PIC Nuclear Density Gauge Operation 3

Question 1

What information must be displayed on the exterior of a nuclear gauge transport case per NRC/DOT requirements?

Accepted Answer

Radioactive material warning label, UN number, and proper shipping name

Answer

DOT regulations require radioactive material labels (Yellow-II or Yellow-III), the UN number (UN2910 or UN3332), and proper shipping name on transport cases.

Question 2

An inspector uses a nuclear gauge on a granular base course and obtains a percent compaction of 96%. The specification requires 95% minimum. The gauge's moisture reading is suspect. What should the inspector do?

Accepted Answer

Take a nuclear density reading and verify moisture independently with an oven-dry or speedy moisture test

Answer

When moisture accuracy is in question, verifying with a reference method (oven-dry or calcium carbide test) ensures the density calculation and compaction percentage are correct.

Question 3

What is the significance of the 'gauge factor' or 'density calibration offset' entered into a nuclear gauge?

Accepted Answer

It adjusts readings to correct for the specific material composition of the material being tested

Answer

Nuclear gauges are calibrated to standard reference materials; a gauge factor corrects for differences in chemical composition (element density and atomic number) of the actual material being tested.

Question 4

A nuclear gauge operator must maintain a distance of at least how many feet from the gauge when it is in use, according to typical NRC license conditions?

Accepted Answer

2 feet

Answer

Most NRC license conditions require operators to remain at least 2 feet from the gauge while a reading is being taken to limit radiation exposure.

Question 5

Which type of radiation emitted by the nuclear density gauge is primarily used to measure moisture content?

Accepted Answer

Fast neutrons from the Americium-241/Beryllium source

Answer

Fast neutrons from the Am-241/Be source are thermalized (slowed) by hydrogen atoms in water molecules; the count of slow neutrons is proportional to moisture content.

(PIC) Paving Inspector Certification Practice Test

(PIC) Paving Inspector Certification Practice Test

PIC Nuclear Density Gauge Operation 3