Disowning Fukushima: How Risk Assessments Erase Nuclear Accidents.

Transcription

1 Disowning Fukushima: How Risk Assessments Erase Nuclear Accidents. 1st INRAG Conference Vienna Apr John Downer

2 The Zero-risk mindset is a thing of the past. (?)

3 Fukushima s costs Unknown and contested, but potentially very severe fallout hazards. (Health & environmental). Enormous financial costs. (Japan Center for Economic Research, late 2011, estimates US$ billion). Heavy social burden (88,000 people evacuated. Most still in temporary housing. Many lost their employment.)

4 Cost-benefit analyses continue to ignore accidents

5 Site planners continue to cluster reactors in single locations

6 Evacuation / Resilience-planning remains inadequate & unrealistic.

7 Most nuclear construction plans continue

8 Why?

9 The 'zero-risk mentality' is justified, institutionally, by deterministic and probabilistic safety analyses.

10 The 'zero-risk mentality' is justified, institutionally, by deterministic and probabilistic safety analyses. eg: Areva assert that the likelihood of a core damage incident in its EPR is of the order of one incident (per reactor) every 1.6 million years.

11 There are compelling logical reasons to believe that nuclear reliability calculations cannot work

12 but these explanations are unnecessary, given the empirical evidence that nuclear reliability calculations do not work.

13 Nuclear plants fail far more often than expert assessments predict Fukushima (2011) (x3) Three Mile Island (1979) Chernobyl (1986) Historical failure rate of 1 in every 1,300-3,600 years (per reactor) Windscale (1957)

14 Question: Why hasn't Fukushima discredited nuclear risk assessment (in most countries)? (Why does the zero-risk mindset persist?)

15 Four narratives or defenses : 1. The interpretive defense: (The argument that the assessments did not actually fail). 2. The relevance defense: (The argument that the failure of one assessment is not relevant to the credibility of others). 3. The compliance defense: (The argument that the assessments were sound, but people did not obey the rules). 4. The redemption defense: (The argument that the assessments were flawed, but now they are fixed).

16 1. Interpretive: Experts can deny that the assessments (or the plant) actually failed. There are different ways to do this:

17 1. Interpretive: Experts can deny that the assessments (or the plant) actually failed. There are different ways to do this: Be economical with the truth. Parse the definition of failure. (eg: If accident is contained, then it is possible to say that the assessments took the failure into account.) Argue that the conditions faced by the plant were beyond its design basis. (ie: say that it wasn t designed to withstand an earthquake / tsunami of that magnitude).

18 1. Interpretive: Experts can deny that the assessments (or the plant) actually failed. There are different ways to do this: Be economical with the truth. Argue that the conditions faced by the plant were beyond its design basis. (ie: say that it wasn t designed to withstand an earthquake / tsunami of that magnitude). [Fukushima] could actually be considered a success given the scale of this natural disaster that had not been considered in the original design. ~American Nuclear Society (April 2011)

19 1. Interpretive: But The fact that Fukushima represents a technical failure is now unambiguous. The design basis of a nuclear plant is an essential element of any reliability assessment. (To say that an event was unexpected because it was beyond design basis, is to say that an essential element of the reliability calculation was wrong.)

20 2. Relevance: If accounts can show that Fukushima s (or, more widely, Japan s) risk calculations were significantly different from other such calculations, then the failings of those calculations can be theirs alone. Thus one can contest the relevance of the accident and its assessment by emphasizing differences between the failing system and others. eg: by highlighting the plant Using a plant built 40 years ago to argue against 21st-century power stations is like using the Hindenburg disaster to contend that modern air travel is unsafe. (George Monbiot, in The Guardian, 2011)

21 2. Relevance: If accounts can show that Fukushima s (or, more widely, Japan s) risk calculations were significantly different from other such calculations, then the failings of those calculations can be theirs alone. Thus one can contest the relevance of the accident and its assessment by emphasizing differences between the failing system and others. or the regulatory regime:

22 2. Relevance: But The fact that the technology is changing does not speak to the risk assessment. In many ways Japan s / TEPCO s procedural & regulatory failures mirror those of other regulatory regimes.

23 3. Compliance: It is possible to argue that the assessments were sound, but people did not obey the rules. All reliability assessments embody implicit and explicit caveats about compliance, such as: given proper maintenance, or if handled correctly. Thus it is possible to exculpate the assessments after a disaster by highlighting operator error, noncompliance, or malfeasance.

24 3. Compliance: But No complex socio-technical system in history has been able to eradicate all human failings, or provide adequate rules for every contingency. An assessment that fails to account adequately for humanerror/malfeasance/non-compliance is missing an essential variable.

25 4. Redemption: Experts can concede the existence of errors in the plant s reliability calculations and then argue that experts have identified the errors, altered the assessments, and remedied the problem. eg: 2012, NRC announced that US Nuclear safety assessments "...do not adequately weigh the risk of a single event that would knock out electricity from the grid and from emergency generators, as a quake and tsunami recently did in Japan". it then promised to reframe its assessments accordingly.

26 4. Redemption: But Who is to say there are not more errors hiding in the calculations? If the real lesson of Fukushima is that all reliability assessments can contain hidden flaws, then there can be no fix.

27 Recap: When the credibility of assessment practices is challenged by a disaster, it is possible to say: 1. The assessments are fine, this accident wasn t really a failure. (Interpretive defense) 2. Assessment practices (and plants, etc) differ, so the fact that one was wrong doesn t mean all are wrong. (Relevance defense) 3. The assessments are fine, but people failed to follow the rules. It will never happen again. (Compliance defense) 4. The assessments were wrong, but now they are correct. (Redemption defense)

28 Conclusion In focusing on the close lessons of Fukushima, public discourse is obscuring a larger lesson: that the safety of nuclear plants is not a property that can be predicted with objective rigor. A wider understanding of this would have significant ramifications for nuclear policymaking and scholarship.

29 Thank You For more see: Downer, J (2014) Disowning Fukushima: Managing the Credibility of Nuclear Reliability Assessment In The Wake Of Disaster In Regulation and Governance. Or john.downer@bristol.ac.uk