Re: UK Embassy in Tokyo - Advice for British nationals affected by Japan earthquake
Government Chief Scientific Adviser provides advice to UK Ambassador to Japan
19 March 2011
Sir John Beddington, Government Chief Scientific Adviser, spoke to Her Majesty's Ambassador to Japan David Warren, on the latest situation in Japan
Transcript of phone call (16.00 hours local time) 18 March.
Good morning everyone, this is David Warren at the Embassy in Tokyo. And thank you for joining us. Thank you also to Professor Beddington for giving us your time again. We had a word before this phone call and I explained there is continuing concern about the situation in Fukushima. We really appreciate your expert assessment, particularly in the light of the amendments to the
British Government Travel Advice asking residents to consider leaving Tokyo and the apparent adjustment therefore in the assessment of the potential health risk in Tokyo.
[Sir John Beddington: JB] Thank you for the opportunity. I wanted to start by clarifying what has changed since I last spoke to everyone at the Embassy and what is happening now.
When we last spoke, concerns were focused around the potential for a meltdown in the reactors. All the analysis we had and nobody is diasagreeing with this, was that the Japanese response to this issue was entirely proportionate. Even with the most unfavourable weather conditions, there were no concerns that radioactivity would reach Tokyo, in any amount to cause a serious health risk.
Since then, the situation has changed. The information we got relatively early on this week was that the ponds, which hold spent fuel rods, had been allowed to dry out, in particular the pond at reactor number four.
Now the problem with this is these ponds contain spent fuel rods and those rods are still highly radioactive. The worry that we had is that radiation could start coming out of these ponds, either through fires or minor explosions, generated by hydrogen gas being produced through reactions. And this would mean rather more radiation would be getting into the atmosphere than would have been the case with the reactors alone. So the ponds represent a really big change in the situation. So that was one of the reasons why we thought that it was important to be rather more precautionary, particularly in the area around the plant, and that was the reason for the suggestion and recommendation that has been adopted that we should go out to 80KM. We have discussed this approach with our scientific colleagues in America. We don't think that there is a massive danger, but we think it is entirely appropriate to be precautionary. You can see from the media reports that there is quite a lot of confusion about what's going on. So that is the first issue.
In terms of Tokyo, we were asked by the PM to look at what we would do if there was to be a really worst case scenario at the plant, coupled with very unfavourable weather conditions. And even in that worst case scenario, and I would emphasise that this is an extremely unlikely case, even if that happened the level of radiation around Tokyo would be extremely modest. Although there would be radiation increases, even in this extreme case, the effect on human health could be substantially mitigated by just taking very simple precautions. By essentially staying indoors whilst the plume of radiation passed over, not having your ventilation on, and keeping your windows closed. These measures would mitigate any significant risks to human health.
So that?s the current situation and I would emphasise again that this is assuming the most plausible worst case for the nuclear side of it, coupled with the most plausible worst case scenario for weather. Both are unlikely, and in the immediate future the weather forecast still has prevailing winds going out to sea. That is expected to continue until early next week & therefore immediate concerns can be allayed.
We are also working on a plan. If there is some form of release of radioactive material, we would know, and we would be able to monitor approximately how long it would take to reach Tokyo given the current weather conditions, typically 6 or 7 hours. Clearly for other conurbations nearer to the site, the time taken would be slightly less than that. Sendai for example is rather closer. And it will depend entirely then on the direction and speed of the wind.
So to sum up, the additional precautionary zone around the plant is in place as a precautionary measure, but we don?t really think there is a massive problem. In the same way, it is sensible to be precautionary in the context of other conurbations but even in the worst case scenarios we are not particularly worried about the actual human health risks. We think it is important to be precautionary, we have done that. We have looked at worst case scenarios & we?ve tried to analyse them. And can I also say we?ve shared these analyses with both our American and French Colleagues who are getting broadly the same sort of results.
[Q] I am not an expert but I?ve been told there is a difference between general radiation and contamination such as radioactive iodine in caesium and other materials. Most of what we?ve hearing about is general radiation. And I?m just wondering if there is any difference and are we just talking about radiation now, and if there is any more danger of contamination in Tokyo now. What the position is on that?
[JB] Basically the situation is the ponds contain a number of elements, for example Caesium. You will get different types of radioactive elements in any one radiation cloud so we?ve taken that into account in the advice that we?ve given. There is an issue about contamination of food & water supplies which I?m happy to deal with later, perhaps in answer to a particular question.
[Q] Given that initially, the reactor seemed to be contained after the earthquake, then we had the explosions. We now have what appears to be a precarious situation, albeit contained in the way that you described. How long do you foresee this situation continuing for?
