Science Media Centre of Japan

Tohoku earthquake one year on – experts respond

kakubayashi — Mon, 12 Mar 2012 02:14:55 +0000

Ver.1.0 (Updated: 120316-13:00)

Feel free to use these quotes in your stories, but please read our notes at the bottom in regards to the information here.

If you have any questions, please don't hesitate to contact us.

On March 11 last year a magnitude 9.0 (Mw) earthquake hit off the coast of Japan triggering a powerful tsunami and resulting in the most serious nuclear accident since Chernobyl. Over 15,000 people were confirmed dead as the tsunami inundated a total area of approximately 561 km2 (217 sq mi) in Japan. A series of fires and explosions within the Fukushima Daiichi nuclear power station triggered a full meltdown in three reactors whilst a fourth was significantly damaged by fire. The Fukushima Daiichi nuclear disaster was rated as a level 7 (major accident) on the international nuclear and radiological event scale. Now, one year after the disastrous events unfolded, nuclear and disaster experts examine the current situation and what lessons can be learnt.

Below are comments from Australian experts provided by the Australian Science Media Centre. The collaboration between the Australian Science Media and the Science Media Centre of Japan is supported by the Commonwealth through the Australia-Japan Foundation which is part of the Department of Foreign Affairs and Trade.

Tony Irwin

Chartered Engineer and is a visiting lecturer for the Masters course in Nuclear Science at the ANU. Tony is the Chairman of the Engineers Australia Nuclear Engineering Panel

Tony worked for British Energy in the UK for more than thirty years commissioning and operating eight nuclear power reactors. Following the Chernobyl accident he was a member of a World Association of Nuclear Operators (WANO) mission that reviewed operating practices at Russian RMBK reactors. In 1999 he moved to Australia and joined the Australian Nuclear Science and Technology Organisation (ANSTO) and was Reactor Manager during the construction and operation of the OPAL research reactor; he retired from ANSTO in late 2009.

On the sequence of events:

We now have a better understanding of what happened:

Event Sequence – Key Events

Event	Reactor 1	Reactor 2	Reactor 3
Loss of all AC supplies	+ 51 mins	+ 54 mins	+ 52 mins
Loss of cooling	+ 1 hr	+ 70 hrs	+ 36 hrs
Water level drops to Top of Active Fuel (TAF)*	+3 hrs	+ 74 hrs	+ 40 hrs
Core damage*	+ 4 hrs	+ 77 hrs	+ 42 hrs
Fire pumps inject freshwater	+15 hrs	-	+ 43 hrs
Hydrogen explosion	+ 25 hrs Service floor	+ 87 hrs Suppression chamber	+ 68 hrs Service floor
Fire pumps inject seawater	+ 28 hrs	+ 77 hrs	+ 46 hrs
Off-site electrical supplies restored	+ 11-15 days
Freshwater cooling	+ 14-15 days

*Estimated source: Tony Irwin

- First core damage estimated to have occurred within 4 hours of the earthquake and reactors 1,2 and 3 cores largely melted within the first 3 days

- Hydrogen explosions caused the main damage and release of radioactivity

- Reactors stable within 2 weeks

On the Fukushima site today:

The four damaged reactors are in a stable cold shutdown state, cooled by water circulated through a treatment plant. Site clean-up, including removal of radioactive rubble, continues. A mid and long-term roadmap for the decommissioning of units 1-4 was issued in December 2011. Phase 1 prepares for the removal of spent fuel from the cooling ponds to commence by 2013. Phase 2 prepares for the removal of fuel debris from the reactor core to commence within 10 years. The final phase completes the decommissioning of the reactors in 30-40 years.

There are still over 100,000 people evacuated from Fukushima Prefecture. In the areas within the 20km evacuation zone with an annual radiation dose of <20mSv/year, it is expected that people will be allowed to return in March 2012. For higher radiation areas, remediation is required before restrictions are lifted by perhaps 2014.

On nuclear power in Japan today:

Before the accident, there were 54 reactors operating in Japan supplying 29% of the electricity demand. Since the accident, as reactors have been shut down for routine inspection (every 13 months) they have not been allowed to restart pending a comprehensive assessment of the response of individual reactors to extreme accidents (‘stress tests”). To date, the Japanese safety authorities have not approved the restart of any reactor.

As of March 2012, there are only 2 reactors operating. Japan trade deficit is at record levels as fuel imports have soared.

On the world situation:

The severity of the accident and the need to ensure reactor safety in extreme events was recognised worldwide. Germany took the political decision to immediately shutdown 8 old reactors, and all reactors by 2022. Most countries announced plans to continue with nuclear power and assess the safety of their reactors. For example, the UK has confirmed the safety of their existing nuclear power plants and has recently approved design certification for two types of new reactor to be built in the UK.

On lessons learnt:

Reactor cooling is essential and must be maintained irrespective of external conditions. Modern reactors, for example the Westinghouse AP-1000 have passive cooling systems that require no external supplies and would have survived even this severe accident. The safety of existing reactors is being assessed to ensure they have diverse and physically separated cooling systems and electrical supplies.

Dr Pradip Deb

Senior Lecturer in Medical Radiations at RMIT University

The Fukushima Daiichi accident has been one of the two major accidents in the international nuclear and radiological event scale (INES) in the last twenty five years (the other one was Chernobyl). The latest IAEA (international atomic energy agency) status report shows that the estimated external doses to the public from the cities within 20 kilometres from Fukushima Daiichi reactors are within the acceptance level for the public (1 mSv). Food monitoring data shows that in more than 99% samples (based on 14344 samples) the radioactive caesium and iodine isotopes (Cs-137 & Cs-134 and I-131) are within the acceptance level.

It is not practical to say that the world should be free of nuclear power. The next generation power reactors will be safer. The lesson we have learnt again is that it is radiophobia that harms us psychologically more than actual radiation doses do. Not only in the developing countries, but also in the technologically advanced countries, people are likely to believe unscientific reasoning about the effects of radiations. Topics of Radiation physics are currently not included in the school curriculum in most of the countries in the world, not even in Japan. To reduce radiophobia, the radioactivity and their effects should be understood by the general public. One way to make the public more trusting of radiation issues is teaching radiation physics starting from the school level science education.

