Prof.T.Shivaji Rao, Director, Center for Environmental Studies, GITAM University, Visakhapatnam.

The International Atomic Energy Agency expert committee enquiry report on Fukushima disaster clearly established that nuclear safety is bound to be impossible for sevral reasons as indicated in the report. For instance the experts warned that complicated structures and organisations during a nuclear accident can result in delays in urgent decision making.

(Note: British expert, Farmer, chose a source term of 5 million curies of Iodine-131 for a 10% core release and predicted high contamination upto 160km. from the reactor. Beattie and Bell used a release of one million curies of Iodine-131 and predicted high contamination upto 144km. from the reactor. Gomberg, an American expert considered the maximum core release under atmospheric inversion conditions and predicted very high levels of radio-active contamination upto 128km from the reactor. All these studies indicate that an accident scenario for the 1100 MW Size-well reactor can be used to predict the socio-economic consequences of a nuclear accident for the different sites like Kovvada in Srikakulam and Jaitapur in Maharashtra to determine their suitability for establishing the proposed nuclear plants.)

According to the experts at least one nuclear incident and $332 millions damages every year are reported for the last 3 decades and most of these accidents are not due to natural disasters like the one at Fukushima. Disasters can occur due to mechanical failures, human errors, terrorist attacks and several radiation spills occurred during operation, transportation and other factors. Some of these events with lesser media coverage have potential to cause considerable damage. About 57 accidents occurred since Chernobyl disaster in 1986 and in addition to about 124 hazardous accidents at Nuclear plants in India between 1993 and 1995. Iodine leak in Tarapur with radiation levels 700 times more than the normal effected 3000 Indians in 1989.

Although contaminated soils due to Bhopal accident can be restored by spending money the long half lives of radioactive pollutants militate against the possibility of restoring lands subject to high levels of contamination by air and water sources and the nuclear waste storage treatment and disposal still is an unsolved problem and thereby nuclear energy has become the fourth most expensive of the alternative sources of energy in spite of the fact that the cost estimates of nuclear energy exclude the costs of safety, storage and decommissioning. Consequently even the advanced passive safety nuclear plants have not coming to operation even in countries like USA.

REACTOR SAFETY: The Nuclear Energy Lobby is very powerful all over the world. In USA they are spending 7 to 8 million dollars on advertising for a return to nuclear power under the threat of Ozone depletion and green-house effect due to pollution from thermal power plants. But a number of Nobel Laureates like Linus pauling, George wald, Hannes Alfven and James watt and eminent scientists like Rosalie Bertel and Willian Caldicott have been strongly opposing nuclear power due to radiation hazards. It is well known that the bombardment of Uranium fuel produces neutrons, heat energy, radio-active fission products and activation products. Hence utmost care is taken to prevent this radiation from escaping into environment and harm the workers and the general public. A 1000 MW Reactor contains several thousand million curies of radio-activity in its core and the radiation delivered nearby could be 100 million rems per hour against 5 rems per year allowed for occupational exposure by the authorities.

Although nuclear radiation cannot be detected by man’s physical senses it gets into the air, water and soil and the food chains and food-webs in nature and gets biologically magnified to contaminate the environment and poison the life systems. It cannot be considered to be clean just because it cannot be seen, smelled, tasted or touched by man. In fact many studies suggested increased cancer rates among workers exposed to radiation at the American nuclear weapon facilities. In a 1984 study report on excess cancer deaths, 9 out of 12 studies established the link between cancer and radiation. One study reported very high death rates from Lymphatic cancer and cancer of cervix and uterus among 19000 women who worked at the Oak-ridge nuclear reservation in Tennessee. Another study reported abnormal death rates from Leukemia and brain cancer among male workers at the Oak-ridge.

