrial dangers that can possibly lead to different kinds of misfortunes. It is important that the employees working on the site are made aware of this. This comes under the responsibilities of safety engineers.
Emergency briefing of employees. Employees must be informed about the emergency procedures to be followed when industrial accidents happen. If not done so, there is a bigger chance that more people can be affected when accidents happen. Panicking and not knowing what to do in a difficult situation can only complicate issues. (Staff, n.d)
Role of Engineers
How can engineers predict and prevent industrial accidents?
Accidents can occur at anytime, anywhere. It is practically difficult to predict most of the industrial accidents. It is the responsibility of the safety engineers to make sure all the employees make it back home daily in good shape after a hard day’s work. Some industrial accidents can be predicted to certain extent by the engineers by researching and analyzing the accident history of the industry. The best way to do this is by establishing a database consisting of the accident and safety records of the industry. It can have details regarding the injured employee’s names, DOB, injury date and time (including day of the week), shift during which accident occurred, accident description and all details regarding the accident. The information from the database can help an engineer in analyzing when and how accidents occur in the industry. In most cases, accidents will continually happen in similar areas or situations unless and until the actual causes of the accidents are found out and rectified. Interacting with other engineers in similar industries is important for ensuring safety. For industries operating in similar manner, the accidents that are likely to occur are also similar.
Engineers should analyze and try to implement the safety measures of those industries with excellent safety record. Engineers must also investigate about the mistakes of industries with poor safety records and learn what not to do. Engineers in an industry should establish clear lines of internal communication. Effective communication is the first step to safety. Safety engineers should be capable of convincing the management regarding what improvements should be made in the industry. The engineers should be organized and the communication should be based on researches and facts, not personal opinions. Engineers should also have effective communication with lower levels of the industry, the workers. Engineers should interact with the workers creating awareness, providing proper training and obtaining feedback from them regarding the working conditions. Accidents can be prevented only if all levels of the industry work together as one. (Langdon, 2008)
Are there acceptable accidents that we have to live with?
Most of the accidents in industries are caused by incompetence of the employees or negligence on the part of the management. By providing suitable training, creating awareness among the employees regarding industrial safety and by practicing preventive measures many of these accidents can be avoided. Even if every preventive measure is implemented, there are still some accidents that are unavoidable. These can be caused by natural disasters that can occur anytime. Accidents occurring due to earthquakes, tornadoes, typhoons, tsunamis and other natural phenomena cannot be evaded and must be accepted. Even though these accidents are catastrophic, we have no choice but to live with it.
Can an engineer learn by making mistakes?
Engineers are responsible for the safety, health and wellbeing of the employees in an industry. Mistakes in an engineer’s work i.e. planning, designing, constructing, operating etc. can be destructive and can cost many lives. Engineers are expected to stick to standards while working to ensure the work is done in perfection. It is the duty of an engineer to conduct proper research and perform feasibility studies before actually implementing his work. Making mistakes are not acceptable for engineers.
Can an engineer make the world safer?
Engineers can make the world safer by creating safer designs, structures and by creating safer working conditions to the workers. By researching about various accidents and misfortunes in different industries, an engineer should learn what to do and what not to do that could compromise the safety of the industry and its workers. When safer working conditions and safer industries are created, the environment is made safe and ultimately the world is made safe.
Industrial accidents happen throughout the world any time leaving undesirable effects. They may be because of workers’ incompetence, management’s negligence or natural disasters. The causes and effects of one of the worst industrial accidents to ever occur, the Chernobyl nuclear disaster is discussed in the report.
By providing suitable training, creating awareness among the employees regarding industrial safety and by practicing preventive measures many of these accidents can be avoided. There can be many reasons for industrial accidents. It is the responsibility of engineers to predict and prevent industrial accidents and thereby ensure safety of the employees and the industry. By creating a safer industry an engineer creates a safer environment and ultimately a safer world.
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