Civil Engineering EPRI Exam Questions
and Answers
Why is civil engineering important in power plants? - Answers -Their main function is to
maintain structural integrity of structures, systems, and components.
Describe the design criteria and requirements for sites - Answers -- Soil structure
interaction
- Soil stability
- Excavation
Describe operating experience with external flooding, including causes, consequences,
and preventive measures for sites - Answers -- Fukushima, Japan: An earthquake and
subsequent tsunami at Fukushima nuclear plant in Japan in March, 2011 caused
flooding that led to loss of all but one of the emergency diesel generators on this six unit
site. ALL units lost off-site power and the on-site electrical distribution equipment.
Engineers had earlier determined thatFukushima could be exposed to a tsunami larger
than the design basis tsunami, but protection features were not installed for a larger
tsunami. Without power for the core cooling equipment, the core overheated and the
fuel cladding burned. Hydrogen gas vented from the reactor exploded in the
containment building, releasing fission products from the fuel to the environment.
- Ft. Calhoun, Nebraska: Record level flooding of the Missouri River caused by
excessive rain threatened the Ft. Calhoun Nuclear Plant in Nebraska in June, 2011, but
there was no damage to the nuclear facility. In addition to the existing protective
features, such as watertight buildings and auxiliary electrical power sources, station
personnel implemented additional, temporary actions to protect the facility. The
additional actions included installation of a water barrier around the facility, installation
of overhead electric power lines to the plant, and the addition of another electric diesel
generator to support the existing emergency generators.
The lessons learned from Fukushima proved advantageous for the staff at Ft. Calhoun.
What is soil-structure interaction? - Answers -It is the dynamic response of a structure
coupled to its supporting medium.
What characteristics do soil-interaction response rely on? - Answers -- The earthquake
ground motion
- The surrounding soil profile
- The structure itself
, What does it mean when there is little or no soil-structure interaction? - Answers -When
there is little or no soil-structure interaction, motion at the base of the structure is
essentially the same as ground motion recorded at a distance away from the structure.
What are the characteristics of structures that allow for low levels of soil-structure
interaction? - Answers -- Light, surface-founded structure
- Founded on rock or stiff soil
What is an example of a structure that can allow for low levels of soil-structure
interaction? - Answers -Single story house or office building.
What is a strong soil-structure interaction? - Answers -When there is strong soil-
structure interaction, motion at the base of the structure is substantially different from
ground motion recorded at a distance away from the structure.
What are the characteristics of structures that allow for high levels of soil-structure
interaction? - Answers -- Massive structure (e.g. containment building for a nuclear
reactor)
- Partially embedded in ground
- Soft soil deposit
What are the main effects of soil-structure interaction? - Answers -- The flexibility of the
foundation causes a decrease in the natural frequency of the system. The frequency
decrease depends on the relative stiffness of the structure with respect to the soil.
- There is an increase in effective damping of the system. The main factor contributing
to the increase in damping is the loss of energy by radiation of waves away from the
foundation.
- The flexibility of the soil results in the introduction of rotational components of the
motion at the base of the foundation when subjected to horizontal motion.
What two reasons is soil stability important? - Answers --Civil engineers make decisions
on placing the plant on engineered backfill or bedrock, the type of backfill material, and
amount of compaction (measure of the density of the soil in the field at a specified
moisture content) required.
- If the soil does not meet civil design properties, the buildings and equipment inside
them would be inadequate to withstand the effects of an earthquake.
What 4 things should be taken into account when conducting a complete soil-interaction
analysis? - Answers -- Variation of soil properties with depth
- Uncertainties in the measured/determined soil properties
- Material nonlinear behavior of the soil
- Possible interaction with neighboring structures.
and Answers
Why is civil engineering important in power plants? - Answers -Their main function is to
maintain structural integrity of structures, systems, and components.
Describe the design criteria and requirements for sites - Answers -- Soil structure
interaction
- Soil stability
- Excavation
Describe operating experience with external flooding, including causes, consequences,
and preventive measures for sites - Answers -- Fukushima, Japan: An earthquake and
subsequent tsunami at Fukushima nuclear plant in Japan in March, 2011 caused
flooding that led to loss of all but one of the emergency diesel generators on this six unit
site. ALL units lost off-site power and the on-site electrical distribution equipment.
Engineers had earlier determined thatFukushima could be exposed to a tsunami larger
than the design basis tsunami, but protection features were not installed for a larger
tsunami. Without power for the core cooling equipment, the core overheated and the
fuel cladding burned. Hydrogen gas vented from the reactor exploded in the
containment building, releasing fission products from the fuel to the environment.
- Ft. Calhoun, Nebraska: Record level flooding of the Missouri River caused by
excessive rain threatened the Ft. Calhoun Nuclear Plant in Nebraska in June, 2011, but
there was no damage to the nuclear facility. In addition to the existing protective
features, such as watertight buildings and auxiliary electrical power sources, station
personnel implemented additional, temporary actions to protect the facility. The
additional actions included installation of a water barrier around the facility, installation
of overhead electric power lines to the plant, and the addition of another electric diesel
generator to support the existing emergency generators.
The lessons learned from Fukushima proved advantageous for the staff at Ft. Calhoun.
What is soil-structure interaction? - Answers -It is the dynamic response of a structure
coupled to its supporting medium.
What characteristics do soil-interaction response rely on? - Answers -- The earthquake
ground motion
- The surrounding soil profile
- The structure itself
, What does it mean when there is little or no soil-structure interaction? - Answers -When
there is little or no soil-structure interaction, motion at the base of the structure is
essentially the same as ground motion recorded at a distance away from the structure.
What are the characteristics of structures that allow for low levels of soil-structure
interaction? - Answers -- Light, surface-founded structure
- Founded on rock or stiff soil
What is an example of a structure that can allow for low levels of soil-structure
interaction? - Answers -Single story house or office building.
What is a strong soil-structure interaction? - Answers -When there is strong soil-
structure interaction, motion at the base of the structure is substantially different from
ground motion recorded at a distance away from the structure.
What are the characteristics of structures that allow for high levels of soil-structure
interaction? - Answers -- Massive structure (e.g. containment building for a nuclear
reactor)
- Partially embedded in ground
- Soft soil deposit
What are the main effects of soil-structure interaction? - Answers -- The flexibility of the
foundation causes a decrease in the natural frequency of the system. The frequency
decrease depends on the relative stiffness of the structure with respect to the soil.
- There is an increase in effective damping of the system. The main factor contributing
to the increase in damping is the loss of energy by radiation of waves away from the
foundation.
- The flexibility of the soil results in the introduction of rotational components of the
motion at the base of the foundation when subjected to horizontal motion.
What two reasons is soil stability important? - Answers --Civil engineers make decisions
on placing the plant on engineered backfill or bedrock, the type of backfill material, and
amount of compaction (measure of the density of the soil in the field at a specified
moisture content) required.
- If the soil does not meet civil design properties, the buildings and equipment inside
them would be inadequate to withstand the effects of an earthquake.
What 4 things should be taken into account when conducting a complete soil-interaction
analysis? - Answers -- Variation of soil properties with depth
- Uncertainties in the measured/determined soil properties
- Material nonlinear behavior of the soil
- Possible interaction with neighboring structures.