[JB] The key issues is whether the Japanese can manage to gets sufficient water into, in particular the holding pond on reactor four, and can continue to get water into the other holding ponds where we understand there have been some water leakages. And in the case of the reactors, again it is the same story. We need to get adequate amounts of water in so they can keep cool. That is going to absolutely essential and we are obviously going to be monitoring the efforts that they are making in this case. In terms of when we can all relax, which I think is really the basis of your question, I would say the answer will be highly dependent on how successful the Japanese are at getting water into both the reactors and the ponds, to top them up. When we know that is happening in a reliable way then we can relax. In terms of the reactors there is obviously a cooling happening due to the natural decay of the radiation products so things will improve over time. I would think that in the order of just over a week, or maybe two weeks, we would have a much better idea of whether we are still in a situation where we have to worry or whether things have really settled down. There is obviously the enormous problem of clean up afterwards and that might take years.
[Q] Could we cover the point about contamination of food and water because that is an issue of serious concern for a lot of people here.
[JB] Very happy to. We posed the question to our colleagues in DEFRA and the Food Standards Agency in the UK. The basic message is quite clearly avoid all food from the region of the plant. Clearly given the scale of the devastation in that area, that consideration is very minor. The sort of ways in which the water could be contaminated depends on whether it?s ground water or from reservoirs. But in both cases, the normal sewage filtration processes would take out the enormous majority of any radioactivity so we don?t have any particular concerns. The Japanese authorities would obviously be monitoring the level of radiation in the water. And if this happened in the UK we are pretty certain the sewage system would deal with the problem.
Even after Chernobyl, and please note the risks after Chernobyl were significantly more dramatic and worrying, the risks for water were negligible because of the filtration process that goes into the normal water processing. Bottled water is not a problem at all. The overall risk from drinking tap water is nothing to do with radiation but obviously given the state, particularly in the North East of Japan, there will be real concerns about broken pipes and sewage and the associated microbiology. So it?s not the contamination of the water supplies by radiation but by bacteria which is of more concern and should be thought about. In terms of the food in the shops, anything that is packaged is no problem at all, but I think it would be unwise to eat food produced in gardens and allotments in the vicinity of the region, and anything left out in the open air, which is rare, should not be eaten. These are very much belt and braces recommendations. Anything in cartoon, tin, bottle or a box, is not a problem.
[Q] I?d like to clarify something you said the other day. You said you are focused on worst case scenarios and giving advice about those. I am trying to understand exactly what that is. You said the pond reactors dried up and then other reactors suffered problems, but there was no magnification in the radiation that might come to Tokyo. What we have been experiencing is explosions have taken place at the plant, and then they have pulled out their staff, and that in turn has caused many pumps to stop working or water to be stopped pouring. I am assuming that if another one of these reactors goes, they are going to pull everybody out and they won?t put people back in for a longer period. Which might make it more inevitable that all of the reactors will go? So am I correct?
[JB] The problem and why we are so concerned about pond 4 is that if pond 4 is allowed to dry up completely & some form of reaction occurs in pond 4, or even a fire, the radiation dosages that will be coming out would be rather hazardous and would certainly undermine any attempt by the authorities to mitigate that problem. Therefore there is the potential of this meaning that we can?t actually mitigate any problems with the other reactors or ponds. That is in fact how we have actually modelled what we have called the plausible worst case scenario. So your insight is correct.
The point about it is that it would occur over time, it?s not going to happen within hours. And we coupled that with a scenario which assumes the weather stays completely constant in one direction and manifestly that?s not going to be the case. So we think we are making extremely pessimistic assumptions.
[Supplementary Question] Just to clarify, you said the other day that even if the reactors were all to go, there would be no cumulative effect and the debris would only go up 500 meters into the air. Is that still your scenario?
[JB ] That?s the case for the reactors but the ponds are a different matter.
[Q ] If ponds are the issue now, which might lead to further radiation, is that because the debris would go up higher? Or what is it that the source of radiation is different?
[JB ] Both really. The point I made in the case of the reactor is that the reactor would melt down, if you failed to keep water in it to keep it cool. There would be a heating up of the core, the core could melt, radioactive material would fall to the bottom of the container vessel, react with concrete causing a build up and then an explosion. But that explosion would be short-lived, in the sense it would send material up to about 500m or so and the height that the radioactive material following such an explosion would be reduced very quickly. For the ponds, they are not going to send up material to that sort of height but will produce a longer and slower emission. It?s not an explosive emission but you could get minor explosions in the pond. It?s why I said the situation has really changed because of the concerns that have been raised about the ponds, particularly pond 4.
