Handling Nuclear Emergencies Flashcards
Radiation Emergency Classification
When is immediate notification to the NRC required?
(10 CFR 20)
- TEDE 250 mSv or more
- Eye dose of 750 mSv or more to the lens
- Skin/extremities dose of 2.5 Gy or more
- Release of material in a quantity of 5 ALI
Radiation Emergency Classification
When is 24-hour notification required to the NRC?
(10 CFR 20)
- TEDE 50 mSv or more
- Eye dose of 150 mSv or more to the lens
- Skin/extremities dose of 0.5 Sv or more
- Release of material in a quantity above 1 ALI
Radiation Emergency Classification
When is 30-day written notice required to the NRC?
(10 CFR 20)
- Doses in excess of occupational limits
- Doses in excess of public limits
- Dose rates or concentrations > restricted area limits
- Dose rates or concentrations > 10x unrestricted area limits
- Anytime you conduct immediate and/or 24-hour notification, a 30-day written notice is also required
Define
Incident
(NCRP 111)
A situation in which an unplanned release of radioactive material or unplanned personnel exposure occurs.
Define
Level One Emergency
(NCRP 111)
When a regulatory limit could possibly be exceeded following an incident.
Define
Level Two Emergency
(NCRP 111)
If personnel doses could possibly produce non-stochastic biological effects (i.e., doses to skin higher than 3 Sv or doses to any other organs greater than 0.5 Sv are possible)
What are the two clasifications of nuclear emergencies by location?
- On-site ⇒ Occurs within the legal geographical boundary of a licensee and all the consequences are confined within that location.
- Off-site ⇒ One which originates at a location outside the facility boundary. Additionally, if radioactive contamination is carried from an on-site accident “out of the gate” via a plume or other transport method, its classification is changed to off-site.
What are the different classifications of incidents by exposure conditions?
- Non-contaminating & Observable
- Non-contaminating & Undiscovered
- Contaminating & Observable
- Contaminating & Undiscovered
Define
Non-contaminating & Observable
(Incident Classification by Exposure Conditions)
- Persons are exposed to an external radiation field from a source or radiation machine for a relatively short period of time.
- Consequences are small, usually on-site.
- Example ⇒ Failure of an accelerator interlock to shut down the beam upon entry of a person into the vault
Define
Non-contaminating & Undiscovered
(Incident Classification by Exposure Conditions)
- Persons are exposed to an external radiation field from a source or radiation machine for a long period of time, because there was an undetected failure in the associated radiation protection features.
- Example ⇒ Accidental loss of industrial radiography sources when undetected
Define
Contaminating & Observable
(Incident Classification by Exposure Conditions)
- Momentary loss of control of radioactive material in unsealed form.
- Loose contamination is subsequently inhaled or ingested by an individual.
- Requires some form of bioassay (in vitro) or in vivo counting.
- Example ⇒ Accidental spill of radioactive solution in a laboratory, chemical explosion in a plutonium processing facility
Define
Contaminating & Undiscovered
(Incident Classification by Exposure Conditions)
- Undetected release of radioactivity
- The radiological problems are similar to a contaminating/observable incident, but the problems are not detected
- Example ⇒ Leaking package transported interstate, required extensive monitoring to track down all affected areas
What are the four different accident phases (i.e., start to finish of an accident)?
- Occurrence
- Emergency
- Recovery
- Restoration
Define
Occurrence Phase
(Nuclear Accident Phases)
The events immediately preceding the accident and the physical happening of the accident.
Define
Emergency Phase
(Nuclear Accident Phases)
Immediate life and property-saving actions taken by personnel in the near vicinity.
Define
Recovery Phase
(Nuclear Accident Phases)
Planned, specifically organized actions taken after the emergency phase to isolate accident consequences and physically secure the area.
Define
Restoration Phase
(Nuclear Accident Phases)
Actions taken at a later date to decontaminate and repair the facility to restore it to pre-accident conditions or to decommission and safely dispose of the damaged sections of the facility.
What are two emergency planning zones (EPZ)?
(10 CFR 50)
- Plume exposure pathway EPZ
- Ingestion exposure pathway EPZ
Define
Plume exposure pathway EPZ
(10 CFR 50)
- Has a radius of about 10 miles.
- Most of the population dose in this zone would be due to direct exposure to a plume of released radioactivity and ground contamination.
Define
Ingestion exposure pathway EPZ
(10 CFR 50)
- Radius of about 50 miles
- Population dose would be due primarily to contaminated drinking water and contaminated food and vegetables
What are the four classes of severity for a nuclear power plant emergency?