Professor James Goff

Director of the Australia-Pacific Tsunami Research Centre and Natural Hazards Research Laboratory, University of New South Wales

Tsunami comment

A year on from the 2011 Tohoku tsunami and we are still asking questions, more than we have answers to. I have been invited by Tohoku University in Sendai to attend a special ‘One-year Memorial of the 2011 Tohoku Earthquake and Tsunami Disaster’. This will happen on the same day as a ‘Forum for International Research Collaboration’. This will be the fourth visit by people from our centre. First in May to carry out some of the earliest international research on the tsunami – how big it was, what it left behind and so on. We visited again in August to revisit this work and to see how things had changed. Currently a member of our team, Dr Catherine Chague-Goff, is also on a Visiting Professorship to the University of Hokkaido. Why so much commitment? Essentially because we want to help the Japanese to understand the 2011 event, its precursors and other events in the region. However, we are also committed to helping our Japanese colleagues. Our centre has skills that the Japanese are interested in exploring and we are keen to work in collaboration with them to make this happen.

What have we learnt so far? Well, one of the more interesting finds in that for nearly 50% of its inundation distance inland the tsunami left almost no sand deposit, just mud and debris. Who cares? Well, if you are looking at how big and how often these events have happened in the past – you need to look for more than just the sand or else you might under-estimate things. Hence the interest in our work and what we have done elsewhere. We have also learnt a lot about the longer term after effects of these events. What one might call the ‘what are things like on the ground one year on’. Yes, much of the debris has been being cleared up, yes much of the evidence of destruction has been erased by diggers and work crews, but what seems a minor point is starting to become an issue – there is still a vast amount of salt in the soil and rice doesn’t like salt – and so in these places crops are hard to grow. There are implications here for long term recovery. Add to this things such as the loss of communities, poor roads, contaminated land and the sheer enormity of the devastated area and you can see that there is no simple fix.

We are returning to Sendai again to start putting the 2011 events in context. We really do need to know how big and how often these events occur because we don’t want to under-estimate the next one, not just in Sendai but for the whole of Japan. We also want to take these lessons with us to the rest of the Pacific so that we can do a better job there as well. Whether we can achieve this quickly or not remains to be seen. We all still have lots to learn.

【Notes】

・ The Science Media Centre of Japan (SMCJ) is an independent, non-profit group for the news media, giving journalists access to evidence-based science and expertise.

・ Regardless of the medium, we welcome our material to be used by journalists who want to make scientific views heard in society.

・ The views expressed in this post are those of the individuals and organisations indicated and do not reflect the views of the SMC or its employees.

・ The SMCJ sends such information to those registered on our mailing list. To sign up, please click on the link below.

（Please be warned that registration involves giving us some information about yourself. Those who we think are not real journalists may be denied access to our mailing list. This is to prevent our information from being abused, and we ask for your understanding. However, considering the emergency we are in now, we have decided to put up all of our information publicly on this website)

　　【Journalist Registration】Please contact us from HERE

【About this article】

○ Feel free to use these quotes in your stories.

○ In terms of crediting the SMCJ (optional), we would ask you to name is as one of the following:

  -Science Media Centre of Japan

  -SMCJ

  -SMC-Japan.org

○ When sharing links, we ask that you please use: http://www.smc-japan.org

【Contact us】

○ Please contact the SMCJ with your comments on our service at:

   Science Media Centre of Japan (Corp)

　　Tel: +81-3-3202-2514

Fax: +81-3-3202-2497

　　E-mail: smc[at]smc-japan.org

BACKGROUND BRIEFING: Fukushima – one year on

kakubayashi — Fri, 09 Mar 2012 11:09:58 +0000

Feel free to use these quotes in your stories, but please read our notes at the bottom in regards to the information here.

If you have any questions, please don't hesitate to contact us.

ONLINE BRIEFING: 10.00am AEDT Tue 6 March

March 11th marks one year since the devastating Tohoku earthquake, tsunami and associated nuclear incidents. We’ve asked several experts to give an update on everything from the current situation on the ground to future nuclear power plant designs, tsunami-proofability and whether experts think that nuclear power has a future.

On 6 March the Australian Science Media Centre hosted an online briefing on this issue. Listen in to the briefing to hear from Japanese, UK and Australian nuclear and tsunami experts and ask questions such as:

- What is the situation on the ground at the nuclear reactor?

- What have we learnt and can we stop it from happening again?

- When can the hundreds of thousands of evacuated residents in Fukushima return home?

- What are the implications for the nuclear power industry worldwide?

- How is the tsunami recovery going?

- Can we become tsunami-proof in the future?

A recording of the briefing is available here.

The collaboration between the Australian Science Media and the Science Media Centre of Japan is supported by the Commonwealth through the Australia-Japan Foundation which is part of the Department of Foreign Affairs and Trade.

SPEAKERS

- Prof James Goff

Director of the Australia-Pacific Tsunami Research Centre and Natural Hazards Research Laboratory at the University of New South Wales and will be in Japan from March 10 for the opening of the International Disaster Prevention Centre at Tohoku University.

- Dr Tetsuo Sawada

Research Laboratory for Nuclear Reactors Energy Engineering, Tokyo Institute of Technology. He’ll be joining us from Japan.

- Prof Richard Wakeford

Professor Epidemiology, Visiting Professor at the Dalton Nuclear Institute at the University of Manchester. Richard was a speaker at the International Expert Symposium in Fukushima – Radiation and Health Risks held last year and was in Japan last week for the International Symposium on the Natural Radiation Exposures and Low Dose Radiation Epidemiological Studies. He worked for British Nuclear Fuels Ltd for almost 30 years until 2006. He'll be joining us from the UK.

- Mr Tony Irwin

Chartered Engineer and Visiting Lecturer for the Masters course in Nuclear Science at the ANU. Tony is the Chairman of the Engineers Australia Nuclear Engineering Panel. Tony worked for British Energy in the UK for more than thirty years commissioning and operating eight nuclear power reactors. Following the Chernobyl accident he was a member of a World Association of Nuclear Operators (WANO) mission that reviewed operating practices at Russian RMBK reactors. In 1999 he moved to Australia and joined the Australian Nuclear Science and Technology Organisation (ANSTO) and was Reactor Manager during the construction and operation of the OPAL research reactor; he retired from ANSTO in late 2009.

