This massive unit quantifies ionizing radiation, representing one quadrillion (10¹⁵) becquerels. It is used to measure the total radioactive inventory of nuclear reactors, high-level waste repositories, or the fallout from major nuclear accidents. Because a single becquerel is a tiny amount of radiation, large-scale radiological assessments require the peta prefix to keep numbers manageable.
Heard on the job
The total release of iodine-131 during the incident was estimated at several hundred petabecquerels.