Take A Free ASNT NDT NR Level 3 Exam Practice Test – Quiz Course

1.

A thermal neutron beam is extracted horizontally from a reactor. Neglecting to scatter by air or other materials in its path, what would you expect the beam path over the first 15 m (49 ft) to do?

2.

Nature of Penetrating Radiation

Neutrons:

3.

Which of the following is true for neutron radiographic conditions?

4.

Interaction between Penetrating Radiation and Matter

When the mass absorption coefficient for neutrons is plotted as a function of the atomic number of the absorber, it presents a:?

5.

You have to neutron radiograph an object that required visualization of very small hydrogenous details behind 76 mm (3 in.) of steel. The standard technique using a tangential beam on a reactor proves insufficient. What would be the recommended approach?

6.

Which of the following statements is incorrect?

7.

From the following penetrating radiations, which one can best be used to radiograph a cylinder of hydrocarbon plastic that is 50 mm (2 in.) in diameter in which we want to image embedded metal parts?

8.

Following neutron capture in a gadolinium-foil converter, which of the following is emitted from the foil surface and interacts in the photographic emulsion to produce a high-resolution latent image?

9.

A fact concerning the reciprocity law failure in neutron radiography is that:

10.

When a neutron-sensitive fluorescent screen is used in conjunction with a photographic film, the film exposure satisfies the Schwarzchild relationship, E=I+p, where p = 0.75. This means that, if a flux, I, gives a satisfactory exposure in 1 minute, a flux 1/10 as great, I₀ /10, will require an exposure time of approximately:

11.

The photographic latent image may be defined as that radiation-induced change in a grain or crystal that renders the grain readily susceptible to the chemical action of a developer. The material of the latent image itself is typical:

12.

Track etch neutron imaging differs from dysprosium transfer imaging in which of the following ways?

13.

Imaging by Fluorescent Materials

When fluorescent materials are employed for neutron radiographic imaging, reciprocity failure is often encountered. This is due to the fact that:

14.

Imaging by Electronic Devices

Electron imaging devices invariably provide:

15.

Substitution of gadolinium-oxysulfide for ZrS-Li°F as the input converter is an electronic imaging device will normally result in:

16.

Radiometry

The “cadmium ratio” of a neutron refers to:

17.

SOURCES OF NEUTRONS Neutron Sources-General Reactors

High-quality neutron radiographs are produced by reactor neutron sources because of the:

18.

Accelerators

Which one of the following generators has a significant neutron yield at the low bombardment energies?

19.

Isotopic Sources

The neutron-producing reaction of Cf-252 is:

20.

Of the isotopic sources employed for neutron radiography, which of the following sources decays by the spontaneous fission process?

21.

RADIATION DETECTORS Imaging Converter Screens

For fast films, thermal neutron fluxes of about 10⁴4 nV (n/cm²-s) represent the minimum useful intensity for conventional transfer neutron radiography utilizing which one of the following conversion screens?

22.

You normally use gadolinium direct exposure methods at your facility. You have available only one gadolinium screen, 36 cm x 43 cm (14 x 17 in.). One day, you wish to neutron radiograph a single very large object (100 cm x 30 cm [39 x 12 in.]) in a single exposure. Obtaining a widely divergent beam is no problem at this facility. Screens, however, are a problem. You are willing to sacrifice some image quality in order to avoid the expense of such a large vapor-deposited screen. To get the best results at the lowest cost you would:

23.

Film principles, Properties, Use with Neutron Converter Screens

A 20 percent increase in exposure (Δ log E=0.08) for a given film convector combination results in a film density change from 2.3 to 2.7. The gradient of the characteristic curve is:

24.

LiF, Zn S(Ag) neutron scintillators, which can be used as a fluoroscopic screen, emit blue light that:

25.

Which of the following facts are true concerning the use of a regular X-ray gadolinium₂0₂ S screen as a neutron converter?

26.

Fluoroscopy-TV and Optical Systems

A practical video neutron-radiographic system could not be based on a:

27.

Gaseous Ionization Detectors

When using a gaseous proportional counter for neutron radiography, the principal ionization event utilizing thermal neutrons is due to which of the following?

28.

Neutron Detectors

Which of the following types of detectors would be least likely to be used for neutron detection?

29.

Neutrons may be detected and measured using a foil activation technique. A foil material suitable for detecting thermal neutrons with this technique is:

30.

A boron trifluoride neutron counter is known as a proportional counter because:

31.

