# How to transfer designed capacity to estimate production ?

1. Jul 31, 2012

### JJ91

Hi,

Today I was reading news about Poland investing into nuclear energy where they estimate the first reactor to start generating in 2023 with capacity of 3MWe.

How can we estimate yearly production of the actual output send to the customer ?

(I'm more into PV technology but I think it's still worth to know such information)

2. Jul 31, 2012

### QuantumPion

If you know the electrical power rating, in megawatts-electric, all you have to do is multiply the power output by the time period the plant operated. So if a 3 MWe plant operated for 300 days, it would produce 300 MW-days of energy. 1 MW-day is equal to 86.4 GJ.

3. Jul 31, 2012

### gmax137

Better check your sources; 3 MW would be a tiny reactor. Typical units are 1000 to 1100 MW electric or more. Even the 'small' modular reactors on the drawing boards today are 25 to 200 MW electric.

4. Jul 31, 2012

### JJ91

Looks basic and my first assumption was just like the replay, thanks.

It looks like it is 3000MWe reactor and its roughly gonna cost 3M euro per MWe so I put the wrong numbers in but it's still the same formula.

5. Jul 31, 2012

### gmax137

3000 MWe would likely be three or (maybe) two reactors. Are you sure that the given value is MWe and not MWth? The thermal (MWth) is the core power and the MWe is the generator output. The ratio is the thermal efficiency of the plant, roughly 33% though the actual value varies from day-to-day depending mostly on the condenser cooling water temperature.

To estimate the yearly production you need to know is your 3000 MWe net or gross? Sometimes part of the generator output goes to run the plant (big pumps). The plant loads could be about 20 to 25 MW per reactor for a 1100 to 1200 MWe unit. The exact value depends on the plant design.

Once you know the MWe net generation, you need to know the capacity factor, which is a percentage of generation vs. the output you'd get if the plant ran continuously. Capacity factors in the US are currently in the 90% range which reflects the plants running essentially continuously except when in refueling, and short refueling periods. Short refueling period requires that alot of the routine maintenance is done on-line. Plants with problems run at lower capacity since they need to shutdown to fix the problems.

So, take the net generation rate, and multiply by capacity factor, then multiply by your time period (year?) to get MWe/year delivery. For example you might have 1100 MWe * 0.9 * 365 * 24 = 8,672,400 MW-hr per year.