Download Exam 1

NE 418/591 Midterm
(40%)
Spring 2017
1) A PWR is to be brought to power near End Of Cycle (EOC). Operating parameters under these conditions are
given below where the reactivity parameters are referenced to Hot Zero Power (HZP), i.e. the system is at
temperature corresponding to (Rx Pwr) REL = 0 (560 F). The control rods are in four banks and insert reactivity
linearly with position as they move out, i.e. at “full out” they insert zero reactivity and at “full in” they insert
their full worth. The control rods move in steps, with a 100 step overlap and 228 steps corresponding to full out.
You can assume the banks move out in order A, B, C, D, and insert in reverse order, i.e. D, C, B, A. Reactor
operations can be complicated by the buildup and decay of the fission products Xe-135 and Sm-149 which can
reach equilibrium conditions in a matter of days. Xe-135 is radioactive and decays away after reactor shutdown.
Sm-149 is stable and reaches steady state concentrations after shutdown.
Problem Parameters
Excess Reactivity
Fixed Burnable Poison Worth
Moderator Temperature Coefficient
Doppler Only Power Coefficient
Equilibrium Xenon Worth
Shutdown Xenon Worth
Equilibrium Samarium Worth
Shutdown Samarium Worth
Soluble Boron Coefficient
Control Bank A Worth
Control Bank B Worth
Control Bank C Worth
Control Bank D Worth
6651
-1400
-33.4
-13.7
-2653
0
-463
-1000
-7
582
973
1171
893
pcm
pcm
pcm/F
pcm/% Power
pcm
pcm
pcm
pcm
pcm/ppm
pcm
pcm
pcm
pcm
You can assume the moderator temperature as a function of power under nominal conditions is given by
Tave =560 + 30×(Rx Pwr) REL
a) Determine the critical Boron concentration at Hot Zero Power (HZP), with Xe and Sm at their shutdown
conditions and all control rods fully inserted.
b) Assuming a HZP Boron concentration of 320 ppm, determine the critical rod position assuming Xe and Sm at
their shutdown conditions.
c) Does the reactor have sufficient excess reactivity to maintain full power once Xe and Sm have reached their
equilibrium values assuming the soluble Boron concentration can be diluted to zero?
d) Briefly describe the sequence of operations required to execute an increase in load maneuver in a PWR
assuming steam generator pressure is to remain approximately constant.
(40%)
2) In the following circuit, A, B and C are circuit elements performing certain function according to the elements
identity
a)
For A= resistor R, B =capacitor C1, C =capacitor C2 find the expression of the frequency response of this
circuit
b) If the element B is removed while A and C still the resistor R and capacitor C2, respectively, what is the
magnitude and the phase of the frequency response and what is the functionality of the circuit? Make a
sketch of the magnitude of the frequency response
c) If A is removed from the circuit, B remains =C1 but element C was replaced by a resistor R1, find the new
functionality of the circuit, i.e. its frequency response and its behavior as a circuit.
(20%)
3) Short answers:
a) Sketch an OpAm that can be used to add signals such that the output is the sum of all inputs and show the
relation between the output and input voltages.
b) Under what conditions can the following OpAmp amplify the input signal?
c)
d)
e)
f)
g)
i)
j)
What is special about gas-filled fission chambers?
How does a pressurizer control pressure in a PWR?
What is the difference between a proportional and Gieger-Mueller Counter?
How is reactor flow rate used to control power in a BWR?
What is the primary difference in Turbine Control Valve operation between BWRs and PWRs?
What is the impact of void fraction on LWR reactivity? Why?
Why are Ioniztion Chambers sensitive to temperature variations?