V.Shkolnik,Yu. Cherepnin,T.Zhantikin
Academy of Science of the RK
Kazakstan

Semipalatinsk Test Site (STS) occupied the territory of nearly 18.5 thousand sq.km. During its existence more than 470 nuclear explosions were made. Most of them were connected with nuclear weapons test. That's why the area of activity are directing to liquidation of nuclear weapons test consequence on STS many times exceeds same one connected with other places, excluding Chemobyl. The majority of problems STS are characteristic for polygons of Kazakhstan. It is possible to tell, that on STS radiologic problems of various test sites are accumulated. Therefore, the basic part of the report is devoted to the analysis of a situation, usual on STS. In the conclusion I shall introduce you to the basic problems and strategy of Kazakhstan in the field of the manipulation with radioactive waste.

The test site scheme compiled on the basis of archive data by representatives of Russian Federation presented on Fig. 1 You can see depicts the location of principal test places and axis's of principal dose-forming traces of radioactive. There exist three main test places: "P"- for atmosphere tests; "B"- for underground tests in boreholes; "S"- for underground tests in tunnels. The tracks of explosion show the date and power of explosion as well as the evaluation of dose charge on environment that appear due to complete split of nuclear explosion products. From this scheme one can observe that nuclear tests resulted in rather complicated situation in the region.

The programme for the environment rehabilitation on the former STS has been worked. It is planned for many year and will be accomplished by stages.

The first stage which is being realised at present include:

• radiation site mapping with selection and radionuclide analysis of
• environment samples;
• reveal of the most polluted areas and their location;
• radiological evaluation of the cleanness of soils, water sources and other
• objects of environment;
• ensurance of radiation monitoring.

Radiation mapping of the STS territory started in the beginning of 90-th with its are-gamma survey. Two tracks tracing from "P" place and determining the pollution of the site with Cesium-137 radionuclides were revealed.

The surface of "B" place is less polluted by products of split but the conducted underground tests influence the environment. It is displayed by radionuclides convey from the cavity of nuclear explosions to the daily surface and water horizons. More over, gases explosions in boreholes where nuclear tests were conducted are observed. These explosions happen through many years after tests. The burning of gases coming out of boreholes is present. This situation is explained by the fact of coal deposits existence closely to the test ground.

At present the west part of deposits is under coal extraction works. Naturally, this increase the activity connected with the study of radiation situation. The accomplished research didn't reveal polluted plots in the places of extraction. But with the activity spread on new territories the study of radiation situation will continue. The scheme of "Karazhira" coal deposit location and boreholes nearing to it is presented on Fig.2.

The nearest borehole where the nuclear explosion was made is situated not far from the place of coal extraction (no more than 5 km). That caused the necessity to arrange complex work to study the radiation situation in this region to undertake the safety measures for personnel if necessary. The selection and analysis of samples for radionuclides content is being conducted. The results showed that concentration of cesium-137 and strontium-90 in soil is slight. Samples taken in silo's of the holes nearest to the deposit contain considerable concentration of cesium-137.That means that there exist the possibility of radioactive substances convey from cavity of underground explosions to daily surface and water horizons. In this connection it is planned to arrange the study of ground by plutonium and ground water by tritium using the existing holes situated on the territory adjoining to the coal deposit.

Besides usual stripping works on coal deposits it is planned to arrange ground loosen with the help of chemical explosions. That will cause the raise and convey of a great amount of dust from the surface layer of soil.

It is planned to arrange works on the study of the territory of the mountain drain of coal deposits by plutonium and the pollution of ground water by tritium on the territory adjoining to the coal deposit.

Figure2 besides coal deposits shows all holes where nuclear explosions were not conducted. The hole N 1419 is specially separated. It was not influenced by nuclear explosions. At present it is filled with water. But the concentration of tritium in it is very great that's why all the nearest holes used for tests are marked at the scheme. Thus, it is evident that:

• places of underground tests have connection with underground horizons; · tritium migration from the places of nuclear tests is considerable;
• spread speed exceeds the speed of underground water moving that is evaluated at 5-10 m/year.

