Dealing with the Aftermath of a Nuclear Accident: Challenges, Lessons Learned, Solutions

Transcription

1 International Conference on Global Emergency Preparedness and Response Organized by the International Atomic Energy Agency in cooperation with CTBTO, EC, Europol, FAO, ICAO, ILO, IMO, INTERPOL, OECD NEA, PAHO, UNEP, UNOOSA, WHO, WMO IAEA Headquarters, Vienna, Austria, October 2015 Dealing with the Aftermath of a Nuclear Accident: Challenges, Lessons Learned, Solutions Abel J. González Argentine Nuclear Regulatory Authority Av. del Libertador 8250; (1429)Buenos Aires, Argentina ; abel_j_gonzalez@yahoo.com,agonzalez@arn.gob.ar

2 Objective To review: challenges presented by the aftermath of accidents; and lessons learned in dealing with this difficult problem. To explore holistic solutions to the problems.

3 Caution My presentation will only deal with the aftermath of accidents with radiological consequences; namely, it will address sequelae, or protracted consequences rather than immediate responses.

4 Content 1. Quandary 2. Mythology Myth of contamination Myth of dose limits 3. Status New recommendations and standards The 1 msv/y conundrum 4. Future 5. Epilogue

5 Quandary

6 Common denominators Large amounts of radioactive substances are deposited and become present in the habitat and consumer products. Such presence is confusedly termed contamination. Simple questions are asked by the affected people. Ambiguity in responses challenges the wellbeing of people!

7 Main culprit: 137 Cs

8 Release of 137 Cs Chernobyl ~ Bq - Fukushima ~10 16 Bq Contamination of: Land, Forests, Water, Foodstuff Consumer products

9 Picture of the aftermath

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12 Contamination colour code ( 137 Cs) Chernobyl kbq/m kbq/m kbq/m 2 >1480 kbq/m 2 Fukushima 1C i /m 2 10 rad/h 1 Bq/m Sv/h 3700 Bq/m 2 1 µsv/h = 8.76 msv/y 422 Bq/m 2 1 msv/y ; 100 Bq/m mSv/y = 10% nat.back.

13 Responding unambiguously to simple and straightforward questions from the public 13

14 Is it safe for me and my family to live here?

15 Are we not in danger!? Are we in danger!?

16 Can we play outdoors? 16

17 Is it safe for us to eat this food?

18 I have been told that the food is within the standards but contaminated, should I tell this to my customers?

19 We were told this water is contaminated; shall we use it?

20 Why I am permitted to drink this water but not to swim in it?

21 Should I terminate my pregnancy? 21

22 Is my child safe??

23 Why doses of 20 msv/year are permitted now, if doses above a dose limit of 1 msv/year were prohibited before the accident?

24 After all, doses were low. Why I have been first evacuated, then relocated and now I am virtually resettled here?

25 Mythology (set of widely held but exaggerated or fictitious stories and beliefs)

26 Contamination Dose limit 26

27 The myth of contamination (the enemy of understanding)

28 The international definition of the term contamination is: presence of radioactive substances on surfaces, or within solids, liquids or gases (including the body), or process giving rise to their presence in such places. However, the popular connotation contamination is impurity or danger. This connotation was not intended in its formal denotation. (Confusedly, the term is also used less formally to refer to a quantity, namely the activity on a surface, or per unit area)

29 Contamination in Latin-based languages The meaning of contamination is not presence: our usage of the term is wrong! Contamination means made impure by exposure to or addition of a poisonous polluting substance. (The term is derived from the Latin contaminare that means make impure, and it was used over the years to identify food that was impure, i.e. poisoned, for religious purposes; e.g., non-kosher food).

30 Unsurprisingly, other languages have translated contamination with the same wrong connotation In Chinese, it was translated as 污染, wūrǎn, which is a combination of 污, dirty, and 染,tinted; its connotation is tinted with dirt!. In Arab, it was translated as UVوث, talawwuth, a worrying term having the connotation of infection! In Russian was translated as Загрязнение, zagryazneniye, meaning impurity and defilement.

