Reactor Physics...?

Question

To profile a flux of a reactor, we irradiated a copper wire. However, the wire was put in the reactor offline. I have a chart of the powering up to a constant flux. Problem is the powering up term.. I know the basic equation, but flux*Exp[ omega * t], but I am not sure how to determine the constant. I was thinking of treating the time it took to power up as a stable period b/c the omega is equal to the inverse of the period. It was suggested to use a straight line from the constant flux extrapolated to zero, but the omega would depend on flux and makes the resulting activtion equation by a the flux insolvable. Would my assumption of treating the power up time as a stable period valid. That would make omgea indepent of flux.

Answer 1

Do you have a graph of the Neutron Flux Measurement as the reactor is powered. This must be available somewhere - even in the Safety Logs.

Otherwise you could try 1/e of your power up time, but this would only be accurate if the controls were moved at the start and then left in one place for the entire power up time.

Safest is: find the graph, look for an appropriate exponential growth (there will be more than one if the control rods are moved every now and then) and get your time constant from that.

This may all be rubbish as I would imagine that the reactor is under automatic control and the rods are moved continually. Think about it - then discuss it with your supervisor,
Otherwise send me a copy of your graph - attached to an email - check for viruses first or yo'll be in my bad books!!!!!!!!!