3. NUCLEAR FUEL PRODUCTION

3.1. General

Industrial production of nuclear fuel has been carried out at the enterprises situated in the Russian Federation. At present these enterprises comprise the AO "TVEL":

• AO "Machinery plant", Electrostal, Moscow region;
• AO "Chepetsky mechanical plant", Glazov, Udmurt Republic;
• AO "Novosibirsk plant of chemical concentrates", Novosibirsk, Novosibirsk region;
• state enterprise "Moscow plant of polymetalls, Moscow.

The production amalgamation "Ulbinsky metallurgical plant" situated in Ust-Kamenogorsk, Republic of Kazakhstan, in cooperation with the enterprises of the AO "TVEL", has also been taking part in the production of nuclear fuel.

The following are the source materials for the production of nuclear fuel: uranium ores and concentrates, uranium oxides, hexafluoride of natural uranium or of uranium enriched by ²³⁵U.

Metallic uranium, its alloys, uranium dioxide fuel of various degree of enrichment by ²³⁵U, and fuel compositions are being produced as a result of the chemical and metallurgical processes. The end products are:

• fuel elements and fuel assemblies for nuclear reactors of various purposes;
• standard slugs on the basis of natural metallic uranium for manufacturing of military plutonium;
• slugs of enriched uranium;
• fuel elements and fuel assemblies for reactors of nuclear power stations (2-5% of ²³⁵U);
• fuel elements and fuel assemblies for transport nuclear energy facilities (high enrichment by ²³⁵U - up to 95%);
• fuel elements and fuel assemblies for research reactors of various degree of enrichment by ²³⁵U.

As a result of the activity of the enterprises for the production of nuclear materials, radioactive wastes appear which, after due processing and having acquired the form of sludges and solid wastes, are sent to storages. Disposal of radionuclides into watersheds and into the atmosphere at all the enterprises are lower than standards allow. There were no radiation accidents leading to the contamination of the environment.

3.2. Characteristics of radioactive wastes

The data on radioactive wastes accumulated at the enterprises for the production of nuclear fuel as of January 1, 1996, is presented in Table 3.1.

At the enterprises situated in the Russian Federation there are solid low- and medium-active wastes which contain uranium radionuclides and ²²⁶Ra Their overall quantity is 5,650 thous. tons with the activity of 1.4x10¹⁴ Bq (3,860 Ci).

According to the inventory of radioactive wastes as of January 1, 1990, there were liquid low-active wastes at the Ulbinsky metallurgical plant. Their volume is 939 thous. m³. They contain uranium radionuclides with the activity of 2.3x10¹¹ Bq (6.1 Ci) . There are 1,351 thous. tons of solid radioactive wastes at the enterprise. These are low- and medium-active wastes with overall activity of 3.8x10¹³ Bq (1,021 Ci). Their activity is determined by uranium radionuclides and by spent sealed emitters of wide nomenclature (²⁴¹Am, ⁹⁰Sr, ²³⁹Pu, ⁶⁰Co, ¹⁷⁰Tm, ¹²⁴Sb etc.).

Table 3.2 shows the following characteristics of the storage of radioactive wastes situated at the enterprises for nuclear fuel production: period of operation, size, volume of the storages, their overall activity and the level of waste activity in the storages. By this time some storages had already been filled and now they are under conservation.

Table 3.3 shows the size of territories contaminated by radionuclides, with special attention given to the corresponding territories on the industrial sites of the enterprises, in the sanitary-protective zones and in the zones of supervision.

The general size of territories of the enterprises contaminated by radionuclides and situated in the Russian Federation as of January 1, 1996, is 1.7 km², of which 0.2 km² has dose rate of more than 2 mSv/h (200 mR/h). The larger part of the contaminated areas is located on the industrial sites of the enterprises (1.5 km²); in the sanitary-protective zones there is 0.11 km² of such areas and in the zones of supervision - 0.12 km². Data as of January 1, 1990, shows that at the Ulbinsky metallurgical plant 0.6 km² in the sanitary-protective zone was contaminated, including 0.07 km² where dose rate was more than 2 mSv/h.

At all the enterprises contamination is mainly due to uranium radionuclides.

3.3. Evaluation of the fullness of information

Data given in Tables 3.1 - 3.3 satisfactorily shows quantitative characteristics of the presence of radioactive wastes and their activity.

Recently (as of January 1, 1990, and of January 1, 1993) the inventory of places and objects of extraction, transportation, processing, use, collection, storage and burial of radioactive wastes and sources of ionizing radiation had been carried out.

