API 510 Inspection Techniques & Nondestructive Testing 5

Question 1

Infrared thermography (IRT) is used during pressure vessel inspection to detect:

Accepted Answer

Hot spots in refractory-lined vessels indicating lining failure or thinning

Answer

Precise weld fusion line defects in austenitic stainless steel

Answer

Hydrogen embrittlement in high-strength steel components

Answer

Chloride stress corrosion cracking under insulation

Question 2

A vessel inspector conducting a radiographic examination notes 'scattered porosity' in a weld radiograph. How is scattered porosity typically evaluated per ASME Section VIII, Division 1?

Accepted Answer

It is compared against acceptance charts that consider pore size, density, and distribution

Answer

It is always cause for rejection regardless of individual pore size

Answer

Only the largest individual pore diameter is measured for acceptance

Answer

Scattered porosity is acceptable in all welds unless pores are clustered

Question 3

During time-of-flight diffraction (TOFD) ultrasonic inspection, the lateral wave is used to:

Accepted Answer

Serve as a timing reference for calculating flaw depth and height

Answer

Detect mid-wall laminations running parallel to the surface

Answer

Indicate the back-wall surface position for thickness measurement

Answer

Identify surface-breaking cracks on the far wall

Question 4

When inspecting a pressure vessel that has experienced high-temperature hydrogen attack (HTHA), the NDT method that can detect the internal microstructural damage (methane voids and fissures) most effectively is:

Accepted Answer

Automated ultrasonic testing using creeping wave or TOFD techniques

Answer

Conventional radiography

Answer

Magnetic particle testing with AC yoke

Answer

Liquid penetrant testing with color contrast method

Question 5

Per API 510, what action is required when the calculated remaining life of a pressure vessel is less than 4 years?

Accepted Answer

The next internal or on-stream inspection interval must not exceed half the remaining life

Answer

The vessel must be immediately taken out of service for repair

Answer

A fitness-for-service assessment must be performed within 30 days

Answer

The maximum allowable working pressure must be reduced by 10%

Question 6

Positive material identification (PMI) is most critical during vessel inspection when:

Accepted Answer

Confirming that replacement materials and weld filler metals are the correct specified alloy

Answer

Verifying that the nameplate data matches the original design drawings

Answer

Checking that all bolting torque values meet code requirements

Answer

Ensuring hydrostatic test water meets chemical purity standards

Question 7

A near-drum inspection of a pressure vessel reveals a 'turtle-back' bulge on the shell. This morphology is most characteristic of which damage mechanism?

Accepted Answer

Hydrogen-induced blistering from wet hydrogen sulfide service

Answer

External stress corrosion cracking from chloride exposure

Answer

Thermal fatigue from cyclic temperature fluctuations

Answer

Erosion-corrosion from high-velocity liquid impingement