Download Multiple-Choice Questions

Multiple-Choice Questions
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students in the 2016 Winter Semester course
EP4P03 Nuclear Plant Systems and Operation.
This material is not to be copied or shared in
either electronic or paper form with anyone not
registered in the above class.
1
1. On a CANDU 9 unit at normal full power operation,
which one of the following components sinks (absorbs)
the greatest proportion of reactor thermal power:
A.
Turbine Generator (exclusive of the condensers)
B.
Moderator Heat Exchangers
C.
Condensers
D.
End Shield Cooling Heat Exchangers.
2
1. On a CANDU 9 unit at normal full power operation,
which one of the following components sinks (absorbs)
the greatest proportion of reactor thermal power:
A.
Turbine Generator (exclusive of the condensers)
B.
Moderator Heat Exchangers
C.
Condensers
D.
End Shield Cooling Heat Exchangers.
3
2. When comparing properties of heavy water and light
water, which one of the following statements is true?
A. Their chemical properties are very different, their physical
properties are similar and their nuclear properties are very
different.
B. Their chemical properties are essentially identical, their
physical properties are very different and their nuclear
properties are very different.
C. Their chemical properties are essentially identical, their
physical properties are similar and their nuclear properties are
identical.
D. Their chemical properties are essentially identical, their
physical properties are similar and their nuclear properties are
very different.
4
2. When comparing properties of heavy water and light
water, which one of the following statements is true?
A. Their chemical properties are very different, their physical
properties are similar and their nuclear properties are very
different.
B. Their chemical properties are essentially identical, their
physical properties are very different and their nuclear
properties are very different.
C. Their chemical properties are essentially identical, their
physical properties are similar and their nuclear properties are
identical.
D. Their chemical properties are essentially identical, their
physical properties are similar and their nuclear properties
are very different.
5
3. Steam is found in a superheated condition at which
one of the following points in a typical CANDU plant:
A. Inlet to the HP Turbine
B. At the outlet of the Reheater
C. Outlet of the LP Turbine in the Condenser
D. In the Deaerator
6
3. Steam is found in a superheated condition at which
one of the following points in a typical CANDU plant:
A. Inlet to the HP Turbine
B. At the outlet of the Reheater
C. Outlet of the LP Turbine in the Condenser
D. In the Deaerator
7
4. The poison over-ride time available in a CANDU 9
reactor that has experienced a reactor trip from 100%
full power is approximately :
A.
2 hours
B. 45 minutes
C. 36 hours
D.
5 minutes
8
4. The poison over-ride time available in a CANDU 9
reactor that has experienced a reactor trip from 100%
full power is approximately :
A.
2 hours
B. 45 minutes
C. 36 hours
D.
5 minutes
9
5. Which one of the following statements is correct
about CANDU fuel?
A. CANDU 9 fuel assemblies use 37 `pencils' to have a large
heat transfer surface between fuel and the PHT coolant
B. The fuel in the CANDU fuel bundle is made of uranium
dioxide that contains 1.71% U235
C. Normally on power fuelling moves 12 fuel bundles at a
time
D. All fuel bundles in a CANDU reactor produce an equal
amount of heat
10
5. Which one of the following statements is correct
about CANDU fuel?
A. CANDU 9 fuel assemblies use 37 `pencils' to have a large
heat transfer surface between fuel and the PHT coolant
B. The fuel in the CANDU fuel bundle is made of uranium
dioxide that contains 1.71% U235
C. Normally on power fuelling moves 12 fuel bundles at a
time
D. All fuel bundles in a CANDU reactor produce an equal
amount of heat
11
6. After the loss of Class 4 power:
A. The Primary Heat Transport Pumps start to rotate in the
reverse direction as flow reverses in the core.
B. The Primary Heat Transport Pumps continue to run
because they are supplied by alternate power supplies.
C. The Primary Heat Transport Pumps stop immediately due
to hydraulic inertia in the system.
D. The Primary Heat Transport Pumps slow down over a
period of a few minutes because large flywheels store
energy to aid in prolonging the coast to a stop period
12
6. After the loss of Class 4 power:
A. The Primary Heat Transport Pumps start to rotate in the
reverse direction as flow reverses in the core.
B. The Primary Heat Transport Pumps continue to run
because they are supplied by alternate power supplies.
C. The Primary Heat Transport Pumps stop immediately due
to hydraulic inertia in the system.