- Unusual Event
- Alert
- Site Emergency
- General Emergency
Define
Unusual event
(Nuclear Power Plant Emergencies)
- An abnormal condition in plant operation which does not pose any public health hazard.
- No off-site emergency response is necessary.
Define
Alert
(Nuclear Power Plant Emergencies)
- The incident results in actual or potential reduction of plant safety
- Off-site response is called for
- No public action is necessary
- Emergency operations centers would activate
Define
Site Emergency
(Nuclear Power Plant Emergencies)
- Involves actual or likely failure of major plant systems with potential significant release of radioactivity.
- Event would not require protection actions beyond the plant boundary.
- Example ⇒ Primary coolant leak that can be made up for with other water sources.
Define
General Emergency
(Nuclear Power Plant Emergencies)
- The actual or imminent release of high levels of radioactivity outside the plant boundary
- Requires complete mobilization of the off-site emergency organizations and probable alert of the general public within the 10 mile EPZ
Medical/Radiological Response
Medical Priorities
- Exposed, contaminated, injured survivors need to receive life and limb saving treatment whether or not they are contaminated.
- Deal with internally contaminated victims. Time sensitive because radionuclides rapidly seek out internal organs where they deposit.
Medical/Radiological Response
Radiological Priorities
- Whole body contamination survey ⇒ Determination of the extent and amount of the radioactive contamination.
- Decontamination ⇒ Assist medical personnel in decontamination of contaminated persons. Clean open wounds, then orifices, then the remaining intact skin.
- Post-Decontamination Analysis ⇒ Full characterization of the contaminants (e.g., radioisotopes, % composition, form)
Rule of Thumb
In vivo test if exposure to a fast neutron field is suspected
500 rem of fast neutrons delivered acutely to the whole body of Reference Man will produce a gamma exposure rate of 1 mR/hr in the armpit.
Radioiodine administration
- Adults over 18 ⇒ 130 mg day-1
- Children 3 - 18 ⇒ 65 mg day-1
- 1 month to 3 years ⇒ 32 mg day-1
- Birth to 1 month ⇒ 16 mg day-1
Plutonium is a hazard from what 3 standpoints?
- Presents an internal hazard from the alpha particle emissions.
- It is a phyrophoric material which means that pieces of the metal can spontaneously ignite when exposed to air.
- Potential for criticality accidents.
Define
Nuclear terrorism
- Theft and use of a complete nuclear weapon.
- Construction and explosion of a crude ncuelar weapon using fissionable material (“improvised nuclear device”).
Define
Radiological Terrorism
- A physical attack on a nuclear facility that releases significant radioactivity.
- The explosion of non-fissile radioactive materials via a radiological dispersal device (RDD)
Four major effects of a nuclear explosion
- Blast wave ⇒ Carries high speed debris
- Thermal Burns ⇒ Produced from the fireball after explosion
- Ionizing Radiation ⇒ From nuclear fission, delivered in a one-minute burst
- Fallout ⇒ 24 hours post-explosion with visible particulate debris
Rule of Thumb
7:10 Rule
From 1 hour post explosion out to 6 months, for each factor of 7 in elapsed time, the dose rate is reduced by a factor of 10.
NCRP
What is the recommended “turn around level” for emergency responders?
- 10 R hr-1
- Entry into fields over 10 R hr-1 should be restricted to lifesaving actions such as removal of injured victims
Emergency Dose Limit Guidelines
DOE
- Property Protection ⇒ 10 rem
- Lifesaving ⇒ 25 rem (TEDE) and 250 rem (skin)
Emergency Dose Limit Guidelines
NCRP
- Property Protection ⇒ 5 rem
- Lifesaving ⇒ 50 rem (TEDE) and 500 rem (skin)
Give two actions which could significantly reduce the dose to the downwind population during the first week following a reactor accident
- Instruct population to remain indoors of closed homes as much as possible.
- Instruct population to relocate by moving to homes of relatives or friends that are outside the affected area
Describe
Protective Action Guide
(EPA)
- Projected dose from a nuclear accident (or contamination event) above which certain protective actions are recommended to prevent/lessen the dose to the general population.
