Blinovskaya Yana Yu., Ph.D.

- Maritime State University named after Admiral G. I. Nevelskoy, Vladivostok, Russia -

Mankind use nuclear energy for about 60 years. The "birthday" of modern nuclear power industry is commonly supposed to be the 27thJune 1954, when for the first time a nuclear reactor with symbolic name "Peaceful Atom" was connected to grid in Moscow-area town of Obninsk near Protva River.

According to International Atomic Energy Agency (IAEA), 436 nuclear reactors were operational and 44 nuclear reactors were under construction as of February 2009 all over the world. Until recently it was generally considered that nuclear power plants, despite being very complicated and potentially hazardous facilities, could be constructed highly fail-safe. Indisputable advantage of nuclear power plants was in smaller fuel consumption and, hence, smaller environmental impact during the operation. Though, the tragic accident of March 2011 at Fukushima NPP (Japan) considerably undermined confidence in safety of nuclear power.

World publicity, research and political organizations are highly concerned with the potential hazardous impact of NPP to people's health and environment.

At the rise of nuclear engineering the scientists inspired by the might of unveiled chances were definitely optimistic about nuclear power plants.

?I am still astonished looking at the nuclear reactor?, ? said Niels Bohr, a Nobel Prize Winner for physics, in 1961.

It worth mentioning that nuclear engineering has a considerable share in world power production. Total number of functional power nuclear reactors is 442, but also there are nearly 300 research reactors, 250 ship-based reactors (submarines, icebreakers and aircraft carriers). The leaders are USA (788.6 billion kWh/year), France (426.8 bln kWh/year), Japan (273 bln kWh/year), Germany (158.4 bln kWh/year), Russia (170.1 bln kWh/year).

As for Russia, it provides full cycle technology of nuclear power engineering, from uranium ore crop to energy production. Now there are 10 operational NPPs (Balakovo, Beloyarsk, Bilibino, Kalinin, Kola, Leningrad, Novovoronezh, Rostov and Smolensk NPPs). Share of nuclear power generation in general structure of power generation is 17%. Most of NNPs are located in European Russia, mainly in north-west (42% of power production).

Relatively short period of NPP operation resulted in a number of catastrophic accidents.

World's first serious breakdown occurred in Canada on 12th December 1952. A technical error of Chalk River (Ontario) NPP personnel resulted in overheating and partial core melting. Approximately 3,800 m3 of radioactive water was discharged into ground in Ottawa River valley. Many accidents related to NPPs were classified until recently. Table 1 lists most significant NPP accidents.

《Table 1》

The largest NPP accidents the world

According to the table, most of the accidents resulted from personnel errors. The same situation is for other radionuclide emissions not covered by this report (military accidents, nuclear waste disposal accidents, nuclear fuel production accidents etc).

Fukushima NPP accident has radically changed the plans of modern nuclear engineering in Russia and abroad. Some governments (mainly in European Union) halt development of nuclear power engineering. The results of the most global nuclear disaster in XXI century still gain their momentum.

It also worth mentioning that Fukushima accident is of radiatiactive, not nuclear origin. There was no acceleration on instantaneous neutrons as in Chernobyl but it did not weakened the graveness of the disaster. The accident was marked with level 5 (of 7 existing) by INES scale with possible transfer to level 6. Dismaying estimates were obtained for all three breakdown units because cooling system was out of order.

But more detailed insight should be done to the world's largest nuclear disaster, i.e. Chernobyl NPP accident.

At the night of 26 April 1986 at reactor number four of the Chernobyl plant during the test of the new voltage regulating system occurred two explosions destroying part of reactor unit and turbine hall.The TNTequivalent of explosions is estimated by about 100-250 tons. The accident was marked by the highest seventh category of danger according to the international INES scale. 8 of 140 tons of radioactive fuel from the reactor were emitted to the air. The fire was extinguished almost after two weeks, until that it triggered the outburst of other dangerous substances to the atmosphere. People in Chernobyl were exposed to radiation 90 times higher than after the bomb fell to Hiroshima. The radius of immediate radioactive pollution was 30 km. The total area which underwent radionuclide impact reached 160 thousand km2. 19 Russian regions with total area of 60 thousand km2 and population of 2.6 million people were polluted. Northern part of Ukraine, Belarus and the west of Russiasuffered most of all. Radioactive depositions reached territories of 20 states in Europe. About 400 thousand citizens were evacuated from the disaster area. A series of fires and breakdowns which occurred in the area from May till August 1986 within the power plant aggravated the situation. According to the report of the United Nations the total number of people who suffered from the accident makes 9 million, about 4 million of them were children. Consequences of the accident are still displayed.

The nuclear history of the Russian Far East is also quite old and not always optimistical. But it is mainly connected with development of the military industry and operation of ship reactors on nuclear submarines.

Thenuclear reactors consume enriched uranium, and the accidents accompanied by the development of uncontrollable reaction (nuclear hazard) are possible under certain conditions. During these reactions radioactive chemical elements (radioactive hazard) are also formed. Thus, ship reactors, as well as the NPPs, also represent nuclear and radioactive hazard.

The disarmament program which was initiated in 1990-s promoted reduction of quantity of dangerous objects in the Far East, and in connection with the scale, duration and technical complexity of these works gained high priority among national problems.

As the report shows, the nuclear engineering is unsafe first of all for the health of population and environment. The gravity of this problem is primarily stipulated by the far-going consequences. Revaluation of the nuclear engineering position after Fukushima accident stimulates development of energy production using alternative sources, mainly renewable and inexaustible. At the same time, the designs of floating nuclear power stations are under consideration.