D. The Primary Heat Transport Pumps slow down over a
period of a few minutes because large flywheels store
energy to aid in prolonging the coast to a stop period
13
7. The electrical energy used by a CANDU plant to power the
equipment inside the Station that is required to operate the
plant is called the Station Service load. For a CANDU 9 nuclear
power plant, the Station Service load is approximately :
A. 75 MW
B. 100 MW
C. 55 MW
D. 10 MW
14
7. The electrical energy used by a CANDU plant to power the
equipment inside the Station that is required to operate the
plant is called the Station Service load. For a CANDU 9 nuclear
power plant, the Station Service load is approximately :
A. 75 MW
B. 100 MW
C. 55 MW
D. 10 MW
15
8. If a CANDU is operating in `NORMAL’ mode of Overall
Unit Control, and the grid load is lost, which of the
following is correct:
A. Reactor Power will increase
B. Reactor Power will decrease
C. Turbine output will not change
D. Turbine output will increase
16
8. If a CANDU is operating in `NORMAL’ mode of Overall
Unit Control, and the grid load is lost, which of the
following is correct:
A. Reactor Power will increase
B. Reactor Power will decrease
C. Turbine output will not change
D. Turbine output will increase
17
9. Which of the following is NOT a function of the
Moderator Purification System?
A. To maintain the purity of the heavy water so that the
production of deuterium and oxygen through radiolysis is
minimized
B. To minimize the corrosion of system components by
removing impurities and controlling the pD of the system
C. To remove Gadolinium Nitrate that was injected when
SDS2 fired
D. To maintain a high isotopic concentration of D2O in the
Moderator System
18
9. Which of the following is NOT a function of the
Moderator Purification System?
A. To maintain the purity of the heavy water so that the
production of deuterium and oxygen through radiolysis is
minimized
B. To minimize the corrosion of system components by
removing impurities and controlling the pD of the system
C. To remove Gadolinium Nitrate that was injected when
SDS2 fired
D. To maintain a high isotopic concentration of D2O in the
Moderator System
19
10. The garter springs that hold the pressure tubes from
making contact with the calandria tubes are made of
Inconel. The number typically installed in a channel is:
A. One
B. Two
C. Three
D. Four
20
10. The garter springs that hold the pressure tubes from
making contact with the calandria tubes are made of
Inconel. The number typically installed in a channel is:
A. One
B. Two
C. Three
D. Four
21
1. Which one of the following is a function of
control absorbers?
A. Driving into core on a SDS trip
B. Partially dropping into core on a turbine trip
C. Driving into core when AZL is low
D. Driving into core following a power reduction
to offset the Xenon transient (poison
override)
22
1. Which one of the following is a function of
control absorbers?
A. Driving into core on a SDS trip
B. Partially dropping into core on a turbine trip
C. Driving into core when AZL is low
D. Driving into core following a power reduction
to offset the Xenon transient (poison
override)
23
2. A channel is fuelled normally on a Darlington reactor.
What is the expected response of the regulating
system?
A. The average zone level increases and individual zone
levels are changed to control the resultant flux tilt.
B. The average zone level decreases and individual zone
levels are changed to control the resultant flux tilt.
C. The average zone level remains constant, but individual
zone levels are changed to control the resultant flux tilt.
D. Nothing, normal fueling requires no response from the
regulating system.
24
2. A channel is fuelled normally on a Darlington reactor.
What is the expected response of the regulating
system?
A.The average zone level increases and individual zone
levels are changed to control the resultant flux tilt.
B. The average zone level decreases and individual zone
levels are changed to control the resultant flux tilt.
C. The average zone level remains constant, but individual
zone levels are changed to control the resultant flux tilt.
D. Nothing, normal fueling requires no response from the
regulating system.
25
3. Level in a liquid zone compartment is
controlled by:
A. Adjusting water inflow to the compartment
B. Adjusting water outflow from the
compartment
C. Adjusting He pressure in the zone control
compartment
D. Adjusting the temperature of the water
26
3. Level in a liquid zone compartment is
controlled by:
A. Adjusting water inflow to the compartment
B. Adjusting water outflow from the
compartment
C. Adjusting He pressure in the zone control
compartment
D. Adjusting the temperature of the water
27
4. In Alternate (Reactor-Leading) mode of Overall Unit
Control, the power generated by the TurbineGenerator in response to a change in reactor power is
modified by:
A. Changing the Steam Generator Pressure Setpoint
B. Controlling the water level in the liquid zone
controllers
C. Adjusting the opening of the Governor Valves
D. Changing the Steam Generator Level Setpoint
28
4. In Alternate (Reactor-Leading) mode of Overall Unit
Control, the power generated by the TurbineGenerator in response to a change in reactor power is
modified by:
A. Changing the Steam Generator Pressure Setpoint
B. Controlling the water level in the liquid zone
controllers
C. Adjusting the opening of the Governor Valves
D. Changing the Steam Generator Level Setpoint
29
5. The height of water in each liquid zone-control
compartment is measured by:
A. Measuring the opening of the inflow valve into
the compartment
B. Measuring the opening of the outflow valve from
the compartment
C. Calculating the difference between the openings
of the in-flow and outflow valves
D. Difference in the helium pressure above and
below the water
30
5. The height of water in each liquid zone-control
compartment is measured by:
A. Measuring the opening of the inflow valve into
the compartment
B. Measuring the opening of the outflow valve from
the compartment
C. Calculating the difference between the openings
of the in-flow and outflow valves
D. Difference in the helium pressure above and
below the water
31
1. Which one of the following statements correctly
describes the characteristics of an Ion Chamber?