[Q]Your advice right now is to consider leaving. It?s not advice to actually leave. Is that unchanged? And secondly at what stage would you change that advice to advice to leave?
[JB] We have indicated what we think our worst case scenario is and we have indicated that you might consider leaving. I think the advice to consider leaving is obviously in part radiation related but there are obviously also other disruptions in the whole of Japan and that would obviously also be a factor in peoples? consideration. Certainly we are not at this stage advising people to leave because of radiation.
[Q] At what stage would you advise people to leave?
[JB] Obviously if our worst case analysis was wrong and we started to see significant emissions greater than we had actually anticipated in our worst case.
[Q] To clarify on contamination of food. Particularly related to your comments on fruit and vegetables grown in certain parts of Japan, and that it would be best to avoid them. I assume you are talking about in the aftermath of a serious emission of radiation, not at the moment, and could you clarify the area in Japan that it would be sensible to avoid?
[JB] I think the immediate vicinity of the plant although manifestly nobody is going to be producing fruit and vegetables out of there at the moment. And it would be in the context of a significant emission of radiation from either ponds or reactors. So, for example, eating a cabbage from your own gardens in Tokyo, you shouldn?t have to have any concerns what so ever.
[Q] Regarding worst case. Every time you have used the example worst case you have always qualified it with plausible. Is there is implausible worst case and what is that worst case?
[JB] Well of course there is an implausible worst case. So let?s take for example the weather. You could have gale force winds operating for a period of 10 days entirely in the direction of Tokyo & therefore carrying any radiation at lightening speed. That would be an implausible worst case. We?ve certainly assumed in our plausible worst case that all the concerns we have about ponds and reactors have actually occurred. In our plausible worst case we are assuming not all the reactors would blow up at the same time nor would all the ponds go up at the same time. That just seems to us to be implausible and therefore not sensible to model it.
[Q] In your current plausible scenario, do you factor in additional ponds where there are not really serious problems right now.
[JB] Yes
[Q] In the worst case, you are saying that the ponds will cause the problems. Assuming the Japanese are not going to actually tell us when that happens, how will we know that something?s actually happened. Is there going to be a massive explosion? Or is going to be a seepage of radiation that we?re going to hear about?
[JB] I think it would be very clear what has happened as there would be a series of small explosions and fires around the pond.
[Q] In a really worst case scenario, which you?ve said is highly unlikely, what levels of radiation might you expect at ground levels in Tokyo?
[JB] radiation will be at the level where you would be able to mitigate any significant human health risk just by taking simple precautions such as staying indoors when the plume is overhead.
[Q] How long would that plume last?
[JB] That depends on the weather conditions of course, but we?ve been assuming, again utterly worst case scenario, our exposure calculations on the basis of 48 hours continuous exposure out of doors.
[Q] You said you have discussions with opposite numbers in US and France. In that case I?m interested in why the French advice is very different. They are recommending nationals to leave. And they are moving their Embassy from Tokyo to Kyoto. Is that based on a difference of view about the science between you and your French counterpart?
[JB] Not as far as I?m aware.
[Q] Potassium Iodide. Should people living in Tokyo be taking this? And particularly perhaps for children and expectant mothers.
[JB] Obviously the need to take potassium iodide depends on the composition of any plume that is coming. Is there someone on the line from the Health Protection Agency (HPA) who could comment on in what circumstances you might take potassium Iodide?
[HPA] ? If we are looking at the worst case scenario then there would be radioactive iodine amongst the radio nuclides in the plume that came to Tokyo. And in that case it would be very sensible for children, pregnant women & nursing mothers to take potassium iodide because children?s thyroids are particularly sensitive to radioactive iodine. You have to take the tablet just before or soon after the plume goes over. If you take the tablet a long time before exposure then it would not do any good. There is no point in taking a tablet unless the worst case scenario happens. But if it does, because of the travel time of the plume to Tokyo there would be time for children to take the tablets, and they would completely block any uptake of radioactive iodine in the thyroid.
[JB] Really sorry. I?m going off to another meeting. Hope I?ve been able to answer most of the questions you have been concerned about. The situation has changed in the case of the ponds, we?re hopeful that the Japanese have been able to get water into those ponds, and obviously we?re monitoring this every day. And very shortly we are going to convene another meeting of SAGE (Scientific Advisory Group in Emergencies) whose membership includes nuclear experts, health experts and so on.
[Embassy] If people have other questions , the Embassy has offered to collect them and pass on Embassy contact ?
Sanae.Nakanishi@FCO.gov.uk
The Health Protection Agency has agreed to answer any health question directly - Questions by e-mail to
Mary.Morrey@HPA.org.uk
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