Annex E Intervention levels
(Reference:Paragraph 4.8.8)
1.0 Generic Criteria
1.1 Generic Criteria (GC) are used in the early stages of an emergency, prior to the availability of actual radiation monitoring data, when technical staff in the PEOC Scientific Section undertake dose projection modelling. Generic Criteria values are calculated to reduce the risk of stochastic effects and are expressed in terms of equivalent dose and effective dose.
1.2 Generic Criteria are compared against the dose projections modelled in order to determine the need for implementation of protective measures for the purposes of:
- Exposure control
- Ingestion control
- Population monitoring and medical management
- Trade control of foodstuff and other commodities
- Transitioning to existing exposure situation
footnote 14 - Emergency workers and helpers
2.0 Operational Intervention Levels
Operational Intervention Levels (OILs) are used once radiation monitoring data is available to determine the need to implement protective measures. OILs are classified as follows:
- Ground Monitoring OILs are used to identify areas (beyond those for response actions that have been taken based on the emergency classification) where the ground deposition of radioactive material warrants protection of the public frequenting or living in the area and restriction of consumption, distribution or sale of food.
- Skin Monitoring (gamma and beta) OILs are used to identify individuals with enough radioactive material on the skin to warrant response actions (such as decontamination). Only the public being evacuated or relocated is expected to possibly have sufficient radioactive material on the skin to warrant response actions, but OILs may be used with other members of the public as well.
- Food, Milk and Drinking Water OILs are used to confirm and adjust initial restrictions on food, milk and drinking water restrictions that were enacted based on OIL 2.
- Thyroid Monitoring OILs are used to identify individuals warranting registration and medical follow-up due to the intake of radioiodine (i.e., evacuated public or those that ingested local produce, country foods
footnote 15 , milk or rainwater etc.) in areas exceeding OIL 2. These may be used with members of the public as well.
Appendix 1 Generic criteria
Protective Action Strategy | Projected Dose | Protective Actions |
---|---|---|
Exposure Control Measures |
50 mSv (5 rem) in the first 7 days (HT |
Iodine Thyroid Blocking |
10 mSv (1 rem) in the first 2 days (E |
Sheltering |
|
100 mSv (10 rem) in the first 7 days (E) |
Evacuation |
|
Population Monitoring and Medical Management |
100 mSv (10 rem) in one month (E) |
Medical follow-up (health screening) |
Ingestion Control Measures |
1 mSv (100 mrem) per year for ingestion of any one of the food/beverage categories (E) |
Restriction of distribution and ingestion of potentially contaminated:
|
Trade Control of Foodstuff and Other Commodities |
1 mSv (100 mrem) / year (E) |
International trade restrictions on non-essential items |
Vehicles, Equipment and Other Items |
10 mSv (1 rem) per year (E) |
Restriction of use for non-essential vehicles, equipment and other items from affected area. |
Transitioning to existing exposure situation |
20 mSv per year |
Target dose to enable transition to existing situation. |
Emergency Workers and Helpers |
50 mSv (5 rem) over the duration of the response. Value may be exceeded voluntarily. |
Restriction of activities for individual emergency workers and helpers. |
Appendix 2 Operational Intervention Levels (OILs)
1.0 Ground monitoring
OIL | When | Ambient Dose Rate 1 m above ground |
Protective Action Strategy | If OIL is exceeded and response action has been taken, proceed to: | If OIL is NOT exceeded, proceed to: |
---|---|---|---|---|---|
1 |
Intermediate Phase (within 24 hours following the end of the release) |
(1000 µSv/hr) |
Evacuation |
-Registration -Skin Monitoring (OIL 5a and 5b) -Thyroid Monitoring (OIL 8) -Decontam -Medical Screening |
Adjust food, milk and drinking water restrictions as per OILs 5, 6 and 7. |
2 |
Intermediate Phase (within 24 hours following the end of the release) |
1 µSv/hr |
Ingestion control |
-Estimate dose from all pathways to determine if medical follow-up is necessary |
|
3 |
Intermediate Phase (0 – 10 days) |
100 µSv/hr for first 10 days after reactor shutdown |
Temporary Relocation |
-Registration -Temporary Relocation within a month -estimate dose from all pathways to determine if medical follow-up is necessary |
|
Intermediate Phase/ Recovery Phases (10+ days to months) |
25 µSv/hr later than 10 days after reactor shutdown or for spent fuel |
Temporary Relocation |
2.0 Skin Monitoring – Gamma and Beta
OIL |
When |
Measurement |
Protective Action Strategy |
If OIL is exceeded and response action has been taken, proceed to: |
If OIL is NOT exceeded, proceed to: |
---|---|---|---|---|---|
4a |
Intermediate Phase |
Ambient dose rate, 10 cm from bare skin of hand or face * : 1 µSv/hr above background |
Decontamination |
-Registration -Additional Decon -Thyroid Monitoring (OIL 8) -Decon -Medical Screening -ITB, if advised by MOHLTC -estimate dose to determine if medical follow-up is necessary |
OIL 8 |
4b |
Intermediate Phase |
Beta count rate, 2 cm from bare skin of hand or face * : 1000 cps |
Decontamination |
* Measurement must be conducted in an area with a background of < 0.5 µSv/hr.