A. A larger self-powered neutron detector, located outside the reactor
that is used during long outages when other instrumentation has
gone off scale low.
B. A detector with an external power supply and a Boron coating
inside that produces Alpha particle induced ionization under
neutron irradiation. It is used for indication and control from very
low to high power.
C. A neutron detector with a high voltage anode, good spatial control
characteristics, and is normally located above the reactor to allow
access for maintenance and testing.
D. A small self-powered detector that produces Beta particle induced
ionization under neutron irradiation, and is used for indication only
at high power.
32
1. Which one of the following statements correctly
describes the characteristics of an Ion Chamber?
A. A larger self-powered neutron detector, located outside the reactor
that is used during long outages when other instrumentation has
gone off scale low.
B. A detector with an external power supply and a Boron coating
inside that produces Alpha particle induced ionization under
neutron irradiation. It is used for indication and control from very
low to high power.
C. A neutron detector with a high voltage anode, good spatial control
characteristics, and is normally located above the reactor to allow
access for maintenance and testing.
D. A small self-powered detector that produces Beta particle induced
ionization under neutron irradiation, and is used for indication only
at high power.
33
1. Which one of the following statements correctly
describes the characteristics of an Ion Chamber?
B. A detector with an external power supply and a Boron coating
inside that produces Alpha particle induced ionization under
neutron irradiation. It is used for indication and control from very
low to high power.
Power
Supply
34
2. Which one of the following statements correctly
describes the characteristics and uses of selfpowered in-core flux detectors?
A. Self-powered in-core flux detectors are used to measure the total
neutron flux in the range of 10-5%FP to 120%FP.
B. Self-powered flux detectors work on the principle that neutron
and gamma radiation eject from the emitter electrons which, after
traveling across the insulator to the collector, create a voltage
difference.
C. Most flux detectors over-respond to neutrons and to gamma rays,
resulting in not enough prompt response, and too much delayed
response as reactor power level changes.
D. The main advantages of the in-core flux detectors are that they
give an immediate and linear response to a change in flux and are
35
the basis of reactor power control from 50%FP to 120%FP.
2. Which one of the following statements correctly
describes the characteristics and uses of selfpowered in-core flux detectors?
A. Self-powered in-core flux detectors are used to measure the total
neutron flux in the range of 10-5%FP to 120%FP.
B. Self-powered flux detectors work on the principle that neutron
and gamma radiation eject from the emitter electrons which,
after traveling across the insulator to the collector, create a
voltage difference.
C. Most flux detectors over-respond to neutrons and to gamma rays,
resulting in not enough prompt response, and too much delayed
response as reactor power level changes.
D. The main advantages of the in-core flux detectors are that they
give an immediate and linear response to a change in flux and are
36
the basis of reactor power control from 50%FP to 120%FP.
3. With respect to the use of neutronic and thermal
power measurements in the reactor regulating system,
which one of the following statements is true?
A. Thermal power measurements cover the whole range
(10-5 %FP to 100%FP) of normal reactor power control.
B. Neutronic devices are too slow to be used exclusively.
C. Thermal power measurements are used to provide
spatial indication of power, neutronics are sensitive only
to bulk power.
D. Thermal power measurements are used to continuously
calibrate neutronic measurements at power levels
above 5%FP.
37
3. With respect to the use of neutronic and thermal
power measurements in the reactor regulating system,
which one of the following statements is true?
A. Thermal power measurements cover the whole range
(10-5 %FP to 100%FP) of normal reactor power control.
B. Neutronic devices are too slow to be used exclusively.
C. Thermal power measurements are used to provide
spatial indication of power, neutronics are only sensitive
to bulk power.
