Nuclear waste of Hanhikivi nuclear power plant

Fennovoima is applying for a construction licence for a 1200 megawatt nuclear power plant to be constructed at Hanhikivi in Pyhäjoki, Northern Ostrobothnia.While producing electricity, the nuclear power plant also generates radioactive substances: nuclear waste. The company cannot obtain a construction licence before it has indicated that it is capable of taking care of the waste so that the waste does not cause danger to people or the environment.  The non-harmfulness requirement is strict. The waste must never cause danger.

The waste management safety requirements binding the company are based on the Nuclear Energy Act. Precise, detailed requirements are presented in the safety regulations and guidelines issued by STUK. STUK’s duty is to supervise that the company fulfills the requirements.

Low, intermediate and high active waste

Radioactive waste from the nuclear power plant can be divided into three categories based on its radioactivity: low, intermediate and high active waste.

Low and intermediate-level nuclear waste from the Hanhikivi nuclear power plant would be disposed of permanently in the area of the plant A decision in principle made by the Government and approved by the Parliament is already available for the solution.

Thus there is no decision in principle concerning a final disposal solution for high-active spent nuclear fuel. Regardless of the solution, the waste would be kept in an intermediate storage in the plant area for several decades after it has been removed from the reactor.  It is only after this that it can be permanently placed in a final repository.

Low and intermediate-level nuclear waste placed in the plant area

The radioactivity of radioactive waste decreases with time. One talks about half-life, the time period during which half of the atoms in a radioactive substance change into other substances. In spite of being halved, the low and intermediate-level nuclear waste generated in the nuclear power plant remains radioactive for so long that storing it to reduce its radioactivity to a safe level is not sensible. Therefore, the waste is processed, packed and disposed of permanently.

Typically 50–100 cubic metres of low and intermediate-level waste is generated in a nuclear power plant per year. Fennovoima intends to permanently dispose of the low and intermediate-level nuclear waste from the Hanhikivi nuclear power plant by placing it in a final repository to be constructed in the bedrock in the plant area.

The nuclear power plants of Loviisa and Olkiluoto take care of their own low and intermediate-level waste using the same method.  In Olkiluoto, a disposal facility for low and intermediate-level waste has been in operation since 1992. The Loviisa final disposal facility was taken into use in 1998.

Spent nuclear fuel placed in Finland’s bedrock

Spent nuclear waste emits considerable radiation when it is removed from the reactor. It takes a very long time until the radiation falls to a safe level. However, initially radiation decreases very quickly. In forty years radiation already falls approximately to one thousandth and in a thousand years to approximately one hundred thousandth of the original radiation intensity.  From the point of view of radiation protection, the most important thing in final disposal is to take care of the first few thousand years.

The spent nuclear fuel generated in Finland must be permanently placed in Finland’s bedrock, because it takes a very long time until the radioactivity of spent fuel has decreased to a non-harmful level. Radiation has fallen to the level of the natural uranium from which the fuel was manufactured after approximately two hundred thousand years.

According to the Nuclear Energy Act, spent nuclear waste may not be taken outside Finland’s borders. Spent nuclear fuel may not be imported into Finland either.

The power of Fennovoima’s nuclear power plant in Hanhikivi would be 1200 megawatts and its planned service life is 60 years. Approximately 2000 tons of high-active spent nuclear fuel would be generated in 60 years. The nuclear power plant would store spent nuclear fuel in the plant area for several decades. During the storage, the waste loses much of its radioactivity and it cools down. In forty years, radiation falls approximately to one thousandth of the level that the fuel had when it was taken out of the reactor.

Fennovoima has not yet reported what method it would use in the intermediate storage of spent nuclear fuel - water basins or dry storage. Both the methods are in use in many countries. In the nuclear power plants of Loviisa and Olkiluoto, intermediate storage takes place using water basins. Dry intermediate storages are in use in many other countries.

After intermediate storage, spent nuclear fuel can be packed for final disposal and placed in a permanent final repository. According to Fennovoima’s plans, final disposal would begin in the 2090s.
In Finland, Posiva Oy, which is owned by Teollisuuden Voima and Fortum, is preparing to take care of the final disposal of the nuclear fuel of its owner companies at Olkiluoto in Eurajoki. The Finnish Parliament confirmed a decision in principle for the project in May 2001. Posiva received a construction licence in November 2015.

Unlike in nuclear power plants, final disposal does not involve high temperatures or pressures. Spent nuclear fuel as such cannot explode, and easily flammable substances are not used when packing the fuel in final disposal capsules. Therefore, an accident occurring in a nuclear waste handling facility would only have local effects. In addition, measures must be taken in planning and using a final disposal facility to prevent vandalism and terrorism.

Because radiation must not cause any harm, people can move in nature and pick berries and mushrooms normally, for example, close to the final disposal area even when nuclear waste is being packed and processed.

Licence process

Fennovoima needs licences required by the Nuclear Energy Act for the final disposal of nuclear waste. The licence process is the same as the nuclear power plant licence process.

For the final disposal of spent nuclear fuel, Fennovoima first needs a favourable decision in principle from the Government, which the Finnish Parliament must confirm. After the decision in principle, it can apply for a construction licence for the final disposal facility and after its construction an operating licence, which are granted by the Government.

In view of the ability of the municipality’s inhabitants to influence the decision, the most important licence phase is the first phase, the decision in principle. The municipality has the right to accept or refuse the construction of the plant in its area. The decision is made by the municipal council, but before that the Ministry of Employment and the Economy, which is the licence authority for the decision in principle, will arrange a hearing round in which citizens’ opinions about the matter are asked for.

For the decision in principle, Fennovoima must also carry out an environmental impact assessment, EIA, for the project. There is a specific citizen hearing procedure for the EIA. 22.06.2016 Fennovoima left the environmental impact assessment programme for the disposal of spent nuclear fuel to the Ministry of Economic Affairs and Employment.
Fennovoima already has a decision in principle for the final disposal of low and interme-diate-level nuclear waste, made by the Government and confirmed by the Finnish Par-liament. The plant’s construction licence would be discussed in the 2020s.

STUK’s duties

All licence phases include a safety assessment conducted by STUK. The company must be able to indicate that all the project phases are as safe as required by Finnish regulations. The plant may not cause any danger to the environment or people during its use or after its closure.

STUK’s duty is to supervise and ensure that the safety requirements of the nuclear power plant project are fulfilled throughout the plant’s life-cycle and to provide assessments and statements of the safety of the project in the various phases of the licence process.

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