- Q&A session

【Notes】

・ The Science Media Centre of Japan (SMCJ) is an independent, non-profit group for the news media, giving journalists access to evidence-based science and expertise.

・ Regardless of the medium, we welcome our material to be used by journalists who want to make scientific views heard in society.

・ The views expressed in this post are those of the individuals and organisations indicated and do not reflect the views of the SMC or its employees.

・ The SMCJ sends such information to those registered on our mailing list. To sign up, please click on the link below.

（Please be warned that registration involves giving us some information about yourself. Those who we think are not real journalists may be denied access to our mailing list. This is to prevent our information from being abused, and we ask for your understanding. However, considering the emergency we are in now, we have decided to put up all of our information publicly on this website)

　　【Journalist Registration】Please contact us from HERE

【About this article】

○ Feel free to use these quotes in your stories.

○ In terms of crediting the SMCJ (optional), we would ask you to name is as one of the following:

  -Science Media Centre of Japan

  -SMCJ

  -SMC-Japan.org

○ When sharing links, we ask that you please use: http://www.smc-japan.org

【Contact us】

○ Please contact the SMCJ with your comments on our service at:

   Science Media Centre of Japan (Corp)

　　Tel: +81-3-3202-2514

Fax: +81-3-3202-2497

　　E-mail: smc[at]smc-japan.org

Fukushima one year on – experts respond

kakubayashi — Fri, 09 Mar 2012 10:31:43 +0000

Ver.1.0 (Updated: 120309-19:30)

Feel free to use these quotes in your stories, but please read our notes at the bottom in regards to the information here.

If you have any questions, please don't hesitate to contact us.

Dr Don Higson

Retired nuclear safety specialist and Fellow of the Institution of Engineers Australia, Fellow of the Australasian Radiation Protection Society

On Engineering

At Fukushima Daiichi, the reactors shut-down safely when struck by the fourth largest earthquake ever recorded. The nuclear emergency was due entirely to loss of on-site power supplies when the power station was inundated by a much larger tsunami than had been anticipated in its design. Clearly, the design of nuclear plants against the risk of flooding needs to be brought up to the level of design against seismic risk.

On the health effects

Rating the nuclear accident at Fukushima as 7 on the International Nuclear Event Scale (INES) has given the misleading impression that it was as bad as the Chernobyl accident. At Fukushima, no physical health effects of radiation have been observed among the general public and effects on workers have been far lower than those at Chernobyl. The INES was meant to aid public understanding of nuclear safety but has, in fact, made it more confused. The INES should be substantially modified or scrapped.

As at Chernobyl, the major public health effect of the Fukushima accident has been psychological, due to the forced relocation of population and exaggerated fears about radiation. In such circumstances, the public must be evacuated from the area as a precaution when it is not known how the situation will develop. However, they would be better off being allowed to return to their homes once it is certain that the situation is under control and that potential exposure levels are no greater than 20 mSv/y. Many people in the world are exposed naturally to higher levels of radiation than this without discernible adverse health effects. It is counterproductive to behave as though 20 mSv/y is a dangerous dose rate.

On the safety of nuclear power

Outside the former USSR, the nuclear industry continues to be one of the safest industries in which to work and the safest way to generate most of the electricity the world needs.

Dr John Price

Currently a consulting engineer. He was a member of the Safety Policy Unit of the National Nuclear Corporation UK where he studied major nuclear power accidents

After the Three Mile Island Accident of 1978, people like me who advocated nuclear power said two things about that incident: the safety systems at the station had contained the radiation and that ‘lessons had been learnt’. What Fukushima demonstrates is that no lessons are ever really learnt. These lessons are many and deep. As an example, there was a very practical lesson from Three Mile Island. Once the fuel cladding overheats, the zirconium metal in the cladding reacts with water to produce hydrogen gas.

The appearance of hydrogen gas during the accident at Three Mile Island caused major alarm, though in the end no damage. So why was no lesson learnt? At Fukushima the buildings of reactors 1 and 3 actually exploded violently while the world watched on television. Unit 2 also probably had a hydrogen explosion inside its containment and this may have caused leaks. Why, given the events of 1978, were the plants at Fukushima, and indeed nuclear plants worldwide, not fitted with the fairly simple means of dispersing hydrogen gas to prevent explosion?

I regard the damage caused by the hydrogen explosions to be the main reasons why recovery from the Accident at Fukushima will take a much, much longer time than some suggest. In a statement that went viral around the world in the week of the Fukushima accident, I said that clean-up will take 50 to 100 years. I still think this is the likely timeframe.

There have been other, more fundamental lessons which were not learnt. Can there ever be proper regulation of Nuclear Power, or indeed any other major risk? Are not the regulators always part of the cause of the accident? For non-nuclear examples, think of the Gulf of Mexico oil spill. Think of situations where people are permitted to build cities in areas subject to Tsunami. Think of recent financial crises. Whoever authorises something also has responsibility for its consequences. They own the benefits and they own the disasters.

Once the plant was agreed to be built, there were many bargains struck between the Japanese regulatory authorities and Tepco, the owner of the Fukushima plant. No matter which government department had been the regulator, no matter how independent the regulator might have wanted to be, compromises had to be made.

Here are some questions which we might hope should have been asked during regular licensing discussions:

· What emergency equipment should be provided for accidents beyond the design basis of the original design?

· What was to be the size of the Tsunami protection?

· Should Fukushima Units 1-4 have been operating in 2011?

All of these questions have associated major costs, whatever the answers. In each of these discussions, the regulator would want more and more expensive things, and Tepco would seek a financially possible compromise.

The last question, as to whether Daiichi 1-4 should have been operating in 2011, seems to have the easiest answer. No. It was an old superseded plant, in the wrong place. Fukushima Daiichi Unit 1 started operation in 1971 using 1960s designs. Units 2 to 4 also used the same design, though they are slightly larger. By the late 1970s, the designer of this type of plant, GE of USA, had already replaced Daiichi’s Mark 1 design of reactor with a design that they said was safer. By the 1990s even safer plants were being offered.

