_191119033708.jpg)
Typically, license holders who operate a sealed source are required to have the source tested for leakage periodically. Records of leak test results are kept for a period of three years after the date of the testing. Reports are often in units of microcuries (µCi) for review and approval by inspectors working in the applicable industries. In the absence of verifiable test results, the sealed source may not be used until testing is done and approval is given by the appropriate authority. The exception is for energy compensation sources, which are required to be tested every 3 years. Approval is given by the Nuclear Regulatory Commission (NRC) or an Agreement State and radiation leak test intervals are not to exceed 6 months.
Individuals can conduct radiation leak tests that must be approved by the Commission or an Agreement State. The instrumentation used must be capable of detecting down to 185 Bq of radioactive material on the test sample. Sealed sources with an activity of 3.7MBq or greater are required to be tested in the United States. Sources with less radioactivity do not typically require leak testing. However, companies, facility managers, and individuals may still perform radiation leak tests on their sealed sources, even if those sources are exempt from regulatory testing.
The wipe samples to be analyzed are taken from the nearest accessible point to the sealed source, where potential leaks exist or contamination would likely accumulate, though testing procedures may vary depending on the activity of the source and the enclosure around the source effecting access to it.
In the event that a leak is identified, license holders are required to remove the source from service and have it decontaminated, repaired, or disposed of by an authorized NRC or Agreement State licensee.
References:
https://www.nrc.gov/reading-rm/doc-collections/cfr/part039/part039-0035.html
https://www.nrc.gov/docs/ML9934/ML993480036.pdf
https://hps.org/publicinformation/ate/q9614.html
https://www.concordia.ca/content/dam/concordia/services/safety/docs/EHS-DOC-103_LeakTestProcedures.pdf