# Presentation: 330440

## Radiological Safety TrainingforUranium Facilities

- Radiological Safety TrainingforUranium Facilities

- Coordinated and Conducted for
- Office of Health, Safety and Security
- U.S. Department of Energy

## Course Content

- Properties of Uranium
- The Nuclear Fuel Cycle
- External Dose Control
- Internal Dose Control
- Criticality Safety
- Emergency Response for Uranium Incidents
- Course Summary

## Module 101

- Properties of Uranium

## Physical Properties of Uranium

- Solid
- Liquid
- Airborne particles
- Gas

- Shiny, silvery metal
- Molten metal, solutions
- Radioactive residue
- UF6

## Uranium

- Atomic number Z = 92
- Radioactive
- Alpha emission
- Fission
- Fission products

## Radioactive Decay Products

- Most are radioactive
- Generally contribute most of the radioactivity
- Can become concentrated during certain processes

## Radioactive Properties

- Radioactive decay products
- Criticality

## Flammability

- Uranium burns in air
- Large amounts of water will extinguish a fire, but
- Uranium plus water produces hydrogen gas
- Special fire extinguishers smother the fire
- Use of water may cause a criticality control concern

## Toxicity

- Heavy metals are toxic
- Uranium is comparable to lead in toxicity

## Chemical Reactivity

- Uranium is reactive
- Many possible chemical hazards
- Uranium metal oxidizes in hours
- Uranium chips ignite immediately
- Uranium in water produces flammable hydrogen gas
- Uranium should be in oil for long-term storage
- Concentration of decay products can cause increased exposure rates

## Colors

- Lower oxides (e.g., UO2) are usually
- dark colored
- less soluble
- Higher oxides (e.g., UO3, UO4, UO4·2H2O) are usually
- orange or yellow colored
- more soluble

## Module 102

- The Nuclear Fuel Cycle

## Importance of Uranium

- Historical:  orange-colored glaze
- Discovery of radioactivity with uranium, Becquerel, 1896
- Discovery of radioactive decay products, Marie Curie
- Decay products:  radium, radon
- Discovery of nuclear fission, 1938
- Plutonium production from uranium, 1940
- First nuclear reactor, Fermi, 1942
- Atomic (nuclear) bomb, 1945

## Naturally Occurring Uranium

- 0.2% (2 ppt) in uranium ore
- 2 ppm in the earth’s crust
- 2 ppb in the oceans

## Sources of Uranium

- United States
- Colorado Plateau
- Wyoming Basin
- Black Hills
- Africa

## Nuclear Fuel Cycle

- Mining and milling
- Conversion to other chemical forms
- Enrichment
- Fabrication of fuel rods
- Use in reactors
- Decontamination & decommissioning
- Waste disposal/storage

## Mining and Milling

- Uranium ore
- Yellowcake
- Uranium mill tailings

## Conversion

- Uranium dioxide		UO2
- Orange oxide			UO3
- Uranium fluoride gas	UF6

## Enrichment

- Natural uranium			0.7% 235U
- Enriched uranium			> 1% 235U
- Highly enriched uranium		> 20% 235U
- Depleted uranium			0.2% 235U

## Uses for Enriched Uranium

- Commercial power reactors
- Naval propulsion power reactors
- Research reactors
- Nuclear weapons

## Uses of Depleted Uranium

- Shielding
- Armor-piercing bullets
- Catalysts
- Armor plating
- Counter weights

## Fuel Reprocessing

- Expose fuel material
- Remove fuel from cladding
- Chemically separate the uranium
- Convert uranium to UF6 for enrichment

## Waste Disposal and Storage

- Low-Level Waste (LLW)
- High-Level Waste (HLW)

## D&D of Uranium Facilities

- UMTRA
- DOE facilities
- Commercial facilities

## Module 103

- External Dose Control

## Beta Radiation

- From the decay products
- Mostly external
- Skin dose
- 30 rad/hr (234mPa - *B*)

## Gamma Radiation

- Usually less than 5 mrem/hr (0.05 mSv/hr)
- Decay products can become concentrated
- Fission products (only for fuel reprocessing)
- Criticality (potentially fatal doses of gamma radiation)

## Neutron Radiation

- Enriched UF6
- Spontaneous fission
- Fission from reactors or experiments
- Criticality accident

- 4-8 mrem/hr
- small
- contained
- potentially fatal

## ALARA - External Dose

- To keep external exposure ALARA:
- Minimize time
- Maximize distance
- Use shielding
- Reduce the amount of radioactive material being used

## Beta Radiation Protection

- Easily detected
- Easily shielded
- Use low-Z elements to minimize bremsstrahlung
- heavy rubber or plastic over objects
- safety glasses for the lens of the eye
- heavy work gloves for the hands

## Module 104

- Internal Dose Control

## Internal Exposure

- Modes of entry into the body:
- Inhalation
- Ingestion
- Absorption
- Injection

## Contamination Control - 1

- Proper contamination control will
- Limit internal dose by minimizing ingestion or inhalation
- Limit external dose by reducing the source
- Prevent the spread of radioactive materials into uncontrolled areas

## Contamination Control - 2

- Contamination can be controlled by
- Evaluation of work activities
- Use of containment devices
- Control and monitoring of airborne contamination
- Minimization of contamination areas
- Control of movement of equipment and personnel
- Protective equipment
- Special radiological surveys and techniques for contamination monitoring
- Special radiological surveys and techniques for release of materials with the potential for uranium contamination

## Airborne Contamination

- Cutting, grinding, welding, etc.
- Ventilation and filters
- Air sampling and monitoring
- Respirators should be considered (as a last resort)

## Protective Clothing

- Coveralls
- Booties or dedicated work shoes
- Gloves, unless there are overriding reasons

## Module 105

- Criticality Safety

## Criticality

- Fission breaks atom into fission products
- Fissionable:  with fast neutrons
- Fissile:  with slow or fast neutrons
- Self-sustaining chain reaction

## Module 106

- Emergency Response for
- Uranium Incidents

- (Facility-Specific)

## Module 107

- Course Summary

## Course Summary

- Physical properties
- Radioactive properties
- Chemical properties
- Toxicological properties and biological effects
- Sources
- Operations and processes
- External dose measurements

- External dose reduction and control
- Internal dose measurements
- Internal dose reduction and control
- Factors affecting criticality
- Criticality safety
- Emergency response