PWR Surge Line Thermal Stratification Analysis Nuclear (Professional Engineering) Quiz, Nuclear Engineering

Question 1

What underlying fluid mechanism drives thermal stratification in PWR pressurizer surge lines?

Accepted Answer

Fluids of different temperatures and densities flowing into horizontal piping without significant mixing

Answer

Direct injection of non-condensable gas into the primary coolant loop

Answer

High-velocity turbulent mixing resulting in uniform fluid density

Answer

Rapid phase change from liquid to superheated steam in vertical risers

Question 2

In a thermally stratified flow within horizontal piping, how are the temperature and fluid layers positioned?

Accepted Answer

Hotter, less dense fluid floats on top of colder, denser fluid

Answer

Hotter fluid concentrates exclusively at the pipe core while cold fluid coats the outer perimeter

Answer

Colder, denser fluid floats above hotter, less dense fluid

Answer

Fluid temperatures are identical along the pipe cross-section

Question 3

What is the typical magnitude of flow velocities within thermally stratified fluid layers inside PWR surge lines?

Accepted Answer

Centimeters per second (cm/s)

Answer

Kilometers per hour (km/h)

Answer

Hundreds of meters per second (m/s)

Answer

Mach numbers exceeding 1.0

Question 4

Which condition describes an out-surge flow event in a pressurizer surge line?

Accepted Answer

Hot water from the pressurizer flowing into a surge line filled with colder water

Answer

Steam discharging into the containment pressure relief tank

Answer

Cold water injection directly from emergency core cooling storage tanks

Answer

Cooler water entering the pressurizer from the reactor vessel upper plenum

Question 5

Which software tool is widely used for conducting finite element analysis (FEA) of surge line thermal stresses?

Accepted Answer

ANSYS

Answer

LabVIEW

Answer

AutoCAD

Answer

MATLAB

Question 6

Which structural locations are considered primary weak points for piping integrity in PWR surge lines under thermal stress?

Accepted Answer

Pressurizer and main coolant line nozzles

Answer

Control rod drive mechanism housings

Answer

Main steam line safety valves

Answer

Condenser hotwell drain lines

Question 7

What primary nuclear component aging mechanism is induced by cyclic thermal loads from stratified flow?

Accepted Answer

Thermal fatigue

Answer

Hydrogen induced blistering

Answer

Neutron embrittlement

Answer

Galvanic corrosion

Question 8

During which plant operational state is thermal stratification in the surge line most pronounced?

Accepted Answer

Plant transients such as heat-up and cool-down

Answer

Extended cold shutdown with drained primary loop

Answer

Refueling outage with core fully unloaded

Answer

Steady-state 100% full power operation

Question 9

What physical structural impact results from differential thermal expansion between the top and bottom of a horizontal surge line?

Accepted Answer

Thermal stresses that cause piping deformation and potential fatigue cracking

Answer

Complete stress relaxation leading to reduced piping loads

Answer

Uniform axial stretching without bending stress

Answer

Immediate ductile rupture of all pipe supports

Question 10

Which portion of the surge line layout is identified as the most critical region for thermal stratification?

Accepted Answer

Entrance of the horizontal section

Answer

Vertical spray nozzle outlet

Answer

Reactor vessel lower head penetration

Answer

Steam generator tube sheet interior

PWR Surge Line Thermal Stratification Analysis Nuclear (Professional Engineering) Quiz, Nuclear Engineering

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