In retrospect, the decision as to whether the units should have had their licenses extended seems reasonably easy for Japan in the 1990s. Replacement could have been planned, new and safer plants could have been built. And nuclear energy would still be fulfilling its promise for Japan. Instead, a different decision was made. They fitted new tyres to their 1971 banger rather than buying the newer and much safer model. I assume that we will eventually find out what happened during regulatory discussions about the Daiichi plants in the 1990s. Whatever did happen in these discussions, the wrong decision was made for Japan, and for the world.

【Notes】

・ The Science Media Centre of Japan (SMCJ) is an independent, non-profit group for the news media, giving journalists access to evidence-based science and expertise.

・ Regardless of the medium, we welcome our material to be used by journalists who want to make scientific views heard in society.

・ The views expressed in this post are those of the individuals and organisations indicated and do not reflect the views of the SMC or its employees.

・ The SMCJ sends such information to those registered on our mailing list. To sign up, please click on the link below.

（Please be warned that registration involves giving us some information about yourself. Those who we think are not real journalists may be denied access to our mailing list. This is to prevent our information from being abused, and we ask for your understanding. However, considering the emergency we are in now, we have decided to put up all of our information publicly on this website)

　　【Journalist Registration】Please contact us from HERE

【About this article】

○ Feel free to use these quotes in your stories.

○ In terms of crediting the SMCJ (optional), we would ask you to name is as one of the following:

  -Science Media Centre of Japan

  -SMCJ

  -SMC-Japan.org

○ When sharing links, we ask that you please use: http://www.smc-japan.org

【Contact us】

○ Please contact the SMCJ with your comments on our service at:

   Science Media Centre of Japan (Corp)

　　Tel: +81-3-3202-2514

Fax: +81-3-3202-2497

　　E-mail: smc[at]smc-japan.org

Fukushima one year on – Japanese experts respond

kakubayashi — Fri, 09 Mar 2012 10:14:42 +0000

Ver.1.0 (Updated: 120309-19:00)

Feel free to use these quotes in your stories, but please read our notes at the bottom in regards to the information here.

If you have any questions, please don't hesitate to contact us.

Below are comments from Japanese experts provided by the Science Media Centre of Japan and translated into English by Translationz. The collaboration between the Australian Science Media and the Science Media Centre of Japan is supported by the Commonwealth through the Australia-Japan Foundation which is part of the Department of Foreign Affairs and Trade.

Tatsujiro Suzuki

Vice-Chairman of the Atomic Energy Commission in the Japanese Cabinet office

The present circumstances assure that Fukushima Daiichi is remarkably stable. However, the condition of the reactor core is not understood and there are still many mysteries about the nuclear reactor.

At present the main concern is the radioactive material being discharged in large quantities into the air. However, I think that this is a short-term concern. I feel as a future prospect, the treatment of contaminated water being generated in large quantities would be more important. The water is being processed; it however is not decreasing. The people at Fukushima Nuclear Power Plant are suffering a lot due to this. The influx has already entered the sea. Effort is being made to build a fence, however this would take time. Groundwater is flowing under the power plant; hence one has to keep watch on underground penetration. In the case of the contaminated water, a liquid waste disposal process has to be set up as it is a high level radioactive waste.

Robots started operating at the power plant a few days ago. However, in the long run, measures have to be taken against the discharge of nuclear fuel. According to an expert of the Atomic Energy Commission, it would take around 30 years for the complete containment of the Fukushima Daiichi accident. There are many matters which have not been experienced so far. Atomic energy experts as well as the best brains from the world over must come together to find the solution to this problem. The government is working towards forming such a system.

When we talk about the area outside the nuclear power plant, the contamination is spreading and a feeling of insecurity has developed amongst the citizens. Hence I think it is necessary that the government and the power company should have a deep sense of responsibility and should search their conscience. I think that the contamination outside the nuclear plant would not affect the health of the citizens. I, however, am extremely sorry that the entire country has fallen into despair due to this.

The government now is trying its best for decontamination. First of all, it is important to provide accurate information for monitoring. Disbelief still exists in the figures provided by the government. The government is putting in effort, but there might be problems in the approaches adopted. The style of communication is bad, the efficiency is poor, the process is not well designed; hence the residents are not feeling relaxed as yet. ICRP is also stating that the residents should be taken into confidence and then decisions should be made together. However the scene has not yet changed. Things are decided by the scientists all by themselves and then they are simply conveyed. The decision making process is not convincing. Therefore there exists a sense of distrust. And this has to be changed.

In the case of decontamination, the standards for external exposure (to radiation) have been set. The annual external exposure of any area should be less than 20mSv. If this isn't the case, people are not permitted to live there. However if it is less than the set standard, the residents can return to their homes. Hence, in the short run it is important that the areas with external exposure of 1~20mSv are decontaminated and made available for the residents. At present, data collection for decontamination has been stopped. It would, however, being full scale from April. As far as decontamination is concerned, there are challenging topics such as the hot spots (the area where the radiation dose is high locally) being jumbled up and the contamination levels desired by the agricultural people and those desired by the common man are different etc. Normally, monitoring is required to be done along with the residents before the decontamination. However it could not be done in this case. In addition, the present grid of monitoring is oversized. If possible it should be done within 100 meter ×100 meter. Even this is not feasible due to shortage of manpower. We would like to collaborate with various people and find out the best approach.

In the long run, it is necessary to differentiate between areas where residents can return and those where they cannot. This should be done at the earliest possible time. However, this needs a political decision. The residents build up expectations when the scientists state that “decontamination is possible”. However the areas where residents cannot return need to be clearly decided with the judgment of experts.

In addition, the citizens have a sense of distrust concerning the safety of other nuclear power plants. This was a tsunami and earthquake beyond the control of the safety standards. Hence now new standards should be created which would factor in such disasters. And the nuclear power plants must comply with these new standards. It is very difficult to create new safety standards in a short time span. Therefore, a stress test needs to be conducted. It seems that easy-to-follow restart criteria are not yet given. I think it is not necessary from an energy demand and supply point of view. However, if a new regulatory agency is formed then it would specify the standards of restart for the nuclear plants which are not operational at present. The new regulatory agency would do its best to convince the residents and make the nuclear plant operational.