31 The problem occurred in Japanese as well Contamination 汚染 (osen) 汚 fouling, dirt, filth 染 dyed, tinted 汚染 fouling with filth? August 25th, 2015

32 Regulating contamination

33 Foodstuff

34 Water

35 Non edible

36 Incoherence in drinking liquids + = 10 Bq/l for 137 Cs + = 1000 Bq/l for 137 Cs 36

37 Incoherence in non-edible vs. edible + = 1000 Bq/kg for 137 Cs + = 100 Bq/kg for 137 Cs 37

38 Changing contamination limits

39 Belarus

40 Japan Rice, meat, vegetables, fish: 500 Bq/Kg 100 Bq/Kg, Milk, milk-powder, infant-food: 200 Bq/Kg 50 Bq/Kg Drinking water: 200 Bq/Kg 10 Bq/Kg

41 The myth of dose limit

42 A dose limit that may be exceeded? In normal language, dose limit would be understood as a point beyond which doses may not pass, a terminal point or boundary for doses, the furthest extent of endurance to radiation exposure. Nobody can understand that a situation is safe, if doses are higher than the dose limit

43 The Japanese expression for dose limit, is unequivocal: 線量限度 Senryō gendo 線 radiation beam, 量 amount, 限 limit, 度 time limit of the amount of radiation dose incurred in the time'

44 44

45 Summary history of the 5mSv/y Shaky Start (rule of thumb) Risk of radiation exposure Risk of non-radiation workers 50mSv/y Reasonable but arbitrary decision Public one order of magnitude lower = 5mSv/y 45

46 ICRP 5 msv/y

47 Statement from the 1987 Como Meeting of the ICRP. Annals of the ICRP 17(4), i-v (1987).

48 Summary history of the 1mSv/y Workers 50mSv/y Public 5mSv/y Reevaluation Hiroshima & Nagasaki doses Factor 5 lower Workers 20mSv/y?? Public 1mSv/y 48

49 ICRP 1 msv/y

50 Summary logic of the 1mSv/y dose limit 1. The risk of safe industries /y /y 2. The radiation risk factor 1%/Sv 3. Occupational limit = 50 msv/y 4. Public limit (one order of magnitude lower) = 5mSv/y 5. Hiroshima reevaluation risk = 5%/Sv 6. New limits: Public limit = 1mSv/y Occupational limit = 20mSv/y???

51 In conclusione.1 msv/y is neither the thesis of a theorem nor a dogma of faith. It is reasonable to question its application! 51

52 Status

53 New Recommendations

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57 A new concept: reference levels for emergency or existing controllable exposure situations Level of dose above which it is judged to be inappropriate to plan to allow exposures to occur. (The chosen value will depend upon the prevailing circumstances of the exposure under consideration)

58 Reference levels bands (msv) Characteristics of the situation Protection requirements >20 to 100 >1 to 20 Sources not controllable, or protective actions disproportionately disruptive Individuals receive benefit from a controllable exposure situation Reduce doses approaching 100 msv. Information and assessment of individual doses. Same 1 or less Individuals exposed to a source that gives them little or no individual benefit but benefits society. Periodic checks on the exposure pathways as to the level of exposure

59 New Standards

60 2 November,

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62 The EC BSS subtle difference In an existing exposure situation, "reference level" means, the level of effective dose or equivalent dose or activity concentration above which it is judged inappropriate to allow exposures to occur as a result of that exposure situation, even though it is not a limit that may not be exceeded.

63 Have they solved the issues of the aftermath?

64 The questions continue to be: Are we safe or not? Why doses of msv/year are permitted after an accident when doses above a dose limit of 1 msv/year were prohibited before the accident?

65 The 1 msv/y conundrum

66 Confusion with 1 msv/y (an old saga) Over the years there has been confusion over the meaning of the dose limit of 1mSv/y. 1 msv/y applies to doses from deliberate endeavors and, within these, from sources that can be controlled. 1 msv/y is lower than the dose from extant sources, many of which are natural sources that cannot be controlled. This position is not easily explainable! Extant doses do not necessarily justify adding doses from controllable sources. Is it proper to control these sources, even if their doses are less than the extant background doses? Does the extant background provide a basis to judge?

67 Application of the Commission's Recommendations to the Protection of People Living in Long-term Contaminated Areas After a Nuclear Accident or a Radiation Emergency. ICRP Publication 111. Ann. ICRP 39 (3).

68 ICRP 111 Dictum (bb) Past experience e.(bikini, Maralinga), nuclear accidents (Kyshtym, Palomares, Chernobyl),..(Goiânia) illustrates the potential importance of ingestion of contaminated foodstuffs eeas far as the setting of reference levels for existing exposure situationsee., past experience shows that typical dose values selected by authorities to manage such situations are close or equal to 1 msv/year, corresponding to the desire to progressively reduce long-term exposure to levels that are close or similar to situations considered normal, i.e within the band of constraints set for public exposure in planned situations.

69 Is 1 msv/y a logical dose limit? Namely, a border beyond which individual doses shall not pass under any circumstance?