D. Thermal power measurements are used to
continuously calibrate neutronic measurements at
power levels above 5%FP. (Gradual transfer from Ion
Chambers at & below 5% to In-Core Detectors at & above 15%)
38
4. Which one of the following statements correctly
describes the characteristics and uses of adjuster rods:
A. The Adjuster rods provide a reserve of positive reactivity to
override any xenon transient that may develop following a
reactor trip or other large power level reductions.
B. Adjuster rod auto out-drive is only initiated by RRS if the average
zone level is below 15%.
C. Adjuster rod auto in-drive is only initiated by RRS if average zone
level is above 75%.
D. If the operating point is within the normal range of control for
the liquid zones, RRS will not initiate adjuster drive movement
because it is good operating practice to leave rods partially in
the core.
39
4. Which one of the following statements correctly
describes the characteristics and uses of adjuster rods:
A. The Adjuster rods provide a reserve of positive reactivity to
override any xenon transient that may develop following a
reactor trip or other large power level reductions.
B. Adjuster rod auto out-drive is only initiated by RRS if the average
zone level is below 15%.
C. Adjuster rod auto in-drive is only initiated by RRS if average zone
level is above 75%.
D. If the operating point is within the normal range of control for
the liquid zones, RRS will not initiate adjuster drive movement
because it is good operating practice to leave rods partially in
the core.
40
4. Which one of the following statements correctly
describes the characteristics and uses of adjuster rods:
B. Adjuster rod auto out-drive is
only initiated by RRS if the
average zone level is below 15%.
C. Adjuster rod auto in-drive is
only initiated by RRS if average
zone level is above 75%.
D. If the operating point is within
the normal range of control for
the liquid zones, RRS will not
initiate adjuster drive movement
because it is good operating
practice to leave rods partially in
the core.
41
5. Which one of the following statements
correctly describes the characteristics and
uses of control absorber rods:
A. The control absorbers are dropped fully into the core when a
Stepback of reactor power level is required.
B. Control Absorber rods are normally located completely
outside the core. They are driven into the core to provide
negative reactivity when the liquid zones have used up their
range of control.
C. Control Absorber auto in-drive is initiated by RRS whenever
the average zone level is above 80%.
D. Control Absorber auto out-drive is initiated by RRS whenever
the average zone level is below 75%.
42
5. Which one of the following statements
correctly describes the characteristics and
uses of control absorber rods:
C. Control Absorber auto indrive is initiated by RRS
whenever the average zone
level is above 80%.
D. Control Absorber auto outdrive is initiated by RRS
whenever the average zone
level is below 75%.
43
5. Which one of the following statements
correctly describes the characteristics and
uses of control absorber rods:
A. The control absorbers are dropped fully into the core when a
Stepback of reactor power level is required.
B. Control Absorber rods are normally located completely
outside the core. They are driven into the core to provide
negative reactivity when the liquid zones have used up
their range of control.
C. Control Absorber auto in-drive is initiated by RRS whenever
the average zone level is above 80%.
D. Control Absorber auto out-drive is initiated by RRS whenever
the average zone level is below 75%.
44
Sim Ex 2.1 POWER MANEUVER IN “ALTERNATE” MODE:
100% to 50% Power Reduction and Return to Full Power
(a) Explain the changes
in Average Zone
Level between each
operating state or
column (8 marks):
45
1.
135Xe
is called a Saturating Fission Product
because:
A. It saturates the fuel and prevents the
production of all other fission products.
B. At the operating temperature of the fuel
135Xe has reached its saturation pressure.
C. Its concentration does not accumulate
without limit in a reactor operating at a
constant power level.
D. It reaches a concentration that is
independent of the neutron flux in the
reactor.
46
1.
135Xe
is called a Saturating Fission Product
because:
A. It saturates the fuel and prevents the
production of all other fission products.
B. At the operating temperature of the fuel
135Xe has reached its saturation pressure.
C. Its concentration does not accumulate
without limit in a reactor operating at a
constant power level.
D. It reaches a concentration that is
independent of the neutron flux in the
reactor.
47
2. Xenon oscillations are a potential problem in
CANDU-9 and similar sized reactors because:
A. Such large reactors are inherently unstable, particularly
in seismically active regions.
B. They can be set off by regional perturbations in the
reactor, for example following the routine refuelling of a
channel.
C. The Reactor Regulating System is designed to control
the overall power output of the reactor, and isn’t
equipped to control regional variations.
D. Such oscillations can slow down the recovery from a
reactor trip, for example if the ion chamber signals are
observed to be fluctuating at power levels below 5%FP.
48
2. Xenon oscillations are a potential problem in
CANDU-9 and similar sized reactors because:
A. Such large reactors are inherently unstable, particularly
in seismically active regions.