Annually the enterprises present to the governing body data on the disposals into water and of atmospheric releases of radioactive substances as well as data on the discovery and rehabilitation of the contaminated territories. Databases on disposals into water, atmospheric releases and contaminated territories of the enterprises of the AO "TVEL" beginning from January 1, 1993, are available. Data on the Ulbinsky metallurgical plant situated in the Republic of Kazakhstan is limited by the material of the inventory as of January 1, 1990.

The profound study of the contamination of territories, the state of storages, the migration of radionuclides from them, the influence on the population living on the territories adjacent to the enterprises may be needed in connection with the necessity to rehabilitate the contaminated territories and to fulfill engineer-and-research work. Purpose program "Rehabilitation of territories contaminated as a result of the activity of the enterprises on nuclear materials production for nuclear weapon" outlines the work on the rehabilitation of contaminated territories at the Machinery plant,Chepetsky mechanical plant, Novosibirsk plant of chemical concentrates and Moscow plant of polymetals.

Table 3.1

Characteristics of radioactive wastes accumulated at the enterprises for nuclear fuel production as of January 1, 1996

Table 3.2

Storages of radioactive wastes at the enterprises for nuclear fuel production as of January 1, 1996

Table 3.3

Territories contaminated with radionuclides as a result of the activity of the enterprises for nuclear fuel production as of January 1, 1996

Open joint-stock company "MACHINERY PLANT"

The enterprise is situated in the city of Electrostal, Moscow region.

It is the first enterprise in the USSR for the industrial production of metallic uranium and for the nuclear fuel production. The work with uranium began here in 1946.

Uranium-containing ores and uranium concentrates were processed at the plant as a result of which pure uranium salts and metallic uranium were produced, with their subsequent casting, plastic deformation and mechanical treatment for the obtaining of moulds of necessary configuration and their hermetization into aluminium cover, i.e., standard uranium slugs. Uranium ore processing ended in 1957 and manufacture of standard uranium slugs - in 1967.

In the 1950's the production of uranium slugs enriched by ²³⁵U began here. In subsequent years the production of fuel elements, fuel assemblies of various types for research reactors, nuclear reactors for nuclear power engineering and transport facilities was developed. Fuel elements were made of enriched uranium which contains various degree of ²³⁵U in the form of uranium dioxide or other compositions. All the above-mentioned items have been produced up to now.

As a result of the uranium ore processing and of the nuclear fuel production, radioactive wastes appear. They are concentrated in two surface storages (No. 240 and No. 298) which are not used now. These storages are situated on the territory of the enterprise. They have the form of trenches without filtration-proof barriers. After natural evaporation of the liquid phase and filtration the trenches are filled with non-radioactive wastes, outdated machinery and metallic scrap. These storages are in need of rehabilitation. The storage No. 240 had been used from 1949 till 1951; the storage No. 298 - from 1950 till 1981. The volume filled is 151 thous. m³. The overall activity of the two storages is 4,2x10¹³ Bq (1143 Ci) and is determined by radionuclides of ²³⁵U and ²³⁸U as well as by ²²⁶Ra. There are no liquid radioactive wastes at the storages.

Since 1981 radioactive wastes in the form of sludge processed by liming are sent to surface sludge storage No. 294a the bottom and walls of which are protected by filtration-proof clay material. The planned volume of the storage is 120 thous. m³, in fact 104 thous. m³ are filled (water including). In the liquid phase activity is lower than permissible concentration. Solid radioactive wastes have the volume of 5 thous. m³ with the overall activity of 9,2x10¹⁰ Bq (2.5 Ci). These are low-active wastes containing uranium radionuclides whose specific activity is about 1,8x10⁴ Bq/kg (5x10^-7 Ci/kg). The intake of radionuclides into the storage during 1995 was 7,4x10⁹ Bq (0.2 Ci).

Disposal of sewage waters at the enterprise is taking place through several outlets. The concentration of alpha-active radionuclides in them is lower than 0,4 Bq/l (1x10^-11 Ci/l) (with the exception of outlet No. 5) with permissible concentration being 81,4 Bq/l (2.2x10^-9 Ci/l). Before 1976 waters contaminated with radionuclides were disposed through outlet No. 5 which resulted in the accumulation of uranium and radium in silts. Now gradual removal of radionuclides from silts with the help of water is taking place. In 1995 the content of alpha-active radionuclides in outlet No. 5 was 6,3 Bq/l (1.7x10^-10 Ci/l) (2x10⁹ Bq (0.053 Ci) during the whole year) which is less than 10% of the standard disposal.

