Contamination and Airborne Control Flashcards

A worker receives a bioassay (urine) result showing detectable Cs-137. What is the most appropriate immediate next step?

Answer: Perform dose assessment to estimate committed effective dose equivalent and determine if an intake occurred

A positive bioassay triggers a formal intake assessment to calculate the committed effective dose equivalent (CEDE) and determine if regulatory limits were exceeded.

Which surface material is generally the most difficult to effectively decontaminate of radioactive contamination?

Answer: Unpainted concrete or porous masonry

Porous materials like concrete allow radioactive material to penetrate into micro-crevices and pores, making complete removal extremely difficult compared to non-porous surfaces.

What is the significance of the 'inhalation class' (F, M, or S) assigned to airborne radioactive materials?

Answer: It indicates the rate of absorption from the lung to blood, affecting dose distribution and biokinetics

ICRP lung absorption classes (Fast, Moderate, Slow) describe how quickly inhaled material transfers from the lung to systemic circulation, which determines dose to lung vs. other organs.

Under what condition must personnel performing entry into a high contamination area use a supplied-air respirator (SAR) rather than an air-purifying respirator (APR)?

Answer: When the oxygen concentration is below 19.5% or airborne concentrations would exceed APR protection limits

SARs are required in oxygen-deficient atmospheres (below 19.5% O₂) or when airborne concentrations are too high for an APR's assigned protection factor to adequately limit intake.

During a facility decommissioning project, elevated airborne activity is detected unexpectedly. What is the correct sequence of actions?

Answer: Stop work, direct workers to evacuate upwind, activate emergency air monitoring, and notify supervision

Unexpected elevated airborne activity requires immediate work stoppage and evacuation to prevent further intake, followed by emergency monitoring and supervisory notification.

What is 'contamination fixation' and when is it used?

Answer: Application of a chemical coating to temporarily immobilize loose surface contamination and reduce re-suspension hazard

Contamination fixation involves applying adhesive coatings or fixatives to bind loose surface contamination in place, reducing airborne hazard during decontamination or demolition activities.

What parameter is used to evaluate the efficiency of a ventilation system in an airborne radioactivity control area?

Answer: Air changes per hour (ACH) and direction of airflow relative to contamination sources

Both the number of air changes per hour and the directionality of airflow (from clean to contaminated zones) determine how effectively ventilation dilutes and removes airborne radioactivity.