What do you mean by transporting radioactive materials?
One of several classes of hazardous materials that are transported on a daily
basis throughout the United States are radioactive materials, sometimes called
"RAM". This particular discussion focuses on this practice.
Can I rely upon the information in this discussion to guide my own shipping
procedures?
Absolutely not. The proper transport of radioactive materials is not a trivial
issue, and mistakes can have negative ramifications. However, you can use
this discussion as an overview of some of the issues and key terminology
associated with RAM transport. Think of it as a starting point in your
understanding of this important subject.
Why is RAM transported in the first place?
Radioactivity is used for a variety of purposes, including medical diagnosis
and therapy, oil exploration, materials testing, weapons production, electric
power production, consumer products, and many other applications. To take
advantage of its beneficial uses, and to dispose of it when required, the
RAM must, by necessity, be transported to the location of interest.
Does the transport of RAM have regulatory implications?
Most certainly! Radioactive materials cannot be shipped without proper adherence
to shipping regulations. To give you an idea of how important RAM shipping
is, each violation of the shipping regulations can cost shippers up to $27500!
What purpose do the regulations serve?
The regulations are important for a number of reasons, most of which involve
safety. Safety is achieved by effectively containing the RAM (essential in
preventing radiation and radioactive materials from negatively impacting
on the environment), controlling the radiation emitted from the package,
preventing a "criticality" for fissile radioactive material, and adequately
dissipating any heat that is generated within the package.
Which federal agencies issue hazardous material shipping regulations in
this country?
The transportation of RAM is regulated jointly at the federal level. The
primary hazardous material regulations (HMR) are issued by the Department
of Transportation (DOT) in Title 49 of the Code of Federal Regulations
(CFR),Transportation . Title 49, Parts 171-178, contains the specific
requirements for the packaging and shipment of RAM, a specific category of
hazardous materials.
Is that the only federal agency?
No. The Nuclear Regulatory Commission (NRC) also has primary transportation
regulations in 10 CFR Part 71, Packaging and Transportation of Radioactive
Materials. To a lesser extent, 10 CFR 20.1906, Standards for Protection Against
Radiation, and 10 CFR Part 61, Licensing Requirements for Land Disposal of
Radioactive Waste, which applies to the siting and operation of near surface
low-level waste disposal sites, contain requirements related to RAM transport.
While not regulatory in nature, the NRC has also published a guidance document
that is updated annually , several regulatory guides, and many information
notices and bulletins on transportation issues.
Where can I find a current version of the HMR?
The DOT regulations are available through the Superintendent of Documents
at the Government Printing Office (GPO) in Washington, D.C. The GPO can be
reached at (202) 512-1800 or via the Internet at http://www.gpo.gov. In addition,
updates to the regulations are published in the Federal Register. The Research
and Special Programs Administration (RSPA) of the DOT provides amendments
and proposed rulemakings through their web site at http://hazmat.dot.gov.
To what extent do the DOT regulations apply?
The DOT regulations apply broadly to the public transportation of all hazardous
materials (which include radioactive materials). Shipment by all modes of
transport within and between states and foreign commerce is included (i.e.,
rail, highway, air, and water). Also included are the methods of transport
such as truck, bus, automobile, shipping vessel, airplane, rail-car, etc.
Are there any exceptions to the DOT's authority?
Yes. Aside from the NRC, a separate government entity, the United States
Postal Service (USPS), regulates postal shipments under 39 CFR Part 124,
Domestic Mail Manual, U.S. Postal Service Regulations.
Why is the NRC involved?
Simply put, the Atomic Energy Act of 1954 (amended) gave the NRC responsibility
for safety considerations involving the possession, use, and transfer (which
includes transport) of three particular classes of RAM known as "by-product",
"source", and "special nuclear material". These classes of material typically
require the issuance of a "license" for their possession and use.
Doesn't this dual jurisdiction present some difficulties?
Yes, especially in the past. However, many years ago, the NRC and DOT signed
a Memorandum of Understanding (MOU) wherein their respective responsibilities
were clearly designated in order to minimize conflicts and overlapping
requirements in the transport of RAM.
What about the various states?
Many states have entered into formal agreements with the NRC to regulate
shipments involving licensed quantities of RAM. The states, in turn, have
developed a consistent set of regulations to handle intrastate transport.
Often they adopt the DOT regulations in their entirety.
Which organizations deal with the regulations (standards) for international
shipments?
Several international organizations are involved in the transport of RAM.
The International Atomic Energy Agency (IAEA) provides the primary basis
for fulfilling this responsibility; however, other more recently created
organizations include the International Civil Aviation Organization (ICAO),
the International Air Transport Association (IATA), and the International
Maritime Organization (IMO). The ICAO and IATA regulate the transport of
RAM by air, while the IMO regulates ocean vessel transportation.
How comparable are the DOT and NRC regulations relative to the
IAEA's?
Regulations issued in this country essentially conform to those of the IAEA,
although some exceptions and differences do exist.
What if I choose not to follow the federal regulations when shipping
RAM?
Not a good move! The DOT and NRC both have enforcement policies which may
result in civil or criminal penalties, cease and desist orders, suspension
orders, and other highly unpleasant enforcement actions. In short, the
regulations must be adhered to just like any other law.
Does anything that is radioactive have to be shipped as RAM?
No. In the context of transportation, radioactive materials are defined as
those materials which spontaneously emit ionizing radiation and have an activity
concentration and a total consignment activity that exceeds the values in
the table in 49 CFR 173.436. Anything that contains lesser concentrations
of radioactivity can be shipped without regard for the DOT regulations.
So, if I want to ship something with less than the activity concentration
in that table, I can do so using any procedures I want?
As long as the radioactivity is essentially uniformly distributed through
the total mass of material being shipped, and as long as you are confident
that it is below those values, the DOT does not consider it to be radioactive.
Therefore, it is "exempt" or not regulated for transport by the DOT or NRC.
When I look at the DOT regulations, I don't see an exemption in units
of "microcuries per gram".
That is because the regulations issued by the IAEA in 1985 and subsequently
adopted by the DOT, utilize the International System (SI system) as the
controlling radiological units for transportation. Therefore, the unit for
radioactivity in the SI system, the "becquerel", takes precedence over the
"curie", the traditional unit of radioactivity. (The "Tool Box" section
of the IEM web page gives you conversions from becquerels to microcuries,
and vice versa.)
What units are used when radiation levels, rather than activity levels,
are reported?
Once again, the SI system takes precedence. Therefore, in this instance,
dose rates are reported in sievert per hour (Sv/hr). The traditional unit
is the rem per hour (rem/hr).
Does the use of the SI units pose any problem for RAM shipments in the
United States?
As you might imagine, it does. The United States has been slow to respond
to the international community's widespread use of SI units. While the
traditional units may still be used for a limited period of time, permanent
changeover to the SI system is forthcoming. From a safety standpoint, it
is very important that companies performing RAM shipments in this country
understand and are "literate" in SI units in order to effect proper radiological
packaging and controls.
Why is proper RAM packaging so important?
Proper packaging is a fundamental and essential component of transportation
safety. The intent is to create a barrier between the environment and the
radioactive material.
What parameters influence the choice of packaging as it affects
safety?
Proper packaging requires knowledge of the radionuclides involved, quantity
(amount) of radioactivity to be shipped, and the "form" of the radionuclide(s).
Where do I find out something about the amounts?
Title 49 (Part 173.435) has a table that lists several hundred radionuclides
and associated so-called "A1" and "A2" values.
What is this A1 and A2 business all about?
Not only does a shipper have to know what radionuclide(s) it is transporting,
but the quantity limits for those radionuclides as well. The A1 and A2 categories
were developed to establish the maximum amount (activity) of a radionuclide
that may be transported in a Type "A" package These categories replaced what
was formerly called the "transport group" designation. Every radionuclide
is assigned an A1 and A2 value.
So what is the difference between A1 and A2?
"A1" is the maximum amount of activity for a particular special form radionuclide
that is allowed in a Type A package, while the "A2" designation is the maximum
amount of activity that can be transported in a Type A package for normal
form materials. (As you might suspect, "normal form" materials are those
that are not classified as "special form".) A special form material is a
single solid piece or a sealed capsulecontaining radioactive material that
can only be opened by destroying the capsule, thus it is certified as being
special form.
So what do A1 values really represent?
A1 values represent conservative (worst case) assumptions regarding external
gamma radiation levels from an unshielded source at a known distance. In
general, the A1 value for a particular radionuclide is defined as the quantity
of that radionuclide resulting in a dose rate of 0.1 Sv/hr (10 rem/hr) at
a distance of one (1) meter from the package. The key points are that A1
values apply only to special form radioactive materials and to direct radiation
concerns. In addition, since external radiation is the only concern, the
assumption is made the radioactive materials inside the package will not
be dispersed if the package is damaged.
And the A2 designation?
The A2 value also looks at worst case assumptions, but takes into account
five exposure pathways rather than just one. These are external gamma radiation,
external beta radiation to the skin, inhalation, ingestion, and external
gamma radiation from immersion in a gaseous cloud of radioactive material
released from a package which has been breached (i.e., a loss of package
integrity). The key points here are that A2 values apply to normal form RAM
and to both external and internal exposure concerns. Unlike the A1 designation,
the assumption is made that dispersal and contamination of the package contents
is probable if the contents were inadvertently released. If you look closely
at the two lists, you will see that an A2 value for a particular radionuclide
can be equal to its A1 value, but it cannot exceed the A1 value.
This sounds a little bit confusing to me!
That's perfectly understandable. Hang in there! Shipping radioactive materials
requires a working knowledge of many separate issues, including at a minimum,
definitions and the appropriate transport regulations (domestic versus
international). Often, further interpretations of these regulations from
individuals experienced in shipping RAM is necessary. Just keep in mind that
the A1 and A2 values were developed as a means of normalizing the radiological
risks for all radionuclides that might be shipped.
Maybe some examples would help me see what you mean.
Good idea. Let's start first with the man-made radionuclides Cesium-137 (Cs-137)
and Cobalt-60 (Co-60). The A1 (special form) limit for Cs-137 is 2 TBq or
54Ci, while the A2 (normal form) limit is considerably lower; only six tenths
(0.6) TBq (16 Ci). For Co-60, the A1 and A2 values are exactly the same -
0.4 TBq or 10.8 Ci each. For Co-60, we can assume that even if five rather
than one exposure pathway is taken into account, there is no greater risk
than if only one pathway is considered. Hence, the A1 and A2 values are
identical. This is not the case for Cs-137 where the risks differ depending
upon the exposure pathway(s).
What do you mean by "special form" materials?
First, remember that the special form designation applies to A1 limits only.
This designation pertains to those materials which, if released from a package,
would present a hazard solely due to external radiation. So, the form of
the radioactivity must be one that would not create exposure conditions via
other pathways.
Can you give me an example?
Sealed (encapsulated) sources of radiation, much like those found in a smoke
detector, are "special form" materials. Because higher radioactivity limits
are permitted, durable metal capsules with a high physical integrity ensures
that the radioactivity therein will not disperse. In addition, only solid
materials can be classified as "special form".
What else?
Special form encapsulation is designed so that the capsule cannot be opened
unless the capsule is destroyed. In other words, no mechanism exists for
opening or loosening the capsule in a manner that could inadvertently release
its contents. Special form capsules also undergo rigorous testing described
in Title 49 before they receive that classification. These include tests
for temperature, impact, percussion, bending, and leakage.
What other types of sources can qualify for special form
designations?
There are several types of sources that satisfy the criteria for shipment
as special form. Examples include neutron sources, density/transmission sources,
industrial radiography sources, and sources used for sterilization and
processing. A copy of a source's certification as special form must be maintained
on file by owners and users of these sources if they intend to transport
them.
What can you tell me about "normal form" radioactive materials?
As mentioned previously, A2 limits apply to normal form materials. These
materials are referred to as "non-special" form, or materials that do not
qualify as special form materials as defined in 49 CFR 173.403.
What's so different about them?
Unlike special form materials, normal form materials may be solid, liquid,
or gaseous and include any material which has not qualified as special form.
Examples might be waste material in a plastic bag, a liquid-containing bottle
housed within a metal container, powder in a glass or plastic bottle,
contaminated soil in a 55 gallon drum, or a gas inside a cylinder.
When is a Type "A" package required for shipping RAM and what do you mean
by a Type "A" quantity?
A Type "A" package may be required when the radioactivity inside the package
does not exceed an A1 or A2 value. A Type A package cannot be used if an
A1 or A2 value is exceeded since it is designed to withstand normal
transportation conditions and minor accidents only. A Type "A" quantity is
a quantity of RAM that does not exceed the A1 value for special form shipments
or the A2 value for normal form in a single package.
Under what situations is Type "A" packaging used?
There are several situations where Type A packaging would be utilized. Examples
might include shipments of radionuclide generators for medical diagnosis
and treatment, moisture density gauges, and radionuclides in liquid form
for medical or research purposes. Type A packaging includes, but is not limited
to, cardboard, wooden and "ammo" boxes, as well as steel drums. The intent
of a Type A package is to prevent loss or dispersal of the package contents
while still maintaining proper radiation shielding under normal transportation
conditions.
Is testing of Type "A" packaging a prerequisite prior to use?
Most certainly. Type A packages are designed to withstand rough handling
conditions. To do so, they must successfully pass a variety of tests including
water spray tests (to simulate the effect on the packaging under wet weather
conditions), drop tests, puncture tests, and crush tests. Performance
requirements for liquids and gases are even more stringent than those for
solids.
When is a Type "B" package required and what is meant by a Type "B"
quantity?
This type of package is required when the radioactivity to be shipped exceeds
an A1 or A2 value. Type B packages must therefore meet all the requirements
for Type A packaging. But they must also have the ability to withstand serious
accident conditions with no subsequent loss of containment and limited loss
of shielding capability. The latter requirement dictates that the packaging
be subjected to a much greater level of testing. A Type "B" quantity is a
quantity of RAM which exceeds the Type A quantity limits in a single package.
Can you provide examples of Type B packaging?
Yes. Wide ranges in the physical package types exist. Examples include packaging
for industrial radiography exposure devices (small) to waste casks and spent
nuclear fuel casks (large).
How much more stringent is the testing?
Well, for example, instead of surviving a four (4) foot fall onto a hard
surface, the case for Type A packages, Type B packages are dropped from a
height of thirty (30) feet onto an unyielding surface. These packages are
also exposed to a severe temperature environment (800 degrees centigrade)
for thirty (30) minutes and water immersion to a depth of at least fifteen
(15) meters - conditions Type A packages are not subjected to. There are
other tests as well. In short, Type B packages are extensively tested prior
to use to provide confidence that structural integrity is maintained during
radioactive material transport of higher activity materials.
How do I know if my package is a Type B package?
Not only must it pass all of the tests, but it must be "certified" as a Type
B package. The NRC and the DOE, through authorizations provided by the DOT
will "certify" all Type B packages for use by issuing a "Certificate of
Compliance".
Where can I find more information about Type B certifications?
A very useful source is NUREG-0383, Directory of Certificates of Compliance
for Radioactive Materials Packages. This document is issued annually by the
NRC in a three volume set. It includes a list of authorized users and approved
packages, Certificates of Compliance, and approved quality assurance programs
for RAM packages.
I've heard the term "Highway Route Controlled Quantity" before. Is that
the same as an A2 quantity?
No. The Highway Route Controlled Quantity (HRCQ) refers to RAM shipments
of high radioactivity levels, typically greater than 3000 times the A1 or
A2 limits (i.e., 1000 TBq or 27,000 Ci), that not only require Type B packaging,
but certain highway routing limitations and requirements.
In what other way are A1 and A2 values utilized in the transport of
RAM?
Fractional multiples of the A1 and A2 (i.e., values less than their respective
limits) are used to set limits for other categories of RAM. These are called
"limited quantities", "excepted articles", and "LSA materials".
What are limited quantities?
A limited quantity is a shipping classification for RAM that allows packages
with a low amount of radioactivity inside to be exempt from most DOT shipping
requirements.
What is meant by "strong, tight packaging" or "excepted
packaging"?
"Strong, tight packaging" or "excepted packaging" refers to packages which
contain radioactivity of a very limited hazard due either to its small amount
or low concentration. The package is designed to contain and protect the
contents during normal shipping activities. An example where this type of
packaging is put to good use on a regular basis is during the transport of
smoke detectors. This commonly used, and very important consumer product
contains an "exempt" or limited quantity of Americium-241 (Am-241). Therefore,
they are typically shipped in excepted packaging.
What are the requirements for excepted packaging?
There are several requirements which must be satisfied. Title 49 of the CFR
supplies the specific details. In general, the removable contamination limits
must not be exceeded, certain radiation exposure rate limitations must be
met either on the package itself or the surface of the unpackaged
instrument/article, "radioactive" markings must be affixed to the package
in an appropriate fashion, and the UN identification number must be on the
package.
This seems like a lot of rules. Is there a logical way of evaluating them
in order to determine the type of packaging required.
Well, let's try this. Start first with the basics, then work your way
to the more complicated. Remember first there are materials that are not
regulated in transport because they do not meet the definition of radioactive
material (i.e., radioactivity less than the concentration shown in 49 CFR
Table 173.436). Once you have determined that your package is indeed radioactive,
it is packaged in the following hierarchy (from least radioactive to highest
radioactivity content): excepted package (i.e., for limited quantities and
excepted articles) which is on the order of 1,000 - 10,000 times less than
the A1/A2 values; Type A package (i.e., for Type A quantities) which can
contain RAM up to the A1/A2 values, and Type B package (i.e., for Type B
quantities) which can contain RAM exceeding the A1/A2 limits. There are also
packages known as Industrial Packages (IP) that are sometimes used to ship
Low Specific Activity (LSA) materials.
You mentioned the term "transport index" before. What does it refer to?
Good question! The transport index or "TI" has been used for many years.
It is defined as the radiation exposure rate, in units of millisieverts per
hour (mSv/hr) (or millirem per hour if multiplied by 100) at a distance of
one meter from the external surface of a package containing radioactivity.
It is a dimensionless number which is identified on the label of a package
so that the carrier or other interested parties can quickly assess the relative
radiation hazard and the corresponding degree of control to be exercised
during handling.
Would you give me an example of a transport index?
Sure. If the exposure rate at one meter, or about 3.3 feet, from a package
is 5.0 mrem/hr, the TI is 5.
I've also heard the term "exclusive use" vehicles before. What are
those?
Exclusive use infers that RAM packages, once loaded on the vehicle, remain
on that vehicle until the final destination is reached. No additional loading
or unloading occurs while the vehicle is in transit. Specific instructions
detailing unloading and shipment maintenance procedures are provided to the
transporter and to the package recipient.
Are there maximum permissible dose rates for packages shipped in a
non-exclusive use vehicle?
Yes there are. Typically, two limits have to be met. First, there must be
a maximum of 200 mrem/hr at any point on the package surface. Second, the
dose rate cannot exceed 10 mrem/hr at one (1) meter from the package. (The
latter figure is reduced if the package is placed on a passenger-carrying
aircraft.) There are additional requirements as well which have to do with
the total transport indexes associated with a group of packages and the
separation distance between packages.
Are the dose rate limits different if an exclusive use vehicle transports
the package?
Yes. But the situation is more complicated because several exclusive-use
vehicle scenarios exist. For example, if a package is carried on a "conventional,
closed, exclusive use vehicle", meaning the package is inside the vehicle
and inaccessible to members of the general public, the following maximum
limits apply: 1000 mrem/hr on the package surface; 200 mrem/hr on all sides,
top, and bottom of the vehicle; 10 mrem/hr at two (2) meters from all surfaces
of the closed vehicle; and two (2) mrem/hr in the driver's compartment. If
the vehicle is an "open" flatbed vehicle where access to the package is
restricted or unrestricted, the limits change. If unrestricted access is
the case, the 1000 mrem/hr limit is reduced to 200 mrem/hr in order to address
additional radiological safety issues..
Seems complicated.
It can be. The point is not to bore you with numbers and scenarios, but rather
to demonstrate that much thought goes into the radiological safety aspects
of these shipments. A variety of issues must be constantly addressed including
the type of vehicle used to ensure radiological over-exposures do not occur.
You have emphasized dose limits on or from radioactive packages. Are there
contamination limits as well?
Yes. The contamination of concern applies to removable (non-fixed) contamination
on the surface of the package. For beta/gamma emitters and so-called "low
toxicity" alpha emitters, the limit is 0.4 Bq over an area of one (1) square
centimeter (cm2), which is equivalent to 2,200 disintegrations per minute
(dpm) per 100 cm2. All other alpha emitters have limits which are a factor
of ten (10) lower. These particular limits apply to transport in non-exclusive
use vehicles. Separate limits apply under exclusive use transport and other
situations.
Why is removable contamination a concern?
Removable or transferable radioactivity can be tracked or spread from one
location to another. For example, a leaking package could contaminate other
nearby packages or be spread by walking from one location to another, including
from the workplace to the home. Removable activity can also be inhaled,
representing an internal dosimetry concern.
How are contamination surveys performed?
The amount of removable activity is determined by taking a wipe or smear
over the defined surface area. The smear is then counted with calibrated
instrumentation, the results (in counts per minute) converted into disintegration
rates, and the findings compared to the applicable regulatory limits.
Are all radioactive materials destined for transport packaged in the same
way?
No. The type of packaging actually selected is dependent upon the classification
of RAM to be shipped. For example, limited quantities and excepted articles
require Excepted packaging, while Type A quantities require Type A packaging,
Type B and Highway Route Controlled Quantities require Type B packaging.
There are other examples as well.
What is fissile material?
As defined by the DOT in Title 49, fissile material refers to Plutonium-238
(Pu-238), Plutonium-239 (Pu-239), Plutonium-241 (Pu-241), Uranium-233,
Uranium-235 or any combination of these radionuclides. These elements can
"fission", or split apart, if in the presence of neutron radiation.
Why is this material a concern in RAM transport?
The transport of fissile materials requires an assessment of not only
radiological safety (i.e., containment of the material), but nuclear safety
(i.e., criticality control). Fissile materials are always a concern in any
situation due to the potential for an accidental criticality. A criticality
results in the release of a large neutron and gamma ray component, sufficient
to result in lethality to an exposed individual that is unfortunate enough
to be in the near vicinity. For this reason, transport of fissile materials
requires prudent safeguards.
How are fissile materials packaged?
Fissile materials are usually packaged as either "Fissile Type A" or "Fissile
Type B" packages, although exceptions do exist. As noted previously, a Type
B package, whether for fissile materials or otherwise, requires greater shielding
and must pass more rigorous testing. Package certification by the NRC or
the DOE is required.
Please provide some examples of materials requiring fissile
packaging.
Sure. Examples include uranium dioxide powder or pellets, "fresh" (unirradiated)
and "spent" (irradiated) fuel from a power reactor, uranium hexafluoride,
and irradiated/unirradiated research reactor fuel.
What do the "LSA" and "SCO" classifications refer to?
LSA means "Low Specific Activity", and SCO means "Surface Contaminated Objects".
These are two important designations involving low-to-medium amounts of
radioactive waste materials.
Where do they come from?
LSA materials are generated from nuclear fuel cycle facilities as well as
a wide variety of industrial, medical, research, and academic communities.
The SCO category is a designation that addresses solid wastes containing
radioactive contamination on the external surfaces on an otherwise
non-contaminated object. SCO materials originate from cleanup, remediation,
and decontamination activities.
Do LSA materials present a radiological hazard?
Yes, but to only a limited degree. This is because the designation "Low Specific
Activity" indicates that not very many radiations are emitted during decays.
How are LSA materials categorized?
LSA materials are categorized into three classes known as LSA-I, LSA-II,
and LSA-III.
Start first with LSA-I. When would I use this category?
The LSA-I designation is generally used for RAM with the lowest level of
radioactivity. Examples include, but are not limited to, naturally occurring
uranium or thorium ores or concentrates of these ores, solid unirradiated
natural or depleted uranium or natural thorium, and mill tailings, contaminated
earth, rubble, and other materials in which the RAM is uniformly distributed
and the average specific activity does not exceed a specified limit.
What about LSA-II?
LSA-II includes water containing tritium (radioactive hydrogen) up to, but
not exceeding, a specified limit, or uniformly-distributed RAM with average
specific activities not exceeding specified limits for solids, liquids, and
gases.
And LSA-III?
This category contains the highest specific activities of the LSA
classifications. Emphasis is placed on solids which meet DOT leach test
requirements; that contain radioactivity either distributed throughout the
solid or essentially uniformly distributed, that contain RAM in a relatively
insoluble form; and that meets specific activity requirements.
What about the Surface Contaminated Object (SCO) designation?
This designation applies to non-radioactive objects . . . that's right -
not radioactive in and of itself . . . that have radioactive contamination
on their surfaces. Two categories exist, known as SCO-I and SCO-II. These
categories address both fixed and removable levels of contamination on both
accessible and inaccessible surfaces. The appropriate contamination limits
are specified in 49 CFR. As you might suspect, higher limits apply for the
SCO-II category.
Can you provide an example?
Sure. Take the situation where mostly fixed alpha contamination is present
on an accessible surface. In this case, the DOT specifies a SCO-I contamination
limit of 4E3 (4000) Bq/cm2 (or 0.1 µCi/cm2). For SCO-II, the corresponding
limits are twenty (20) times higher (8E4 Bq/cm2 or 2.0 µCi/cm2). With
knowledge of these limits, measurements of surface contamination can be taken
and the results used to establish compliance. Other limits exist for non-fixed
(removable) contamination and for beta radiation on accessible and inaccessible
surfaces.
Are there any problems with the SCO classification system?
Unfortunately, yes. An appropriate method must be used to determine the ratio
of fixed to non-fixed contamination. In addition, it is not always clear
whether a surface is accessible or not. For these and other reasons, the
NRC and DOT have collaborated on a guidance document (NUREG-1608) to assist
in the categorization and transport of SCO's.
How are packaging requirements determined for LSA and SCO
materials?
In general, the packaging of these materials is based, as you might expect,
on the potential radiological hazard of the material to be transported. In
some cases, "strong tight packaging" will suffice. In other cases, Type A
and "greater than Type A" packaging is necessary. In still other instances,
more durable packaging (i.e., "industrial packaging")is required such as
for LSA-II and LSA-III materials, relative to the LSA-I category, due to
their higher specific activities. Liquids generally require more durable
packaging than solids due to the greater radiological risk from spillage.
In addition, the packaging is influenced by the type of shipment (i.e., exclusive
versus non-exclusive). The DOT in 49 CFR provides further information and
requirements of the types of packaging needed for LSA and SCO shipments .
How are the potential hazards from the transport of RAM addressed by the
DOT?
One specific approach is through compliance with 49 CFR Part 172 which describes
hazardous materials ("Hazmat") communications. Part 172 covers a diverse
number of issues including appropriate shipping papers, package marking and
labeling, vehicle placarding, emergency response information and Hazmat employee
training.
How do I know whether a material selected for transport is a hazardous
material?
Subpart B of 49 CFR 172 contains a listing of materials considered hazardous
for the purposes of transportation. If your shipment is on this list, the
DOT considers it to be hazardous.
Is there any other information provided with this listing?
Yes! The requirements for shipping papers, marking and labeling, and vehicle
placarding are provided. In addition, the hazard class, "UN" identification
number, and the proper shipping name (or where to find it) is identified.
Why are labels typically required on RAM Packages?
Labels provide a useful purpose: they alert an individual that a package
contains RAM and that the package may require special handling and controls
on where it is stowed and how much separation is required between packages.
What labels are typically used?
White-I, Yellow-II, and Yellow-III labels are used. A White-I label contains
an all white background with the conventional three-bladed radiation symbol
(the "trefoil") in the upper half of the label and the word "RADIOACTIVE"
followed by a single red stripe in the lower half. This label signifies low
external radiation hazards and no special stowage or handling conditions.
The appearance of a yellow color on the upper half of the label with two
vertical red stripes (Yellow-II) indicates that external radiation levels
from the package are sufficiently high to warrant stowage considerations.
A package bearing a yellow label with three red stripes (Yellow-III) signifies
still higher radiation levels and the vehicle must then be placarded
"RADIOACTIVE".
How do I know which label to choose?
There are two principal criteria: The maximum dose rate at the surface of
the package and the transport index.
What are hazard classes and where does radioactive material fall
under?
Hazard classes are part of the classification system found on a placard,
label or shipping paper which defines the type of material being carried
in transport and the associated hazard. In order, Hazard Class 1 applies
to explosives, Class 2 to gases (flammable, nonflammable, poisonous, corrosive),
Class 3 to flammable liquids, Class 4 to flammable solids, Class 5 to oxidizers
and organic peroxides, Class 6 to poisonous and infectious materials, Class
8 to corrosives, and Class 9 (miscellaneous). RAM is classified as a Class
7 hazard.
What do you mean by "proper shipping name"?
Part 172 lists several commonly used and proper shipping names. The word
"proper" simply means that the designation is acceptable for the purposes
of RAM transportation. Each designation usually begins with the word "Radioactive
Material" and ends with the United Nations or "UN" number. Examples include
"Radioactive Material, excepted package - limited quantity of material --
UN 2910" or "Radioactive Material, low specific activity -- UN 2912" or
"Radioactive Material, Type A package, special form, UN333", or .....
(you get the idea).
Is it always clear which shipping name to use?
Not in all cases. However, the intent of 49CFR172.101(c)(11) is to provide
assistance in this regard.
What else?
There are less frequently encountered proper shipping names for radioactive
materials which pose a greater hazard from a secondary hazard than from the
radioactivity itself. For example, you may encounter the designation "Pyrophoric
metals, m.o.s., with a UN 1383 designation for pyrophoric thorium. This material
has a low specific activity and consequently poses a low radiological hazard;
however, under the proper conditions, it can catch on fire. There are several
other examples as well.
Why do you keep referring to shipping papers? Are they always
necessary?
Most of the time. A complete and correct description for a shipment of hazardous
materials is vitally important - not only to the carrier and the recipient,
but to emergency response personnel in the event of an accident. Having said
that, the list of required items on the shipping papers is rather extensive.
What goes on shipping papers?
Items that must appear include, but are not limited to: the proper shipping
name, the UN hazard class and identification number, the letters "RQ" if
the shipment is a "hazardous substance", emergency response telephone numbers,
the words "radioactive materials" (unless these words are already contained
in the proper shipping name), the name of each radionuclide in the material,
a description of the physical and chemical form of the material, the
radioactivity content, the radioactive label on each package (i.e., White
I, Yellow II, and Yellow III), and appropriate group notations for shipment
of LSA or SCO materials (e.g., LSA-I, SCO-II, etc.). Please be aware this
list is not complete and that qualifying comments apply to some of the listed
items.
Are there any exceptions to the requirement for shipping papers?
Yes. Excepted packages meeting certain DOT requirements are exempted from
providing this documentation.
What type and level of training is required to package and ship RAM?
Employees who transport hazardous materials, i.e., "Hazmat Employees", must
be trained and tested pursuant to the requirements of 49 CFR 172. The essential
training categories specified by the DOT are general awareness/familiarization
training, function-specific training, and safety training. Initial training
is required within a specified time frame (90 days) for new employees assigned
to a specific job. Recurrent training is also required within three (3) years
(or 90 days for employees assigned to a new job for which they have not been
previously trained). Records must be maintained attesting that training and
testing requirements have been met.
I guess training is always good, but is all this really necessary?
It is estimated that over 4 million RAM packages are transported annually
in the United States. While an excellent safety record has been achieved
over the past fifty years, which corresponds to the advent of the nuclear
age, this is due in large part to effective training in the proper packaging
of these materials.
Are there other reasons?
Yes. Radiation and radioactivity have negative connotations for many people.
Effective training and adherence to the regulations has resulted in no known
deaths or serious injuries to transportation workers, emergency services
personnel, or the general public. It is important that this track record
be maintained to promote confidence and a feeling of safety among the populace.
What is the most important lesson in this discussion?
Actually, there is more than one. Radioactive material is transported on
a daily basis in the United States by rail, truck, water, and air. Safe transport
of these materials is based primarily on the use of proper packaging. While
there are risks associated with the transportation of RAM, namely the risks
from a vehicle accident and the associated radiological ramifications, these
risks have been demonstrated historically to be quite low. When they occur,
emergency response plans exist and are implemented by trained personnel to
respond appropriately and in a timely fashion. However . . .
Yes??
Adhering to the shipping regulations can be easier said than done. While
we presented some general terminology and some examples in this discussion,
it is important that experienced and trained individuals who know and understand
all of the twists and turns of the regulations be involved in the packaging
and transport of your radioactivity or radiation source. History has shown,
over and over again, that a tentative or flippant attitude to shipping always
comes back to haunt the shipper. And by the way, the "I didn't know what
you meant" excuse gets you nowhere . . . fast.
Copyright © Integrated Environmental Management, Inc., 1999