In 1995 atmospheric release of radioactive wastes (uranium radionuclides) at the enterprise was 6,3x10⁸ Bq (0.017 Ci) which is 68% of the permitted release.

The size of the territory contaminated by uranium radionuclides and radionuclides of ²²⁶Ra is equal to 0.14 km² on the industrial site due to plots having local contamination and containing surface storages of radioactive wastes with dose rate of more than 10 mSv/h. In the sanitary-protective zone and in the zone of supervision it is 0.12 km² due to parts of the B2 brook and water basin in the state farm "Fryazevo" which contain contaminated silts with dose rate from 2 to 10 mSv/h.

Open joint-stock company "CHEPETSKY MECHANICAL PLANT"

The enterprise is situated in the city of Glazov, Udmurt Republic.

The work with uranium began here in 1949. The source material was uranium concentrates, including those depleted by radionuclides of ²³⁵U, and uranium-containing ores which were processed with the result of obtaining uranium tetrafluoride and metallic uranium. Standard uranium slugs for industrial reactors were made of metallic uranium. The production of standard slugs diminished beginning in 1986. It was transmitted to the Novosibirsk plant of chemical concentrates to which metallic uranium is sent from the Chepetsky mechanical plant.

Liquid radioactive wastes of uranium production in the form of sludge, after being processed with the help of lime, are sent through the pipeline to a plain storage of poured type with a protective dam made of sand-and-gravel mixture and having no filtration-proof barrier. The storage which had been used in 1952-1980 is now under conservation. Its volume is 2.8 mln m³ and its overall activity is 1,5x10¹³ Bq (400 Ci) (low-active wastes). Radioactivity is due to radionuclides of uranium, thorium and ²²⁶Ra. The storage of radioactive wastes now under operation is analogous to the above-mentioned one. It has no filtration-proof barrier either and has been used since 1965. The liquid settled in it and having concentration of uranium lower than 1.8 mg/l, which can be treated as non-radioactive waste, is sent to the underground storage where it is dumped into the depth of 1,500 m. The volume of the storage under operation is 3.6 mln m³ 80% of which is filled in. The overall activity of the wastes in the storage is 5,5x10¹⁰ Bq (1,5 Ci).

Solid radioactive wastes are transported to the site for waste processing where inflammable wastes are burned, outdated machinery is cut and non-inflammable solid wastes are stored.

The overall amount of radioactive wastes accumulated at the enterprise is 4 mln tons.

In the existing disposal of sewage waters into the river of Cheptsa (cooling waters of the thermal-electric station and storm run-off, clarified disposals from ash storage of the thermal-electric station, common disposals after their biological decontamination) the content of radionuclides does not exceed maximum permissible value. In 1995 the overall activity of radionuclides (uranium, thorium, ²²⁶Ra, ²¹⁰Po) in sewage waters (54 mln m³) was equal to 1,2x10¹¹ Bq (3.45 Ci). As far as uranium radionuclides are concerned it amounts to 17% of permissible disposal.

Atmospheric release in 1995 was 9,6x10⁸ Bq (0,026 Ci) of uranium radionuclides, i.e. 74% of maximum permissible value.

As a result of the activity of the enterprise, on the industrial site and in the sanitary-protective zone there are plots contaminated by radionuclides of uranium, thorium, ²²⁶Ra. These are: storages (both conserved and now operating); plots of the industrial site where ores had been heaped in the first years of the enterprise's operation; territories of the old enriching plant and of the now operating uranium hydrometallurgical technological process; the first stage of ash storage of the thermal-electric station which had been previously used for contaminated machinery storing. The size of the contaminated territories on the industrial site is 1.34 km² with dose rate from 0.2 to 2 mSv/h. Some plots have dose rate of more than 10 mSv/h. In the sanitary-protective zone the size of the contaminated plots is 0.01 km² with dose rate up to 10 mSv/h. Specific alpha-activity of the contaminated territories lies in the interval (7,4 - 74)x10³ Bq/kg ((2 - 20)x10^-7 Ci/kg).

The whole complex of measures aimed at the rehabilitation of the contaminated territories has been worked out at the enterprise. A new storage site equipped with filtration-proof barrier will be built as well as a special site for the processing of solid radioactive wastes.

