Am I at Risk of Radiation Exposure?

The ongoing uncertainty of the Japanese nuclear crisis has left people around the world questioning the danger of radiation contamination in their own communities. How much is the general public really at risk of radiation? Because D-tect Systems specializes in detecting threats from radioactive and chemical sources, we offer this article to provide some information on some of the current radiation risks in context and some general guidelines on radiation safety.

The first step in qualifying contamination risks is to separate fact from fiction. The way the public views radiation has mostly been shaped by a few incidents in modern history: Chernobyl and Hiroshima/Nagasaki. These extreme cases have influenced many to assume that radiation is an exotic and deadly phenomenon. In reality, our environment is steeped in radiation that our bodies absorb without any ill effect. The most important factor in understanding the impact of radiation is quantity – how high radiation levels are and how these levels translate to risk.

To give some idea of safe radiation levels, natural background radiation – the radiation that we are exposed to every day from cosmic rays and naturally-occurring radioactive materials – is about 3 mSv (300 mrem) per year. According to the FAA, A coast-to-coast airplane trip will expose you to about 5 µSv per hour (which comes out to 43.8 mSv/yr for continuous flight), and a year of watching four hours of television of day adds up to about 20 µSv total (2 mrem). These quantities are pretty small compared to a federal occupational limit of radiation exposure set by OSHA at 50 mSv (5000 mrem) per year. Now let’s compare the situation in Japan to all this. Recent reports from the International Atomic Energy Agency stated that radiation levels at the perimeter of the Fukushima Daiichi nuclear complex have been measured at 1 – 3 mSv/hr. Although this is an elevated radiation level and prolonged exposure could be dangerous, the short-term radiation level set for Japanese workers working on the nuclear complex is 250 mSv, and would take considerable time to reach.

Although the risks of serious widespread radiation contamination in this case are low, the procedures outlined by government agencies should always be strictly adhered to. These procedures aim to limit the spread of radiation and minimize risk to exposed areas. Although the specific instructions given out for each incident vary, here are a few general guidelines that should always be followed.

First, in case of radiation contamination, get people (including yourself) out of harm’s way as quickly as possible and notify authorities. Radiation spreads easily though blowing dust and smoke, so radiation-free secure zones must be established by sealing off areas from the outside environment by closing and weather-proofing doors and windows and placing food and water in well-insulated areas such as basements.

Second, since human skin generally acts a good barrier against low-level radiation, the biggest threat is breathing in radioactive materials or somehow ingesting them. Make sure to wear a face mask in areas that may be contaminated and wash hands regularly. If you suspect someone has been exposed to radioactive dust, the best solution is usually as simple as discarding contaminated clothing and washing with soap and water, as this will rid the body of radiation before it can cause damage. As an additional precaution against significant amounts of radiation, potassium iodide tablets are sometimes given to protect the thyroid gland.

Third, preparation is vital when it comes to any kind of disaster, and we recommend everyone keep an emergency kit close at hand so that they can be personally prepared in case of any crisis. This kit should include such things as food and water for a few days, water filtration kit, emergency blanket, rain gear, batteries for radios and detectors, dust mask, extra clothing, flashlight, candles, waterproof matches, cooking utensils, necessary medications, and a first aid kit. Although we generally take these supplies for granted, shortages can occur quickly in crisis situations.

Preparation is vital when it comes to any kind of disaster, and we recommend all public safety personnel keep an emergency kit close at hand so that they can be personally prepared to serve the public. This kit should include such things as food and water for a few days, emergency blanket, rain gear, batteries for radios and detectors, dust mask, extra clothing, candles, waterproof matches, cooking utensils, necessary medications, and a first aid kit. Although we generally take these supplies for granted, shortages can occur quickly in crisis situations.

Although the current nuclear crisis continues to make headlines and is a great source of fear for many, it is important to know the real risks involved and how to cope with them. With a little knowledge of radiation safety, and material preparation for a crisis, we can minimize future risks and know better what we’re up against.

D-tect Systems is supplier of advanced radiation and chemical detection equipment sold around the world. www.dtectsystems.com.

Protecting the Public from a Nuclear Power Plant Radiation Leak

How can you feel safe? How much warning will you have?

The ongoing battle to control the reactors at the Fukushima Nuclear Plant is terrifying to follow, but also leads millions that live near nuclear power plants to look over their shoulder and wonder “what if”? How many of us live within 50 miles of a nuclear power plant? In the U.S. alone, there are 104 nuclear power plants, most with multiple reactors.

When a leak is detected, there are two primary tools to measure the radiation: dosimeters and radiation detectors. Both provide different critical functions.

Dosimeters are the important instruments at the radiation leak. When worn on the body, often clipped to a pocket or belt, they measure how much radiation your body has absorbed. This is critical because the human body can absorb an amazing amount of radiation without damage, but there is a limit. A dosimeter shows when it is time to get away from the radiation before health consequences can occur. Everyone working in an area of high radiation needs to have a dosimeter. Especially the workers trying to stop a radiation leak.