Future energy policy of Japan

As far as energy policy is concerned, in the short run, the demand and supply measures for this summer must be formulated. Relevant data is now being collected. Investigations are also being made on the assumption that electricity generated using nuclear power would be zero. In the long run, the only decision that has been made is that dependency on nuclear power plants would be reduced. Discussion over the future energy mix is not clear. The government has promised that it would provide the alternatives by this spring and things would get decided with a national debate in summer. As national debate is a new concept, it would require cooperation from the government as well as the entire nation including experts from various fields. We need to urgently find a process which would convince everyone that “The decision was taken after a debate”.A significant philosophy needs to be formed to decide the energy mix with certain standards, as a society. I think apart from the debates by the government commission, it would be better if the debates are done everywhere and communicated to the government at the end.

※ SMCJ Comment: Tatsujiro Suzuki was associated with sociological studies of science and technology through technology assessment research. He is also active in interaction with the society. Hence, in Japanese organizations where there is a strong tendency of confining issues bureaucratically, he is considered as a significant spokesman of Cabinet office Atomic Energy Commission.

Assistant Professor Hiroaki Koide

Kyoto University Research Reactor Institute

Things which have been learnt one year after the Fukushima disaster

We’ve realized that we don't know anything. If the accident was at a thermal power plant, it would have been possible to inspect the actual accident site and find out the details. However, in the case of a nuclear power plant disaster it is not possible as there are radioactive materials. The people who were promoting nuclear power generation so far say that the disaster was “unanticipated". As the accident was unanticipated, the measuring devices required to investigate the cause of the disaster are also not installed. Furthermore, the so-called measuring devices which were installed have broken down. It is of utmost importance to know the whereabouts of the nuclear fuel, and the melted reactor core. These facts however are not known.

Future prospects

If we talk about the scene at the nuclear plant, then the problem is that we don't know the extent the melted reactor core would spread to. It would be important to know the kind of measures that would have to be taken to prevent the spread of the contamination. If the melted reactor core drips underground and comes in contact with groundwater, radioactive material would spread in the environment. Therefore, it is important to set up barriers beforehand and prevent such contact.

Another problem is the spent nuclear fuel in the pool. Daiichi reactor 4 has been badly damaged. Efforts should be made to prevent further damage to this pool. This, however, is difficult due to frequent aftershocks and the high radiological dose levels. In the event of a big aftershock and the pool breaking down, the spent nuclear fuel would spread in the environment in the absence of a barrier. The workers have already started clearing up the debris. Moreover TEPCO might be looking at this problem as a top priority.

※ SMCJ Comment: Hiroaki Koide is considered by the Japanese media to be a pioneer among the experts who have adopted a stance supporting denuclearization. He has mentioned his stance in a well-known Japanese national daily as well as in weekly magazines. He is in the limelight in the alternative media.

Assistant Professor Tetsuo Sawada

Research Laboratory for Nuclear Reactors Energy Engineering at the Tokyo Institute of Technology

Various events occurred within a week of the disaster. If the systems before the disaster are compared with those afterwards, does it develop as expected? If the condition of the reactor core is taken into account, then the fuel of the reactor cores is damaged from Daiichi reactor 1 to Daiichi reactor 3. And a significant proportion of the core fuel has melted. It is not very clear about the exact quantity of the core fuel that is damaged and whether it has spread in the furnace. There is a possibility that some fuel might have leaked out of the containment vessel and some quantity has melted. I think there is no marked change according to the circumstances reported by the Tokyo Electric Power Company (TEPCO) a few days after the Fukushima disaster. For example, if Daiichi reactor 1 is taken into consideration, then it is not clear whether the percentage of the core fuel that has melted is 70 or 100.

The problem of contamination and decontamination of any region due to radioactive material is a serious issue. It has been confirmed that in late March radioactive material was dispersed in areas including Itate, Fukushima Prefecture. The quantity of the discharged radioactive material and the dispersed radioactive material distribution has not changed a lot since then. Major emission into the environment stopped immediately after the disaster. However, the problem is coping with the substances that have already been discharged. Air dose rate observed in Minamisoma and Itate has not yet reduced. The matter has become serious as the circumstances are very difficult to comprehend and deal with. And it can be said that now the seriousness of the matter has increased from last March-April.

There is one more point which needs to be considered seriously. Areas within a 20-kilometere radius of the plant have been left uninhabited. This area was declared as a 'no-go’ zone. However, this area has been neglected over the past year. The rubble caused by the tsunami and the wreckages of houses due to the earthquake etc. are all lying untouched. If the situation continues like this then there would be much deterioration and decay. Furthermore, if there is new vegetation growth then it would advance the immobilization of the radioactive material. It has been also heard from the residents who have returned that the circumstances are getting worse due to the stand adopted.How does one process and control the radioactive material that has been discharged into the environment? How can the people from the affected area cope with the radioactive material? These issues are very important. However, their solution is difficult. There was some information available from the knowledge gained following the Chernobyl accident, regarding the discharge of cesium in large quantities. However, I now comprehend the present circumstances and their gravity, after my frequent visits to Minamisoma and Itate, listening to the tales of residents after the actual discharge. It can be said that even my thoughts have changed.

An atomic energy regulatory agency is to be established in April. It seems that though the organizational structure of the agency would change, the content would be almost the same. I, however, am not clear as to how it should be. Neither am I in a position to comment on it. The future concern is the measures for the Daini power plant. There are frequent big earthquakes in this area following the earthquake in Sumatra in 2004. The possibility of a future earthquake of the same magnitude and that could possibly lead to a tsunami also exist. If such a situation occurs then the Fukushima power plant will become even more compromised. The circulatory system of the cooling pool of the reactors need to be maintained. It is necessary to have preventive measures in order to maintain the present cold shutdown, just in case something else goes wrong.

Lastly, there is another concern regarding the water shielding wall. At first, there was a situation when the water accumulated in the reactor building and the trench would not lessen even after being pumped out. The chances of groundwater leakage have been stated. Therefore it was decided to build a water shielding wall as a temporary measure. Since it would cost approximately 100 billion yen to build it, TEPCO took the stance that it would only build it if it got support from the Government. As a result the plan was cancelled. Even at this point in time, the relation between the groundwater flowing under the power plant and the water flowing outside it is not known. There might not be a leakage of contaminated water on a large scale. The question of quantity remains. I think there is a possibility of leakage being present at the moment.