Open joint-stock company "NOVOSIBIRSK PLANT OF CHEMICAL CONCENTRATES"

The enterprise is situated at the outskirts of the city of Novosibirsk.

The work with uranium began here in 1949. The source material were uranium ore and concentrates (before 1978), uranium hexafluoride of various degree of enrichment by ²³⁵U. Chemical processing with the aim of obtaining uranium oxides and metallic uranium is being carried out. The Chepetsky mechanical plant also supplies the enterprise with metallic uranium and the Ulbinsky metallurgical plant supplies it with pellets of uranium dioxide. The end product is standard slugs of natural uranium and fuel assemblies of enriched uranium for various purposes.

Radioactive wastes containing uranium radionuclides are transported by the sludge pipeline to the storage which is situated 7.5 km from the city. The storage is of ravine-poured type with one-row dam.

The first stage of the storage had been operating in 1954-1964 and had no filtration-proof barriers. At present the storage is partly dried out and is overgrown with vegetation. The size of the storage is 0.042 km², the amount of solid wastes is 360 thous. tons with the activity of 7,4x10¹² Bq (200 Ci).

The second stage of the storage has been operating since 1964 up to the present. Its planned size is 0.16 km² and the volume - 950 thous. m³. In fact 800 thous. m³ are filled in with the activity of 2,3x10¹³ Bq (615 Ci). As a result of the filtration of waters, 50 thous. m³ of water runs out from the lowest part of the storage annually. A part of the water is pumped into the storage again and the remaining part gets into nearby rivers and brooks. Taking into account the critical state of the dam of the second stage of the storage, the lowest part of the dam was reinforced with sand, road-metal and other materials in order to make it higher.

The third stage of the storage is designed. It will have clay barrier. Clarified water will be returned to the enterprise.

The overall amount of solid radioactive wastes as of January 1, 1996, is 1,270 thous. tons. Their specific activity is 2,4x10⁴ Bq/kg (6.75x10^-7 Ci/kg) (low-active wastes).

Sewage waters containing radionuclides are not transported into open water reservoirs.

In 1995 atmospheric release of ²³⁸U was 4,8x10⁸ Bq (0.013 Ci) and that of ²³⁵U - 5,2x10⁸ Bq (0.014 Ci), which amounts to 60% and 80% of permitted release, correspondingly.

On the industrial site and in the sanitary-protective zone of the enterprise there are plots contaminated with uranium radionuclides: the first and the second stages of the storage; the territory where the sludge pipeline connecting the industrial site and the storage runs; separate plots of radioactive contamination on the territory of the industrial site; the floodplain of the river of Eltsovka. The size of the contaminated territory of the industrial site is 0.001 km², in the sanitary-protective zone it is 0.047 km² with dose rate up to 10 mSv/h. Rehabilitation measures are being taken on the contaminated territories of the enterprise.

State enterprise "MOSCOW PLANT OF POLYMETALLS"

The enterprise is situated in the city of Moscow on the bank of the Moskva river and is surrounded by highly populated city areas.

In 1932-1972 the plant had been processing radioactive source material containing natural radionuclides of thorium and uranium and had produced thorium and rare earth products of high purity.

At present the plant does not work with radioactive substances. There are neither disposals of radionuclides into water nor their atmospheric releases.

As of January 1, 1996, 0.059 km² is contaminated including 0.004 km² on the industrial site (separate spots) and 0.055 km² in the sanitary-protective zone (the bank of the Moskva river). Dose rate reaches 10 mSv/h, radioactivity is determined mainly by radionuclides of thorium. As far as the contaminated soils of the banks of the Moskva river are concerned, their overall contamination makes it possible to treat them as solid radioactive wastes (low- and medium-level) and plots of radioactive contamination themselves - as uncontrolled storage. The overall amount of the contaminated soils exceeds 126 thous. m³. Taking into account possible landslides of the bank, getting of radioactive substances into water cannot be excluded. Measures against landslides have been taken on the steep bank of the river. It has been turfed. Slow migration of radionuclides in the direction of the river is however still observed.

Data of the investigation of the radiation situation at the enterprise shows that the whole complex of first-priority measures should be taken in order to guarantee the ecological safety of the nearby population. These include: conservation of the abnormal plots of the steep bank to prevent further contamination in the direction of the Moskva river; capture of the surface sewer from the steep bank to prevent dissemination of radionuclides and wash-out of the territory. The project of the fulfilment of corresponding works is being carried out.

Production amalgamation "ULBINSKY METALLURGICAL PLANT"

The enterprise is situated in the city of Ust-Kamenogorsk, Republic of Kazakhstan.