Infact the recent reassessment of the Japanese bomb victims has proved that cancer risk is 15 times greater than the radiation risk factors accepted by the International Committee on Radiation Protection (ICRP) in 1977. A reduction in radiation dose is bound to be opposed by the nuclear industry as it will make nuclear power very expensive. However the national and international organizations that specify the standards cannot remain unconcerned about these crucial problems of life and death. In Britain, the annual radiation dose limits have been revised in 1987 to 50 milli-rems to the general public. In USA the dose limits were set at 25 milli-rems to the general public by the Environmental Protection Agency (EPA) and the Energy Research and Development Agency has recommended for a drastic reduction to 5 milli-rems.
MODES OF REACTOR FAILURE: Serious concern about the dangers of operating nuclear power plants created panic among the public due to an accident in 1979 at the Nuclear power plant k own as three Mile Island accident in Harrisburg of Pennsylvania, USA. A series of equipment failures, misleading readings from the instruments and human errors caused the abnormal heating of the reactor core and these grave errors prevented emergency systems from operating properly.

Small amounts of radioactive gases from the plant escaped into the atmosphere and caused health risks to the public including a few excess cancer deaths among 20 lakhs of people living within 50 miles of the plant. Sabotage, an earthquake, a human error or equipment failure can cause a reactor accident in which a main pipe in the primary cooling circuit can get fractured. In such a case the control rods would switch off the reactor so that nuclear fission process is stopped immediately. Even then the disintegration of the fission products cannot be stopped and there will be decay heat. In a 650 MW power plant, the heat formation by such disintegration will be 200MW for 3 seconds after the reactor is switched-off and it will be 30 MW after one hour and 12 MW after 24 hours and the decay heat due to disintegration continues for several months.

Under normal working conditions in the reactor the fuel casing surface has a temperature of 350oC (660oF) while the interior of the fuel rods will be at 2,200oC (4000oF), approaching the melting point of the fuel. If the cooling liquid is lost the surface of the fuel rods heats up rapidly and within 10 to 15 seconds fuel casing would breakdown and within a minute the casing would melt and the fuel rods also began to melt. Unless the emergency core cooling system comes into operation within the first few minutes, the reactor core and the fuel of about 100 tonnes and the supporting structure would melt and collapse on the floor of the inner-most fuel tank. To meet such an accident due to loss of cooling agent, the reactor is provided with several emergency cooling independent systems based on theoretical calculations. During an experimental test the systems failed; the emergency coolant failed to cool the reactor core as it escaped through the leak in the cooling circuit and also owing to a layer of steam forming between the hot surface of the fuel rods and the emergency coolant, and the remaining emergency coolant fluid could not carry away the heat generated by the fuel rods. If the core cooling system fails to work in time, almost in a minute, the reactor core melts and if the coolant water is added at this belated time, it would make the situation worse. The melted metals in the fuel reactor react violently with this coolant water and produces great volume of heat and the steam and hydrogen thus produced would be released in such a great quantities and at such a high pressure that the pressure tank would burst and there will be no other technical control measure that can stop the melting process and the molten core would sink into the ground causing what is known as China syndrome. Practically all the gaseous fission products and some of the volatile and non-volatile products would be thrown into the atmosphere. In a 1000 MW reactor the fission products accumulated after one year would approximate the amount that will be released by about 1000 atom bombs of the Hiroshima variety.

RESIDUAL HEAT FROM A 650MW REACTOR & LOSS OF COOLANT LEADING TO EXPLOSION (Diminishing heat and sequence of failures due to loss of coolant after the reactor is stopped.)