B. They can be set off by regional perturbations in the
reactor, for example following the routine refuelling of
a channel.
C. The Reactor Regulating System is designed to control
the overall power output of the reactor, and isn’t
equipped to control regional variations.
D. Such oscillations can slow down the recovery from a
reactor trip, for example if the ion chamber signals are
observed to be fluctuating at power levels below 5%FP.
49
2. Xenon oscillations are a potential problem in
CANDU-9 and similar sized reactors because:
B. They can be set off by regional perturbations in the
reactor, for example following the routine refuelling of
a channel.
50
3. After a reactor trip in the CANDU 9 reactor, which one
of the following statements correctly describes the
response of the Liquid Zone Control system:
A. All compartments have their levels frozen at the level they
were at when the reactor trip occurs so that they don't lower
level and introduce positive reactivity to the reactor core.
B. They respond to the signals of the Reactor Regulating System
so as to maintain control over spatial flux distribution.
C. They go to the maximum allowed level (95% for CANDU-9)
and stay there until the trip is cleared and a request to raise
power results in a negative power error.
D. They go to the lowest permissible level (5% in CANDU-9) so
as to help override the Xenon poison as it builds up following
the reactor trip.
51
3. After a reactor trip in the CANDU 9 reactor, which one
of the following statements correctly describes the
response of the Liquid Zone Control system:
A. All compartments have their levels frozen at the level they
were at when the reactor trip occurs so that they don't lower
level and introduce positive reactivity to the reactor core.
B. They respond to the signals of the Reactor Regulating System
so as to maintain control over spatial flux distribution.
C. They go to the maximum allowed level (95% for CANDU-9)
and stay there until the trip is cleared and a request to raise
power results in a negative power error.
D. They go to the lowest permissible level (5% in CANDU-9) so
as to help override the Xenon poison as it builds up following
the reactor trip.
52
4. Which one of the following statements correctly
describes Poison Prevent operation?
A. Isolating the moderator poison addition system from
the moderator
B. Allowing the reactor to poison out following a SDS
trip because of insufficient decision and action time
C. Allowing RRS to insert adjusters into core following a
power reduction to offset the Xenon reactivity
transient
D. Maintaining reactor power high enough following a
turbine trip such that a poison out will not occur
53
4. Which one of the following statements correctly
describes Poison Prevent operation?
A. Isolating the moderator poison addition system from
the moderator
B. Allowing the reactor to poison out following a SDS
trip because of insufficient decision and action time
C. Allowing RRS to insert adjusters into core following a
power reduction to offset the Xenon reactivity
transient
D. Maintaining reactor power high enough following a
turbine trip such that a poison out will not occur
54
5. A reactor has been operating at 30% FP for a very long time.
Power is then raised to 100% FP and remains at that value.
Which one of the following statements correctly describes the
sequence of events?
A. The Xe-135 concentration will increase, go through a
maximum, and over many hours return to its original value.
B. The Xe-135 reactivity will become and remain more negative
than initially.
C. The Xe-135 reactivity will first become less negative, but will
eventually tend to a value more negative than its original
value.
D. The Xe-135 will burn out more quickly and its concentration
will quickly go to 0.
55
5. A reactor has been operating at 30% FP for a very long time.
Power is then raised to 100% FP and remains at that value.
Which one of the following statements correctly describes the
sequence of events?
A. The Xe-135 concentration will increase, go through a
maximum, and over many hours return to its original value.
B. The Xe-135 reactivity will become and remain more negative
than initially.
C. The Xe-135 reactivity will first become less negative, but
will eventually tend to a value more negative than its
original value.
D. The Xe-135 will burn out more quickly and its concentration
will quickly go to 0.
56
2. A pressurizer steam bleed valve fails open with a
CANDU 9 unit operating at full power. Which one of the
following is not an expected initial response?
A.
B.
C.
D.
The bleed condenser pressure increases
The main circuit pressure decreases
The pressurizer level decreases.
The bleed valves open further.
57
2. A pressurizer steam bleed valve fails open with a
CANDU 9 unit operating at full power. Which one of the
following is not an expected initial response?
A.
B.
C.
D.
The bleed condenser pressure increases
The main circuit pressure decreases
The pressurizer level decreases.
The bleed valves open further.
