Original post by park1996
Why is coolant used in a nuclear power station? Why don't nuclear power stations just heat up water and turn it into steam, why go through the process of heating up the coolant which heats up the water and then turns it into steam.
thanks.
thanks.
The coolant has three functions:
1) to transport excess heat away from the reaction vessel for driving the steam turbines;
2) to moderate the nuclear reaction by slowing down the ejected neutrons
3) to physically separate radioactive materials which are in direct contact with the fuel rods from the steam used to drive the turbines.
Without moderation, the reaction cannot be controlled and excess heat will rapidly melt the fuel rods creating an excess pressure in the reaction vessel which can then result in a pressure explosion spreading highly radioactive material over a wide area.
This is exactly what happened in the Fukushima disaster when the Tsunami flooded the generators powering the coolant pumps and stopped the cooling process. The reactors built up pressure releasing hydrogen gas which then created a chemical explosion.
In the 1986 Chernobyl disaster, poor coolant system design led to an uncontrolled situation during a safety test when the coolant pumps could not spin up fast enough before an explosive pressure built up in the reaction vessel.
Are you OK with this?
Original post by uberteknik
The coolant has three functions:
1) to transport excess heat away from the reaction vessel for driving the steam turbines;
2) to moderate the nuclear reaction by slowing down the ejected neutrons
3) to physically separate radioactive materials which are in direct contact with the fuel rods from the steam used to drive the turbines.
Without moderation, the reaction cannot be controlled and excess heat will rapidly melt the fuel rods creating an excess pressure in the reaction vessel which can then result in a pressure explosion spreading highly radioactive material over a wide area.
This is exactly what happened in the Fukushima disaster when the Tsunami flooded the generators powering the coolant pumps and stopped the cooling process. The reactors built up pressure releasing hydrogen gas which then created a chemical explosion.
In the 1986 Chernobyl disaster, poor coolant system design led to an uncontrolled situation during a safety test when the coolant pumps could not spin up fast enough before an explosive pressure built up in the reaction vessel.
Are you OK with this?
1) to transport excess heat away from the reaction vessel for driving the steam turbines;
2) to moderate the nuclear reaction by slowing down the ejected neutrons
3) to physically separate radioactive materials which are in direct contact with the fuel rods from the steam used to drive the turbines.
Without moderation, the reaction cannot be controlled and excess heat will rapidly melt the fuel rods creating an excess pressure in the reaction vessel which can then result in a pressure explosion spreading highly radioactive material over a wide area.
This is exactly what happened in the Fukushima disaster when the Tsunami flooded the generators powering the coolant pumps and stopped the cooling process. The reactors built up pressure releasing hydrogen gas which then created a chemical explosion.
In the 1986 Chernobyl disaster, poor coolant system design led to an uncontrolled situation during a safety test when the coolant pumps could not spin up fast enough before an explosive pressure built up in the reaction vessel.
Are you OK with this?
Yes, thank you so much. You've helped me out massively.
Original post by park1996
Why is coolant used in a nuclear power station? Why don't nuclear power stations just heat up water and turn it into steam, why go through the process of heating up the coolant which heats up the water and then turns it into steam.
thanks.
thanks.
Some do- they are called Boiling Water Reactors. Liquid water comes in at the bottom and gets heated to boiling when passing through the core. Because they take radioactive steam out of the primary circuit and pass it through the turbines, all the turbines get contaminated.
Original post by Cora Lindsay
Some do- they are called Boiling Water Reactors. Liquid water comes in at the bottom and gets heated to boiling when passing through the core. Because they take radioactive steam out of the primary circuit and pass it through the turbines, all the turbines get contaminated.
yeah, the diagram used by british exam boards, or at least ocr, shows separate reactor coolant and steam circuits. this is the main type used in britain so far (some bwr are proposed for Wylfa afaik)
*possibly* exams in parts of the world where bwr types are more established would use different diagrams.
Original post by Joinedup
yeah, the diagram used by british exam boards, or at least ocr, shows separate reactor coolant and steam circuits. this is the main type used in britain so far (some bwr are proposed for Wylfa afaik)
*possibly* exams in parts of the world where bwr types are more established would use different diagrams.
*possibly* exams in parts of the world where bwr types are more established would use different diagrams.
That's correct. Most UK reactors use CO2 gas as primary coolant and transfer the heat to a secondary water circuit. The Sizewell B Pressurised Water Reactor uses water in both primary and secondary circuits, and the PWR is the most common reactor type worldwide, with BWRs second. Nobody else uses UK-style gas-cooled reactors on any significant scale, although they have some very attractive engineering and operating features.
Some BWRs are indeed proposed by Horizon for Wylfa and its other sites
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