RISK DUE TO ACCIDENTS:For making a probabilistic safety assessment of a nuclear plant for a specified location, an estimate of the socio-economic consequences due to an unlikely severe accident must be made in 2 steps. Firstly, the magnitude and nature of release of toxic radio-isotopes  into the environment, known as, the “source term” must be determined.  Secondly, the source term must be used in modeling the atmospheric dispersion of radio-activity under different  stability conditions and the consequent impact in terms of health effects on people and damage to agriculture and animal husbandry, houses and properties must be assessed.  Even for reactor designs with strong containment structures, some kinds of accidents which can by-pass the containment occur.  In case of Chernobyl with the sudden failure of the first 3 barriers, namely the fuel-matrix, cladding and cooling system and the absence of a strong containment, the radio-isotopes immediately flashed out, escaped into the environment, and the emission continued for 10 days. In case of Three Mile Island, the 3 barriers failed on a longer time scale of 3 hours while the containment retained all but a trace of radio-activity that escaped from the core for a short duration.

For calculating the consequences of an accident for a 1100 MW pressurized water reactor at size-well in England, the Westing house corporation and the British authorities considered the source terms for containment by-pass for the maximum release of radio-isotopes from the core of the reactor.  They used the National Radiological Protection Board (NRPB) “MARC” suite of programmes for the atmospheric dispersion modeling.  Under the worst conditions, this model predicts that people have to be evacuated down-wind upto 140 to 170km from the reactor.  The damage due to an accident has been estimated at 2400 million pounds inclusive of health and housing costs, losses in agriculture and non-agriculture fields, cleaning and decommissioning expenses and supplementary costs of alternate power supply etc. Similar studies on socio-economic consequences of postulated accidents at nuclear plant sites were made by different experts to determine the suitable location.  For instance a British expert, Farmer, chose a source term of 5 million curies of Iodine-131 for a 10% core release and predicted high contamination upto 160km. from the reactor.  Beattie and Bell used a release of one million curies of Iodine-131 and predicted high contamination upto 144km. from the reactor.  Gomberg, an American expert considered the maximum core release under atmospheric inversion conditions and predicted very high levels of radio-active contamination upto 128km from the reactor.  (See here)

If the American Nuclear Power plant managers are taking interest inprotecting public health and the environment by taking up emergency planning zones upto 50 miles or 80km from the nuclear plant site for estimating the peak levels of radiation exposure for evacuating people for and settling them in safer places the Indian Government and the nuclear plant managers are violating this standard in India and thereby are positively considering that the life of an Indian is far inferior than that of an American citizen and thereby are aoviding the public health norms in planning for nuclear power plants to ensure safety of the public and the environment and thereby the Indian people are not taken as co-partners as in other countries.

All these studies indicate that an accident scenario for the 1100 MW Size-well reactor can be used to predict the socio-economic consequences of a nuclear accident for the different sites like Kovvada in Srikakulam and Jaitapur in Maharashtra to determine their suitability for establishing the proposed nuclear plants.

MULTIPLE CAUSES FOR REACTOR FAILURES

A reactor may be designed to be safe for a given magnitude of  earthquake and a Tsunami wave to withstand or to withstand both.  But if a third risky event like a terrorist attack that devastated the world trade center in NewYork , Bomb attacks that destroyed Dams in Germany during the second world War  or a missile attack is experienced by a nuclear plant, nobody can guarantee the safety of the reactors.  Hence Nuclear Safety is a myth particularly under Indian nuclear industrial work culture and hence India must follow the Japanese Prime Minister in abandoning nuclear reactors and promote alternate sources of energy.  Nuclear reactor proliferation is the greatest threat to human life amounting to an undeclared nuclear waragainst mankind posing a threat to our civilization.

Advanced  passive safety Reactors

Questioning the safety of nuclear reactors Dr.Hannes Alfven, a noble laureate said “although the nuclear experts devote more effort to safety problems than others, the real question is whether their blue-prints will work as expected by them in the real world and not only in their technological paradise.”

The growing number of nuclear incidents show that it is impossible to ensure complete safety even the most modern passive safe reactors.  Decay heat  needs pumped cooling water for an year to prevent over heating nuclear plants are some of the most sophisticated and complex energy systems and no matter how will they are designed and engineered, they cannot be deemed fail-proof.