※ SMCJ Comment: Tetsuo Sawada faced the media as an expert after the earthquake disaster and tried to explain the situation. As a result, he became popular as 'a scholar beholden to the government' on the Internet. However, at present, as one of the founders of the Minna-no (Everybody's) Energy and Environment Conference (MEEC, http://www.meec.jp/ (only in Japanese), he is participating in a debate for social decision making regarding future energy policies including alternative energy.

【Notes】

・ The Science Media Centre of Japan (SMCJ) is an independent, non-profit group for the news media, giving journalists access to evidence-based science and expertise.

・ Regardless of the medium, we welcome our material to be used by journalists who want to make scientific views heard in society.

・ The views expressed in this post are those of the individuals and organisations indicated and do not reflect the views of the SMC or its employees.

・ The SMCJ sends such information to those registered on our mailing list. To sign up, please click on the link below.

（Please be warned that registration involves giving us some information about yourself. Those who we think are not real journalists may be denied access to our mailing list. This is to prevent our information from being abused, and we ask for your understanding. However, considering the emergency we are in now, we have decided to put up all of our information publicly on this website)

　　【Journalist Registration】Please contact us from HERE

【About this article】

○ Feel free to use these quotes in your stories.

○ In terms of crediting the SMCJ (optional), we would ask you to name is as one of the following:

  -Science Media Centre of Japan

  -SMCJ

  -SMC-Japan.org

○ When sharing links, we ask that you please use: http://www.smc-japan.org

【Contact us】

○ Please contact the SMCJ with your comments on our service at:

   Science Media Centre of Japan (Corp)

　　Tel: +81-3-3202-2514

Fax: +81-3-3202-2497

　　E-mail: smc[at]smc-japan.org

Can computer models based on fundamental laws assist the treatment for cancers?

kakubayashi — Fri, 25 Nov 2011 06:11:58 +0000

Ver.1.0 (Updated: 111125-12:00)

Feel free to use these quotes in your stories, but please read our notes at the bottom in regards to the information here.

If you have any questions, please don't hesitate to contact us.

Over the last decade, scientists have been intensely investigating on TRAIL, a protein released by our immune system, to treat malignant cancers. The benefit of using TRAIL, as compared to conventional chemo- or radio- therapies, is that it specifically destroys carcinomas without affecting the surrounding normal tissues. This is done through a mechanism known as the programmed cell death or apoptosis. However, the TRAIL-based treatments so far have not been overtly successful as many carcinomas are able to ‘cheat’ the death signal, triggered by the TRAIL, into a survival signal.

A team of scientists from the Keio University in Japan has formulated a method using a computational model and, with its aid, predicts a novel target that would in return cheat the cancer cells to switch from survival to apoptosis mode. The work of Dr. Kumar Selvarajoo and colleagues, utilizing the fundamental physical law of conservation, pinpoints an intracellular target, whose removal reroutes most of the resultant signaling flux of TRAIL into a predetermined direction along the caspases-induced death pathway. Their findings are published in Scientific Reports, a newly launched journal of the Nature Publishing Group.

Paper: Vincent Piras, Kentaro Hayashi, Masaru Tomita, and Kumar Selvarajoo. "Enhancing apoptosis in TRAIL-resistant cancer cells using fundamental response rules", Scientific Reports, November 07, 2011. click here for link.

Dr. Kumar Selvarajoo

Assistant Professor, Institute for Advanced Bioscience, Keio University, Japan

* Dr. Selvarajoo is team leader for the research

Cancer biologists focus either to suppress the cell survival pathways or to enhance the apoptosis mechanisms independently. We felt a systemic approach considering both processes at the same time is necessary. Our previous experience working on the Toll-like receptor signaling models, based on fundamental physical rules, helped us to identify a target at the crossroad of the survival and apoptosis pathways in TRAIL signaling.The scientists predict that a novel molecule interacting with p62 could be a crucial target for enhancing apoptosis of TRAIL-resistant cancer.

Although we suggest this, experimental validation is required for final confirmation as a next step. Nevertheless, using the law of nature to address biological problems could potentially revolutionize the way we understand and treat complex diseases such as cancer and inflammation. In this respect, we feel very optimistic.

Vincent Piras

Doctorate student, Institute for Advanced Biosciences, Keio University, Japan

- Vincent Piras and Kentaro Hayashi, joint first authors for the study, say that the currently known signaling process of TRAIL is insufficient.

First, we developed a computational model to match experimental data with simulations. We found that the topology we know of TRAIL’s downstream signaling needs to be adjusted in order to make trustable simulations. We modified the crosstalk very carefully with response rules and checked it with biological plausibility. In total, we had to make three major insertions. Adding this information into our model, we were able to simulate accurately the key survival and death molecules in wildtype and several mutant cancer cells. To our knowledge, this is the first time a single computational model can simulate multiple experimental conditions”, says Vincent Piras, a final-year doctoral student.

Dr. Mariko Okada

Team leader, Laboratory for Cellular Systems Modeling, RIKEN Research Center for Allergy and Immunology, Japan

A detailed model and large amounts of experimental data are needed to carry out cell simulations. These data are fed into the model, so it can be adjusted bit by bit to simulate the living cells. However, this task is incredibly tedious. This new approach from Piras et al. starts from an average model, and uses precise theories to change it into a model that is more likely to be true, giving us the chance to look into unexplored reactions and cuts down the work to simulate it. My own research includes looking at the cell signaling for the cell fate, so programs like this would be invaluable. The most difficult part of research is gathering a huge amount of data, putting them into several models and comparing different models. The program from this team makes this work easier, and I think it would make simulations much more accessible for biologists working on cell reactions.

I think this team's research would be useful to cell simulation and modeling, just like the K super computer is right now. I also think that by adjusting this program itself, it could be used to look at cell signals during drug screening tests.

Professor Janet Oliver

Regents' Professor and Harvey Chair, Department of Pathology, University of New Mexico

Targeted strategies intended to arrest particular growth-promoting or apoptosis-defying pathways in cancer cells often fail to prevent tumor growth.

