# How to find information about energy density of HWR?

1. Aug 5, 2011

### vifteovn

I need some help finding out the energy density of different heavy water reactors. In IAEA research reactor database they only list the thermal output of some HWR - RR, but they lack information about the dimensions of the core, thereby making it difficult to figure out their energy density.

The reason for wanting to find out this is that I want to compare the energy density of other HWR with the HWR Iran are building at Arak.

Have a nice weekend

2. Aug 5, 2011

### Astronuc

Staff Emeritus
In addition to thermal power, one would need the dimensions of the core to determine the average power density, or alternatively one would need the dimensions of a particular assembly and the number of assemblies in the core.

3. Aug 6, 2011

### vifteovn

I found a crude estimate by comparing IR-40 with Dhurva in India and NRU in Canada. Dhruva and NRU's cores are cylindrical with the diameter the same as the height. By assuming that condition for IR-40 and taking the energy density of Dhruva I found the dimensions of IR-40. But that was only two reactor cores. To find out if this is even close I would like to compare with some other HWR as well.

I think the approach figuring out the assemblies is going to be rather difficult. I could ask the Iranians, but I don't think they'll give me a lot of information :)

4. Aug 6, 2011

5. Aug 7, 2011

### vifteovn

Yeah, I read about that. But that makes no sense to me. Why are they making RBMK looking fuel intended for IR-40, but have operated a heavy water production plant (HWPP) next door for the last four five years.

Can RBMK fuel even work in a HWR reactor? Are not the fuel rods spaced to tight together for that?

So I still assume IR-40 is a heavy water reactor. I guess its more expensive to make a HWPP than some mock fuel bundles for confusion...

6. Aug 8, 2011

### vifteovn

With the data from the three reactors I have I end up with this result:

NRU (fueled with LEU): energy density: 11,9 MWth / m3
Candu (fueled with SEU): energy density: 7,64 MWth / m3
Dhurva (fuel with natural uranium): energy density: 7,41 MWth / m3

Taking Iran on its word that IR-40 is 40MW, that gives us: volume = thermal power / energy density. I'm also guessing that they will not use LEU fuel since they don't have so much uranium, and if they want to extract pu-239 they want a low enrichment.

Volume of IR-40: 40MW / 7,5 MWth / m3 = 5,3 m3

I "guess" the dimensions them to be 1,85m in diameter and 1,95m in height. Is this a crazy estimate?

7. Aug 8, 2011

### zapperzero

Has to be much longer (at least as long as a fuel assembly).

8. Aug 8, 2011

### vifteovn

Then you assume they use RBMK fuel rods? I just cant figure out why they want to use modified RBMK fuel rods. Is not fuel rods the least difficult thing to manufacture for a advanced nuclear state?

To be sure, when literature says "the core" they mean the active region of the fuel rods including moderator and / or coolant + neutron reflector?