U.S. NRC Blog

Transparent, Participate, and Collaborate

Category Archives: Nuclear Materials

REFRESH: Do Not Fear Your Smoke Detector – It Could Save Your Life

Maureen Conley
Public Affairs Officer

refresh leafWe sometimes get calls from people worried about radiation from smoke detectors in their homes. There are many reasons why the public need not fear these products.

Ionization chamber smoke detectors contain very small amounts of nuclear material. They might use americium-241, radium-226 or nickel-63. These products detect fires early and can save lives. [We explained how smoke detectors work in greater detail in an earlier blog post.]

The Atomic Energy Commission granted the first license to distribute smoke detectors in 1963. These early models were used mainly in factories, public buildings and warehouses. In 1969, the AEC allowed homeowners to use smoke detectors without the need for a license. Their use in homes expanded in the early 1970s. The NRC took over from the AEC in 1975.

Makers and distributors of smoke detectors must get a license from the NRC. They must show that the smoke detector meets our health, safety and labeling requirements.

smokedetectornewMost smoke detectors sold today use 1 microcurie or less of Am-241. They are very safe. A 2001 study found people living in a home with two of these units receive less than 0.002 millirems of radiation dose each year. That is about the dose from space and the earth that an East Coast resident receives in 12 hours. Denver residents receive that dose in about three hours. These doses are part of what is known as “background radiation.”

The radioactive source in the smoke detector is between two layers of metal and sealed inside the ionization chamber. The seal can only be broken by the deliberate use of force, which obviously we discourage. Still, even then it would result in only a small radiation dose. The foil does not break down over time. In a fire, the source would release less than 0.1 percent of its radioactivity. It’s important to understand that none of the sources used in smoke detectors can make anything else radioactive.

What about disposing of smoke detectors? A 1979 analysis looked at the annual dose from normal use and disposal of Am-241 smoke detectors. The study used actual data and assumptions that would overstate the risk. It allowed the NRC to conclude that 10 million unwanted smoke detectors each year can be safely put in the trash.

The 2001 study looked at doses from misuse. It found that a teacher who removed an americium source from a smoke detector and stored it in the classroom could receive 0.009 millirems per year. If the teacher used the source in classroom demonstrations, handling it for 10 hours each year would give less than a 0.001 mrem dose. A person who swallowed the source would receive a 600 mrem dose while it was passing through the body.

I hope this information allays concerns. Unless you remove and swallow the source, your dose from a smoke detector could not be distinguished from what you get throughout your day. And that smoke detector could save your life.

 REFRESH is an occasional series during which we revisit previous blog posts. This originally ran on June 11, 2013. We are rerunning now in honor of Fire Prevention Week. According to the National Fire Protection Association, the week was established to commemorate the Great Chicago Fire, which killed more than 250 people, left 100,000 homeless, destroyed more than 17,400 structures and burned more than 2,000 acres. This year’s theme is Smoke Alarms Save Lives: Test Yours Every Month.


NRC Joins Five Other Agencies in Addressing Uranium Contamination on the Navajo Nation

Dominick Orlando
Senior Project Manager


Navajo coverLast year, after five years of work to reduce risks from uranium contamination on territory that is part of the Navajo Nation, the NRC, along with four other federal agencies, reported on our progress to Congress. This week, the five federal agencies issued a plan that spells out how we’ll continue coordinating that work for the next five years.

 The agencies’ second Five-Year Plan builds on lessons learned from the first five years. It reflects new information and defines the next steps to address the most significant risks to human health and the environment. The new plan commits us to working together to reduce these risks and find long-term solutions.

 In October 2007, Congress asked the agencies to develop a plan to address the contamination on Navajo land, which dates back to the 1940s when uranium was in high demand. The Navajo Nation had large uranium deposits but regulations were not what they are today and mining companies left extensive contamination requiring cleanup. Legislation and new regulatory provisions were put in place to address these issues.

 The 2013 report capped off a five-year program the agencies conducted, in consultation with Navajo and Hopi tribal officials, to address uranium contamination on their land. Part of this work was government-to-government consultations with the Navajo.

 The program was a joint effort among EPA, the NRC, the Department of Energy, the Bureau of Indian Affairs, the Centers for Disease Control and the Indian Health Service. It focused on collecting data, identifying the most imminent risks, and addressing contaminated structures, water supplies, mills, dumps, and mines with the highest levels of radiation. We also learned more about the scope of the problem and the work that still remains.

 The NRC’s role is to oversee the work done by DOE, which is the long-term custodian for three sites storing uranium mill tailings—a sandy waste left over from processing uranium—and one former processing site. We do that by reviewing and, if acceptable, concurring on DOE’s plans to clean up contaminated groundwater, visiting the sites to evaluate how DOE is performing long-term care activities, and reviewing DOE’s performance and environmental reports.

