1. Protection of the public and the environment standards? Rodolfo Avila

2. Outline Risk - a probabilistic concept How to quantify risks The ICRP’s Representative Individual Example: Assessments for High Level Waste Repositories Standards Handling of uncertainties

3. Definition of Risk The word risk derives from the early Italian “risicare”, which means to dare Risk is the "possibility of loss or injury: peril.” (Webster Dictionary, 1999)

4. Decision under uncertainty Ingredients: A partition of possible states of affairs The possible acts that the agent can undertake The utilities of the consequences of each possible act, in each possible state of affairs of the partition

5. Le pari de Pascal Pensees, 1660 God is, or he is not. Which way should you incline? ”Reason cannot answer” God isGod is not Devoted+ ∞0 Bohemian-∞-∞0

6. Antoine Arnauld 1662 Fear of harm ought to be proportional not merely to the gravity of harm, but also to the probability of the event (”La logique, ou l´art de penser” a bestseller at the time) The concept of risk has (two) elements: the likelihood of something happening and the consequences if it happens

7. Expectation The expected value of an act is the sum of the products (Utilities x probabilities) God isGod is not Expectation Devoted+- 0/+/- Bohemian-∞-∞+-∞-∞

8. Dominance expected value rule In every admissible probability distribution, one act has greater expected value than every other act, then this act dominates the others in expected value If one act dominates the others in expected value DO IT!

9. What is probability? The ancient Greek word  meant plausible or probable. Socrates defined it as ”likeness to truth” Probability is a measure of our confidence that something is going to happen. Probable means to be expected with some degree of certainty

10. Conditional probabilities Any probability P(E) of an event E is conditional to some stipulated model or assumption (A 1 ), it should strictly be written P(E|A 1 ), i.e. the probability of E, given A 1. There may be other assumptions (A 2, A 3, A 4, … A i ) in addition to the assumption A 1 believed to be the most likely. How can this fact be taken into account?

11. ”A priori” and ”a posteriori” A priori probability- estimated before the fact. Can be reliable ”only for the most part” A posteriori probability- estimated after the fact. By taking a sufficient large sample, you can increase your confidence in the estimated probability to whatever degree you wish. But, how reliable this probability is for predicting future events?

12. Measuring Risk Risk is the probability that the Exposure is above the Standard The Risk Quotient RQ = Exposure/Standard

13. From Releases to Harmful Effects Releases Contamination Exposure of Man Exposure of biota Effects of Man Effects on biota

14. Representative individual - ICRP Since dose to the public cannot be measured directly, it must be estimated using environmental concentrations and appropriate habit data. Therefore, for the purpose of protection of the public, it is necessary to define a hypothetical exposed person to be used for determining compliance with the dose constraint and for introduction of a practice. This is the representative individual. The representative individual is the hypothetical individual receiving a dose that is representative of the most highly exposed individuals in the population.

15. Dose Distribution Dose constrain

16. Example HLW repository

17. The regulatory requirement One way of defining the most exposed group is to include the individuals that receive a risk in the interval from the highest risk down to a tenth of this risk. If a larger number of individuals are considered to be included in such a group, the arithmetic average of individual risks in the group should be used for demonstrating compliance with the criterion for individual risk in the regulations (i.e. 10 -6 per year)…. If the group only consists of a few individuals, the criterion of the regulations of individual risks can be considered of being complied with if the highest calculated individual risk does not exceed 10 -5 per year….

