Fukushima nuclear accident studies

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Question:

What should we as environmental and health scientists do about the Fukushima accidents?

Answer:

There is an urgent need to do technical, environmental, and health studies in, around, and near Fukushima nuclear reactors that were damaged in the March 2011 earthquake and tsunami. The local officials, experts, and researchers are fully tied up with the practical work in helping people, preventing further damages, and cleaning the environment. Therefore, there should be an outside expert task force of Japanese and foreign researcher. This task force is not immediately involved in the emergency actions of the accident, and thus they have capacity to plan, design, and execute sample collection and research in the accident area. There is no time to wait for normal budgetary cycles of institutes, as the research actions must be started now, before the situation is over and signs of exposures have been cleaned up. We ask anyone who has the possibility and capability of participating to sign up. For instructions, see Contributing to Opasnet.


More important lessons by far can and must be learned from the nuclear power consequences of the Japanese earthquake than from all previous nuclear events combined. This research plan is based on an open letter by Matti Jantunen. [1]

Reactors & power plants

In Japan, 14 reactors were hit by the earthquake which fell within their design criteria, tsunami which exceeded their design criteria of 5 m by a factor of 2…4, and complete destruction of their external infrastructures, in particular power and transportation networks. I am not aware of how such destruction was included in their design criteria. Three of the affected reactors were in the Onagawa power plant (in operation since 1985…2002), closest to the epicentre, undamaged; 6 in Fukushima Dai-ichi, 3 severely damaged by the consequences (1971…76), and 3 closed down at the time of the earthquake (1978…79); 4 in Fukushima Dai-ni (1981…86), all safely closed down after the accident; and 1 in Tokai (1978), furthest away and also safely closed down.

The nuclear events in Japan mark the first by many dimensions:

  1. The accidents in Japan are the first caused by natural (earthquake and tsunami) environmental events, and destruction on the key external societal infrastructures; power and transportation networks and community support functions.
  2. …the first involving a significant number of reactors (BWRs) with their designs and constructions ranging from the late 1960’s up to 2002. At first look it appears that those completed after the Three Mile Island accident survived the earthquake and its consequences, those completed before failed.
  3. …the first simultaneously affecting a number of nuclear plants – and simultaneously with a major natural disaster – and, thus, stretching the national resources to the extreme.

The modelled events reflect what the modellers can imagine, are able and find useful to model. Real life events are always much richer in causes, impact pathways and consequences. This was certainly the case in TMI, Chernobyl and a number of smaller and less publicized events. The current Japanese events are far richer than all of the previous events combined, and also much more relevant for reactor safety and accident consequences than the Chernobyl accident which involved a very different reactor type (RBMK) of which only a few are in use and only in the former Soviet republics.

Research of the Japanese reactors affected by the earthquake, tsunami and infrastructure destruction should therefore involve all 14 reactors and focus on:

Concerning the impacts of the earthquake and tsunami, what and why failed, what and how could be safely recovered, why and how most reactors/plants survived, which safety systems remained functional and which failed, which changes and improvements required after TMI, after Chernobyl and/or for other reasons turned out valuable and which did not.

How the external societal infrastructure destruction was prepared for, what was included in such assessments and preparations and – again – what worked, what failed, what and how could be recovered after the failures.

How sufficient were the equipment/hardware, labour, expertise, management and leadership resources to deal with the crisis, what were the bottlenecks, how much and how could they be stretched (and trained as necessary) by involving e.g. firefighters, army personnel, foreign (e.g. the US Navy aircraft carriers) and international (IAEA, FAO, WHO) resources. What advantages and difficulties did these extensions bring on one hand in the form of capacity expansion, critical skills and knowledge, on the other in the form of training needs, communication problems, incompatibilities, etc.

The key purpose of these studies is to significantly broaden the scope and increase the accuracy and precision of nuclear risk predictions, help improve nuclear power safety as well as emergency preparedness and international co-operation in the case of severe nuclear reactor events.

Environment

Land environments

It appears that outside of the powerplant area and its immediate environment, the nuclear fallout deposition in Japan falls in the range of what was experienced in the Scandinavian countries after Chernobyl (avg/max I-131 levels 100/400 kBq/m2, and Cs-137+Cs-134 23/110 kBq/m2 in Southern and Central Finland, both max higher in Sweden). Of the low temperature evaporating compounds I-131 in the regions surrounding Fukushima is found at similar levels, Cs-134 & -137 lower relative to I-131. At this time (29.3.2011) it appears that in spite of some traces of Pu reflecting (Pu-238/Pu-239,-240 isotope ratio) fresh release, the non-volatile fallout which was created in the initial explosion of the Chernobyl reactor, is missing in Fukshima. From the Chernobyl reactor explosion these isotopes were released as actual fuel particles, characterised by Sr-89 & -90, Zr-95, Nb-95, Ba-140, Ce-141, Pu-239&-240, and deposited in significant concentrations (up to 40…60 kBq/m2, except lower, max 2 kBq/m2 for Sr and in the order of a few Bq/m2 for Pu) to Belorussia, Poland, Sweden and Finland after Chernobyl. (Jantunen et al. Health Phys 60(3) 1991, Reponen et al. J Environ Radioact 21 1993).

The research efforts in Japan should relate to the results of Chernobyl in Europe, and cover at least:

  • The final levels, distributions and composition of this fallout in the indoor and outdoor environments need to be studied and compared to the respective 1986 (and onwards) Chernobyl data from around Europe.
  • The decay of these levels (Cs-137 in particular) in the different indoor and outdoor (natural, rural/farming and urban environments) need to be followed through a sufficient number of years to establish respective environmental half lives (see Reponen et al. Health Phys 60(4) 1991). This information is critical for long term external exposure assessment.
  • Similarly, the levels need to be followed in farm products, wild freshwater fish, game and berries and compared to European post Chernobyl experience. This information, again, is critical for internal exposure assessment and management as deemed necessary.