 We will work closely with EPA, DOE, the New Mexico Environment Department, and the Navajo during the cleanup of the Northeast Church Rock site—which EPA and Navajo officials identified as the highest priority site for cleanup. The NRC will also be part of outreach activities detailed in the plan, including participating in stakeholder workshops and contributing, as appropriate, to educational and public information activities.

 Five years from now, we look forward to being able to say that with close coordination among all the parties, we have continued to make major progress in addressing concerns about uranium contamination.

NRC’s Materials and Waste Management Programs Coming Back Under One Roof

Chris Miller
Merge Coordinator and Director of Intergovernmental Liaison and Rulemaking


When Congress created the NRC in 1974, it established three specific offices within the agency. One of them was the Office of Nuclear Material Safety and Safeguards, or “NMSS” in NRC shorthand. This office was charged with regulating nuclear materials and the facilities associated with processing, transporting and handling them.

fuelcyclediagramThis charge was, and is, broad. The NRC’s materials and waste management programs cover facilities that use radioisotopes to diagnose and treat illnesses; devices such as radiography cameras and nuclear gauges; and decommissioning and environmental remediation. It also includes nuclear waste disposal and all phases of the nuclear fuel cycle, from uranium recovery to enrichment to fuel manufacture to spent fuel storage and transportation.

And there’s more. The program also does environmental reviews and oversees 37 Agreement States, which have assumed regulatory authority over nuclear materials, and maintains relationships with states, local governments, federal agencies and Native American Tribal organizations.

As with all organizations, the NRC’s workload has ebbed and flowed in response to a multitude of factors. Over the years, NMSS went through several structural changes to address its workload changes. In 2006, NMSS was gearing up for an increase in licensing activity related to the processing, storage and disposal of spent nuclear fuel. At the same time, the Agreement State program was growing, requiring additional coordination with the states—a function then housed in a separate Office of State and Tribal Programs.

To meet these changes and ensure effectiveness, the NRC restructured NMSS. Some of its programs were moved, including the state and tribal programs, into the new Office of Federal and State Materials and Environmental Management Programs (FSME). NMSS retained fuel cycle facilities, high-level waste disposal, spent fuel storage, and radioactive material transportation. FSME was responsible for regulating industrial, commercial, and medical uses of radioactive materials and uranium recovery activities. It also handled the decommissioning of previously operating nuclear facilities and power plants.

The NRC’s materials and waste management workload has now shifted again. At the same time, the agency is exploring ways to reduce overhead costs and improve the ratio of staff to management.

So, NRC staff launched a working group last fall to review the organizational structure of the NRC’s materials and waste management programs. With the focus shifting to long-term waste storage and disposal strategies, and an increasing number of nuclear plants moving to decommissioning, the group recommended merging FSME’s programs back into NMSS.

NRC’s Commissioners approved that proposal last week, and the merger of the two offices will be effective October 5. We think this new structure will better enable us to meet future challenges. It will improve internal coordination, balance our workload and provide greater flexibility to respond to a dynamic environment.

Current work, functions and responsibilities at the staff level will be largely unchanged. The management structure will realign into fewer divisions, with fewer managers.

In their direction to the staff, the Commissioners asked for careful monitoring of the changes and a full review after one year. We fully expect these changes to improve our communications both inside and outside of the agency, and provide for greater efficiency and flexibility going forward.

“Negative Ion” Technology—What You Should Know

Vince Holahan, Ph.D.
Senior Level Advisor for Health Physics


You may have heard about colorful silicone wristbands and athletic tape infused with minerals that are supposed to release “negative ions.” You might even be wearing one. They are touted as improving balance and strength, enhancing flexibility and motion, and improving mental focus and alertness. They’ve been sold on the Internet or in retail stores across the U.S.

The minerals these products contain can vary from volcanic ash and titanium to less familiar ones such as tourmaline, zeolite, germanium and monazite sand. They may also contain naturally occurring radioactive elements, including uranium and thorium. In trace amounts, these materials do not warrant much attention. But the radioactive emissions—that is to say gamma rays—from several of these products were detected on entry to the country by U.S. Customs and Border Protection officials using radiation monitoring equipment.


While they may be radioactive, these products are not expected to create any health impacts. The amount of radiation given off by these products is well below the level that would cause any health concern or illness, even if worn over several years.

But NRC licensing requirements for uranium and thorium depend on the amount of radioactive material present. We commissioned the Oak Ridge National Laboratory to do an analysis that found enough radioactive thorium in several ion technology products that they require an NRC license for manufacture, distribution and possession in the U.S.