58
3. Overpressure protection for the Primary Heat Transport
System is provided by:
A. PHT Bleed Valves that relieve into the Bleed
Condenser
B. PHT Liquid Relief Valves that relieve into the Bleed
Condenser
C. PHT Bleed Valves that relieve into the Pressurizer
D. PHT Liquid Relief valves that relieve into the
Pressurizer
59
3. Overpressure protection for the Primary Heat Transport
System is provided by:
A. PHT Bleed Valves that relieve
into the Bleed Condenser
B. PHT Liquid Relief Valves that
relieve into the Bleed Condenser
C. PHT Bleed Valves that relieve
into the Pressurizer
D. PHT Liquid Relief valves that
relieve into the Pressurizer
60
3. Overpressure protection for the Primary Heat Transport
System is provided by:
A. PHT Bleed Valves that relieve into the Bleed
Condenser
B. PHT Liquid Relief Valves that relieve into the
Bleed Condenser
C. PHT Bleed Valves that relieve into the Pressurizer
D. PHT Liquid Relief valves that relieve into the
Pressurizer
61
4. The Pressurizer level setpoint is ramped up as reactor
power (RP) increases. Which one of the following
statements is correct?
A. Increased setpoint accounts for boiling in the
Reactor Outlet Headers as RP increases.
B. Increased setpoint accounts for increased boiling
in the Pressurizer as RP increases.
C. Increased setpoint accommodates swell in the
Main Circuit as RP increases.
D. Increased setpoint allows for transfer of inventory
to the Main Circuit as RP increases.
62
4. The Pressurizer level setpoint is ramped up as reactor
power (RP) increases. Which one of the following
statements is correct?
A. Increased setpoint accounts for boiling in the
Reactor Outlet Headers as RP increases.
B. Increased setpoint accounts for increased boiling
in the Pressurizer as RP increases.
C. Increased setpoint accommodates swell in the
Main Circuit as RP increases.
D. Increased setpoint allows for transfer of inventory
to the Main Circuit as RP increases.
63
5. If the PHT is operating in `Normal Mode’ of control and
a leak develops in the PHT pressure envelope:
A. Pressurizer level will stay constant and D2O
storage Tank level will fall
B. Pressurizer level will fall first and then D2O Storage
Tank level will begin to fall
C. D2O Storage Tank level will fall first and then
Pressurizer level will fall
D. Pressurizer level will fall but D2O Storage Tank
level will stay constant
64
5. If the PHT is operating in `Normal Mode’ of control and
a leak develops in the PHT pressure envelope:
A. Pressurizer level will stay constant and D2O
storage Tank level will fall
B. Pressurizer level will fall first and then D2O
Storage Tank level will begin to fall
C. D2O Storage Tank level will fall first and then
Pressurizer level will fall
D. Pressurizer level will fall but D2O Storage Tank
level will stay constant
65
1. In a steam generator at full power the light water at the top of the
tube bundle is very wet steam. However steam exits the steam
generator towards the turbine at almost 100% quality. Which one of
the following statements correctly explains this increase in steam
quality?
A. The reheater in the steam generator above the tube bundle
adds the remaining heat of vaporization to dry the wet steam.
B. Cyclone separators and then steam scrubbers mechanically
remove the liquid water from the wet steam and return the
liquid water to the bottom of the steam generator via the
downcomer annulus.
C. The wet steam is passed through the pre-heater where the
remaining heat of vaporization is added to dry the steam.
D. Cyclone separators and then steam scrubbers mechanically
remove the liquid water from the wet steam and this liquid
water is discharged to the lake via the blowdown header. 66
1. In a steam generator at full power the light water at the top of the
tube bundle is very wet steam. However steam exits the steam
generator towards the turbine at almost 100% quality. Which one of
the following statements correctly explains this increase in steam
quality?
A. The reheater in the steam generator above the tube bundle
adds the remaining heat of vaporization to dry the wet steam.
B. Cyclone separators and then steam scrubbers mechanically
remove the liquid water from the wet steam and return the
liquid water to the bottom of the steam generator via the
downcomer annulus.
C. The wet steam is passed through the pre-heater where the
remaining heat of vaporization is added to dry the steam.
D. Cyclone separators and then steam scrubbers mechanically
remove the liquid water from the wet steam and this liquid
water is discharged to the lake via the blowdown header. 67
1. In a steam generator at full power the light water at the top of the
tube bundle is very wet steam. However steam exits the steam
generator towards the turbine at almost 100% quality. Which one of
the following statements correctly explains this increase in steam
quality?
B. Cyclone separators and
then steam scrubbers
mechanically remove the
liquid water from the wet
steam and return the
liquid water to the bottom
of the steam generator via
the downcomer annulus.
68
2. Which of the following is true about steam generator
level:
A. Level setpoint is ramped up from zero power to full
power to accommodate the level increase due to swell.
B. Level setpoint is ramped down from zero power to full
power to accommodate the level decrease due to shrink.
C. Level setpoint is ramped up from zero power to full
power to minimize volumetric changes in the PHT during
power changes.