Marine environments

The release of fission product radioactivity to the marine environments is – with possible exception of some underwater nuclear weapons test in the ‘50’s – uniquely high. For human exposure and risk the draining of most of the liberated radioactivity to the open sea – once it was unavoidably released – was a blessing rather than a curse. In the sea at large and in long term, its impacts are also likely to be small and transitional, considering the radiation absorption of water, dilution capacity of the sea and the overwhelming quantity of natural radioactivity contained in the seas. Locally and in a shorter term, however, the impacts fill be felt by the fishing industry due to the sea bottom deposition of the long lived Cs-isotopes for a period of time. The research should cover:

  • quantification of the total release into the sea,
  • determination of its dispersion, accumulation in sea bottom flora and fauna, as well as food chain/web mobility and accumulation in fish, whales, seals and marine birds, as well as possible biological and ecological impacts in those systems.
  • Similarly the levels of Cs-134&-137 should be studied and followed in the local seafood in the North-West coast of Japan, as well as down the ocean current carrying the radioisotopes further away.

The key purpose for all these studies should be to increase our understanding on land based – natural, farming and urban – and marine radioecology, and to provide high quality data for modelling. Therefore, concentration and deposition data should be always collected with all the supporting information essential for model development and testing, i.e. as complete inputs for existing and new models.

Health

The most immediate health effects which, if any, are likely to emerge are miscarriages in March-April-May of 2011, malformations (teratogenic) in babies that were fetuses in the critical time window of (from the top of my head 4..6 weeks) in the second half of March 2011 in the most affected area, and thyroid cancers of children and the whole population in the affected areas in the coming years.

The first study of miscarriages should include populations (i) exposed to both radiation and tsunami, (ii) to radiation but no tsunami, (iii) to tsunami but not radiation, and finally population s which (iv) were not exposed to either. The reason for this complexity is that radiation and the stress induced by the earthquake and tsunami may act independently and/or synergistically to induce miscarriages.

The teratogenic effect of high short term radiation exposure should be investigated by a strong study design based on a simultaneous time series study from e.g. one year before the accidents to 2 years after it in the impact area combined with a simultaneous time series in otherwise comparative areas in Japan, which were only exposed to background radiation levels. Such an effect was observed in the form of inceased Dow’s syndrome, which among the children born in January 1987 in Belarus was ca. two times (0.25%) the average level of the other months of 1981-92.

Individual level I-131 doses of children (and the general population) in regions/locations ranging from high to background deposition should be determined and their thyroid cancer incidence should be followed up for 10 years, possibly more, to duplicate the WHO study on the children’s elevated thyroid cancer levels in Belorussia after the Chernobyl accident.

In addition, longer term general cancer epidemiology study should be initiated with individual radiation dose evaluations – including both the short term peak exposure mostly caused by the short lived I-131 fallout and the long term elevated radiation exposure caused by Cs-134 & -137 fallout – and assessment of their other carcinogenic exposures and risk factors involving populations (i) exposed to both radiation and tsunami, (ii) to radiation but no tsunami, (iii) to tsunami but not radiation, and finally populations which (iv) were not exposed to either. The study should also involve the cleanup workers as a high exposure subgroup.

Stress and risk perception caused by the correct as well as false information about the Fukushima power plant damages and releases should be studied, again, separating between the populations (i) exposed to radiation, earthquake and tsunami, (ii) two of the three, (iii) one of the three, and finally populations which (iv) were not exposed to any of these. Such impacts are independent of actual radiation doses and likely to me more significant in terms of societal cost and citizens’ perceived well-being and health as they were in the populations affected by the Chernobyl accident. What makes the current situation of particular interest is the fact that three dramatic stress factors appeared in all possible combinations.

The purpose of these studies is to increase the scientific understanding of individual as well as public health impacts of high acute short term peak radiation dose as well as lower level long term elevated radiation exposure levels of severe light water reactor accidents, and also to analyse and compare the public health impacts of the psychosocial stress caused by both severe nuclear accidents and by natural disasters.

Why EU?

Japan has certainly the high quality scientific and technical experts to study any of these issues without external help. The reasons, why significant European resources, both research funding and manpower should be involved and involved soon are different and twofold:

  • The sheer quantity of the work that should be performed on a very broad front and with great urgency to ensure that all the new achievable scientific, technical, environmental and societal knowledge can be produced is overwhelming for the Japanese – or any country’s - resources. Such resources have been trained and budgeted for rather normal continuing needs, can certainly be expanded by overwork, refocusing of the activities, etc. but they cannot be multiplied in the matter of months in any country. Involving scientists and experts, who share common literature, conferences and societies and often personally know each other globally can multiply the resources, and, thus, the new information/knowledge and its benefits.
  • Such collaboration cannot begin too soon. Months and years after the events details begin to fade, vivid personal memories are modified by later emotions, own reasoning, explanations of the others and public truths, and the impacts and traces of the earthquake, tsunami and nuclear releases are cleaned away, repaired and decay.
  • The world outside Japan will learn much more, faster and more concretely from the events and its consequences in Japan by participating in the studies both locally and in common international research projects. Working on the spot with own hands and mind increases both knowledge and understanding much more thoroughly than reading papers and reports years later and thousands of kms away.

See also

Keywords

Nuclear energy, tsunami, earthquake, nuclear accident

References

  1. ↑ Matti Jantunen: Lessons to be learned from Fukushima for European nuclear risks & safety. Written in Paris, 29.3.2011 for THL and the European Commission.

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