"S" ground presents the mountain massif with more than 180 tunnels. At present in the frame of Kazakhstan-American agreements the Republic of Kazakhstan carries out works on liquidation of nuclear tests infrastructure on the territory of Semipalatinsk test site. This work includes the tunnels' shut by different means-by sapping the tunnels' portals or by creation of concrete walls with further rehabilitation of relief. The programme of tunnels' shut is planned for 3 years.Fig.3 presents the scheme of "S" ground where the stages of tunnels' shut are shown year by year. As it is seen in 1998 all the tunnels of mountain massif will not be accessible for the nuclear explosions use. In the framework of activity connected with tunnels' shut dozimetrical and radiological accompany of works is connected with prior investigation and radioecological expertise conduction. The scheme of near-mouth parts of tunnels radioactive investigation was worked out.Fig.4 deals with radiation situation on one of the tunnels according to the power of exposition dose and surface beta-pollution. The used scheme of investigation consists of 34 points for measuring the intensity of exposition dose, density of surface pollution by alpha-and beta-radiation. Ground samples and smears of tunnels' walls are being selected and analysed; and in tunnels with water manifestations additional samples of water are taken for determination of tritium and caesium content in it. According the results of investigation recommendations are being made and permissions are being given to conduct works on tunnels' shut.

Results of the work on tunnels' shut are presented on Fig.5. Despite of the fact that these works are carried out in the frame of nuclear tests infrastructure destruction they improve the ecological state in the region. Figure6 presents the table characterising the reduction of tunnels' radioactive pollution in the result of their shut. It's clearly seen that that the intensity of exposition dose, surface alpha- and beta-pollution's reduce considerably. But in tunnels with water-revealing features water itself to a certain degree is polluted with radionuclides. And probably just these tunnels will determine the radiation situation in mountain massif in future. In this connection, monitoring of tunnels with water revealing features is being realized. At present the problem of reduction of water flows influence, running from galleries, on environment is under study.

At the same time planned investigation of the less polluted territories are carried out at present. Firstly it reefers to the periphery parts of the territory.

Such works are being carried out at present in the frame of the first stage of environment rehabilitation on the former STS.

It is supposed to pass a part of STS territory to economical use at the second stage. Territories with radionuclide polluted level lower standard norms can be passed even for people settling and agriculture works. The rest part of the territory can be used for another activity (including mineral resources prospecting and extraction)when all requirements of nuclear security are ensured. Obviously, the problems of environmental rehabilitation concern the territories with radionuclide level pollution prevail the standards existing in Kazakhstan.

The character of measures for environmental rehabilitation is different for different parts of STS. In parts closely adjoining to epicentres of nuclear explosions only radiation monitoring and works on prevention of radionucleds spread from polluted zones are used. The following works are to be carried out on the rest parts of the territory:

• their purification and radionuclides waste burying;
• restoration of disturbed soils using the complex of agrotechnical measures.

Environmental rehabilitation is the problem of great significance as STS region has great potential economical resources, namely production of agriculture goods, minerals extraction. Exploitation of coal deposits has been carried out for several years; geological prospecting of minerals has only started.

As it is known in Kazakhstan there are the big volumes of radioactive waste. The sources of the creation of radioactive waste are the following main factors:

• Uranium mining and milling activity, including uranium extraction geological works;
• Activity of mining and milling enterprises, which were extracting and processing of raw materials characterised by the increased contents of radioactive elements;
• Nuclear explosions;
• Power and research nuclear installations;
• Use of radioisotope production in medicine, science, industry.

We shall consider these factors in more detail.

Kazakhstan takes one of the first places in the world on quantity of prospected uranium stocks (about 50 % of uranium stocks of former USSR). A long time (more than 40 years) development more than 20 deposits was conducted. The enterprises of this industry branch are located practically on all territory of Kazakhstan. The largest of them are Tselinny mine and chemical Company (Central Kazakhstan), Ulba metallurgical plant, Irtysh chemical-metallurgical factory (East Kazakhstan), Caspian mine and metallurgical combine (Western Kazakhstan), uranium mines of Southern Kazakhstan.

At realisation prospecting, and processing processes on uranium mining and milling enterprises were made radioactive waste, total weight which is about 220 million Tons with activity more than 250 thousand Ci. On a modular condition these about are divided on solid and liquid, on specific activity on low level and intermediate -level waste.

This waste require additional study with the purpose of determination of a opportunity of their further use as building materials or raw material for deeper extraction of radioactive elements and complex extraction of chemical elements.

