Nuclear power station

What does fusion mean?

In certain conditions, two light atomic nuclei (e.g. hydrogen isotopes, deuterium and tritium) can fuse to form a heavier nucleus. This nuclear reaction produces a very large quantity of energy per reaction. This is how the sun and stars produce their energy.

The military uses fusion to create thermonuclear hydrogen bombs. Controlling electronuclear fusion is technically very demanding. Research carried out since the 1960s has not yet enabled a reactor to be designed that is capable of producing electricity.

What is meant by the classification of a nuclear power station?

Nuclear power stations, which are the main use of nuclear in the civil sphere, are industrial sites that produces electricity. They use one or several nuclear reactors, a kind of boiler, to produce heat that vaporises the water present. The water vapour then causes a turbine to rotate which is coupled to an alternator. It is the alternator that produces the electricity. The electrical output of the reactor varies from several megawatts to around 1,500 megawatts.

There are several different types of nuclear reactors of different classifications:

  • boiling water reactors;
  • reactors that use natural uranium and are graphite-moderated or moderated by heavy water;
  • pessurised water reactors;
  • gas-cooled reactors;
  • fast neutron and sodium-cooled reactors.

Pressurised water reactors (PWRs) are the most widely used classification of nuclear reactor.

How do pressurised water reactors work?

Pressurised water reactors (PWRs) are the most widely used classification of nuclear reactor. These reactors use the energy produced by nuclear reactions to produce heat. This heat turns water into water vapour which is then used to turn a turbine and then an alternator that produces electricity. This principle of transforming heat into electricity is the same as that used in all other thermal power stations which instead use fossil fuel to produce their heat. Boiling water reactors and gas-cooled reactors are also both used in Europe.


Are there any nuclear power stations located close to Luxembourg?

The three countries that neighbour the Grand Duchy of Luxembourg all have nuclear sites located within a 100 km radius that produce over 10,000 megawatts of electricity (MWe).

The closest nuclear reactors, those at Cattenom in France and Tihange in Belgium, are all pressurised water reactors.

In France

  • Cattenom

The closest nuclear power station to Luxembourg is Cattenom in France, which is located 8.5 km south of the border and 25 km from Luxembourg City. This nuclear power station has four pressurised water reactors each with a power output of 1,300 MWe. The first started production in April 1987 and the fourth in January 2012. Cattenom nuclear power station is France's second largest in terms of electricity production.

  • Chooz

There is a second French nuclear power station in Chooz, 70 km west of the border with Luxembourg. The station has two sections (Chooz A, a Franco-Belgian constructed and run project, and Chooz B, a French project) with three 1,450 MWe nuclear reactors.

In Belgium

  • Tihange

The Tihange nuclear power station is located 65 km north-west of Luxembourg. The three reactors have an overall output of 3,016 MWe and account for around 30% of Belgian electricity production.

In Germany

  • Biblis

The Bibis nuclear power station is one of the oldest in Germany, and has been inactive since March 2011 following the decision of the federal government of Germany to stop using civil nuclear power.

  • Philippsburg

The Philippsburg nuclear power plant has two reactors: the first unit, a boiling water reactor with an output of 926 MW, was shut down in March 2011 and the second unit, a pressurised water reactor with an output of 1,458 MW, will be shut down in 2017.

Is it possible that a nuclear accident could occur at one of the power stations nearby?

A nuclear reactor produces huge amounts of energy and radioactive substances inside the reactor tank (the reactor core). This radioactivity continues to produce heat, even after fission reactions cease. An active reactor cooling system remains necessary to keep the reactor core temperatures reasonably low. This cooling system requires a large volume of cold water and electricity to supply the pumps. Without this cooling system an accident is inevitable.  This is why a nuclear accident can never be ruled out. The different barriers and safety systems do however reduce the likelihood of an accident.

What happens when a serious nuclear accident occurs?

In a pressurised water reactor, the most serious accident that could occur is if the active cooling system of the reactor core stops functioning. This causes the core to fuse (partially), a scenario that could lead to the reactor core melting and the tank being destroyed. In general, if the reactor building is not destroyed then the radioactive products can remain contained in the building for a period of up to 24 hours. In such a case, there will only be low levels of radioactive substances released which will not pose any particular risk to the population. This temporary retention enables the emergency services to implement measures to protect the population.

If after a certain period the pressure inside becomes too great, the reactor will no longer be contained and the ventilation system will open. In the nuclear reactors close to Luxembourg, the ventilation systems are equipped with filters that would substantially reduce the quantity of radioactive substances released.