A new publication from Piras et al. throws light on resistance mechanisms to therapies using TRAIL, a ligand for the so-called Death Receptors, TRAIL-R1 and TRAIL-R2 (also called DR and DR5) whose expression is often altered on cancer cells. The team developed a dynamic mathematical model to represent the TRAIL signaling network in tumor cells when different combinations of death and competing decoy receptors are expressed and when different downstream signaling molecules in TRAIL-sensitive pro-survival and pro-apoptotic pathways are perturbed. Their model helps to explain why single agent therapy so often fails and, importantly, predicts new targets in the TRAIL signaling pathways for combination therapies that may shift the flux of signals firmly towards apoptosis.

Professor Alfredo Colosimo

Department of Human Physiology and Pharmacology, Biophysics and Medical faculty, Sapienza University of Rome

I had the chance to meet personally prof. Selvarajoo in the occasion of a seminar he delivered in Rome, and was impressed by both the relevance of his work and the efficacy of his presentation style.

In particular, I could appreciate the novelty of his computational approach to find a rationale in the often contrasting data concerning the malignant cells resistance to many pharmacological treatments.

The paper recently appeared in Scientific Reports clearly describes his strategy and results in a very significant case of therapy-resistant cancer cells; it also indicates a strategy to overcome the problem in quite general terms.

In my opinion the merit of such an approach is at least twofold: i) it underlines the necessary use of simplifying assumptions and of appropriate "systemic" viewpoints in the quantitative description of complex biological systems, and ii) it shows the importance of working out realistic and flexible models, directly inspired by the current experimental information and, at the same time, easily amenable to any further improvement.

【Notes】

・ The Science Media Centre of Japan (SMCJ) is an independent, non-profit group for the news media, giving journalists access to evidence-based science and expertise.

・ Regardless of the medium, we welcome our material to be used by journalists who want to make scientific views heard in society.

・ The views expressed in this post are those of the individuals and organisations indicated and do not reflect the views of the SMC or its employees.

・ The SMCJ sends such information to those registered on our mailing list. To sign up, please click on the link below.

（Please be warned that registration involves giving us some information about yourself. Those who we think are not real journalists may be denied access to our mailing list. This is to prevent our information from being abused, and we ask for your understanding. However, considering the emergency we are in now, we have decided to put up all of our information publicly on this website)

　　【Journalist Registration】Please contact us from HERE

【About this article】

○ Feel free to use these quotes in your stories.

○ In terms of crediting the SMCJ (optional), we would ask you to name is as one of the following:

  -Science Media Centre of Japan

  -SMCJ

  -SMC-Japan.org

○ When sharing links, we ask that you please use: http://www.smc-japan.org

【Contact us】

○ Please contact the SMCJ with your comments on our service at:

   Science Media Centre of Japan (Corp)

　　Tel: +81-3-3202-2514

Fax: +81-3-3202-2497

　　E-mail: smc[at]smc-japan.org

Effects of large earthquakes on a global scale

kakubayashi — Wed, 30 Mar 2011 08:20:51 +0000

Ver.1.1 (Updated: 110330-16:23)

Feel free to use these quotes in your stories, but please read our notes at the bottom in regards to the information here.

If you have any questions, please don't hesitate to contact us.

* Please be aware that the comments below are in response to the information that was available at the time they were given.

Over the past month there have been a number of earthquakes occurring around the Pacific. A new study published in Nature Geoscience on March 27 has found that large earthquakes over the last 30 years have not triggered other large earthquakes on a global scale, but could on a regional scale. One of the paper's authors, Tom Parsons, gave us some comments.

* Please note that this research does not focus on earthquakes that have solely occurred around Japan, and looks at all earthquakes greater than magnitude 5 across the globe.

Paper: Tom Parsons & Aaron A. Velasco, "Absence of remotely triggered large earthquakes beyond the mainshock region", Nature Geoscience (2011) link here.

Tom Parsons

Geophysicist, US Geological Survey

Q: What did you think about the March 11 Tohoku earthquake?

When I first got notification about the Tohoku earthquake, the reported magnitude was M=7.9 at 14 km depth. I was first concerned about a tsunami. I found a live Japanese TV feed on the web and was horrified to see the tsunami hit in real time while simultaneously seeing the magnitude be revised upward repeatedly towards M=9.

Q: In terms of your latest paper, did you think there was a chance another earthquake would hit Japan?

I was also mindful of the earthquake triggering issue, so I was monitoring the global seismicity rates. This event seems consistent with prior findings that there are many aftershocks regionally, but no obvious evidence of a global effect.

Q: Is there still a risk now, 12 days on from the M9.0 quake?

The concern looking forward is indeed whether more damaging earthquakes might follow, and this is what many researchers around the world are trying to quantify. Certainly we know that many aftershocks will happen and have happened. The majority of these will be small, and their rate decreases with each passing day. Nonetheless, continued preparedness is certainly the wise choice.

Q: Another large earthquake hit Burma on March 24. Do you think this could be linked to the earthquake in Japan?

I can't say it isn't linked; however this would require it following a physical process that we do not understand because of the long distance and time between the earthquakes. It seems to be the only large earthquake that has happened outside of the regional aftershock zone of the 11 March event. We would thus suggest that it is more likely a coincidence, based on our study of the last 30 years worth of earthquakes.

【Notes】

・ The Science Media Centre of Japan (SMCJ) is an independent, non-profit group for the news media, giving journalists access to evidence-based science and expertise.

・ Regardless of the medium, we welcome our material to be used by journalists who want to make scientific views heard in society.

・ The views expressed in this post are those of the individuals and organisations indicated and do not reflect the views of the SMC or its employees.

・ The SMCJ sends such information to those registered on our mailing list. To sign up, please click on the link below.

（Please be warned that registration involves giving us some information about yourself. Those who we think are not real journalists may be denied access to our mailing list. This is to prevent our information from being abused, and we ask for your understanding. However, considering the emergency we are in now, we have decided to put up all of our information publicly on this website)

　　【Journalist Registration】Please contact us from HERE

【About this article】

○ Feel free to use these quotes in your stories.

○ In terms of crediting the SMCJ (optional), we would ask you to name is as one of the following:

  -Science Media Centre of Japan

  -Science Media Centre of Japan (Corp)

  -SMCJ

  -SMC-Japan.org

○ When sharing links, we ask that you please use: http://www.smc-japan.org

【Contact us】

○ Please contact the SMCJ with your comments on our service at:

   Science Media Centre of Japan (Corp)

　　Tel/Fax: 03-3202-2514

　　E-mail: inquiry[at]smc-japan.org

Rolling blackouts, are they valid or not?

kakubayashi — Fri, 25 Mar 2011 09:07:45 +0000

Ver.1.1 (Updated: 110325-18:17)

Feel free to use these quotes in your stories, but please read our notes at the bottom in regards to the information here.

