Search for building materials as sources of elevated radiation dose

Area of Science:

• Environmental Health
• Radiological Physics
• Building Science

Background:

• Elevated gamma radiation and radon progeny in buildings pose health risks.
• Identifying radioactive building materials requires reliable assessment methods.
• Previous methods lacked systematic approaches for predicting indoor radiation levels.

Purpose of the Study:

• To test a systematic procedure for identifying building materials causing elevated gamma radiation and radon progeny.
• To develop and validate calculational models for predicting indoor radiation exposure rates and radon concentrations.
• To assess the feasibility of using radiation surveys and radionuclide analysis for material characterization.

Main Methods:

• Conducted radiation surveys of building materials using a NaI(T1) detector.
• Measured 226Ra concentration to infer 222Rn progeny working levels.
• Developed an exposure rate index and utilized calculational models for prediction.
• Validated predictions by measuring exposure rates and 222Rn concentrations in newly constructed and older buildings.

Main Results:

• The systematic approach accurately predicted gamma radiation exposure rates and 222Rn concentrations.
• Elevated gamma radiation was detected in older buildings using concrete blocks with phosphate slag.
• Calculational models predicted increases of 10 μR/hr in exposure rates and 0.2 pCi/L in 222Rn concentrations due to specific radium levels.
• Observed levels were consistent with predictions, though ground infiltration was a major source of radon.

Conclusions:

• The proposed systematic procedure is effective for identifying and quantifying radiation risks from building materials.
• Calculational models provide reliable predictions for indoor radiation levels based on material properties.
• Phosphate slag concrete blocks can contribute to elevated indoor radiation, but ground radon influx is significant.