D. Level setpoint is ramped down from zero power to full
power to minimize volumetric changes in the PHT during
power changes.
69
2. Which of the following is true about steam generator
level:
A. Level setpoint is ramped up from zero power to full
power to accommodate the level increase due to swell.
B. Level setpoint is ramped down from zero power to full
power to accommodate the level decrease due to shrink.
C. Level setpoint is ramped up from zero power to full
power to minimize volumetric changes in the PHT during
power changes.
D. Level setpoint is ramped down from zero power to full
power to minimize volumetric changes in the PHT during
power changes.
70
2. Which of the following is true about steam generator
level:
A. Level setpoint is ramped up
from zero power to full
power to accommodate the
level increase due to swell.
71
3. The Steam Generator Level Control program at
Darlington uses a 3-element control scheme at high
power. Which one of the following answers correctly
identifies the three elements?
A. Steam generator pressure, level and feedwater flow.
B. Steam generator pressure, level and steam flow.
C. Steam generator pressure, feedwater flow and steam flow.
D. Steam generator level, steam flow and feedwater flow.
72
3. The Steam Generator Level Control program at
Darlington uses a 3-element control scheme at high
power. Which one of the following answers correctly
identifies the three elements?
A. Steam generator pressure, level and feedwater flow.
B. Steam generator pressure, level and steam flow.
C. Steam generator pressure, feedwater flow and steam flow.
D. Steam generator level, steam flow and feedwater flow.
73
3. The Steam Generator Level Control program at
Darlington uses a 3-element control scheme at high
power. Which one of the following answers correctly
identifies the three elements?
D. Steam generator level, steam flow and feedwater flow.
74
4. Which of the following statements is correct in SOLID
Mode?
A. Feed and Bleed flows are regulated according to the difference
between Pressurizer Level and Pressurizer Level Setpoint.
B. For pressure control the parameter controlled is Pressurizer
Pressure.
C. For inventory control the setpoint is ROH Pressure.
D. All inventory changes are via the Pressurizer and Bleed
Condenser.
75
4. Which of the following statements is correct in SOLID
Mode?
A. Feed and Bleed flows are regulated according to the difference
between Pressurizer Level and Pressurizer Level Setpoint.
B. For pressure control the parameter controlled is Pressurizer
Pressure.
C. For inventory control the setpoint is ROH Pressure.
D. All inventory changes are via the Pressurizer and Bleed
Condenser.
76
5. Which of the following statements correctly describes
some of the steps in the movement of the feedwater
towards the Steam Generators?
A. From Condenser to LP and HP heaters, then to Boiler
Feedpumps.
B. From Deaerator to Boiler Feedpumps and to LP and HP
heaters.
C. From Condenser to Condensate Extraction Pumps to Boiler
Feedpumps to Deaerator.
D. From LP Heaters to Deaerator to Boiler Feedpumps to HP
Heaters.
77
5. Which of the following statements correctly describes
some of the steps in the movement of the feedwater
towards the Steam Generators?
A. From Condenser to LP and HP heaters, then to Boiler
Feedpumps.
B. From Deaerator to Boiler Feedpumps and to LP and HP
heaters.
C. From Condenser to Condensate Extraction Pumps to Boiler
Feedpumps to Deaerator.
D. From LP Heaters to Deaerator to Boiler Feedpumps to HP
Heaters.
78
5. Which of the following statements correctly describes
some of the steps in the movement of the feedwater
towards the Steam Generators?
D. From LP Heaters to Deaerator to Boiler Feedpumps to HP Heaters.
79
1.
A loss of feedheating steam flow to the High Pressure Feedheaters occurs on
a CANDU 9 unit operating in “Alternate” OUC mode at high power. Which
one of the following best describes the impact on the thermodynamic cycle?
A. Actual steam flow out of the steam generators will increase resulting in
lower turbine/generator power (less MWe output) for the same reactor
power.
B. Feedwater temperature entering the SGs will increase resulting in less
heating needed in the preheater and therefore more heat being used to boil
the water. For the same reactor power more steam will be produced
resulting in higher turbine power (more MWe output).
C. Feedwater temperature entering the SGs will decrease resulting in more
heating required of the preheater and less heat being used to boil the water.
For the same reactor power less steam will be produced resulting in lower
turbine power (less MWe output).
D. The reduction in feedheating steam flow means less steam is directed to the
turbine resulting in higher turbine/generator power (more MWe output) for
the same reactor power.
80
1.
A loss of feedheating steam flow to the High Pressure Feedheaters occurs on
a CANDU 9 unit operating in “Alternate” OUC mode at high power. Which
one of the following best describes the impact on the thermodynamic cycle?