The first product of the radioactive source material - thorium oxalate - was produced in 1949. Since 1953 concentrates of uranium have been processed to get oxides. In 1973 the production of fuel pellets from dioxide uranium powder enriched by ²³⁵U was organized. Up to the present time the end product designed for the manufacture of fuel elements of energy rectors is transported to the Novosibirsk plant of chemical concentrates.

Radioactive wastes containing radionuclides of uranium are transported to the storage.

The data of the results of the inventory of storing and burying of radioactive wastes as of January 1, 1990, are given below.

The old storage (plots 1-4) had been operating between 1953 and 1970. It is situated 1 km from the industrial site and has the size of 0.064 km². Its bottom is compacted with loam and plastic clay. To conserve the storage, local soil was used. The surface of the storage is overgrown with grass. It contains solid wastes of various productions, including 350 thous. tons of wastes of the uranium production with medium level of activity - 10¹³Bq (269 Ci). Dose rate of gamma radiation on the territory of the storage does not exceed background level, i.e. 0.14 - 0.17 mSv/h.

The new storage is situated 2.3 km from the enterprise.

Plot 1c has been operating between 1962 and 1986. Its bottom is compacted with clay. The size is 0.073 km². It was being filled with non-radioactive wastes of beryllium production. After the end of use 1 mln tons of gypsum fluoride was put on the surface of the storage with the aim of conservation. It contains radionuclides of uranium with medium level of activity - 4,5x10¹² Bq (121 Ci). Dose rate on the site of the storage is 0.6 - 10 mSv/h.

The plot of shops No. 1 and No. 3 had been operating in 1970-1986. The bottom is condensed with clay. The size is 0.227 km², planned volume is 1.7 mln m³. Clarified water is not to return to the enterprise. The sewage of various production works was stored in bulk, including 320 thous. m³ of uranium production (low-active) with activity of 9,4x10¹⁰Bq (2.55 Ci). After crossing the planned mark, clarified sewerage was transported to plot 1 or 2. Dose rate is up to 2 mSv/h.

Plot 2 has been operating since 1987. It is of poured type with compacted soil, clay closure and polyethylene layer. Its size is 0.251 km², planned volume is 2.5 mln m³. 620 thous. m³ are filled in with low-active sludge of uranium production, its activity being 1,3x10¹¹ Bq (3.55 Ci). Dose rate is up to 2 mSv/h. The wastes of the beryllium and tantalum productions are also transported into plot 2.

The construction of plot 3 having planned volume of 4.3 mln m³ and size of 0.32 km² was projected.

In 1969-1970 the burial with coating of stainless steel had been operating at the enterprise. It contains 445 tons of solid wastes of uranium production having medium level of activity - 10¹² Bq (27 Ci). Dose rate at the place of storage is up to 0.6 mSv/h.

In 1976 the burial for spent sealed emitters of ionizing radiation having the sump of stainless steel began to be exploited. Its volume is 0.24 m³. As of January 1, 1990, there were the following emitters there: of long-lived isotopes of ²⁴¹Am - 4,4x10¹¹ Bq (11.8 Ci), ⁹⁰Sr - 1,85x10¹⁰ Bq (0.5 Ci), ²³⁹Pu, ⁶⁰Co, ¹⁴⁷Pm, ²⁰⁴Tl - less than 10⁸Bq, as well as of relatively short-lived isotopes of ¹⁷⁰Tm - 2,2x10¹³ Bq (584 Ci), ¹²⁴Sb - 1,1x10¹¹ Bq (2.9 Ci), etc.

As of January 1, 1990, there was the following amount of wastes at the enterprise: solid radioactive wastes - 135.1 thous. tons with the activity of 3,8x10¹³ Bq (1021 Ci); liquid radioactive wastes - 939 thous. m³ with the activity of 2,3x10¹¹ Bq (6.1 Ci).

In 1990 the content of uranium radionuclides in the sewage waters of the enterprise was equal to 4,4x10⁹ Bq (0.12 Ci), which is less than permitted disposal.

Atmospheric release in 1990 was equal to 5,2x10⁹ Bq (0.14 Ci) of uranium radionuclides, i.e. 80% of permitted release.

The overall size of the territory contaminated with radionuclides as of January 1, 1990, was determined by the storages situated in the sanitary-protective zone of the enterprise and was equal to 0.6 km² with dose rate exceeding 2 mSv/h.

REFERENCES

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