The nuclear accident at Three Mile Island of 28 March 1979 in the United States is an example of an accident with core fusion where radioactive substances that resulted from the fusion were kept within the containment structure (concrete building inside which the tank, the reactor core and the vapour generators are located).

In contrast, during the accident at Fukushima on 11 March 2011 that was caused by an earthquake and tsunami, hydrogen explosions caused a breach in the containment enclosure and large quantities of radioactive substances were released.


What does fission mean ?

Fission is a nuclear reaction that consists of projecting a neutron onto a heavy unstable atom (uranium 235 or plutonium 239). The atom absorbs the neutron by splitting into 2 lighter atoms. This produces energy, radioactive radiation and two or three neutrons capable of causing another fission. The continuation of this reaction is called a chain reaction. The energy that is produced by this fission reaction is used to heat water in nuclear power stations to produce electricity.


How can a chain reaction be controlled?

The design of the nuclear power stations currently in use in the European Union guarantees, by the laws of physics, that the fission reaction is balanced.  Any increase in temperature leads automatically to a reduction in the number of neutrons which then reduces the number of fissions and therefore heat production.

There was no such a mechanism for self-regulation in the reactors at Chernobyl nuclear power station. This design fault was the cause of the accident at Chernobyl on 26 April 1986.


What are the main factors that influence the consequences of a nuclear accident?

Every nuclear accident is different because the consequences of an accident vary greatly depending on the quantity of radioactive substances released and on weather conditions.

The amount of radioactive substances released depends on the accident itself and the safety systems available in the reactor at the time of the accident.

Weather conditions determine the dispersal (direction and distance) of the radioactive releases.

This is why in the event of an accident, measures to protect the population are based on a radiological evaluation and generally only concern part of the territory within the planning zones.


Could an accident such as the one at Fukushima occur at Cattenom?

It is not possible to completely rule out a serious accident occurring at one of Europe's nuclear power stations. It should however be noted that the situation that resulted in the accident in Japan, a combination of an earthquake and a tsunami, is very unlikely to occur at Cattenom. The Cattenom power station is effectively located 22 metres above the level of the Moselle river and in an area with low levels of seismic activity.


Could an accident like the one that occurred in Chernobyl happen at Cattenom?

The design of the nuclear power stations currently in use in the European Union guarantees, by the laws of physics, that the fission reaction is balanced.

Any increase in temperature leads automatically to a reduction in the number of neutrons which then reduces the number of fissions and therefore heat production.

There was no such a mechanism for self-regulation in the reactors at Chernobyl nuclear power station.

This design fault was the cause of the accident at Chernobyl on 26 April 1986.


Is Luxembourg prepared for a nuclear accident?

Oui. Il n’y a pas de centrale nucléaire au Luxembourg, mais la proximité des centrales française de Cattenom et belge de Tihange a amené le gouvernement du Grand-Duché de Luxembourg à élaborer un plan d’intervention d’urgence en cas d’accident nucléaire (PIU) tels qu’ils existent dans tous les pays. Ce plan décrit l’implémentation des mesures nécessaires à la protection de l’ensemble de la population.

Les principales mesures de protection sont :

  • la mise à l’abri ;
  • la prise de comprimés d’iodure de potassium ;
  • et l’évacuation d’une partie de la population.

Le plan d’intervention d’urgence en cas d’accident nucléaire prévoit également une communication étroite entre les autorités, les médias nationaux et la population.

Les acteurs centraux de la gestion de crise sont :

  • la Cellule de crise ;
  • la Cellule d’évaluation radiologique ;
  • et la Cellule communication / information.

What is the difference between an incident and an accident?

In order to distinguish between the different types of incident and accident and their scope, the International Atomic Energy Agency (IAEA) in Vienna has developed an international classification scale for nuclear events called the INES scale (International Nuclear Event Scale). This scale is divided into 8 degrees of safety risk. As a classification tool, this scale aims to make the severity of civil nuclear accidents and incidents more understandable for the media and the public.


What direct consequences could a serious accident at a nuclear power station have?

In the event of a serious accident at a nuclear power station, there is a risk that radioactive substances could disperse, which could pose a risk to both man and the environment. In the unlikely event that the power station's systems AND the safety barriers fail, a radioactive cloud could escape and spread throughout the environment.

Which types of radiation could be emitted from a nuclear power station as the result of an accident?

In the event of a serious nuclear accident, several types of toxic radioactive elements can be released, including caesium and strontium. However, the most dangerous is iodine 131, a radioactive isotope which has a very short half-life (8 days) and is highly radioactive. It is particularly dangerous as it attaches to the thyroid gland.