Instrumentation

The output of most non-imaging neutron detectors is:

32.

Gaging and Control Processes

A gaging setup can distinguish 5% changes in the intensity of a transmitted neutron beam. If the average thickness of a sheet being gaged attenuates the neutron-beam intensity by a factor of 20 (~3 mean free paths), how small a change in thickness will be detectable?

33.

A system of gaging in which the radiation is collimated and projected through a test item and the quantity of unabsorbed radiation is measured is referred to as the:

34.

Generally, the sensitivity and accuracy of thickness gaging by reflection methods are:

35.

PERSONNEL SAFETY AND RADIATION PROTECTION Exposure Hazards

Where isotopic sources are employed for field neutron radiographic applications, the radiation levels near the biological shield should not exceed:

36.

Specific Neutron Hazards

Which of the following neutron personnel monitoring conditions is incorrect?

37.

Operation and Emergency Procedures

“Occupational dose” as applied to the exposure of an individual to radiation in a restricted area or in the course of employment in which the individual’s duties involve exposure to radiation shall:

38.

The rad, as used in USNRC Title 10, Chapter 1 CFR, Part 20, is a measure of the dose of any ionizing radiation to body tissue in terms of the energy absorbed per unit mass of the tissue. One rad is the dose corresponding to the absorption of how many joules (ergs) per gram of tissue.

39.

An unrestricted area means:

40.

Units of radioactivity are commonly measured in terms of disintegrations per unit of time or in curies. One curie is:

41.

What is the maximum dose that a worker can be permitted to receive in a restricted area in any one calendar quarter?

42.

THE RADIOGRAPHIC PROCESS Imaging Considerations – Sensitivity

According to the standard ASTM E-545, which of the following is an acceptable level of neutron radiographic sensitivity?

43.

Contrast and Definition

Which of the following parameters do not directly affect radiographic definition?

44.

Film contrast refers to:

45.

In general, the contrast of radiographic films (except those designed for use with fluorescent screens):

46.

Specimens with uniform thickness and composition by definition have: 

47.

The sharpness of the outline in a radiographic image is referred to as:

48.

The poor radiographic definition could be the result of:

49.

Based on the characteristic curves of the films below, which film provides the highest contrast?

50.

Geometric Factors

When a given resolution is desired in a radiograph, a compromise must be made between attainable resolution and neutron flux at the image plane because:

51.

Converter or intensifying screens are utilized in both direct and indirect photographic techniques. Which of the following is arranged from the highest to the lowest cross section for thermal neutrons?

52.

Converter or intensifying screens are utilized in both direct and indirect photographic techniques. Which of the following is arranged from the highest to the lowest cross section for thermal neutrons?

53.

Converter or intensifying screens are utilized in both direct and indirect photographic techniques. Which of the following is arranged from the highest to the lowest cross section for thermal neutrons?

54.

Intensifying Screens

Dy-164 has a cross-section of 2 700 10^-28 m². (2 700 barns) for the 1.25-minute half-life activity, and 800 10^-28 m² (800 barns) for the 140-minute half-life activity. Considering activation transfer neutron radiography in which there is minimal delay between foil neutron exposure and film contact, and assuming a long transfer period (12 hours), which of the following is true?

55.

Scattered Radiation

The problem of scatter in a hydrogenous object being radiographed can be reduced by:

56.

Source Factors

Given a neutron beam with an L/D of 250, a thermal flux of 10⁶ n/cm²-s, and a 36-43 cm (14-17 in.) exposure area, what is the geometric sharpness for a test object of 6 mm (0.25 in.) thick?

57.

Indium-resonance neutrons:

58.

Detection Media

Which of the following converters cannot be used for transfer neutron radiography?

59.

Cold neutrons can be detected with high efficiency, for imaging by:

60.

The relative n/y ray sensitivity of metal screens that of converters is generally about scintillating-screen converters for direct exposure radiography.

61.

Exposure Curves

The contrast observed in a radiographic image is greater when:

62.

Film Processing Darkroom Equipment and Chemicals

Which statement concerning darkroom equipment and chemicals is incorrect?

63.

In automatic processing, over-replenishment of the fixer solution may result in:

64.

Background Lighting

The contrast sensitivity of the human eye is greatest when the surroundings compared to the area of interest on a radiograph are:

65.

For best contrast sensitivity, the film viewing room should have lighting:

66.

When reviewing film, background lighting should:

67.

