Reference, Questions and Help > Definitions

Doppler coefficient

(1/4) > >>

Another name used for the fuel temperature coefficient of reactivity.

Rad Sponge:

--- Quote from: Rennhack on Nov 23, 2005, 03:37 ---Another name used for the fuel temperature coefficient of reactivity.

--- End quote ---

I am reading about this right now, as I type.

So was this ever part of the Navy Reactor Principles discussion or did it just get "N/A"d? Did I miss something?

We never really discussed FUEL Temperature Coefficients if memory serves me correctly.  I could be wrong.  We always seemed to talk of MODERATOR Temperature Coefficients in the Navy.

Here is a link if you want a quickie explanation:

Rad Sponge:
Thanks man, that explains it a little better than my current text.

Due to the Enrichment of the Fuel and it's design Doppler wasn't very prevalent in Naval reactors. In truth the Doppler coefficient in civilian reactors isn't hugely high compared with other coefficients however it's always there and as soon as fuel starts heating up it starts feedback. This is important as in most cases there is a significant time constant before the moderator sees any heatup and reacts. That's why on a BWR there's a time delay on the power to flow trips. A commercial PWR doesn't need the time constants because it's Power to Flow trips are based on number of Pumps Running as a flat out comparison with Power.

If you have any questions about Doppler just ask. Self Shielding and Energy Boxes are quite the concept. Doppler gets more negative as the core ages due to the buildup of Pu and it gets less negative as the core heats up because the doppler bands lower however there are more of them due to self shielding going away. It always remains negative.

It effects the resonance escape probability.



[0] Message Index

[#] Next page

Go to full version