NUCLEAR POWER PLANT OPERATIONS ·
CERTIFICATION EXAMINATION
EDF QUESTIONS AND
ANSWERS GOOD LUCK
2026/2027
A comprehensive 150-question examination covering
the seven PWR systems competencies, aligned with
EDF operating standards and ASN regulatory
requirements.
2026/2027 Edition · 150 Questions · Sections 1 to 7
Aligned with EDF Nuclear Power Plant Operations Standards and ASN
Regulations
,EDF QUESTIONS AND ANSWERS GOOD LUCK 2026/2027
Section 1: Nuclear Reactor Fundamentals & Safety
Q1: According to EDF design baselines for the 900 MW CP series, standard nominal primary circuit
operating conditions are closest to which of the following?
A. About 155 bar and 290-330 degrees C, with Tcold near 287 degrees C and Thot near 323 degrees
C [CORRECT]
B. About 70 bar and 220-260 degrees C, which are typical boiling water reactor conditions
C. About 300 bar and 450-500 degrees C, characteristic of supercritical fossil-fired plants
D. Atmospheric pressure and about 100 degrees C, since primary water is kept below boiling at all
times
Correct Answer: A
Rationale: The PWR primary circuit is kept highly subcooled at approximately 155 bar precisely to
suppress bulk boiling while allowing hot-leg temperatures near 323 degrees C, per the EDF CP series
design baseline. The second option describes BWR conditions where steam is generated in the vessel, and
the third option describes supercritical fossil practice; the fourth option is impossible because a PWR core
at power requires pressurized liquid water for forced cooling and moderation.
Q2: During a power ascension the operator notes that primary average temperature (Tavg) is climbing.
What is the correct understanding of the moderation feedback that follows?
A. Water density rises, moderation improves, and positive reactivity is added that accelerates the
power rise
B. Water density falls, moderation weakens, and the negative moderator temperature coefficient
inserts negative reactivity that self-limits the power rise [CORRECT]
C. Moderation is unaffected by temperature because fuel geometry fixes the lattice, so reactivity
stays constant
D. The Doppler effect reverses sign at power so that heating now adds positive reactivity
Correct Answer: B
Rationale: In the EDF PWR design the moderator temperature coefficient is strongly negative at power,
so thermal expansion of the water reduces its slowing-down power and inserts negative reactivity, a key
self-stabilizing feature credited in safety demonstrations. The first option reverses the physics, the third
option ignores the density effect central to PWR feedback, and the fourth option is wrong because the fuel
Doppler effect remains negative at all power levels.
PWR Systems Competencies - 2026/2027 Edition 1
,EDF QUESTIONS AND ANSWERS GOOD LUCK 2026/2027
Q3: Which statement correctly describes the RCC control rod assemblies used in an EDF CP series PWR?
A. Rods are inserted from the bottom of the core by hydraulic pressure and held out by check valves
B. Rods are made of natural boron steel and move continuously by screw drives without step counters
C. Rod cluster control assemblies travel in guide tubes within fuel assemblies, are withdrawn from
the top by magnet-stepped drive rods, and use silver-indium-cadmium absorber with some boron
carbide rods [CORRECT]
D. Rods are replaced every cycle because silver-indium-cadmium melts at nominal primary
temperature
Correct Answer: C
Rationale: EDF RCC assemblies are bottom-guided, top-driven, gripper-rod mechanisms moved in
discrete steps by magnetic jack coils, with Ag-In-Cd absorber in black rods and B4C in grey or black rods
depending on the series. Bottom-entry hydraulic designs (the first option) belong to BWR practice,
continuous screw drives (the second option) do not exist in the EDF design, and Ag-In-Cd melting point
far exceeds primary temperature (the fourth option).
Q4: At 50 percent power the team performs a small primary dilution. Which sequence best describes the
reactivity effects that follow?
