Mixed Deck — All NRRPT Topics Flashcards

What is the NRC's occupational dose limit for the lens of the eye per year?

Answer: 150 mSv

The NRC sets the annual occupational dose limit for the lens of the eye at 150 mSv (15 rem) per 10 CFR 20.1201.

A nuclear power plant's Technical Specifications (Tech Specs) are legally binding because they are:

Answer: Incorporated into the operating license as Appendix A

Technical Specifications are incorporated as Appendix A of the facility's NRC operating license, making them legally enforceable license conditions.

What is the derived air concentration (DAC) used for in internal dosimetry?

Answer: To establish the airborne concentration that equals one ALI when inhaled for a full work year

The DAC is the airborne radionuclide concentration that, if breathed for 2,000 hours, would deliver one annual limit on intake (ALI).

What is the purpose of a 'two-person rule' in high radiation areas?

Answer: To ensure a second person is present to assist or get help in the event of an emergency

The two-person rule in high radiation areas ensures that if one worker becomes incapacitated, the second can provide assistance or summon emergency help.

A 17-year-old student is working in a lab under an NRC license. What are their annual occupational dose limits compared to an adult worker?

Answer: 10 percent of the adult limits

According to 10 CFR 20.1207, the annual occupational dose limits for minors (individuals under 18 years of age) are 10 percent of the annual dose limits specified for adult workers. This means their total effective dose equivalent limit would be 0.5 rem (5 mSv).

When using the 'point source' approximation to estimate shielding requirements, which condition invalidates this approximation?

Answer: When the source dimensions are comparable to or larger than the distance to the point of interest

The point source approximation is only valid when the source is small compared to the distance to the receptor; for distributed sources, more complex geometric calculations are required.

According to ICRP recommendations, what tissue weighting factor (wT) is assigned to the gonads?

Answer: 0.12

ICRP Publication 103 assigns a tissue weighting factor of 0.08 to the gonads; the value 0.12 applies to the colon, lung, stomach, and breast.

Which type of radiation is stopped by paper?

Answer: Alpha particles

Alpha particles are relatively heavy, positively charged particles consisting of two protons and two neutrons. Due to their large mass and charge, they interact strongly with matter, causing them to lose energy rapidly over a very short distance. Consequently, they can be easily stopped by a thin sheet of paper, the outer layer of skin, or even a few centimeters of air.

The ALARA principle as applied to radioactive waste management means:

Answer: Waste generation, worker doses during handling, and public doses should be minimized as reasonably achievable

ALARA (As Low As Reasonably Achievable) applied to waste management requires optimizing processes to minimize both waste generation and radiation doses during handling, storage, and disposal.

What does the term 'stay time' refer to in radiological control planning?

Answer: The calculated time a worker can remain in a radiation field without exceeding a specified dose

Stay time is the maximum duration a worker may remain in a radiation field to keep the received dose within planned limits.

What is the primary radiological hazard associated with uranium mill tailings?

Answer: Alpha-emitting thorium-230 and the ingrowth of radon-222 gas

Uranium mill tailings contain Th-230, which decays to Ra-226 and then Ra-222 (radon), a carcinogenic alpha-emitting gas that can migrate off-site and pose inhalation hazards.

What is the main function of a radiation safety officer?

Answer: Ensure radiation safety compliance

The Radiation Safety Officer (RSO) is a key individual responsible for developing, implementing, and overseeing all aspects of the radiation safety program within an organization. Their main function is to ensure compliance with all applicable radiation safety regulations and institutional policies. This role is critical for protecting workers, the public, and the environment from radiation hazards.

A radiation protection technician is selecting shielding for a high-energy beta-emitting source. To minimize the production of Bremsstrahlung radiation, what type of material should be used as the primary shield?

Answer: Low-Z material, such as plastic or aluminum

Bremsstrahlung (braking radiation) is produced when beta particles (electrons) decelerate rapidly in a material. The production of these secondary x-rays is proportional to the atomic number (Z) of the shielding material. Therefore, a low-Z material like plastic or aluminum should be used as the primary shield to stop the beta particles, which minimizes Bremsstrahlung production. A high-Z material can then be placed after the low-Z shield to attenuate any Bremsstrahlung that is created.

The cross section for neutron capture (n,γ) in most nuclides generally varies with neutron energy as:

Answer: Proportional to neutron velocity (1/v law at low energies)

At thermal energies, neutron capture cross sections follow the 1/v law, meaning they are inversely proportional to neutron velocity (and thus increase at lower energies).

The half-value layer (HVL) of a photon beam is related to the linear attenuation coefficient (μ) by:

Answer: HVL = ln(2)/μ = 0.693/μ

From the exponential attenuation equation I = I₀e^(−μx), setting I/I₀ = 0.5 and solving gives HVL = ln(2)/μ ≈ 0.693/μ.

What is the correct sequence for donning personal protective equipment (PPE) when entering a contaminated area?

Answer: Respirator → coveralls → inner gloves → booties → outer gloves

Respirator is donned first to protect airways before other PPE is put on, followed by coveralls, gloves, and booties to minimize contamination risk during donning.

According to the U.S. NRC emergency classification system, which level is declared for events involving an actual or imminent substantial core degradation with a potential for loss of containment integrity, where offsite releases can be reasonably expected to exceed EPA Protective Action Guides?

Answer: General Emergency

A General Emergency is the most severe classification level. It signifies events that have led to, or will shortly lead to, substantial reactor core damage with the potential for uncontrolled radioactive releases that could affect the public beyond the site boundary, necessitating offsite protective actions.

A sealed source inventory verification must be conducted at minimum every:

Answer: 6 months

NRC regulations (10 CFR 39.37 and similar) require physical inventories of sealed sources at least every 6 months to verify presence and integrity.

A high radiation area (HRA) is defined under 10 CFR 20 as an area where radiation levels could result in a dose equivalent exceeding what value in one hour at 30 cm from the source?

Answer: 100 mrem (1 mSv)

Per 10 CFR 20.1003, a high radiation area means radiation levels that could result in an individual receiving a dose equivalent in excess of 100 mrem in one hour at 30 cm.

Why is documentation of incidents important?

Answer: To document compliance and responses

Documentation of incidents, such as radiation spills or overexposures, is vital for demonstrating regulatory compliance and for continuous improvement of safety protocols. It provides a clear record of the event, the corrective actions taken, and the effectiveness of the response, aiding in future prevention and training.