Iodine-131 and caesium-137 make up the bulk of the radionuclides released following a nuclear accident.

What are the different phases of a nuclear accident?

There are two separate phases in a severe nuclear accident:

  • the nuclear alert phase;
  • the post-accident phase.

The emergency response plan for nuclear accidents drawn up by the government provides for a series of measures that will be triggered in each of the two phases.

The nuclear alert phase includes:

  • the threat phase;
  • the release phase.

The same is the case for the post-accident phase, with specific measures triggered for:

  • the  transition phase;
  • the management phase for long-term consequences.

If there is a nuclear accident, will there be a nuclear explosion?

No. Nuclear power plants are designed so they will not explode.

The consequences of an accident at a nuclear power station are not the same as those of an atomic bomb exploding. An accident at the Cattenom nuclear power station would not cause the pressure or heat waves that the explosion of a nuclear bomb would. It is therefore unlikely that there would be any immediate victims outside of the nuclear site as a result of the direct effects of the nuclear accident. However, an increase in long-term illnesses including cancer is likely.

Nevertheless, il is not possible to completely rule out that an explosion could occur within the reactor walls as a result of the presence of hydrogen. Although somewhat unlikely as the power station is equipped with systems to recombine hydrogen, such an explosion could be large in scale and could lead to the containment being opened and therefore entail a significant increase in the radioactive substances released.

What to do in the event of a nuclear alert?

The Luxembourg government has published a brochure entitled 'What to do in the event of a nuclear alert?' which both lists the alert procedures and protective measures set by the emergency response plan and informs the public about what to do if there is a nuclear accident at Cattenom.

Distributed to all households in Luxembourg, this brochure is available in several languages on the website

In the event of a severe nuclear accident, the concerns of the authorities will focus primarily on the protection of the population against any exposure, or even contamination, as a result of radioactive release. The implementation of the corresponding measures depends on the severity of the accident.

Any decision relating to the implementation of a measure will be communicated to the population via the media and on the website

You should listen to one of the national radio stations and remain calm.

Has Luxembourg signed cooperation agreements concerning nuclear sites with its three neighbouring

The government of the Grand Duchy of Luxembourg has signed specific agreements with France and Belgium on nuclear cooperation. These agreements form the basis of the following exchange protocols and procedures:

  • the protocol regarding the alert and the exchange of information in a radiological emergency between France and the Grand Duchy of Luxembourg;
  • the procedure for notifying and providing information to the Luxembourg authorities in the event of an incident or accident at the Cattenom nuclear electric power station;
  • the procedure for notifying and exchanging information between the Luxembourg, Belgian and Dutch authorities in the event of nuclear crisis situations that could have cross-border consequences.

Bilateral agreements have also been signed on civil protection for the event of a nuclear emergency and operational contacts have been established with the civil protection authorities of neighbouring countries.

On a European level, the ECURIE alert system (European Community Urgent Radiological Information Exchange) enables Member States to exchange information in the event of a nuclear emergency. This computer system, with a star-like configuration, enables a State to launch an alert if a nuclear accident that could have cross-border consequences occurs at one of its power plants. In the context of the European Civil Protection Mechanism, the CECIS system (Common Emergency Communication and Information System) enables exchanges to be carried out and mutual assistance to be provided between all the European Union's civil protection authorities.


Do the partners of the Greater Region work together?

Yes. The different stakeholders involved in the response to a nuclear emergency within the Greater Region regularly organise exercises or participate in bilateral and international exercises. The aim of these (inter)national exercises is to prepare for a possible radiological or nuclear accident by training the response teams from the emergency services and the Armed Forces in rescue and decontamination. Some of these are simple exercises for the communication and exchange of radiological data, while others are more complex and focus on implementing national emergency plans.

The scenarios are prepared by the Institute for Radiation Protection and Nuclear Safety (Institut de radioprotection et de sûreté nucléaire, IRSN) in France and simulate a serious accident with the risk of core meltdown. These exercises are carried out in real time with a real alert raised to the authorities and real meteorological conditions.

The exercises enable various procedures to be tested, including  transmitting an alert, putting in place the respective crisis centres,  implementing communication procedures, information on the evaluation and  prognosis of the installation, information on the radiation situation  and shared information on the decisions taken/envisaged etc.

In 2012 and 2013, Luxembourg took part in a series of 3 cross-border crisis management exercises focussing on potential problems with the Cattenom nuclear power station. The first exercise, organised under the presidency of Saarland, focussed on activating the crisis cells and the cross-border measures for sharing information. The second, managed by Luxembourg, concerned extending emergency measures and planning for evacuating the population. The third concerned post-accident management and was organised by France.