3.0 Food, Milk and Drinking Water Samples
OIL |
When |
Foodstuff Category |
Gross Alpha (α) Activity |
Gross Beta (β) Activity |
Protective Action Strategy |
If OIL is exceeded and response action has been taken, proceed to: |
If OIL is NOT exceeded, proceed to: |
---|---|---|---|---|---|---|---|
5* |
Interme-diate Phase |
Drinking Water (Tap) |
1 (Bq)/L |
10 (Bq)/L |
Ingestion control -Restriction of distribution and sale of potentially contaminated drinking water, milk and other foodstuffs and beverages |
OIL 6 and/or OIL 7 AND -restrict consumption, distribution and sale -estimate dose from all exposure pathways to determine if medical follow-up is necessary |
No further restrictions |
Milk |
1 (Bq)/kg |
30 (Bq)/kg |
|||||
Other Foodstuffs and beverages |
3 (Bq)/kg |
30 (Bq)/kg |
* OIL 5 is intended to be used as a rapid screening tool in the field. In certain circumstances, it may be desirable to proceed directly from OIL 2 to OIL 6.
OIL |
When |
Activity Concentration |
Protective Action Strategy |
If OIL for EITHER marker is exceeded and response action has been taken, proceed to: |
If OIL is NOT exceeded, proceed to: |
---|---|---|---|---|---|
6 |
Intermediate Phase |
1000 (Bq)/kg of I-131 200 (Bq)/kg of Cs-137 NOTE: both 1-131 and Cs-137 must be assayed |
- Ingestion control -Restriction of distribution and sale of potentially contaminated drinking water, milk and other foodstuffs and beverages |
OIL 7 AND -restrict consumption, distribution and sale -estimate dose from all exposure pathways to determine if medical follow-up is necessary |
No further restrictions |
OIL of 7 for all the rows. Columns 2-6 contain no merged cells.">
OIL |
Radionuclide* |
Symbol |
Drinking water ((Bq)/L) |
Milk ((Bq)/kg) |
Other Foodstuffs and Beverages ((Bq)/kg) |
---|---|---|---|---|---|
7 |
Strontium-89 |
89Sr |
300 |
300 |
1000 |
Strontium-90 |
90Sr |
30 |
30 |
100 |
|
Ruthenium-103 |
103Ru |
1000 |
1000 |
1000 |
|
Ruthenium-106 |
106Ru |
100 |
100 |
100 |
|
Iodine-131 |
131I |
100 |
100 |
100 |
|
Cesium-134 |
134Cs |
100 |
300 |
1000 |
|
Cesium-137 |
137Cs |
100 |
300 |
1000 |
|
Plutonium-238 |
238Pu |
1 |
1 |
3 |
|
Plutonium-239 |
239Pu |
1 |
1 |
3 |
|
Plutonium-240 |
240Pu |
1 |
1 |
3 |
|
Plutonium-242 |
242Pu |
1 |
1 |
3 |
|
Americium-241 |
241Pu |
1 |
1 |
10 |
* The radionuclides included here are those which have biological and radiological properties which make them generally expected to provide the most significant dose from the ingestion of drinking water, milk and other foods and beverages following a nuclear emergency.
4.0 Thyroid Monitoring
OIL |
When |
Measurement |
Protective Action Strategy |
If OIL is exceeded and response action has been taken, proceed to: |
If OIL is NOT exceeded, proceed to: |
---|---|---|---|---|---|
8 |
Intermediate Phase |
Ambient Dose rate, 1 cm from skin: 2x to 10x background* |
Population monitoring and medical management Decontamination |
-Registration -ITB, to further reduce uptake if not already taken, AND if directed to do so by MOHLTC (CMOH) -medical screening -estimate dose from all exposure pathways |
Registration and record of dose |
* Must be measured post-decontamination
Footnotes
- footnote[14] Back to paragraph Projected dose in the 1st year as a target dose to enable transition to existing exposure situation.
- footnote[15] Back to paragraph Country foods are non-commercial foodstuffs which are obtained directly from nature as a result of being foraged, hunted, gathered, fished, or picked.
- footnote[16] Back to paragraph HT = thyroid dose (equivalent dose)
- footnote[17] Back to paragraph E = effective dose
- footnote[18] Back to paragraph This value is flexible and adjustments may be made depending on feasibility and justifications needed to reach criteria values. If Generic Criteria cannot be met, transition to existing exposure situation may still occur if other Generic Criteria are not exceeded. [From GSR-7]
- footnote[19] Back to paragraph If safe evacuation is not possible, the protective action strategies employed would include sheltering and ITB.