Reactors are highly complex machines with an incalculable things including inter connected linkages that could go wrong.  In the Three Mile Island Reactor accident one malfunction led to another malfunction and then to a series of others until the core itself began to melt and even the best experts did not know how to respond .  A combination of electrical, mechanical and human failures can disable the reactor itself.  Indian work culture is not as reliable as the work culture of the nuclear plant operators of a highly technically advanced country like Japan where the Fukushima reactor accidents proved that nuclear accidents  cannot be forecast  and prevented  in time and hence under Indian work culture of unreliable dimensions and unfavourable circumstances like the growing social unrest due to political corruption that promotes terrorist activities including bombing, accidents as are occurring in major cities like New Delhi, Mumbai and Hyderabad  the nuclear plants are bound to fail in the long run.

Terrorist Attacks on Nuclear Plants-Report to U.K. Government
Kovvada Nuclear Plant  claimed to be safe due to improvements

(Public Citizen Critical Mass Energy Project WISE NC 275 June 87)857. 1987 – U.S.A.

The Government and its officials are the public servants who have to work to promote peoples welfare and national progress by promoting the right methods of development in preference to the wrong methods of development which are ecologically unsound, economically ruinous and socially unacceptable and the Gandhian principles of sustainable development must be upheld because Indian ethos not only preaches but practices in letter and spirit the slogan of SARVEJANA SUKHINOBHAVANTU.

Why nuclear reactor safety is considered as a myth by German chancellor Angela Merkel and Japanese  ex- prime minister, Naoto Kan

When the Swiss Government wanted to buy the US Reactors in 1973 , they demanded experimental proof that the dome containment would retain the radioactive pollutants released during a Loss of Coolant Accident (LOCA). Actual  Test is very expensive,Moreover, since an actual test would be more dangerous than nuclear bomb testing, assurances on reactor safety are entirely based on tests on paper using simulated mathematical models.

As such test results can not take into account the different permutations and combinations of malfunctions from defective materials, mechanical or human errors, sabotage, bombing, terrorism, missile hits, aero-plane crashes etc. they become invalid.

In other words, nobody can do all the necessary testing nor even anticipate what kind of tests are needed. At best, the experts may be able to simulate and estimate the answers to some of the questions asked by the people but do the people know all the questions that are yet to be asked for making the reactors absolutely safe for all time for different Natural and Man-made errors? Hence the proof of reactor safety could not be given and still has not been demonstrated.

But when the tests on the Emergency core cooling system designed to flood the core during a loss of coolant Accident[LOCA] were run at the National Reactor Testing Station in Idaho, mechanical failures occurred. When the tests were run during 1970-71 all the six tests conducted by the Aero-jet Nuclear Company failed. Subsequent experiments at Oak-ridge National Laboratoreis indicated that the Zircaloy-clad fuel rods of the Light water reactors may swell, rupture and block the cooling channels, and thereby obstruct the emergency cooling water from reaching the core and such obstruction which holds back the emergency core cooling water leads to a catastrophe sometime or the other. Thus reactor safety is most often a myth!

Questioning the safety of nuclear reactors Dr.Hannes Alfven, a noble laureate said “although the nuclear experts devote more effort to safety problems than others, the real question is whether their blue-prints will work as expected by them in the real world and not only in their technological paradise”

According to Brahma Chellany:  “The chain of incidents engulfing all six Fukushima reactors was triggered by their close proximity to each other.
With a flare-up at one reactor affecting systems at another, Japan has ended up with serial blasts, fires, spent-fuel exposures and other radiation leaks at the Fukushima complex.

The lesson: A string of events can quickly overwhelm emergency preparedness and safety redundancies built into reactor systems.This seriously calls into question India’s decision to approve construction of six to 12 large reactors at each new nuclear park.”
http://www-pub.iaea.org/MTCD/publications/PDF/te_1624_web.pdf

For more information, readers can access these articles:

http://tshivajirao.blogspot.com/2011/10/why-nuclear-accidents-are-difficult-to.html