Radiation detectors are faster and more sensitive than dosimeters, react instantly when radiation is detected, and indicate the amount of radiation.  If dosimeters are like a doctor looking over your shoulder to continually measure your health, radiation detectors are more like guard dogs. Radiation detectors are used just like guard dogs – they can monitor a perimeter and provide instant warning if that perimeter is violated. They can also be used to inspect people and vehicles for radiation. When people leave a contaminated area they are scanned with radiation detectors to quickly determine who needs to go through decontamination and who can be waved on.  Often contamination is in the form of dust present on skin, clothes and shoes. This contamination can be washed off once detected. The people who need radiation detectors are those who establish and guard the perimeter around ground zero, control the road blocks, evacuate the local population, control hospital admittance, and check people and vehicles for contamination as they leave the danger area.

How much warning will you have if a radiation leak occurs at the local nuclear power plant? Radiation detectors inform the authorities that a leak has happened within seconds.  Then it’s up to the authorities and the local emergency management team to determine how to respond and what the public needs to know.  And if a perimeter needs to be established and  an evacuation ordered.

After the leak is stopped, how can you feel safe living next to a Nuclear Plant? How do you know radioactive dust isn’t blowing around during windy days? Those same radiation detectors keep monitoring radiation levels 24/7.  They are sensitive enough to detect very small levels of radiation and can be set to alarm at far below hazardous levels. No radiation contamination can move without detection within a network of these devices.

Radiation is invisible to us, but we have the tools to track its every move.

Mark Kaspersen is the Director of Engineering of D-tect Systems, producers of radiation detection equipment sold around the world. www.dtectsystems.com.

Radiation Detector Overview

“The only thing constant in life is change.” -  François de la Rochefoucauld

Although they report on thousands of different stories each day, the covers of newspapers in recent weeks have all carried a similar theme – instability.  On-going political changes in many parts of the world, as well as the rapid power transfers and challenges in the Egypt, Yemen, Libya, and many bordering countries have made it clear that political unrest is on the rise.  Recent upheavals have also made it clear that finding security in an increasingly unstable world is a difficult task. 

Adding to political turmoil, terrorist organizations have become increasingly aggressive in both their tactics and technology.   The release of diplomatic cables lays bare new plans by terrorist organizations, such as the Taliban, to construct ‘dirty bombs’ – weapons designed to spread radioactive material over large areas.  We here at D-tect Systems focus on this increasingly relevant area of that security effort: radiation detection. 

With dozens of detector types utilized of literally thousands of radiation detection products, matching the right technology to a threat is a daunting task.  To make this search a little easier, we’ve compiled a general overview of some of the main radiation detectors currently in use.

Geiger-Mueller Tubes, with low sensitivity and a wide range, are the most commonly used detectors on the market.  Available in sizes from ring-worn dosimeters to giant cargo scanners, Geiger-Mueller detectors can pick up certain types of alpha, beta, and gamma radiation.  The downside to these kind of detectors is that they are much less sensitive to radiation than other detector types and cannot differentiate between radiation types.  They are also too slow to detect moving radiation, but are cheap and durable.

Sodium Iodide (NaI(Tl)) and Cesium Iodide (CsI(Tl)) are among the most common gamma radiation detectors.  These two types of materials are commonly referred to as inorganic scintillators because of their composition and method for detecting radiation.  Unlike Geiger-Mueller Tubes, they are fast, sensitive, and can measure the actual energy of gamma rays.  D-tect Systems’ MiniRad-D and MiniRad-V devices uses CsI(Tl) detectors equipped with photo-multiplier tubes that allow the operator to detect radiation from tens of meters away.  

CsI(Tl) detectors, like those used in the MiniRad-D, can detect gamma radiation from even some shielded sources.

Plastic Scintillators (PVT) use the same detection method as NaI(Tl) and CsI(Tl) detectors but usually require much larger detector sizes the achieve the same sensitivity.  They are commonly used in high-volume portal monitors and come in a variety of shapes and sizes.

Lanthanum Bromide (LaBr3) detectors are capable of finding energy peaks more quickly (known as detector efficiency) than a corresponding NaI(Tl) detector, but LaBr3 detectors exhibit internal radioactivity that reduces its spectral resolution at energies below 100 keV.  The current cost of LaBr3 detectors is generally much higher than that of comparable NaI(Tl) detectors. 

 

High Purity Geranium (HPGe) detectors figure into the top end of radiation detection and identification.  Devices using HPGe detectors are able to identify isotopes 2-3 more quickly than NaI(Tl) partly because they need sense far less radiation to come up with an identification.  The downside to this type of detectors is that HPGe detectors must be cooled with liquid nitrogen to operate, which makes HPGe devices bulky and much more expensive than scintillator units.

Cadmium Zinc Telluride (CZT) detectors have higher resolution and stability (for gamma rays and x-rays) than NaI(Tl), but are expensive in large crystal volumes.  Many CZT systems contain arrays of multiple small CZT detectors because the detection sensitivity increases with volume and some directionality can be established this way.  The Rad-ID device by D-tect Systems is available in configurations that contain four or eight CZT crystals, as well as a large NaI(Tl) detector. The combination of multiple detector types allows the Rad-ID to quickly and accurately identify over 110 radioactive isotopes.

Detection systems for neutron radiation (extremely high-energy radiation produced by elements such as Uranium and Plutonium) are also critical for security.  This type of radiation only comes from a few highly-controlled materials. The most commonly used neutron radiation technology involves the use of He3 tubes and requires relatively large volumes.  D-tect Systems’ Rad-ID device has neutron radiation detection capabilities with an optional He3 tube.

So whatever kind of radiation detection you need, we hope this short overview allows you to make informed decisions to help ensure security in an unstable world.