27 April 2011

A Visit at the Areva Nuclear Power Plant

Not long ago I discovered the Areva Nuclear Plant - a educational project by the University of Denver. It is sponsored by AREVA, a industrial conglomerate and world market leader in nuclear technology.

The plant itself is located besides several other sims dealing with science topics. Since the Fukushima disaster nuclear power is again worldwide controversial discussed so I decided to do my part to shed some light on this - for many people still pretty mysterious - technology.
While making my way through the pretty impressive complex the obviously biased display of nuclear power left quite a bad taste though.

The Areva Nuclear Power Plant complex as seen from the air. 
Since the AREVA Power Plant is a full-scale replica the whole complex looks pretty overwhelming first. But lets go through it step by step: In the front you can see the building where the emergency power supply is located. Behind it the reactor building and the concrete dome of the containment structure of the reactor itself can be seen. Apart from the cooling towers the massive concrete dome is perhaps the most distinctive part of a nuclear plant. Since I haven't discovered any cooling towers on the AREVA-Plant I assume the it works with fresh-water cooling using the adjacent sea-water like the Fukushima Plant. Thats pretty typical for plants located near the coastline. On the left side are the turbine- and transformation buildings located.

Starting point of my exploration was the Uranium Cafe not far from the power plant itself. The name and classical style of the cafe began to make me wonder since nuclear power seems to be a bit too "cool" there...

A quite nicely made diner indeed. If it just wont remind me on the naivety towards nuclear power they had in the 1950s...

Outside some pure porpaganda did await me. Links to pro-nuclear-power websites, groups, posters and books like on the welcome-point shown below.

I don't feel like smiling: Obviously the university's views on nuclear power are not the most balanced: Clicking on the smiling cooling towers gives you a link to join a group which tells you the "The Truth About Nuclear Energy" according to its charter...

They also offer a "tour bus". Too bad its a pure sightseeing ride giving you no additional information about the site like an automatic tour guide using open chat.

After the rather disappointing tour I decided to explore the place on my own. Luckily the blue chairs you can find almost everywhere are offering a comfortable teleport service. First I headed to the control room.

Some schematics of the reactor core and the coolants. Its a pressurized-water-reactor like the majority of modern reactors.

The reactor vessel itself is located beneath the containment structure consisting of several meters of steel enforced concrete.
The plant uses the heat caused by nuclear reaction for producing electric power. Its fuel is usually uranium-235, which produces neutrons at its natural radioactive decay. If a neutron hits another uranium-235-nucleus it splits into lighter (radioactive) elements producing more neutrons which also hit uranium nuclei which again release neutrons... etc - a fission chain reaction has started.

  A pretty handy feature: Clicking a red ball hovering above the reactor reveals whats usually well covered. The reactor's fuel rods and the flow of the primary coolant.  
To keep the nuclear reaction under control neutron absorbers can be moved in between the fuel rods for limiting the amount of neutrons hitting other uranium-235 nucleus.

A nuclear reaction however not only produces heat but also a high degree of radioactive radiation which requires massive shielding to protect the environment from.

In Fukushima the fuel rods did melt due to the failure of the cooling system and the nuclear reaction became totally uncontrollable. The heat eventually became that high the containment structure - as well as most likely the reactor vessel itself - did break. Releasing deadly radiation into the atmosphere.

 The reactors primary coolant constantly  transports the heat produced by the nuclear reaction away from the core.

The hot and high pressurized water  (red valves) goes to the heat exchanger where the heat gets transferred to the secondary coolant.

Both coolants never get in direct contact for preventing any exchange of radiation. The cooled down water from the primary coolant returns again into the reactor core closing the circle.

The high pressurized steam of the now heated up secondary coolant drives several turbines which transform the high pressure into electric power.

The transformer building which transforms the electric power to the needed voltages.

These transmitter eventually feed to the public grid. The dolphin joyfully jumping out of the water is a bit much don't you think?

Used nuclear fuel rods were stored into the cooling pond.
The used fuel rods contain - besides leftover uranium - the highly radioactive fission products cesium, iodine and strontium. The cooling process of these rods takes months and needs constant maintenance to prevent a meltdown.

  Two huge diesel generators represent the plants emergency power supply.  
The diesel generators were the part of the power plant in Fukushima which got destroyed by the tsunami leading to the meltdown of several reactor blocks. These days is also the 25th anniversary of the Chernobyl-disaster in 1986. Of the about 800,000 people who were deployed there as "Liquidators" some 50,000 - 100,000 have died until today.

Despite having my doubts about about whether to post this rather serious article here among usually rather cheeky and playful entries I feel the topic is too important to just go over it. The University's close connection to the AREVA conglomerate and its way of praising nuclear power was the main reason. Claiming this enormously dangerous technology as the only practical way to fight global warming is an alarming belittlement and distortion of facts I haven't really expected by a rather renowned institution.

1 comment:

  1. Rudy Barbarossa30 April 2011 at 02:02

    Thank you for doing this entry. Timely and informative.