Film Badge / TLD ServicesAll employees should use personnel dosimetry badges to track the amount of absorbed occupational radiation they receive working around nuclear gauges. There are provisions that allow you to bypass this requirement. If you can document that the average annual dose is less than 500 mrem most states and the NRC allow you to forgo badges. Check with your regulatory agency to see if you have this option. These badges, also known as film badges or TLD’s ( Thermolumnescent Dosimeters ) are small clip–on devices that should be worn, typically on a belt-loop, whenever in the presence of gauges. Proper use of the gauge and adherence to the principles of ALARA will typically result in an annual radiation absorption rate of less than 1% of the 5,000mrem limit. Users of roof gauges, which only emit neutron radiation, should check with their regulatory agency for dosimetry requirements. If an unusually high exposure is recorded on an employee’s dosimeter report the RSO should conduct and document an investigation that includes a history of gauge use during the quarter as well as speculation as to what may have caused the high reading. Reasons could include leaving the badge near a gauge, visits to a doctor or dentist, leaving the dosimeter in direct sunlight, etc. If a dosimeter is lost or damaged the RSO should conduct an investigation to determine how it was lost or damaged, a summary of activities performed while lost or damaged, an assessment to determine the probable dose during the timeframe and what steps are being taken to prevent such future occurrences. The report records must be kept on file permanently. A photocopy of these records should be made available to employees upon request. Employees leaving the company should likewise take a final report for their personal records. This record must be supplied to a new employer that utilizes nuclear instrumentation. While dosimetry service and records are very important your selection of a dosimetry provider should be based on the following: The dosimetry provider should be, or act as an agent for, a National Voluntary Laboratory Accreditation Program (NVLAP) approved lab. You may be surprised to find that your current dosimetry provider is only acting as a middleman for one of the larger NVLAP Labs. That’s okay providing the price is right. There is essentially no difference in analysis quality if the lab is NVLAP approved. Your badges or TLD’s and reports should come in on a timely basis. Go with the best pricing - these charges can add up quickly. Watch out for set-up charges and long term agreements. You can save a lot of money by choosing the right company. You should be using a quarterly service – monthly service is generally not necessary and is usually more expensive. Check with your regulatory agency for minimum requirements. There are only a handful of NVLAP providers. The large providers are Global Dosimetry and Landauer. Many manufacturers and gauge repair companies offer dosimetry through these two companies – they are just acting as a middleman, although some will actually save you more money than going directly to the large provider, as well as offering more direct interaction. You should always shop around for the best service and pricing.
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