The Technology Context – B101

Isar 2 Report

Isar 2 nuclear station is in German and it has one reactor active. The type of reactor is classed as PWR (Pressurized Water Reactor). Isar 2 nuclear station generates electricity by a process called chain Reaction, which happens when with a nucleus hits a pack full of Uranium.

Nuclear power has always been a debatable topic in society. In WWII, the nuclear bomb shocked the world and its impacts will forever be remembered. Nowadays the chain reaction in nuclear power station releases power which is hundred times or even thousand times more powerful than the nuclear bomb dropped in Japan. People have good reason to worry about it, especially if the nuclear power station is build near their area, if there is one little mistake, the outcome will be devastating and its affect will last for many generations.

As the Earth’s natural resources such as coal and natural gas are running out day by day, scientist are urgently searching for alternative means of producing energy, Nuclear power has become their favourite. Uranium is a common natural resource like tin, tungsten and molybdenum. Nuclear power is clean and doesn’t release harmful greenhouse gas like coal does. The actual producing energy isn’t expensive but it is expensive because of the money spend on safety and disposal of nuclear waste.

The reason why nuclear energy is very expensive now is because money has to be spent on safety measures. Therefore in this report, I will mainly focus on how Isar 2 resolves the problem with the safety measures, and I will be look into how Isar 2 will deal with the safety measurement in the near future and what social domain effect it has.

To build one nuclear power station needed 7 years but to build the natural gas station or hydraulic station only requires 2-3 years. Also nuclear power stations are very expensive to build. Isar 2 was build in 1988 and cost almost £2 billion. If all components work fine in the nuclear station, it can be operated for 30-40 years. Compared to other types of energy resource, nuclear power station is extremely difficult to build. It has extremely high requirements for the safety, because nuclear stations are on the national security list. If any nuclear leakage or terrorist attack look place, the after effects will be devastating.

Maximum physical shielding

The passive safety features are supplemented by a comprehensive range of automated 'active safety features.' The reliability of these features is based on their multiple redundancies, and on the fact that they operate independently of each other in separate locations.


Above is a Cross-sectional view of a reactor building

Each nuclear facility has got its own power supply so that they don’t rely on each other. The reactor cooling systems are designed to make sure that heat generated by the reactor can be reliably controlled. The electronic reactor protection system is the 'nervous system' controlling all active safety systems. It constantly monitors and compares all the key operating parameters of the plant. Thus, if a parameter reaches a limit value, the reactor protection system automatically triggers the necessary protection measures without any need for input from plant operating personnel. For example, if necessary, the protection system may initiate a rapid shutdown and after cooling procedure.

Passive Safety features

'Passive safety features' are the first-line safety mechanisms used in nuclear power plants. Passive safety structures seal in the radioactive materials contained in the reactor core under all operating conditions (including accidents), keeping them separate from the outside environment. The fuel pellets themselves, the fuel-rod casings, reactor pressure vessel, biological shield, steel containment structure, and outer reinforced concrete shell of the reactor building are the five most important passive safety features

1st feature

Uranium oxide crystal lattice. The reason why for having this is so that uranium is not highly concentrated, therefore the chain reaction later can be controlled.

2nd feature

Metal fuel rod cladding tubes. For the chain reaction, will be separated rather than concentrated in one place. This makes it easier for the operators to control the nuclear chain reaction.

3rd feature

Reactor pressure vessel integrated in the cooling cycle. This is the whole cooling system overview for the reactor.

4th feature

Steel containment structure, so to make sure that there is no leakage of radiation.

5th feature

Reinforced concrete outer shell, extra protection layer.

Controlled chain reaction


The above diagram shows the uncontrolled chain reactions, which is when one reaction triggers another reaction and will have infinite energy produced which could lead to a disaster.



The above shows the controlled chain reaction, where high speed neutrons make the first reaction with a set of uranium and then go through the water molecules which acts like a resistor, for slowing the neutrons down.

Nuclear Disposal

The radioactive waste products produced by Isar 2 nuclear power plants spent fuel elements warrant the most careful consideration because they pose the greatest radiation risk. Up until recently, Germany's laws on radioactive waste disposal allowed only two options for dealing with spent fuel elements: reprocessing or direct permanent storage.
However, Germany does not yet have a permanent storage facility, so up until recently the practice has been either to reprocess the elements or send them directly to central temporary storage facilities in Ahaus and Gorleben. The reprocessing waste was vitrified (incorporated into glass moulds), placed in purpose built containers, such as Castor canisters, and then transported to one of the two central temporary storage facilities.


But however, Isar 2 does have temporary storage facilities on site and the above diagram, shows the whole process for disposal of nuclear wastes.

Isar 2 disposes the nuclear the nuclear waste by transporting to developing countries in Africa and elsewhere and burying it in deep geological storage. People are still advocating burring it indefinitely at ground level. Though something many scientists have opposed for years. Disposal is still a problem and so what to do with nuclear waste is still attracting media attention.

Because of this, some European governments started to be concerned about safety and the environmental issues and some nuclear station were scheduled for decommission. Some north European countries even passed a law that before 2010 all the existing nuclear power plants should be shut down. According to the International Energy Agency – IEA, in the near future the usage of nuclear energy will be decreased, from the present’s 17% down to 8% in 2020.

At the moment, in Asian countries like India, they are committed to building six new nuclear reactor, Isar 2 is considering selling some equipment to Indian companies.

But Isar 2 is still committed to give its full power, E.ON company states that there are only reasons for giving up nuclear power, the first factor is when the nuclear energy can be replaced by the natural gas and the second is the public sensitivity to nuclear waste. Until then Isar 2 is still be scheduled for decommission in 2040.

From the information gathered, it would appear that nuclear energy is better than most types of energy resources. However, nuclear energy suppliers need to spend more money on safety issues. Therefore I believe that in the future, as technology becomes more advanced, we will find safer ways to use nuclear power and handle its waste. Then maybe nuclear energy will play a more major part in our lives.

Reference

• http://www.eon.com/
• http://www.uic.com.au/
• http://www.heise.de/bin/tp/issue/r4/dl-artikel2.cgi?artikelnr=24691&zeilenlaenge=72&mode=html
• http://www.kernenergie.de/r2/de/
• http://www.world-nuclear.org/
• http://www.euronuclear.org/
• Book: Journal of Nuclear Energy By Elsevier Science (Firm)
• Book: Annals of Nuclear Energy By Elsevier Science
• Book: Preparing the Ground for Renewal of Nuclear Power By Behram Kurşunoğlu, Stephan L. Mintz, Arnold Perlmutter
• http://www.eon.com/
• http://www.world-nuclear.org/education/phys.htm
• http://www.eon-kernkraft.com/frameset_german/nuclear-power-plant/nuclear-power-plant_locations/energy_nuclearpower_kkisar1.jsp
• http://library.thinkquest.org/17940/texts/fission_power/fission_power.html
• http://ocw.mit.edu/NR/rdonlyres/Nuclear-Engineering/22-812JSpring2004/55ABD4F2-4FF8-4386-9055-D8F1C38A2193/0/lec15note.pdf