|Use of Radiation in Inspection
Answers to Common Questions
(The Truth about Safety & Effectiveness of X-ray & Gamma Based Systems) 1
|As a leading supplier of x-ray and Americium-241 (gamma) based inspection equipment for more than 40 years, we at filtec want to help our customers make informed decisions for the safety and effectiveness of our equipment. We have an excellent record of high quality equipment, performance, and service since 1958 and we stand behind all of our filtec x-ray and gamma based products. We have retained the help of a national radiation expert to answer some of the common questions that we are asked about x-ray and gamma based equipment including:
1. Does use of x-ray or gamma radiation for inspection pose a health risk?
NO. Although the sources are different, x-ray and Americium-241 (gamma) based inspection machines both use the same LOW ENERGY radiation for inspection. The radiation level outside of the machines is less than 0.05 mrem/hour. The regulatory limit for exposure of the public (persons not trained for radiation safety) is 40 times greater at 2 mrem in an hour, or 100 mrem in a year above natural background. Thus, no special precautions are needed when working around either x-ray or gamma inspection machines. It might also be helpful to know that an average person in the US is exposed to 620 mrem a year from natural background and man-made radiation. To put this in perspective, a single CT scan exposes a patient to 200 to 2,000 mrem of radiation. On the average across the US, people are exposed to more than 200 mrem a year from radon in their homes.
2. Do x-ray and gamma based systems pose a significant safety risk?
NO. In normal operation, neither x-ray nor gamma based systems pose a safety risk. Some x-ray generators contain cooling oils, which could pose a risk of leakage in the case of an industrial fire. Gamma based systems do not pose a similar risk because the Americium-241 used in gamma sources is fused into a solid ceramic and sealed in a stainless steel housing that is designed to withstand temperatures of any industrial fire.
Some inquiries have been made as to whether the helium gas that the Americium-241 source emits could cause a breach of the stainless steel housing that holds the source. This cannot happen. The stainless steel housing is designed to withstand 7,000 psi of pressure. The helium release builds pressure to only 30 psi over the 60 year recommended working life of filtec gamma machines. This is less than 0.04% of the pressure that the housing is designed to withstand.
3. What is the Effective Working Life (“EWL”) of x-ray and gamma based machines?
X-ray and gamma based systems use the same sensors and inspection electronics and should give you many years of reliable use.
4. What is the significance of the Recommended Working Life (“RWL”) of gamma sources?
RWL is our recommendation as to working life based on performance and safety experience, gained from over 40 years of industrial inspection. We adjust our recommendation periodically as we gain more experience with the sources. So far our experience has been exceptional resulting in three extensions of our recommendation as to RWL.
When we initially released our gamma inspection machine (FT-50) in 1966, we suggested a RWL of 15 years for our gamma sources. We have made periodic adjustments to the RWL based on performance and safety experience extending the RWL from 15 to 30 years, from 30 to 40 years, and now from 40 to 60 years. We will review the RWL again well before 2030 when the sources that were put in operation before1970 come up against the current 60-year RWL.
5. Does purchasing a machine that uses Americium241 result in production of a radioactive material that would not otherwise exist?
NO. Americium is produced continuously as a byproduct of the operation of nuclear reactors and is recycled from nuclear waste. This byproduct of the operation of nuclear reactors is widely used primarily in home smoke detectors and a much smaller amount is used in industrial gauges. No additional production is required for filtec devices.
6. Is registration and licensing of x-ray and gamma based machines complex?
NO. X-ray and gamma based machines are each subject to state or Federal regulations to protect the health and safety of workers in facilities using such devices.
The Nuclear Regulatory Commission (NRC) has national regulatory authority on the use of Americium-241 based systems. Thirty-seven states regulate gamma sources by agreement with the NRC. These states apply the NRC rules. The NRC regulates the use of Americium in the 13 states that do not have an agreement with the NRC. Therefore, all states follow the same regulations for gamma sources. The NRC regulations call for initial registration of each gamma source and then payment of an annual registration fee similar to a car registration fee. Registration of sources is mainly for accountability to the NRC or states to assure that you are keeping track of your machines. Meeting the registration requirements should not take more than about an hour or two a year.
X-ray devices are not subject to a uniform national policy but are regulated on a state-by-state basis with varying regulatory requirements. All states require the registration of x-ray machines. However, there are differences on the timing and process for registration. Therefore, it is important to consult your manufacturer or the State regulatory authority concerning the requirements of the particular state in which you are installing an x-ray machine.
7. Are regulatory requirements for x-ray and gamma based machines cumbersome?
NO. Users of x-ray and gamma based machines must follow similar requirements which include:
8. Is it difficult to get x-ray and gamma based machines serviced?
NO. X-ray equipment must be serviced by registered x-ray service providers and gamma-based equipment must be serviced by licensed gamma source service providers. Your factory representative is fully licensed and registered to service your equipment. There are also independently licensed or registered service organizations throughout the country.
9. Is it difficult to move x-ray or gamma based machines between facilities?
Both x-ray and gamma based systems must be installed by properly licensed or registered personnel. Shipping of these machines is simple and straightforward. In most states there is a requirement to notify the state when you intend to move an x-ray or gamma based machine. Your factory representative has the specialized containers necessary to ship gamma-based equipment.
10. Is it likely that we could be subject to significant fines with respect to our machines?
NO. Fines could be imposed on owners of x-ray or Americium-241 devices for gross negligence in handling of the devices. This is very rare, however, and would not occur if the machines are simply maintained in normal operation at a facility. When a machine is no longer needed or in use, the manufacturer should be notified.
11. Does the EPA have anything to say about our x-ray or gamma based systems?
NO. The EPA has no regulatory authority over radioactive materials. This authority belongs exclusively to the NRC and the 37 states that regulate gamma sources by agreement with the NRC.
The EPA is responsible for addressing radioactive materials that could be released in the environment. The EPA has a voluntary program where they have worked with industry representatives to seek alternative solutions for radioactive devices that could be abandoned and become an environmental contaminant. The fixed sources used in inspection equipment are insignificant in terms of radioactivity and do not have the risk of being inadvertently left unattended or abandoned at a job site.
12. Is there any proposed legislation that would add to the cost of administration of x-ray or gamma based systems?
NO. At this time we are not aware of any regulations pending with the NRC or States that would impact the cost of administering gamma-based machines. In December of 2010 the NRC voted down a proposed regulation that would have changed the licensing requirements. A number of states have introduced or are considering introduction of changes to licensing and registration fees that apply to x-ray and gamma based systems. Your manufacturer’s rep can give you the details if you should have a specific question.
13. I have heard that there have been closures of disposal facilities. Did any of these facilities that were closed take radioactive sources of the type we use?
NO. There have been no closures of facilities that take the type of radioactive material used in our inspection equipment. The Department of Energy has a long-term on-going program for disposal of radioactive materials such as Americium-241. There is no need to be concerned about ability to dispose of Americium-241 sources.
14. Do I need to be concerned because my source cannot be turned off like an x-ray generator?
NO. Americium-241 sources are very stable and emit only a very small amount of radiation. When in normal use in the machine, there is no danger to employee health and safety. If there is a need, it is simple to eliminate the radiation altogether by merely closing the manual shutter.
15. Is there any other factor that affects the operating life of my equipment?
The only other factor that affects the operating life of your equipment is the reliability of the electronics. We have an excellent record of reliability for over 40 years.
If you should have any questions please email us at firstname.lastname@example.org
1 Prepared by Ray Johnson, LPE, Certified Health Physicist, and Fellow of the Health Physics Society