A. Doppler positive heating dominates immediately, before any boron effect is felt
B. The negative moderator coefficient adds reactivity first, then boron dilution cancels it
C. Nothing measurable happens because soluble boron changes require a full reactor trip to detect
D. Positive reactivity from boron dilution appears first and is then opposed by the negative moderator
temperature coefficient as Tavg climbs and by Doppler broadening in the fuel [CORRECT]
Correct Answer: D
Rationale: A dilution reduces soluble boron concentration and adds positive reactivity directly; the
resulting power rise raises fuel temperature (negative Doppler) and coolant temperature (negative MTC),
which terminate the transient in a controlled way as described in EDF reactivity control practice. The first
option inverts the order and sign, the second option reverses the causality, and the third option is wrong
because boron dilutions are carefully metered and monitored under the operating rules (RGE).
Q5: In EDF system nomenclature, the reactor protection system whose logic channels generate automatic
reactor trip and engineered safeguards actuation signals is designated:
A. RCC, the reactor control command system
B. RRA, the shutdown cooling system
C. RPR, the Reactor Protection and Safeguard system (Protection Reacteur et Sauvegarde du
Reacteur) [CORRECT]
D. RGL, the rod control and position indication system
Correct Answer: C
Rationale: RPR is the EDF designation for the protection system that acquires process variables, applies
two-out-of-four or similar voting logic, and commands reactor trip and safeguards actuation. RCC is
control rod drive, RRA is residual heat removal, and RGL is rod speed control, so none of the other
options performs the protection and safeguard function.
PWR Systems Competencies - 2026/2027 Edition 2
, EDF QUESTIONS AND ANSWERS GOOD LUCK 2026/2027
Q6: The defense in depth framework applied by ASN and EDF defines five levels. Which assignment is
correct?
A. Level 3 covers control of design basis accidents using engineered safety features, while Levels 1
and 2 cover normal operation and anticipated transients [CORRECT]
B. Level 5 covers prevention of abnormal operation, and Level 1 covers off-site emergency response
C. Level 3 covers severe accident mitigation, and Level 4 covers normal operation
D. There are only three levels, and Level 3 covers quality assurance of safety systems
Correct Answer: A
Rationale: In the five-level defense in depth concept, Level 1 prevents abnormal operation, Level 2
controls anticipated transients, Level 3 controls design basis accidents with engineered safety features such
as RIS and ASG, Level 4 manages severe accidents, and Level 5 handles off-site emergency response. The
second and third options scramble the level assignments, and the fourth option misstates the framework
entirely.
Q7: A steam generator shell in the RCP system is being classified for design and procurement. Under EDF
and RCC-M practice, what is the correct classification rationale?
A. It is unclassified because the secondary side is non-radioactive under normal operation
B. It is a Class 3 item because steam generators are considered ordinary heat exchangers
C. It is treated as a monitoring-only component because integrity is assured by APG blowdown alone
D. It is a Class 2 pressure boundary item of the RCP system because it is part of the second barrier
whose rupture would challenge core cooling, designed and inspected to RCC-M requirements
[CORRECT]
Correct Answer: D
Rationale: Steam generators sit on the primary pressure boundary and form part of the second
confinement barrier, so EDF classifies them high in the safety hierarchy and manufactures them to
RCC-M rules with in-service inspection of tubes, welds and shells. The first option ignores radioactive
inventory on the primary side, the second option contradicts the safety classification, and the third option
confuses a chemistry support function with mechanical integrity requirements.
Q8: Following a double-ended guillotine break of a main primary pipe (large LOCA), which response
sequence does the design basis rely on?
A. Operator-driven manual boration within one hour, since automatic systems are designed to trip
and wait
B. Automatic reactor trip and safety injection, passive accumulator injection as pressure collapses,
then high-head and low-head injection and finally switchover to containment sump recirculation
[CORRECT]
C. Steam generator feeding with ASG alone, since the break self-isolates when pressure equalizes
D. Containment spray only, because reflooding of the core is impossible after a large break
Correct Answer: B
Rationale: The large LOCA design basis sequence is automatic trip plus SI actuation, passive discharge of
the accumulators (Reservoirs Resu) when primary pressure falls below their nitrogen setpoint, pumped
high-head and low-head injection from the borated water storage tank, and long-term recirculation from
the containment sump, all staged automatically per the A1.1-type EOP logic. The first option
underestimates the automatic design, the third option confuses secondary and primary cooling, and the
fourth option contradicts the ECCS reflooding demonstration.