81
1.
A loss of feedheating steam flow to the High Pressure Feedheaters occurs on
a CANDU 9 unit operating in “Alternate” OUC mode at high power. Which
one of the following best describes the impact on the thermodynamic cycle?
A. Actual steam flow out of the steam generators will increase resulting in
lower turbine/generator power (less MWe output) for the same reactor
power.
B. Feedwater temperature entering the SGs will increase resulting in less
heating needed in the preheater and therefore more heat being used to boil
the water. For the same reactor power more steam will be produced
resulting in higher turbine power (more MWe output).
C. Feedwater temperature entering the SGs will decrease resulting in more
heating required of the preheater and less heat being used to boil the
water. For the same reactor power less steam will be produced resulting in
lower turbine power (less MWe output).
D. The reduction in feedheating steam flow means less steam is directed to the
turbine resulting in higher turbine/generator power (more MWe output) for
the same reactor power.
82
2. Steam is found in a superheated condition at which
one of the following points in a typical CANDU plant:
A. Inlet to the HP Turbine
B. Outlet of the LP Turbine in the Condenser
C. In the Deaerator
D. At the outlet of the Reheater
83
2. Steam is found in a superheated condition at which
one of the following points in a typical CANDU plant:
D. At the outlet of the Reheater.
84
4.
A CANDU 9 reactor is operating at full power, when a turbine generator trip
occurs. Assuming the unit responds correctly, which of the following
describes the expected response of the STEPBACK program and RRS?
A. The Reactor Power alternate mode setpoint is automatically set to 60%FP by
the STEPBACK program on a turbine generator trip; RRS then controls the
liquid zone levels by raising the levels to reduce reactor power, and the
Control Absorber (CA) rods are maintained at their present position
following any STEPBACK program action.
B. Reactor power is reduced by the action of the STEPBACK program dropping
the CA rods fully into core, and RRS withdraws the CA rods and drain the
Liquid Zone levels to restore power back to 60%FP.
C. The CA rods are dropped into core as far as necessary until power is below
60%FP, and RRS controls Liquid Zone levels and withdraws the CA rods to
control reactor power to a value determined by the lowest actual power
plus the offset of the deviation limiter.
D. The STEPBACK program rapidly reduces reactor power by dropping the CA
rods partially into core by a timed opening of the clutch mechanism
contacts. RRS then raises the average Liquid Zone level in accordance with
85
the Reactivity Control Diagram.
4.
A CANDU 9 reactor is operating at full power, when a turbine generator trip
occurs. Assuming the unit responds correctly, which of the following
describes the expected response of the STEPBACK program and RRS?
A. The Reactor Power alternate mode setpoint is automatically set to 60%FP by
the STEPBACK program on a turbine generator trip; RRS then controls the
liquid zone levels by raising the levels to reduce reactor power, and the
Control Absorber (CA) rods are maintained at their present position
following any STEPBACK program action.
B. Reactor power is reduced by the action of the STEPBACK program dropping
the CA rods fully into core, and RRS withdraws the CA rods and drain the
Liquid Zone levels to restore power back to 60%FP.
C. The CA rods are dropped into core as far as necessary until power is below
60%FP, and RRS controls Liquid Zone levels and withdraws the CA rods to
control reactor power to a value determined by the lowest actual power
plus the offset of the deviation limiter.
D. The STEPBACK program rapidly reduces reactor power by dropping the CA
rods partially into core by a timed opening of the clutch mechanism
contacts. RRS then raises the average Liquid Zone level in accordance with
86
the Reactivity Control Diagram.
5. After a loss of Class 4 power:
A. The Primary Heat Transport Pumps start to rotate in
the reverse direction as flow reverses in the core
B. The Primary Heat Transport Pumps continue to run
because they are supplied by alternate power
supplies
C. Primary Heat Transport Pumps need to be restarted
within 3 to 5 minutes or the reactor core will overheat
D.The Primary Heat Transport Pumps slow down over a
period of a few minutes because large flywheels store
energy to aid in prolonging the coast to a stop period
87
5. After a loss of Class 4 power:
A. The Primary Heat Transport Pumps start to rotate in the
reverse direction as flow reverses in the core
B. The Primary Heat Transport Pumps continue to run
because they are supplied by alternate power supplies
C. Primary Heat Transport Pumps need to be restarted
within 3 to 5 minutes or the reactor core will overheat
D.The Primary Heat Transport Pumps slow down over a
period of a few minutes because large flywheels store
energy to aid in prolonging the coast to a stop period
88