Among solid waste there are tailings from hydrometallurgical enterprises, polluted by radionuclides the equipment, materials, soil, which are subject irrevocable storage. On specific activity solid waste of given group is low level and only less than 1% from total volume - average activity.

Number of Kazakhstan deposits of polimetals, phosphorus rare earth contains uranium, which at a production of ores is extracted together with main ores and, as a rule, is not divided and can be accumulated in concentrates, and more often leaves in tailing. On some coal deposits top of a part coal are also accompanied uranium. This coal will not be realised as a fuel, and is subject to radioactive waste management. During the study of the territory with oil deposits were find the areas with soil and industry equipment contamined by natural radionuclides Ra-226 and Th-232. Radwaste of this group makes 1.57 million Tones with total activity of 520 Ci.

As a result of conduction of nuclear explosions (atmospheric and underground) on Semipalatinsk test site and other sites were formed the waste of low activity on a earth surface and average activity in cavities of explosions in a kind of melt mountain mass.

The volumes are evaluated in 12.3 million Tones with activity of surface contamination of 11.6 thousand Ci and underground contamination 12.87 million Ci.

At the territory of Kazakhstan there are 5 nuclear installations, including one power nuclear reactor BN-350 (Aktau-city) 4, research nuclear reactors (3 - in Kurchatov-city of Semipalatinsk area, 1 - in Almaty).

Potential radiation danger of nuclear installation exists directly only during their technological activity, in duration 30-40 years, i.e. less vital term of one human generation. After closing of nuclear reactors the direct danger disappears, but there is the special danger of a fulfilled nuclear fuel and a radwaste, formed for a time of operation of object.

Total mass of intermediate level radwaste ( solid and liquid ) is at present time about 9,000 tons with activity 26,560 Ci, mass of low level waste is 3,000 tons with activity 50 Ci.

Probably, that will by 2005 occur high level waste in connection with scheduled dismantling of BN-350 and one of research reactors in Kurchatov-city.

In A Kazakhstan in many branches of a national economy use production of firm "Isotope", basically, in a kind of radiation sources is used. Every year about 100 thousand of sources with activity up to 25,000 Ci are use. Annually more than 10 thousand of sources sets out for storage. The radionucleads types of sources are from H-3 to Am-241.

The territory of the Republic of Kazakhstan is conditionally divided to four regions according transport connection infrastructure: North, West, South and West (Fig. 7).

The distribution of the radioactive waste for the regions of Kazakhstan is shown at the Table 1.

The cadastr of the radioactive waste and scheme of the radioactive waste disposal were created during the preparation of the conception using data of practical work, materials of questionnaires and calculations. The cadastr takes into account practically all types of the radioactive waste and estimates the conditions of their storage.

The analyse of the data connected with radioactive waste for regions of the Republic of Kazakhstan shown necessary of construction of the regional disposal facilities for a little part of the low-level waste and all of the intermediate level waste. The main part of the low-level waste (waste from mining industry) have to storaged on the places of their disposal or near this places with observance of rules and requirements on isolation of waste from environment. The decision for construction of disposal facilities for high-level waste and spent fuel have to decide after getting of the results of experience of the low-level and intermediate level waste disposal facilities exploitation and after establishing in Kazakhstan the nuclear power plants construction program.

The general purpose in the field on radioactive management is the safe and effective ensuring of the present and future generations radiation protection from radioactive influence and environment protection from radioactive contamination both by normal and extraordinary situations.

The purpose of Concept on radioactive waste management is based on the following main principles:

• safety level for future generation have to be the same which is normal for the present generation.
• radioecology safety have to based on the condition that safety level sufficient for human protection will be also sufficient for protection of other living creatures.

The stages of realisation of the conception are following:

• activity on addition to kadastr of radioactive waste and places of their storage and disposal;
• ensuring of the legal base for the activity on radioactive waste management;
• execution of the radiation monitoring on the nonuranium mining and milling enterprises, which products the raw materials and waste with natural radionuclides;
• co-operation of research and design organisations of Kazakhstan for work in the field of design, methodical and scientific ensuring of the activity on the creating of radioactive waste management system using the experience of the develop countries in this area;
• creating of the General scheme of the distribution of the radioactive waste of Kazakhstan, were have to be account radiological, geological, climatic, seismically, landscapical, social-economical and other factors.

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