Operational Dosimetry
ALARA Stay Time & Dose Budget
Calculates maximum worker stay time for an RWP dose limit, projected dose for a planned task duration, or maximum permissible exposure rate for a shift.
t = Allowable Dose / Exposure Rate
Input Parameters
Calculation Goal
Dose Limit Presets
High Radiation Area
Calculated Result & Visual Analysis
Nominal Solved Value Updated automatically
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Enter parameters on the left to calculate.
Geometry & Field Diagram
Interactive Model
Sensitivity Curve
Governing Equation & Parameters
Stay Time (s) = [Allowable Dose (R) / Exposure Rate (R/hr)] × 3600
| Symbol | Parameter | Default Unit | Definition |
|---|---|---|---|
| t | s | Maximum work duration in the radiation field. | |
| D | R | Administrative dose budget or accumulated task exposure. | |
| Ẋ | R/hr | Surveyed dose rate in the work area. |
Health Physics Notes & Related Calculators
Operational Guidance
- Fundamental time-control equation: Accumulated Dose = Exposure Rate × Stay Time.
- Field practice sets an Electronic Personal Dosimeter (EPD) turn-back alarm at 80% of the RWP administrative dose limit to allow safe egress.
- US NRC 10 CFR 20.1201 annual occupational Total Effective Dose Equivalent (TEDE) limit is 5,000 mRem (5 Rem); typical daily RWP administrative limits are 50–100 mRem.
- Under 10 CFR 20.1702, respiratory protection task-time penalties must be weighed against external gamma dose rate to minimize total worker dose.
Related Calculators
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