In the same context, Luxembourg took part in several International Nuclear Emergency Exercises (INEX) organised by the Nuclear Energy Agency (NEA) of the OECD (Organisation for Economic Cooperation and Development).

Is there regular and transparent information available about Cattenom?

On 20 April 2011, a Special Summit of the Greater Region was held in Metz to discuss the safety of nuclear power stations in the Greater Region in general, and the Cattenom site in particular. Faced with the legitimate expectation of the inhabitants on both sides of the border to receive clear, transparent and reliable information on the conditions in which the nuclear site functions, the decision was taken to expand the membership of the Cattenom Local Commission for Information (Commission locale d’information de Cattenom, CLI) in order to bring in other affected parties from the Greater Region.

The CLI is responsible for circulating the results of its work in an accessible form as widely as possible to provide information for the public.

Following the Summit of the Greater Region, in 2012 the CLI was opened up to cross-border partners from the Greater Region that had previously only been observers. Luxembourg is represented by the High Commissioner for National Protection and a representative from the Association of Luxembourg Towns and Communes (Syndicat des villes et des communes luxembourgeoises, SYVICOL).

Another consequence of this expansion is that the CLI's information bulletin, 'La Lettre de la CLI' (the CLI's letter), which has been published since 2008, is now also translated into German.

If a nuclear accident occurs at Cattenom, will information be exchanged between the countries involved?

Yes, in the event of a nuclear emergency, sharing information with neighbouring countries will play an important role in ensuring that all the necessary data is available to implement the different measures included in the government's emergency response plan.

Luxembourg signed an agreement with France in 1983 regarding sharing information in the event of an incident or accident that could have radiological consequences. This agreement provides for the following provisions regarding:

  • shared information immediately following incidents or accidents that occur in the territory of one or other of the States, which could have radiological consequences affecting the territory of the other State;
  • the implementation of an appropriate system for sharing information available 24 hours a day;
  • the nature of the information to be shared;
  • sharing liaison officers in the event of the implementation of response plans.

In order to settle all bilateral issues related to nuclear security and safety, a joint Franco-Luxembourg Committee was created in 1994 alongside two technical groups to solve practical and technical issues related to nuclear security and safety, radiation protection and civil security.

In the event of an accident the manager of the Cattenom power station shall inform the Luxembourg authorities by means of the SELCA system, the System of exchange and liaison between Cattenom and the authorities (Système d’échange et de liaison entre Cattenom et les autorités), a network of dedicated telephone lines which act as a direct link between the different command posts in the event of a radiological emergency.

The German Länder Rhineland-Palatinate and Saarland are also part of this system.

If necessary can Luxembourg count on international assistance?

Yes, depending on the situation, the Luxembourg authorities can request international assistance to help organise a response to the crisis.

In 1986, Luxembourg signed two International Atomic Energy Agency (IAEA) conventions, one of which, the Convention on Assistance in the Case of a Nuclear Accident or Radiological Emergency, enables a country to offer or request assistance in the event of a nuclear accident.

Twice a year, the members of the convention meet and review their joint activities and plan new ones. These revisions are based in particular on:

  • member States' preparation of emergency plans;
  • organising and executing international exercises;
  • cross-border cooperation, information exchanges and the organisation of exercises;
  • the means of communication and information exchange in a nuclear crisis with identification of the points of contact and warning of the contracting parties;
  • the harmonisation of emergency plans and regional levels of response;
  • the development of technical documents to help countries: prepare emergency plans and exercises.

Can Luxembourg's civil protection count on European assistance?

If the scale of an emergency situation proves too great for its national response capacity, a country hit by a disaster can obtain coordinated assistance from the countries participating in the European Civil Protection Mechanism :

  • In 2001, the European Union created the European Civil Protection Mechanism which currently has 32 participating countries,
  • At the heart of this civil protection mechanism is the Emergency Response Coordination Centre (ERCC) which is managed by the European Commission's Humanitarian Aid and Civil Protection department (ECHO). It facilitates communication on a daily basis and in the event of a crisis and coordinates the actions of the teams and resources for civil protection within and outside of the Union. This centre is operational all year round, 24 hours a day ;
  • The type and scale of civil protection operations deployed depend on the resources of the participating countries. Most participating States offer their help free of charge, to show their solidarity with the country hit by disaster. This assistance could take the form of aid in kind, sending teams and material and deploying experts to help evaluate and coordinate European action.

As a member, Luxembourg has recourse to these instruments should the need arise.


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