NRC staff experts on radiation worked with federal agencies and state regulators to determine the most appropriate path forward. Products containing negative ion technology — that is to say containing licensable amounts of radioactive material — should not be sold at the present time because they have not been licensed, as required, by the NRC.

Anyone wishing to dispose of a negative ion product may simply put it in their trash. This is OK because, although the amount of radioactive material requires licenses for manufacture and sale, it does not require any special handling or disposal.

We cannot say whether these products work as advertised. If you have them or know someone who does, our best advice is to throw them away. Anyone with health concerns should talk to their doctor. In the meantime, we’ll continue to do all we can to make sure they are being regulated properly.

NRC Science 101: The What and How of Geiger Counters

Joe DeCicco
Senior Health Physicist
Source Management and Protection Branch

In earlier Science 101 posts, we talked about ionizing radiation and different types of radiation. In this post, we’ll look at the Geiger counter, an instrument that can detect radiation.

science_101_squeakychalkJust to recap, the core of an atom (the nucleus) is surrounded by orbiting electrons, like planets around a sun. The electrons have a negative charge and usually cancel out an equal number of positively charged protons in the nucleus. But if an electron absorbs energy from radiation, it can be pushed out of its orbit. This action is called “ionization” and creates an “ion pair”—a free, negatively charged electron and a positively charged atom.

Humans cannot detect creation of an ion pair through their five senses. But the Geiger counter is an instrument sensitive enough to detect ionization. Most of us have heard or seen a Geiger counter. They are the least expensive electronic device that can tell you there is radiation around you—though it can’t tell you the original source of the radiation, what type it is or how much energy it has.

How does it work? A Geiger counter has two main parts—a sealed tube, or chamber, filled with gas, and an information display. Radiation enters the tube and when it collides with the gas, it pushes an electron away from the gas atom and creates an ion pair. A wire in the middle of the tube attracts electrons, creating other ion pairs and sending a current through the wire. The current goes to the information display and moves a needle across a scale or makes a number display on a screen. These devices usually provide “counts per minute,” or the number of ion pairs created every 60 seconds. If the loud speaker is on, it clicks every time an ion pair is created. The number of clicks indicates how much radiation is entering the Geiger counter chamber.

You hear a clicking sound as soon as you turn on the speaker because there is always some radiation in the background. This radiation comes from the sun, natural uranium in the soil, radon, certain types of rock such as granite, plants and food, even other people and animals.

The background counts per minute will vary; the needle will move or the number will change even when there is no know radiation source nearby. Many different things cause this fluctuation, including wind, soil moisture, precipitation (rain or snow), temperature, atmospheric conditions, altitude and indoor ventilation. Other factors in readings include geographical location (higher elevations give higher counts), the size and shape of the detector, and how the detector is built (different chamber material and different gases).

geigercounterDepending on the elevation and the type of Geiger counter, a typical natural background radiation level is anywhere from five to 60 counts per minute or more. Because background radiation rates vary randomly, you might see that range standing in one spot. It is important to understand that the Geiger counter indicates when an ion pair is created, but nothing about the type of radiation or its energy.

Other types of instruments can provide an exposure rate (expressed as milliroentgen per hour or mR/hr). These counters must be calibrated to read a particular type of radiation (alpha, beta, gamma, neutron, x-ray) as well as the amount of energy emitted. The reading will only be accurate for that type of radiation and that energy level. And these instruments need to be calibrated regularly to be sure they are providing correct information over time.

For more sophisticated environmental radiation readings, check out the Environmental Protection Agency’s nationwide system, RadNet. Using equipment far more sensitive than a Geiger counter, it continuously monitors the air and regularly samples precipitation, drinking water and pasteurized milk.

Over its 40-year history, RadNet has developed an extensive nationwide “baseline” of normal background levels. By comparing this baseline to measurements across the U.S. states in March 2011, following the accident at the Fukushima reactors in Japan, the EPA was able to detect very small radiation increases in several western states. EPA detected radiation from Japan that was 100,000 times lower than natural background radiation—far below any level that would be of concern. And well below anything that would be evident using a simple Geiger counter, or even Geiger counters spread across the country.

If RadNet were to detect a meaningful increase in radiation above the baseline, EPA would investigate immediately. With its nationwide system of monitors and sophisticated analytical capability, RadNet is the definitive source for accurate information on radiation levels in the environment in the U.S.

By the way, the Geiger counter is also called a Geiger-Mueller tube, or a G-M counter. It was named after Hans Geiger, a German scientist, who worked on detecting radiation in the early 1900s. Walter Mueller, a graduate PhD student of Geiger’s, perfected the gas-sealed detector in the late 1920s and received credit for his work when he gave his name to the Geiger-Mueller tube.


Get every new post delivered to your Inbox.

Join 1,489 other followers

%d bloggers like this: