Highly Enriched Uranium - CNSC Online - Canadian Nuclear Safety Commission

How Do We Safely Transport Liquid Highly Enriched Uranium?

Highly Enriched Uranium

Table of contents

Highly Enriched Uranium

Safe Transport

How Do We Safely Transport Highly Enriched Uranium?
Business as Usual: Safety First

Highly Enriched Uranium

Safe Transport

Dangerous goods are transported throughout Canada and across the border every day, by land, sea, and air.

These can cause harm if they escape into the environment so there are specific transport safety requirements designed to minimize the chance that this can happen.

During transport, all dangerous goods require the right placard on the vehicle.

Highly Enriched Uranium

Safe Transport

Nuclear substances are classified as dangerous goods. Different nuclear substances pose different risks, depending on their nature and their radioactivity level, if they were to be accidentally released into the environment.

The CNSC makes and enforces strict rules for transport of nuclear substances. The goal is to keep transport completely safe in both normal or accident situations. These rules work - there has never been a transport accident involving nuclear substances in Canada that resulted in an impact on the health and safety of people or the environment.

The special rules depend on what nuclear substance is being transported.

Let's take a closer look at one scenario: the safe transport of liquid highly enriched uranium liquid from Chalk River Laboratories back to the United States for safe storage and eventual recycling.

Highly Enriched Uranium

What is Highly Enriched Uranium?

What does “highly enriched” mean?

Uranium occurs naturally and is composed primarily of two isotopes, U238 and U235.

U238 constitutes over 99% of natural uranium and U235 less than 1%.

U235 can sustain a nuclear fission chain reaction, so it is called a “fissile” nuclear substance. This makes it useful in nuclear reactors and in the production of medical isotopes.

To make Highly Enriched Uranium (or HEU), the proportion of U235 is raised to exceed 20%. This is done by concentrating the amount of U235 in natural uranium.

Natural Uranium

  • Less than 1% Uranium-235
  • Used in CANDU Nuclear Power Reactors

Low-Enriched Uranium

  • Less than 20% Uranium-235
  • Used in light-water nuclear reactors, like those in the United States

Highly Enriched Uranium (HEU)

  • More than 20% Uranium-235
  • Used to make medical isotopes

Highly Enriched Uranium

HEU in Canada

HEU is a key ingredient for the production of the medical isotope Molybdenum-99 which decays naturally to Technetium-99m which is used every day for nuclear medical imaging.

At Chalk River Laboratories, the NRU Research Reactor produces Molybdenum-99 with the help of HEU.

By-product from the medical isotope extraction process prior to 2003 was in liquid form.

This by-product liquid HEU is in safe storage at the Chalk River Laboratories in a secure, CNSC-licensed vessel called a Fissile Solution Storage Tank.

Highly Enriched Uranium

HEU Repatriation

Born in the USA

The HEU originally came from the United States.

Canada, along with over 30 other countries, has a Repatriation Agreement with the United States which has the special facilities for recycling it.

The Government of Canada has committed to returning, or “repatriating”, HEU liquid to the United States by 2018.

Highly Enriched Uranium

How is HEU Transported?

The liquid HEU will be transported inside a specially designed package. The CNSC does not perform the transport, but will certify the package and license the shipments.

Transport packages have been used to ship nuclear substances for decades, and there is a long legacy of testing these packages to survive even extreme transport accidents.

The package designed for the cross-border transport of liquid HEU must be certified by the Canadian Nuclear Safety Commission (CNSC), the United States Nuclear Regulatory Commission (USNRC) and the United States Department of Transportation (USDOT).

The CNSC will only certify the package when it is certain that it satisfies all regulatory requirements.

Other fissile materials like solid HEU have been safely transported for many years the same way, and there have been no accidents resulting in a release of nuclear substances from these shipments.

The package is designed to prevent the material from “going critical” (sustaining a chain reaction), even under accident conditions.

The HEU will be transported by road vehicle and will be the only cargo on the vehicle. Other kinds of transport are also a safe and secure option.

Highly Enriched Uranium

Package Design

The Transport Package

HEU in liquid form is planned to be transported approximately 250 litres at a time, 00sealed in four 64-litre containers which are in turn sealed within a Transport Package. 99% of the weight of a Transport Package (over 23,000 kg) consists of protective shielding against impact, heat, water pressure, and radiation - only 1% of the weight is actually liquid HEU!

Click on a marker to learn more...Click on a marker to learn more...

components of a transport package Liquid HEU Container Impact Limiter Cask Lid Inner Shell Gamma Shield Outer Shell Neutron Shield Tank Outer Case
Liquid HEU Container

The liquid HEU is loaded in four specially designed stainless steel containers within the Transport Package. These provide primary containment of the liquid HEU. The welded lids have special valves for fill and drain operations. Each container holds about 64 litres of liquid HEU.

Impact Limiter

These end caps on the package are like the crumple zones in a race car. The aluminum honeycomb construction is designed to absorb the energy of an impact, reducing the risk of damage during normal use or if an accident was to happen.

Cask Lid

The Containers are sealed in place with a steel lid. This stepped lid has Teflon and metallic O-rings to prevent any liquid movement in or out of the container area, and provides secondary containment of the liquid HEU. The lid is closed with twelve 2.25cm diameter bolts.

Inner Shell

The inner and outer stainless steel shells are welded together at the top and bottom to encase the lead gamma shield.

Gamma Shield

Gamma rays are similar to high-energy X-rays and are emitted from some types of radioactive materials, like liquid HEU. To absorb and block this radiation, a thick jacket of lead surrounds the containers.

Outer Shell

The inner and outer stainless steel shells are welded together at the top and bottom to encase the lead gamma shield.

Neutron Shield Tank

The shield tank is a stainless steel shell filled with an ethylene/glycol and water solution that is 1% boron by weight. This solution is very effective at absorbing neutron radiation, which is emitted by some radioactive materials, like liquid HEU.

Outer Case

The exterior of the transport package, made of thick steel, protects against heat, water pressure (in the event of immersion) and puncture impacts. It is the outermost shell of sealed armor that isolates the nuclear material from the environment.

Highly Enriched Uranium

Package Testing

Tested for Worst Case Events

To make sure the design meets all standards, the Transport Package design is tested against both normal and accident conditions which may be encountered during transport. Package tests are designed to produce damage to the package equivalent to that which would be produced by a very severe accident. Package tests must follow very strict testing procedures and protocols based on international standards.

Reality Check
Would a certified package "survive" in real accidents?

Historical transport accidents have been analyzed to simulate the most extreme conditions a transport package would have to survive. From these studies and computer simulations, it has always been concluded that the health and safety risk to people and the environment would only be minimal using certified package designs.

The package is dropped from 9m onto a hard surface

9m drop test

What Happens

The package is dropped from 9m onto a hard surface

What This Simulates

Damage equivalent to a severe road accident

Test Result: Package safety is maintained

This package passed the test because it has proven it will not leak any radioactive contents and that it will still provide the required radiation shielding and heat dissipation. The package can be prepared for the next test.

The package is dropped from one metre onto a rigid bar approximately 15cm in diameter

1 metre penetration drop

What Happens

The package is dropped from one metre onto a rigid bar approximately 15cm in diameter

What This Simulates

Piercing impact on the package wall that may result from an accident

Test Result: Package safety is maintained

This package passed the test because it has proven it will not leak any radioactive contents and that it will still provide the required radiation shielding and heat dissipation. The package can be prepared for the next test.

The package is engulfed in flames for 30 minutes at approximately 800 degrees Celsius

Thermal Test

What happens

The package is engulfed in flames for 30 minutes at approximately 800 degrees Celsius

What This Simulates

A fuel fire that could occur in a road accident with a large fuel leak from a transport vehicle. In this scenario, the fire has completely surrounded the transport package.

Test Result: Package safety is maintained

This package passed the test because it has proven it will not leak any radioactive contents and that it will still provide the required radiation shielding and heat dissipation. The package can be prepared for the next test.

The package is submerged under 15 metres of water for 8 hours

Water submersion test

What happens

The package is submerged under 15 metres of water for 8 hours

What This Simulates

An accident near a river, lake, or sea. This depth is chosen because the water depth near most bridges, roadways or harbors would be less than 15 metres

Test Result: Package safety is maintained

This package passed the test because it has proven it will not leak any radioactive contents and that it will still provide the required radiation shielding and heat dissipation.

Pass or Fail

Pass or Fail

What happens

All these tests are done one after another to the same package. The package passes testing if, after all the testing, the radiation levels and leakage rates are within safe limits. These limits depend on the size and weight of the package, and the nature and radioactivity of the contents. This is an important part of obtaining certification for the package design by the USNRC, USDOT and CNSC. The package can be used for transport of liquid HEU across the border on when fully certified.

Highly Enriched Uranium

Safe Transport

The Big Picture

HEU won't move without a licence from the CNSC. Every shipment of fissile material, like the HEU, requires a specific licence for transport due to its security nature. The CNSC will issue the transport licence only when it is sure that the shipment meets all regulatory requirements, including plans for emergencies, communications, security measures, and use of a certified package. Explore the map and learn what it takes to get this kind of transport licence.

Click on a marker to learn more...Click on a marker to learn more...

a map showing the elements of secure transport Atomic Energy of Canada Ltd: The Consignor Approved Emergency Plan CNSC Approved Security Plan Certified Transport Package Trained Transport Personnel Cross-Border Responsibilities Exact Route: Not Disclosed Shipment Tracking Labeling and Placards
Atomic Energy of Canada Ltd: The “Consignor”

Atomic Energy of Canada Ltd (AECL) has a CNSC licence to produce medical isotopes and store HEU (in solid and liquid form) on site at Chalk River. AECL also has the role of “consignor” for the shipments of liquid HEU from the Chalk River facility. Being a consignor means that AECL is responsible for loading the liquid HEU into transport packages and preparing emergency and security plans for the shipments.

Approved Emergency Plan

An emergency response assistance plan (“ERAP”) must be provided by AECL and approved by Transport Canada. AECL has an ERAP in place and approved by Transport Canada which covers the transport of fissile material including HEU in solid and liquid form. Transport Canada regulations also require that the consignor display a 24-hour emergency telephone number on all shipping documents.

CNSC Approved Security Plan

Shipments of fissile material like liquid HEU must have a security plan in place that is approved by the CNSC Nuclear Security Division. The security plan includes a threat assessment and the security measures used to counter these threats. It also includes communication and coordination plans with authorities along the route and an alternate emergency route. Although all the information about the shipment is shared with the CNSC for approval, some elements of the plan are kept secret from the general public since disclosing them would compromise security and therefore safety.

Certified Transport Package

At the core of safe transport is a certified package for the nuclear substance. The package for liquid HEU carries approximately 250 litres, about the volume of four large fire extinguishers. Although it has been adapted from a previously certified package design it must receive new certifications from both Canada and the United States to carry liquid HEU. This includes certifications from the US Nuclear Regulatory Commission and the US Department of Transportation, which are then revalidated by the CNSC for use in Canada. The CNSC would issue a certificate only if it is satisfied that the design meets all CNSC requirements.

Trained Transport Personnel

Drivers are required to be trained on the transport of dangerous goods regulations as well as the transport company's radiation protection program.

Cross-Border Responsibilities

The US Department of Energy/National Nuclear Security Administration (USDOE/NNSA), under their Global Threat Reduction Initiative (GTRI), is the lead agency responsible for the US Origin Nuclear Removal program. The USDOE has the responsibility to implement the overall program including accepting the responsibility for nuclear material, establishing contracts with appropriate public and government agencies as well as obtaining government authorizations to transport the material in the United States.

Exact Route: Not Disclosed

The shipment will use dedicated vehicles, and there will be a border crossing from Canada to the United States. However, some details are kept secret from the public for the same reason that the Prime Minister's or President's specific driving routes are not always revealed - it makes transport safer because it increases security. These routes are pre-approved and agreed to by authorities in both Canada and the United States and can also include emergency alternate routes.

Shipment Tracking

Security measures to track and protect the trucks are kept secret, otherwise these measures might become ineffective.

Labeling and Placards

Like many dangerous goods shipments, there is a chance that you might see one of these vehicles on the road. They will display the required labels and placards that describe the classification of dangerous goods. In the case of liquid HEU, the placards will be a yellow and white losange with the radioactive trefoil and the number 7 on it, to indicate that the truck carries dangerous goods which fall into the Class 7 - radioactive dangerous goods. Labels also provide some additional information such as maximum radioactivity in the package and radiation level at 1 metre from the package.

Highly Enriched Uranium

CNSC: Nuclear Watchdog

Canada is fulfilling its international obligations under nuclear non-proliferation by shipping liquid HEU back to the United States for reprocessing. The CNSC makes sure this transport is safe.

No HEU will be transported outside of the Chalk River site without a licence from the CNSC.

The CNSC will issue the transport licence only when it is certain that the shipment meets all regulatory requirements.

Highly Enriched Uranium

For more information on our activities