18. Lake Mire Coast Forest Running Water Coast Mire + + + + + +

19. Dose Distribution

20. Selecting the appropriate type of standard Releases Contamination Exposure of Man Exposure of biota Effects of Man Effects on biota Release rate Concentrations Dose rates, doses probability of effects Total releases Affected area Collective dose number of effects

21. Measuring Risk with Probabilistic Standards

22. Measuring Risk Risk is the probability that the Exposure is above the Standard The Risk Quotient RQ = Exposure/Standard

23. Risk Profile 1

24. Protection of the public and the environment standards? Rodolfo Avila

25. Outline Risk - a probabilistic concept How to quantify risks The ICRP’s Representative Individual Example: Assessments for High Level Waste Repositories Standards Handling of uncertainties

26. Definition of Risk The word risk derives from the early Italian “risicare”, which means to dare Risk is the "possibility of loss or injury: peril.” (Webster Dictionary, 1999)

27. Decision under uncertainty Ingredients: A partition of possible states of affairs The possible acts that the agent can undertake The utilities of the consequences of each possible act, in each possible state of affairs of the partition

28. Le pari de Pascal Pensees, 1660 God is, or he is not. Which way should you incline? ”Reason cannot answer” God isGod is not Devoted+ ∞0 Bohemian-∞-∞0

29. Antoine Arnauld 1662 Fear of harm ought to be proportional not merely to the gravity of harm, but also to the probability of the event (”La logique, ou l´art de penser” a bestseller at the time) The concept of risk has (two) elements: the likelihood of something happening and the consequences if it happens

30. Expectation The expected value of an act is the sum of the products (Utilities x probabilities) God isGod is not Expectation Devoted+- 0/+/- Bohemian-∞-∞+-∞-∞

31. Dominance expected value rule In every admissible probability distribution, one act has greater expected value than every other act, then this act dominates the others in expected value If one act dominates the others in expected value DO IT!

32. What is probability? The ancient Greek word  meant plausible or probable. Socrates defined it as ”likeness to truth” Probability is a measure of our confidence that something is going to happen. Probable means to be expected with some degree of certainty

33. Conditional probabilities Any probability P(E) of an event E is conditional to some stipulated model or assumption (A 1 ), it should strictly be written P(E|A 1 ), i.e. the probability of E, given A 1. There may be other assumptions (A 2, A 3, A 4, … A i ) in addition to the assumption A 1 believed to be the most likely. How can this fact be taken into account?

34. ”A priori” and ”a posteriori” A priori probability- estimated before the fact. Can be reliable ”only for the most part” A posteriori probability- estimated after the fact. By taking a sufficient large sample, you can increase your confidence in the estimated probability to whatever degree you wish. But, how reliable this probability is for predicting future events?

35. Measuring Risk Risk is the probability that the Exposure is above the Standard The Risk Quotient RQ = Exposure/Standard

36. From Releases to Harmful Effects Releases Contamination Exposure of Man Exposure of biota Effects of Man Effects on biota

37. Representative individual - ICRP Since dose to the public cannot be measured directly, it must be estimated using environmental concentrations and appropriate habit data. Therefore, for the purpose of protection of the public, it is necessary to define a hypothetical exposed person to be used for determining compliance with the dose constraint and for introduction of a practice. This is the representative individual. The representative individual is the hypothetical individual receiving a dose that is representative of the most highly exposed individuals in the population.

38. Dose Distribution Dose constrain

39. Example HLW repository

40. The regulatory requirement One way of defining the most exposed group is to include the individuals that receive a risk in the interval from the highest risk down to a tenth of this risk. If a larger number of individuals are considered to be included in such a group, the arithmetic average of individual risks in the group should be used for demonstrating compliance with the criterion for individual risk in the regulations (i.e. 10 -6 per year)…. If the group only consists of a few individuals, the criterion of the regulations of individual risks can be considered of being complied with if the highest calculated individual risk does not exceed 10 -5 per year….

41. Lake Mire Coast Forest Running Water Coast Mire + + + + + +

42. Dose Distribution

43. Selecting the appropriate type of standard Releases Contamination Exposure of Man Exposure of biota Effects of Man Effects on biota Release rate Concentrations Dose rates, doses probability of effects Total releases Affected area Collective dose number of effects

44. Measuring Risk with Probabilistic Standards

45. Measuring Risk Risk is the probability that the Exposure is above the Standard The Risk Quotient RQ = Exposure/Standard

46. Risk Profile 1