Thus, the Russian nationalcorporation "Rosatom" plans startup of the first-ever floating nuclear power station. It is a large-scale project which is planned to be launched forthe extreme north and other severe environmental conditions. "Rosatom" plans to construct 12 floating power stations to export, because some regions have no alternative to nuclear energy, as designers declare.

But absence of such alternatives is not quite grave argument in favor of atomic engineering. It does not actually concerns the NPP, but mainly environmental impact of their operation.

In the course of regular operating mode of a power plant the impact is considered as emissions which can be divided to gas and aerosol (emitted to the air through a pipe), and liquid discharges (harmful admixtures as solutions and fine suspensions), as well asthermal influence. Considerable environmental impact is connected with recycling of the used fuel. In this case radioactive pollution occurs.

Accidents would result in all these impacts, and consequences would depend on scale of the accident.

Let's consider how the exposure impacts human body. Radioactive substances penetrate into human body with various intensity, it depends on their chemical properties. We will consider consequences of radioactive impact by the example of an accident which occurred at the reprocessing plant of "Mayak" nuclear facility in Chelyabinsk in 1957. Radioactive waste contaminated Chelyabinsk, Sverdlovsk and Tyumen areas, forming so called ?East Ural trace?. The contamination was non-uniform due to thefeatures of local relief and atmospheric condition at the moment of accident. According to vegetation condition there were allocated two interconnected processes.

1. The short period of radioactive fallout. The vegetation became primary accumulator of radionuclides and was exposed to direct radiation. The maximal pollution was registered in leaves and bark.

2. Active migration of radionuclides to the soil. Part of these substances was repeatedly absorbed by plants, resulting in corresponding impacts. Comparatively uniform distribution of pollutants in all plant organs was noted.

Within two years after the accident trees concentrated almost lethal doses of radiation. It was noticeable by the forest stand condition. Less exposed trees were characterized by reduction of width of annual rings. Radiation also resulted in weaker watering (drying of trunk). Time of forest stand restoration in high exposure area reached 10 years. Unlike vegetation, the radiation impact to the person is being registered during a longer period. Depending on the mode of radiation, featuresand time of exposure differ. The most dangerous is gamma radiation. Consequences of radioactive pollution reveal themselves through various dangerous diseases, among them are carcinoma, leukemia, metabolic disorder, infertility. How to deduce radiation from an organism? This question certainly bothers many people. Unfortunately, there are no very effective and quick ways of clearing the body of radio nuclides. Some food and vitamins help to clear an organism of small doses of radiation. But if the radiation is serious only a miracle can help.

What was the reaction among population of the Russian Far East to possible contamination after Fukushima accident? Russian people still remember the nuclear disaster in Chernobyl. Despite assurances of competent authorities that there was no danger, the region population independently traced radiation level. For a long time demand for production which helps to lower radiation degree remained. In particular, iodine-containing products were bought up.

The whole world sympathizes with Fukushima victims in Japan, and Russia isn't an exception. Cargoes of the humanitarian help and technical support were ready to delivery within a few hours after the accident. But the consequences will be noted for several decades. How will it be reflected on the environment? How will it be displayed in the neighboring regions?

Despite being too close to the source of pollution, Russian Far East did not experience direct exposure.

Our university organized an expedition on the training vessel "Nadezhda" from April 30th till May 30th 2011 which was devoted to estimation of environmental condition in the Sea of Japan (East Sea) after Fukushima-1 NPP accident. The expedition was mainly involved, besides measuring background radiation level in the water area and shelf zones, in revealing dynamics of aerosol fields in the atmosphere over the Sea of Japan to find possible channels of aerosol transfer from Japan to Primorsky Krai.

Measurements of background radiation level carried out by this expedition in the water area of the Sea of Japan revealed that the level was close to the long-term average values.

The expedition route was planned not only to conduct all available studies in Russian maritime area, but also to single out the water areas from where radionuclides from Japan to the Russian coast could be transfered. To carry out the researches hi-tech equipment was used. The expedition revealed no excess of natural radioactive background in the investigated water areas. I.e. it is possible to assert that the accident did not result in the increase of background radiation level in the study area, no radioactive isotopes in sea water stations and phytoplankton were registered.

However, complete understanding of the situation with possibility of radioactive material input through the ocean surfaceand atmosphere is possible only as a result of long-term monitoring of processes which are responsible for transfer of radionuclides from Japan to shelf water of Primorsky Krai. Such transfer can follow the atmospheric processes. And if by June the wind pattern isfavorable in these area, i.e. winds of west and northwest directions prevail (thus practically excluding the possibility of radioactive aerosol transfer from Fukushima-1 NPP to the shelf water), when summer comes the monsoon wind frequently changes tosouth and southeast directions. Therefore studying of these processes should be continued.

We should remember the sad consequences of nuclear disasters. Despite the fact that we, the modern people, would not manage without and would not refuse the blessings of civilization, we should remember the wisdom of American Indians which sais that when a human will kill the last animal and catch the last fish and destroy the last river, it is then he will understand that money is not good for eating.

We are capable to reduce reckless overproduction of natural resources, use of dangerous substances, including radioactive compounds, and our task is not only to reveal dependence of decision-making to the environmental condition and to minimize related negative impact, but also to define optimal technologies to solve environmental issues.

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