PWR Systems Competencies - 2026/2027 Edition 3
CERTIFICATION EXAMINATION
EDF QUESTIONS AND
ANSWERS GOOD LUCK
2026/2027
A comprehensive 150-question examination covering
the seven PWR systems competencies, aligned with
EDF operating standards and ASN regulatory
requirements.
2026/2027 Edition · 150 Questions · Sections 1 to 7
Aligned with EDF Nuclear Power Plant Operations Standards and ASN
Regulations
,EDF QUESTIONS AND ANSWERS GOOD LUCK 2026/2027
Section 1: Nuclear Reactor Fundamentals & Safety
Q1: According to EDF design baselines for the 900 MW CP series, standard nominal primary circuit
operating conditions are closest to which of the following?
A. About 155 bar and 290-330 degrees C, with Tcold near 287 degrees C and Thot near 323 degrees
C [CORRECT]
B. About 70 bar and 220-260 degrees C, which are typical boiling water reactor conditions
C. About 300 bar and 450-500 degrees C, characteristic of supercritical fossil-fired plants
D. Atmospheric pressure and about 100 degrees C, since primary water is kept below boiling at all
times
Correct Answer: A
Rationale: The PWR primary circuit is kept highly subcooled at approximately 155 bar precisely to
suppress bulk boiling while allowing hot-leg temperatures near 323 degrees C, per the EDF CP series
design baseline. The second option describes BWR conditions where steam is generated in the vessel, and
the third option describes supercritical fossil practice; the fourth option is impossible because a PWR core
at power requires pressurized liquid water for forced cooling and moderation.
Q2: During a power ascension the operator notes that primary average temperature (Tavg) is climbing.
What is the correct understanding of the moderation feedback that follows?
A. Water density rises, moderation improves, and positive reactivity is added that accelerates the
power rise
B. Water density falls, moderation weakens, and the negative moderator temperature coefficient
inserts negative reactivity that self-limits the power rise [CORRECT]
C. Moderation is unaffected by temperature because fuel geometry fixes the lattice, so reactivity
stays constant
D. The Doppler effect reverses sign at power so that heating now adds positive reactivity
Correct Answer: B
Rationale: In the EDF PWR design the moderator temperature coefficient is strongly negative at power,
so thermal expansion of the water reduces its slowing-down power and inserts negative reactivity, a key
self-stabilizing feature credited in safety demonstrations. The first option reverses the physics, the third
option ignores the density effect central to PWR feedback, and the fourth option is wrong because the fuel
Doppler effect remains negative at all power levels.
PWR Systems Competencies - 2026/2027 Edition 1
,EDF QUESTIONS AND ANSWERS GOOD LUCK 2026/2027
Q3: Which statement correctly describes the RCC control rod assemblies used in an EDF CP series PWR?
A. Rods are inserted from the bottom of the core by hydraulic pressure and held out by check valves
B. Rods are made of natural boron steel and move continuously by screw drives without step counters
C. Rod cluster control assemblies travel in guide tubes within fuel assemblies, are withdrawn from
the top by magnet-stepped drive rods, and use silver-indium-cadmium absorber with some boron
carbide rods [CORRECT]
D. Rods are replaced every cycle because silver-indium-cadmium melts at nominal primary
temperature
Correct Answer: C
Rationale: EDF RCC assemblies are bottom-guided, top-driven, gripper-rod mechanisms moved in
discrete steps by magnetic jack coils, with Ag-In-Cd absorber in black rods and B4C in grey or black rods
depending on the series. Bottom-entry hydraulic designs (the first option) belong to BWR practice,
continuous screw drives (the second option) do not exist in the EDF design, and Ag-In-Cd melting point
far exceeds primary temperature (the fourth option).
Q4: At 50 percent power the team performs a small primary dilution. Which sequence best describes the
reactivity effects that follow?