- Committed doses from passage of the plume are not included as a projected dose from a later phase of contamination
- 1st year PAG is 2 rem TEDE
List two qualitative and three quantitative measures to test for exposure to airborne 90Sr
Qualitative
- Analysis of nose wipes for 90Sr/90Y
- Detection of beta radiation w/ a GM pancake probe looking for contamination present on the face or nares (nostrils)
Quantitative
- The activity “q” estimated to be present on the filter of a worker’s personal air samples
- The activity “q” estimated to be present in a 24-hour urine sample
- The activity “q” estimated to be present in a 24-hour fecal sample
To assess surface deposition of plutonium, what photon emissions are you looking for?
17 keV ⇒ Provides estimate for total activity of Pu isotopes and 241Am
60 keV ⇒ Provides estimate of total activity of 241Am
Need to account for
- 2.5 emission ratio
- Attenuation by source material and air
Because of much greater attenuation of the 17 keV photons compared to the 60 keV photons, combined measurements can help account for attenuation correction
What are top 3 considerations in deploying a rescue team during a criticality accident?
- Would rescue operations cause a secondary criticality?
- Did the primary criticality accident cause the release of highly active fission/activation products?
- Does the available nuclear criticality information suggest the accident victim already receive a dose above the lethal threshold?
Name the primary exposure pathways and radiation sources (during a criticality accident) for:
Workers in the room at the time of the accident
External radiation from the neutron and gamma rays emitted during the prompt criticality phase of the accident
Name the primary exposure pathways and radiation sources (during a criticality accident) for:
Rescue team (assume criticality has stopped)
External radiation from beta and gamma radiation emitted by neutron activation and fission products release during the accident
Name the primary exposure pathways and radiation sources (during a criticality accident) for:
Other individuals within 0.1 to 1 km at the time of and following the incident
External radiation from the neutron and gamma rays emitted during the prompt criticality phase of the accident
AND
External radiation from beta and gamma radiation emitted by neutron activation and fission products release during the accident
Note ⇒ Depending on distance-from shielding-of any released radionuclides and internal exposure from inhaled radioactive aerosols
Describe a method that can be used to “quick sort” quickly screen persons potentially involved following a criticality accident
Detection of neutron activation products in the body by using a GM survey meter
23Na + 1n → 24Na
24Na → 24Mg + -1β
Note ⇒ 24Na has a 15 hour T1/2
What are two medical interventions that could change the health outcome an individual exposed to 750 rad (whole body, deep dose)?
- Blood transfusions
- Bone marrow transplants
Note ⇒ Must be administered within the first month following the incident
Why are large acute radiation doses presented in “rad” and not “rem”?
- rad ⇒ Related closest to the threshold for the non-stochastic effects of cell death and organ/tissue formations
- rem ⇒ Reserved primarily for chronic occupational exposures, and used to estimate the risks of stochastic effects of cancer and hereditary disease
In addition to performing a bioassay, list five action to be taken following an accidental intake of 131I
- Report the accident to the appropriate regulatory authority
- Estimate the worker’s thyroid dose and report the dose to the worker’s supervisor and appropriate regulatory authorities
- Review incident with the worker and his/her supervisor including discussions on regulatory requirements and laboratory control procedures to prevent recurrence
- Train the worker on expected biological effects commensurate with exposure potential
- Implement a change/requirement that prevents further accidental intakes
What are the factors that determine effectiveness of DTPA (pentetic acid)
- Timeliness of DTPA administration shortly after intake to minimize the time 239Pu has to deposit in the bones and liver
- The inhalation chemical compound class – This affects solubility and transportability of 239Pu, which affects the deposition into bones and liver and ultimately the final dose to the worker
- The type of DPTA (zinc or calcium) and whether the general toxicity of DTPA would conflict with the overall/general health of the worker
List four action to ensure the extent of a spill is determined and contaminated areas properly isolated
- Except for members of a survey team, prevent personnel access to all potentially contaminated areas
- Monitor for contamination any personnel who had access within the last 24 hours, focus on shoes bottoms. Remove all contaminated clothing and shoes and bag
- Interview the same personnel to determine all onsite and offsite locations they have been
- Perform contamination surveys using wipes and portable instrument (e.g., thin window detector) to determine extent of contamination and need for decontamination
List three items to take to the scene of a spill to assess and control the spill.
- Thin-window pancake GM detector attached to a rate meter w/ audible output for monitoring individuals and surfaces for beta activity.
- Absorbent paper to cover and confine surface contamination.
- Floor tape, yellow rope, stanchions, and signs to demarcate and prevent access to contaminated areas.
What three follow up actions should you take in the work area upon discovery of a hot particle?
- Monitor other individuals who have been working in the area for hot particle contamination
- Identify and isolate the source of the hot particles
- Minimize spread of hot particles by proper cleanup of affected surfaces