70 No, 1 msv/y shall not be regarded as a border beyond which individual doses must not pass No logical arguments sustain this dogma. All over the world, people incur additional 1 msv/y (and more) by just changing the place where they live and nobody considers this as a radiation protection issue.

71 Is 1 msv/y a sensible value for restricting additional doses committed by individuals due to controllable endeavors, e.g., a continuously expanding activity?

72 Yes, 1 msv/y may be regarded as a sensible restriction for continuous activities committing people to radiation exposure If not, endeavors such as a massive expansion of the generation of nuclear electricity could become unsustainable.

73 Doses after 1 year of operation D 1 st year 2 nd year 3 rd year e. e e. n th year t 2 November,

74 Doses after 2 years of operation D 2 nd year 3 rd year 4 th year e. e 1 st e. year 2 nd year 3 rd year e. e e. n th year t 2 November,

75 Doses after 3 years of operation D 3 rd year 4 th year 2 nd 5 year th year 3 rd year 4 th year e. e. e e e. 1 st year 2 nd year 3 rd year e. e e. n th year t 2 November,

76 EQUILIBRIUM = first year committment 2 November, 2015 IRPA11: Sievert Lecture 76

77 Bo Lindell: Radiation and Man 1973 Sievert Lecture IRPA 3: Washington DC, USA IRPA11: Sievert Lecture 77

78 Tomorrow Today 2 November,

79 If today s nuclear electricity generation expands, in order to restrict future doses, it would be necessary to limit the doses committed over time by unit practice, i.e. to limit the collective dose commitment per unit energy of nuclear-electricity produced. 2 November,

80 For this purpose 1 msv/y would be a reasonable restriction Because it will imply a sensible control of a large expansion of nuclear power, whereby people would even in the long term not incur additional doses higher than a fraction of typically elevated background doses. 2 November,

81 However, this and other logical uses of a 1 msv/y dose restriction, should not imply that 1 msv/y is a demarcation between safe and unsafe!

82 The Future

83 If a problem persists, perhaps the problem is ourselves!

84 We need a bath of humility! The time is ripe to recognize that there is a problem with the myriads of: dose reference levels and Bq/m 3 s, e..and particularly with the 1 msv/y!

85 Errare humanum est, perseverare autem diabolicum (To err is human; to persist in committing such errors is of the devil)

86 We have to stop following classical routes. Science and society have changed and it is our obligation to respond to the demands of the people we want to protect. Wolfgang Weiss

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88 The radiological protection community has an ethical duty to learn from the lessons and resolve identified challenges. Before another large accident occurs, it should be ensured that: Radiation risk and potential effects are properly interpreted; e. Recommendations on public protection levels are consistent.... Acceptable contamination levels are clearly defined. ee Failures in fostering information sharing on protection policy after an accident is addressed with recommendations to minimize lapses in communication.

89 Challenging the status quo

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93 KBq/m

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97 Lognormal probability distribution of 134Cs + 137Cs activity concentration in mushrooms during the 12 months after the accident

98 Epilogue

99 A few humble suggestions to solve the conundrum

100 (1) Let us abandon the language stating that 1 msv/y is a dose limit

101 (2) State unambiguously that it is not scientifically feasible to attribute retrospectively health effects to doses of around 1mSv/y

102 (3) Explain why it is reasonable to restrict to 1 msv/y the additional committed doses from a continuously increasing activity, such as the generation of nuclear energy

103 (4) Unequivocally define protracted radiological aftermaths as extant exposure situations, namely a set of circumstances delivering low radiation exposures which are already in existence when a decision on control has to be taken.

104 (5) Search for international consensus for levels of activity that can be deemed to be safe without any further consideration and which, therefore, may be exempted from any regulatory control

105 I would like to share with you a basic doubt Is the dosimetric approach appropriate for extant situations of public exposure to low radiation doses?

106 A simple (rather than simplistic) proposal Exempt any situation where the activity density and concentration of 137 Cs are: < 100 KBq / m 2 < 0.1 KBq / Kg (Perhaps also include exemptions of: one order of magnitude less for 131 I and 90 Sr and two orders of magnitude less for 241 Am, 238 Pu and 239 Pu)

107 Communication! The radioactive cesium on land and in consumer products is lower than the international safe values of 100 KBq/m2 and 100 Bq/Kg. We confirm that THE SITUATION IS SAFE. (Hurrah!!!, 139 characters!!!!)

108 Av. del Libertador 8250 Buenos Aires, Argentina Thank you!