RE: Reactivity Units

["Minnema, Douglas" <Douglas.Minnema@ns.doe.gov>]

A different way of looking at this is that $1 of reactivity is equal to the
effective delayed neutron fraction ("beta-eff") in the reactor.  This
becomes a normalization factor for each reactor, since the 'effectiveness'
of the delayed neutrons in a system depends on the design of the reactor,
and can vary significantly based on neutron spectrum.  To put the equation
into words,

system reactivity in $ = [(delta k)/k]/beta-eff

As previously noted by Dan, the values go positive when above delayed
critical (DC), negative when going below DC, and exactly zero at delayed
critical.

Doug Minnema, PhD, CHP
Defense Programs
<Douglas.Minnema@ns.doe.gov>

what few thoughts i have are truly my own ...

> -----Original Message-----
> From:	Michael McNaughton [SMTP:mcnaught@lanl.gov]
> Sent:	Tuesday, August 08, 2000 12:58 PM
> To:	Multiple recipients of list
> Subject:	RE: Reactivity Units
> 
> At 10:20 AM 8/8/00 -0500, you wrote:
> >One cent of reactivity is therefore 1/100 of the reactivity needed to go
> prompt critical.
> 
> More precisely: One cent of reactivity is 1/100 of the reactivity needed
> to
> go from delayed critical to prompt critical.
> 
> mike
> Mike McNaughton
> email: mcnaught@LANL.gov or mcnaughton@LANL.gov
> phone: (505)667-6130
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