I am trying to figure out what happens to the power when a prompt jump occurs. From Nuclear Reactor Analysis by Duderstadt and Hamilton, a prompt jump approximation can be done to yield the following equation:(adsbygoogle = window.adsbygoogle || []).push({});

[itex]\frac{P_{2}}{P_{1}}[/itex] = [itex]\frac{\beta-\rho_{1}}{\beta-\rho_{2}}[/itex]

Now the question is for a CANDU reactor that has 0.7% enriched uranium. If the delayed neutron fraction for U235 is 0.00682 then for the CANDU reactor the fraction of delayed neutron is 0.00682*0.007=4.77E-5. (Not sure if I did this part correctly).

Ignoring fast fission of U238, there was a step increase of +3mk in an initially critical reactor, then the power change is just:

[itex]\frac{P_{2}}{P_{1}}[/itex] = [itex]\frac{4.77E-5-0}{4.77E-5-0.003}[/itex]

but this yields a negative ratio which does not make sense..I am thinking I calculated the delayed neutron fraction incorrectly.

Any help is appreciated!

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# Finding power change due to prompt jump

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