As low as reasonably achievable is the optimisation principle of radiation protection: doses are reduced as far as is reasonable once economic and social factors are considered, even when they are already below limits. In practice it means pre-job briefings, dose estimates, mock-up training, temporary shielding, remote tools, flushing hot spots and post-job reviews. Plants have ALARA committees and track dose against goals for every job and outage.
Put lead blankets on the loop before the insulators go in, that's an easy ALARA win.
ALARA cuts both ways: spending more dose installing shielding than the shielding saves is a classic rookie plan, and RP will reject it.
Also heard as
- as low as reasonably achievable
- optimisation
- ALARP
Related terms
Time, distance, shielding
The three basic ways to cut external dose: spend less time near a source, stay farther away and put material in between.
Shielding
Material placed between a radiation source and people to absorb radiation and reduce dose rate.
Collective dose
The sum of individual doses received by a group of people, in person-sievert or person-rem.
RWP
Radiation work permit: the document that sets radiological conditions, controls and dose limits for a specific job.
Hot spot
A small spot on piping or equipment with a much higher dose rate than its surroundings.