653 Technical project description

Figure 3-9. Fuel pellets and manufacture of fuel rod bundles. 3.7.2.4 Transport and storage in the nuclear fuel produc- tion chain

At the concentration plant, the natural uranium concen- trate is packed into 200-liter drums, which are loaded into containers and transported by ship or by train to interme- diate storage and the conversion plant. The uranium con- centrate is only slightly radioactive, and the steel transport containers provide adequate radiation protection. The transport only requires equipment suitable for transporting hazardous materials.

After the conversion, the uranium hexafluoride is stored in a solid form in pressurized 8.45-ton containers, in which it is transported to the enrichment plant using a train or trucks. As uranium hexafluoride is chemically highly toxic, appropriate precautionary measures are applied in the transport operations.

For transportation, the enriched uranium is packed, in solid form, into containers similar to the ones used to transport it to the enrichment plant. The transport con- tainer has a double structure, and it is thermally protected to withstand, for example, a fire occurring during an acci- dent (Figure 3-10).

The fresh nuclear fuel elements are transported from the fuel production plant to the nuclear power plant in special containers which protect the fuel elements during transport (Figure 3-11). Due to low radioactivity, no special radiation protection is required.

3.7.3 Quality and environmental objectives set

for the supply chain of nuclear fuel

The quality requirements set for nuclear fuel are associated with the functionality and reliability of the fuel. Included in the scope of functionality are the flexibility of use, high energy yield, and long service life in the reactor. Reliability

means that the fuel rods remain in good condition under all operating conditions as well as exceptional conditions. The design and manufacture of fuel rod bundles is gov- erned by strict quality standards. Fuel manufacturers and buyers have comprehensive quality control programs and procedures in place in order to ensure that the fuel rod bundles comply with the set requirements. Quality control includes the performance of specific tests and inspections on the fuel materials, assemblies, and their components, as well as the equipment used to manufacture them. Quality assur- ance is based on inspections performed by external auditors as well as control of the test and inspection results, the pur- pose of which is to ensure that the work processes in differ- ent manufacturing phases and the associated inspections are carried out in compliance with requirements and that the end result meets the requirements set for it. The programs must comply with the requirements set by the national nuclear power authorities of the home countries of both the producer and the purchaser. In addition, all major nuclear fuel suppliers apply in their operations the international quality management standards, as the ISO 9000 standard. As required by the Nuclear Energy Decree, the Radia- tion and Nuclear Safety Authority (STUK), supervises the compliance of the design, manufacture, transport, storage, handling, and use of nuclear fuel with the relevant rules and regulations. The requirements pertaining to the phases listed above are presented in the STUK regulatory guides on nuclear safety dealing with nuclear materials.

In addition to quality parameters, the buyers also pay attention to the environmental aspects of the fuel produc- tion process. Issues relating to environmental impacts are assessed according to criteria set by the buyer’s own envi- ronmental policy. The fuel suppliers may be expected to have in place an environmental management system or oth- erwise prove that environmental matters are managed in an

66 3 Technical project description

acceptable manner. The minimum requirement is that the operations of the producer comply with national legislation and regulations.

WNA, WANO (World Association of Nuclear Oper- ators), and IAEA (International Atomic Energy Agency) have produced international instructions and guidelines concerning the best practices to be observed in the different phases of nuclear fuel production with regard to both safety and the environment. In particular, the principles of the WNA guidelines are intended for countries where legisla- tion has not yet reached a standard where sufficient consid- eration of issues such as environmental matters would be ensured. (WNA 2008)

The buyers of nuclear fuel carry out audits in the com- panies and production plants operating at the different stages of the uranium production chain. One purpose of the audits is to form an idea of the standard of environmental protection management in the companies comprising the fuel production chain, the degree to which environmental regulations and standards are observed, and the manage- ment of industrial safety matters.

During the audits, attention is paid to matters such as emissions caused by the operations and the monitoring

thereof, transportation, subcontracting, contribution to services for the local population, safety and security, risk analyses, handling of exceptional situations, and radiation protection. In the audits, attention is also paid to possible areas of improvement, which are discussed with the produc- tion company.

3.8 Use of chemicals

According to the legislation governing the use of chemi- cals, the chemicals to be used should, if possible, be selected among the least harmful ones. Approximately 200 tons of various chemicals will be used at the nuclear power plant every year. The majority of the chemicals will be various acids and bases used in the production of power plant process water and the control of chemical reactions in the plant’s water circulation systems. Chemicals will also be used for cleaning the closed steam cycle equipment and pipelines and preventing corrosion. The most frequently used bases and acids, such as sodium hydroxide, sulfuric acid, and boric acid, will be stored in tanks with volumes of 20–50 m3_{.Other chemicals will be stored in various con-}

Figure 3-10. Enriched uranium transport containers. (E.ON 2008)

Figure 3-11. Transport containers of fuel rod bundles. (E.ON 2008)

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