Density-Judging Radiographic Quality

Photographic density refers to the quantitative measure of film blackening. When no danger of confusion exists, photographic density is usually spoken of merely as “density.” Density is defined by the equation:

68.

Contrast

Radiographic contrast for neutron radiography is a function of the:

69.

Radiographic contrast in neutron radiography can sometimes be increased by the proper choice of converter foils. If a gadolinium foil were chosen in place of an indium foil, you might be seeking contrast enhancement from:

70.

Definition

Standard ASTM E-545 uses a maximum of how many sensitivity indicators?

71.

Artifacts

The appearance of colored stains on a processed radiograph could be caused by:

72.

Prolonged washing of film in water above 68 °F has a tendency to:

73.

The ASTM beam purity indicator is designed primarily to indicate:

74.

The image quality indicator is generally made of:

75.

Exposure Calculations

You design a divergent collimator NR system on a given beam port such that the exposure area is 10 x 10 cm (4 x 4 in.), and the geometric unharness is 50 μ at 1 cm (0.4 in.) separation between detail and screen. Using the same neutron source beam tube, you now redesign for a 30 x 30 cm (12 x 12 in.) exposure area and a geometric unharness of 100 μ at 1 cm (0.4 in.). The larger aperture and divergence cause a flux depression at the source of a factor of 2 as compared with the first system. The new exposure time required when using gadolinium foil and Kodak SR film on a thin object is 300 seconds. Estimate the original source flux and exposure time.

76.

In order to provide the initial evaluation as to the practicality of a particular direct neutron radiograph exposure method, which term is not needed?

77.

RADIOGRAPHIC TECHNIQUES Blocking and Filtering

A filter material commonly used in a neutron beam to improve the neutron-to-gamma ratio is

78.

Multifilm Techniques

Which of the following is the most inclusive?

79.

Enlargement and Projection

With the normal divergent collimator, image magnification occurs as the spacing between the object plane and the detector plane increases. If L is the source-to-object distance, and t is the object-to-image plane distance, then the magnification is:

80.

Autoradiography

A practical application of autoradiography subsequent to neutron activation is:

81.

Flash Radiography

High-speed radiography can be best performed by:

82.

Fluoroscopy

One of the main disadvantages of a fluoroscopic system is:

83.

Fluoroscopy possesses certain advantages over film radiography such as its:

84.

Microradiography

Which of the following parameters has minimal or no effect on resolution when making a microradiograph?

85.

Laminography (Tomography)

In tomography, the plane of the object that will be in focus is determined by the:

86.

Gaging

Isotopic sources have certain advantages over radiation generators for gaging in that:

87.

Real-Time Imaging

Which of the following is not associated with real-time neutron imaging?

88.

Image Analysis Techniques

Assuming 10° electrons associated with a particular feature of an image, the expected variation due to statistical consideration is:

89.

Image Analysis Techniques

Assuming 10° electrons associated with a particular feature of an image, the expected variation due to statistical consideration is:

90.

RADIOGRAPHIC INTERPRETATION Image-Object Relationships

The best standard for image-object relationship is:

91.

Material Processing as It Affects the Use of Item and Test Results Material Considerations

Radiographic detection of small amounts of explosives in thick steel will give the best contrast if what kind of neutrons are used?

92.

Compared to thermal neutrons, in crystalline materials, cold neutrons are:

93.

Discontinuities: Their Causes and Effects

Particles of foreign material such as sand or slag that are embedded in the cast metal are indicative of the:

94.

One lower limit of detectability of microporosity in materials can be caused by:

95. Codes, Standards, Specifications, and Procedures

As stated in the “Standard Method for Determining Image Quality in Thermal Radiographic Testing,” ASTM E-545-75, which of the following statements are justification for preparing a process control radiograph for Verification of specified exposure and sensitivity requirements?

(1) The part setup does not provide for the location of image quality indicators to give adequate

(2) The part configuration necessitates a film-to-beam orientation which does not provide satisfactory density measurements for the calculation of exposure by collimated thermal neutrons.

(3) The size or setup of parts is such that the background film density variation across the film exceeds 5% (+2.5% variation from the numerical mean of 5 measurements).

(4) The part materials necessitate the use of a conversion screen that responds to neutrons of energies other than thermal in order to give adequate readings.

(5) The size or setup of parts is such that the object-scattered neutron level relative to background density, sensitivity, or facility-scattered neutron exposure requirements is cause for non-conformance.