What is the Doppler coefficient and how does it affect wave frequency?

[googlefans]

hello,everybody .Doppler coefficient will be positive?

 

[Naty1]

Is this what you are asking about:

http://en.wikipedia.org/wiki/Doppler_broadening

 

[Astronuc]

hello,everybody .Doppler coefficient will be positive?

Whether the Doppler coefficient (for resonance absorption) is positive or negative depends on the composition of the fuel/core.

If resonance absorption leads to more (n,γ) and less fission then it has a negative effect on reactivity in a critical system.

If the absorption leads to more fission and less (n,γ), then it has a positive effect.


In an LWR (water moderated reactor) the Doppler coefficient is negative. The U-238 resonances absorb neutrons more readily, and to some extent, the resonance absorption of U-235 and Pu-239 resulting in (n,γ) compete with those resulting in fission.

Some fast and intermediate spectrum reactors may have a positive Doppler coefficient with certain configurations. Such configurations are to be avoided.

References:
http://www.barc.gov.in/publications/eb/golden/reactor/toc/chapter1/1_1.pdf
http://www.inl.gov/technicalpublications/Documents/4502642.pdf

 

[googlefans]

Whether the Doppler coefficient (for resonance absorption) is positive or negative depends on the composition of the fuel/core.

If resonance absorption leads to more (n,γ) and less fission then it has a negative effect on reactivity in a critical system.

If the absorption leads to more fission and less (n,γ), then it has a positive effect.


In an LWR (water moderated reactor) the Doppler coefficient is negative. The U-238 resonances absorb neutrons more readily, and to some extent, the resonance absorption of U-235 and Pu-239 resulting in (n,γ) compete with those resulting in fission.

Some fast and intermediate spectrum reactors may have a positive Doppler coefficient with certain configurations. Such configurations are to be avoided.

References:
http://www.barc.gov.in/publications/eb/golden/reactor/toc/chapter1/1_1.pdf
http://www.inl.gov/technicalpublications/Documents/4502642.pdf

thank you very much