A. Doppler positive heating dominates immediately, before any boron effect is felt
B. The negative moderator coefficient adds reactivity first, then boron dilution cancels it
C. Nothing measurable happens because soluble boron changes require a full reactor trip to detect
D. Positive reactivity from boron dilution appears first and is then opposed by the negative moderator
temperature coefficient as Tavg climbs and by Doppler broadening in the fuel [CORRECT]
Correct Answer: D
Rationale: A dilution reduces soluble boron concentration and adds positive reactivity directly; the
resulting power rise raises fuel temperature (negative Doppler) and coolant temperature (negative MTC),
which terminate the transient in a controlled way as described in EDF reactivity control practice. The first
option inverts the order and sign, the second option reverses the causality, and the third option is wrong
because boron dilutions are carefully metered and monitored under the operating rules (RGE).
Q5: In EDF system nomenclature, the reactor protection system whose logic channels generate automatic
reactor trip and engineered safeguards actuation signals is designated:
A. RCC, the reactor control command system
B. RRA, the shutdown cooling system
C. RPR, the Reactor Protection and Safeguard system (Protection Reacteur et Sauvegarde du
Reacteur) [CORRECT]
D. RGL, the rod control and position indication system
Correct Answer: C
Rationale: RPR is the EDF designation for the protection system that acquires process variables, applies
two-out-of-four or similar voting logic, and commands reactor trip and safeguards actuation. RCC is
control rod drive, RRA is residual heat removal, and RGL is rod speed control, so none of the other
options performs the protection and safeguard function.
PWR Systems Competencies - 2026/2027 Edition 2
, EDF QUESTIONS AND ANSWERS GOOD LUCK 2026/2027
Q6: The defense in depth framework applied by ASN and EDF defines five levels. Which assignment is
correct?
A. Level 3 covers control of design basis accidents using engineered safety features, while Levels 1
and 2 cover normal operation and anticipated transients [CORRECT]
B. Level 5 covers prevention of abnormal operation, and Level 1 covers off-site emergency response
C. Level 3 covers severe accident mitigation, and Level 4 covers normal operation
D. There are only three levels, and Level 3 covers quality assurance of safety systems
Correct Answer: A
Rationale: In the five-level defense in depth concept, Level 1 prevents abnormal operation, Level 2
controls anticipated transients, Level 3 controls design basis accidents with engineered safety features such
as RIS and ASG, Level 4 manages severe accidents, and Level 5 handles off-site emergency response. The
second and third options scramble the level assignments, and the fourth option misstates the framework
entirely.
Q7: A steam generator shell in the RCP system is being classified for design and procurement. Under EDF
and RCC-M practice, what is the correct classification rationale?
A. It is unclassified because the secondary side is non-radioactive under normal operation
B. It is a Class 3 item because steam generators are considered ordinary heat exchangers
C. It is treated as a monitoring-only component because integrity is assured by APG blowdown alone
D. It is a Class 2 pressure boundary item of the RCP system because it is part of the second barrier
whose rupture would challenge core cooling, designed and inspected to RCC-M requirements
[CORRECT]
Correct Answer: D
Rationale: Steam generators sit on the primary pressure boundary and form part of the second
confinement barrier, so EDF classifies them high in the safety hierarchy and manufactures them to
RCC-M rules with in-service inspection of tubes, welds and shells. The first option ignores radioactive
inventory on the primary side, the second option contradicts the safety classification, and the third option
confuses a chemistry support function with mechanical integrity requirements.
Q8: Following a double-ended guillotine break of a main primary pipe (large LOCA), which response
sequence does the design basis rely on?
A. Operator-driven manual boration within one hour, since automatic systems are designed to trip
and wait
B. Automatic reactor trip and safety injection, passive accumulator injection as pressure collapses,
then high-head and low-head injection and finally switchover to containment sump recirculation
[CORRECT]
C. Steam generator feeding with ASG alone, since the break self-isolates when pressure equalizes
D. Containment spray only, because reflooding of the core is impossible after a large break
Correct Answer: B
Rationale: The large LOCA design basis sequence is automatic trip plus SI actuation, passive discharge of
the accumulators (Reservoirs Resu) when primary pressure falls below their nitrogen setpoint, pumped
high-head and low-head injection from the borated water storage tank, and long-term recirculation from
the containment sump, all staged automatically per the A1.1-type EOP logic. The first option
underestimates the automatic design, the third option confuses secondary and primary cooling, and the
fourth option contradicts the ECCS reflooding demonstration.
PWR Systems Competencies - 2026/2027 Edition 3
