Lecture 7 Flashcards by Anna B

Flux shape for infinite slab

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Flux shape in infinite cylinder

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Flux shape in finite cylindrical core

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Buckling in finite cylinder

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Peak to average power

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Diffusion lengths

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Diffusivity equation

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Multiplication factor with two group approximation

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Migration length equation

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Reflector savings for

a >> M

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Reflector savings for

a << M

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Buckling in reflected reactor

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Adding a reflector _____ the flux distribution, thus ____ the ratio of peak to average flux

flattens, lowers

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The worth changes most rapidly when the tip is _______ of the core, where the flux is largest.

near the midplane

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Buckling change with reactivity change equation

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Rod bank has large enough effects in reactivity and on the flux distribution that the ______ technique is no loger applicable

pertubation

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Change in non-leakage probablity w/ different migration length and buckling

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Increased fuel temperature results in a ________ in the resonance escape probablity because of doppler effects

decrease

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Magnitidue of fuel temp coefficient _____ with increasing fuel temperature

decreases

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Becomes more _______ with burnup because of ______

negative, Pu-240

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Moderator temperature coefficient

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Moderatore coefficient derives primarily from _____ changes with changes in the __________ playing a secondary role

density, thermal spectrum

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MTC becomes more ______ with boron concentration because of larger reduction in poision content from reduced density.

positive

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MTC becomes more _____ with burnup primarily because of reduction in boron concentration

negative

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Large negative value would be limiting for a ________ incidence

cold water injection

MTC becomes more _______ with control rod insertion because of hardened neutron spectrum and increased leakage

negative

For the fuel temperature coefficient for fast reactors, doppler effect is ______ in magnitude

smaller

For the coolent temperature coefficient for fast reactors, decreased density _____ the neutron spectrum and thus increases ____ and \_\_\_\_.

hardens, eta, k_infinite

For the coolent temperature coefficient for fast reactors, decreased density _____ the migration length, and thus ______ leakage, resulting in ______ reactivity.

lengthens, increases, increased.

Isothermal temperature coefficient, α_T

α_f + α_c

Power coefficient α_p=

In PWR, power coefficient becomes ______ with burnup

more negative

The temperature defect is

reactivity decrease from cold shutdown state to hot zero power condition

Power defect is

reactivity decrease from hot zero power to hot full power

Excess reactivity is the value that ρ would take if

all moveable control poisions were instantiously removed from the core.

Factors determining excess reactivity

temp defect, power defect, cycle length

Transient heat transfer model,

Very slow transient with small step reactivity insertion, or Quasi-steady state heat transfer equation

With .95$ insertion, _____ before fuel gains enough temp for \_\_\_\_\_\_

large power spike, negative feedback

Without temperature feedback, transients would pass through ______ at one second

prompt critical

Reactavity at t with reactivity insertion, ρ(t)=

Short time phenomena:

typical time intervals of milliseconds to seconds, transient analysis

Medium time phenomena:

hours to days, Xe and Sm effects

Long time phenomena:

several months or years, fuel depletion analysis

I-131 reaches it's saturation value \_\_\_\_\_, and will be proportional to the \_\_\_\_\_\_\_

quickly, reactor power

Cs-137 increases ______ with time over the few years the fuel is in the reactor and the amount is proportional to \_\_\_\_\_\_

linearly, the total energy produced

Equilibrium concentration of Xenon, X(∞) =

Xenon after reactor shutdown, X(t) =

Xenon reactivity effect, ρ(t) =

For a sufficiently large operating flux, the xenon concentration _____ following shutdown.

rises

Peak concentration occurs _____ hours after shutdown

11.3

Samarium concentration, S(∞) =

Equilibrium concentration of Pm and I

Samarium after reactor shutdown, S(t) =

Samarium concentration _____ following shutdown

rises

Uranium concentration, N(t) =

conversion ratio, CR(t) =

Power as function of p'''_max, peaking factor, and volume

The achievable maximum power density is dependent on _______ properties and that the _______ and _____ that can be tolerated

material, temperatures, pressures

F_q=

F_rF_xF_l

F_q for a uniform cylindrical core =

3.63F_l

p'''(r,z) =

volume averaged coolant outlet temp T_o =

Average fuel temp T_f=

The temperature at the rod's hottest point, which is along it's centerline, determines the limitation on the \_\_\_\_\_\_\_

linear heat rate