Why Nuclear Power Increase, When Cooling Water Temperature Increase?

I hope your not planning on becoming a nuclear power plant operator. If this is a school study problem, you need to start the class again.

If I understand your question, all HEAT engines require a differential temperature between their cold and hot operating conditions. Their output power and efficiency depend on this temperature difference. If you raise the cooling water temperature to keep the output power the same, the heat source temperature must increase, which means more energy from the nuclear fission source.

See Carnot thermal efficiency equation.

If you want 100% efficient engine with low differential temperature, just use absolute zero as the cold heat exchanger.

In laymen's terms:

Nuclear power generation is the result of a thermo-nuclear reaction event.

The energy from increasing CW temperature accelerates the nuclear reaction by adding further thermal excitation to the atoms causing the electrons orbit(s) to become more unstable.

This instability in the electron orbits increase electron collisions which in turn produces more nuclear reaction energy.

If not checked/controlled, the reaction can reach the point of thermal runaway very quickly.

You mean Neutrons.

i think ,its is not correct answer.

because when cw temperature increase,its increase condensate temperature.

if condensate increase temperature, we need less thermal power required to heat up .

I am reminded yet again of my argument with a colleague regarding why thugs on movies pushed their gun forward before firing a bullet. My colleague incorrectly said it was to increase the speed of the bullet, you are effectively trying to say the same thing (sort of). Do you think there be a measurable difference in speed in this case? Do you think the speed difference is anywhere near significant?

Consider carefully what a few degrees difference would actually make when you look at the whole nuclear power plant system process loop. Will there be a measurable difference? Now do you think the increase in loop efficiency is anywhere near significant? If it were you would be preheating the water using power from the nuclear reactor as a standard practice.

In the operation of a nuclear power plant it actually does not increase due to operational and environmental procedures. The nuclear plant has a maximum limit on their cooling water discharge temperatures. They also have inlet water coming in to be used to provide this cooling. The nuclear operators must regulate the volume of the inlet water to compensate for its temperature and the temperature of the discharge water. Too much cooling water and the reactor power generation rate goes down. Not enough and the discharge water gets too warm. Change this so it is out of balance and big problems happen.

The first commercial nuclear power plant in the US, Oyster Creek Nuclear Generation Station, Oyster Creek, NJ, had a series of these temperature deviation incidents. When it started operation the discharge water, which flowed out of Oyster Creek, a tributary of Barnegat Bay, the temperature increased so much that it was killing fish since they were attracted to the warm water. It also brought ship worms from southern states which ate up wooden boats and docks. In another incident the reactor was shut down quickly because of an emergency and there was a fish kill because the water temperature went down so quickly. Nothing similar has happened on the intake located on Forked River, an adjacent tributary of Barnegat Bay. These incidents have happened numerous times since it began generating electricity in 1969.

http://www.nrc.gov/info-finder/reactor/oc.html

http://elr.info/sites/default/files/litigation/6.20352.htm

Theory is fine but the world doesn't work in theoreticals.

Good Luck, Old Salt

in winter temperature 1o c

temperature of water is less and less flow pass in condenser and also nuclear power is less

in summer temperature 25 c

temperature of water is increase and flow also increase in condenser and nuclear power also increase

when cw temperature increase,condensate water also increases.

logical we need less thermol power required to heat up this water.but thermal and nuclear power increased,please tell me why?

In a commercial nuclear power plant there is not change in thermal and nuclear power unless the operators plan it. In order to maintain the same power they will adjust the input water volume/time with temperature to maintain the same power level, usually 100%. If intake water is a lower temp, example 4^oC, they use less intake water to maintain the desired cooling. If the intake water is 25^oC, they will increase the volume of intake water at this higher temperature to maintain the same power level. With good operators, which the NRC demands, consistent power levels are maintained. There is no change in thermal and nuclear power. Balance the water and rods and the system runs nice. Remember Chernobly?? Too much rod and not enough cooling water.

Good Luck, Old Salt

This is a question about any "Main Steam Cycle" System. Could be nuclear or oil or coal or whatever.

The purpose of the condenser is to change the low enthalpy steam effluent from the turbine back to liquid water so that the main steam cycle and continue.

A warmer condenser will have a lower operating vacuum. ( The saturation temperature of the steam will be higher with a lower vacuum ---a higher absolute pressure.)

Less enthalpy is extracted from the steam as the turbine exhausts into the warmer condenser. This means that the main steam cycle is less efficient overall. (Fewer calories are being extracted from the main steam.)

So, if the load remains the same and the other factors affecting plant efficiency remain the same, the power input into the main steam system has to increase as the pressure in the condenser rises. ( As the vacuum decreases.)

Since the same power is drawn by the load, and the plant operating losses are considered to remain the same, the power has to go up to compensate for the reduced efficiency in the condenser.

Of course the hotwell temperature does actually matter, but this is a school question, and they often forget to tell you what to ignore. The part of the energy needed for preheating of the condensate is probably prob'ly coming from aux exhaust or some other "waste source of heat" and you just have to ignore those things to think about this question.

At least that is how things worked years ago when we were chasing commie subs around in the Med.

Good luck.

It would help greatly if you would describe the type of nuclear reactor that you are working on. There are three common types; BWR (Boiling Water Reactor), PWR (Pressurized Water Reactor), and the RBMK.

If your reactor uses light water as a coolant, graphite as a moderator and does not have a true containment vessel, then it is a RBMK design. Without knowing the reactor type your question is subject to guessing and the answers you get may or may not be applicable to your exact situation.

Clearly there are no nuclear engineers participating in this thread (and I'm not one either, but I am familiar with reactor designs from an auxiliaries aspect). OP's statement "...if inlet cooling water temperature inrease (sic) any reason,nuclear power also increaseing (sic)...", is true for only one type of commercial nuclear reactor, the infamous RMBK graphite modulated type used in Chernobyl.

Unlike the more common Pressurized and Boiling Water Reactors (PWR/BWR) which have negative thermal coefficients of reactivity, the RMBK exhibits a large positive thermal coefficient of reactivity; i.e., as the temperature of the reactor coolant increases so does the power output. This happens because "...(w)hen the coolant water temperature increases, the boiling increases, which creates voids. Thus there is less water to absorb thermal neutrons that have already been slowed down by the graphite moderator, causing an increase in reactivity..." (Wikipedia), which is also the answer to OP's question.