If you have any questions, please don't hesitate to contact us.

* Please be aware that the comments below are in response to the information that was available at the time they were given.

Professor Shinichi Iwamoto

Department of Electrical Engineering and Bioscience, Faculty of Science and Engineering, Waseda University

Q: Why are rolling blackouts the only option?

A: This was the only option. We’re 10 million kW of power short and there’s no other way to balance the supply and the demand. Blackouts happen when the running frequency drops. Tokyo Electric power runs at 50Hz with a variation of plus or minus 0.2Hz. If the frequency changes by more than 1Hz, the relay detects this, rejects the load, and causes an unexpected blackout. To prevent this from happening, the company can only warn people and purposely cut power to certain areas.

Q: We’ve had power shortages in the past, but I remember it was just a matter of refraining from using some electricity. Can’t we do that this time?

A: The amount of power we’re short of this time is much larger. 10 million kW is equivalent to 10 nuclear reactors producing 1 million kW of power each. It’s not as simple as asking the supply and demand contract or site’s workers to come to a stop.

Q: How long is this going to go on for?

A: I think this’ll go on until the thermal power plants have started up again. That means we’ll have rolling blackouts until the end of April. It won’t be a normal stop and start, because the workers will need to check nothing has been damaged by the earthquake before re-starting the plants. That’ll take much longer than usual. Note that the thermal power plants account for 60% of the installed power generation capacity of TEPCO.

Q: What can we (people living in Japan) do to help?

A: The first thing that comes to mind that everyone could do is not to use the heater when it’s cold. I’m 60 years-old now and I remember we didn’t have heaters when I was a kid, and every household was on a 10A contract. But now every house has three to four heaters and 40 to 50A contracts. If people could stop turning on heaters, it would help drop the demand of the electricity a lot.

【Notes】

・ The Science Media Centre of Japan (SMCJ) is an independent, non-profit group for the news media, giving journalists access to evidence-based science and expertise.

・ Regardless of the medium, we welcome our material to be used by journalists who want to make scientific views heard in society.

・ The views expressed in this post are those of the individuals and organisations indicated and do not reflect the views of the SMC or its employees.

・ The SMCJ sends such information to those registered on our mailing list. To sign up, please click on the link below.

（Please be warned that registration involves giving us some information about yourself. Those who we think are not real journalists may be denied access to our mailing list. This is to prevent our information from being abused, and we ask for your understanding. However, considering the emergency we are in now, we have decided to put up all of our information publicly on this website)

　　【Journalist Registration】Please contact us from HERE

【About this article】

○ Feel free to use these quotes in your stories.

○ In terms of crediting the SMCJ (optional), we would ask you to name is as one of the following:

  -Science Media Centre of Japan

  -Science Media Centre of Japan (Corp)

  -SMCJ

  -SMC-Japan.org

○ When sharing links, we ask that you please use: http://www.smc-japan.org

【Contact us】

○ Please contact the SMCJ with your comments on our service at:

   Science Media Centre of Japan (Corp)

　　Tel/Fax: 03-3202-2514

　　E-mail: inquiry[at]smc-japan.org

Effects of radioactive materials

kakubayashi — Tue, 22 Mar 2011 08:53:35 +0000

Ver.1.1 (Updated: 110323-16:08)

Feel free to use these quotes in your stories, but please read our notes at the bottom in regards to the information here.

If you have any questions, please don't hesitate to contact us.

* Please be aware that the comments below are in response to the information that was available at the time they were given.

According to information as of March 22 08:52 JST.

Professor Shunichi Yamashita

Graduate School of Biomedical Sciences, Nagasaki University

President, Japan Thyroid Association

Prof Yamashita has recently been requested by the Fukushima prefectural governor to be the area's nuclear radiation health risk management advisor.

About the initial evacuation

"During the first week, it was unfortunate that the quick succession of unpredicted events had made it difficult for everyone to share information. I first became aware of the seriousness of the situation when the government issued an evacuation warning that didn’t follow the usual standards. Normally people living within 10km of the site would be evacuated in the case of an emergency. People would first be asked to stay indoors, and then be given the order to evacuate if the radiation levels wouldn’t drop. In the current case, people living within 20km were evacuated, and then people living within 30km were told to stay indoors. It doesn’t make sense that people who had been evacuated to a safer area should be asked to stay indoors.

"The series of troubles at the reactor were unprecedented. Radiation continues to come out at an on-again, off-again basis. The type of radiation coming out varies, and so do the amounts. We need to continue monitoring the area and find out whether the 30km indoor evacuation order was necessary."

The effects of radioactive material as compared to the Chernobyl disaster

"Radioactive material has spread across a number of places. In a way though, radioactive materials emit what’s called a tracer, which is very easily detected and measured. The amounts that have been recorded so far will not have an effect on people’s health. If the extent of the Chernobyl nuclear disaster could be represented by Mount Pinatubo’s eruption in the Philippines, the incident at Fukushima would be represented by the Mount Unzen or Shinmoedake volcanic eruption. In either case, there’s a risk of getting burns or something more life threatening from the volcanic ash or lava, but moving away from the area lowers these chances. The only difference between the two is that Mt Pinatubo’s effect spread across the entire world, whereas Mt Unzen or Shinmoedake only affected a small area.

"Radioactive material coming out of Fukushima Daiichi is like ash spewing out of an erupting volcano. Moving away 20km will significantly lower its effects. The amount of radioactive material that has been released up to now is getting smaller and smaller as is the area over which it is being spread. A person who gets radioactive material on their skin can easily wash it off. It’s wrong to say that even a trace of exposure would be dangerous."

Currently, the chances of getting cancer are not rising

"Human bodies already contain about 1000 to 5000Bq of radioactive potassium. Taking a radon bath will obviously result in your body absorbing radon too. As long as the amount of these radioactive materials are small (10 – 500μSv) then there shouldn’t be a problem over a relatively short period of time.

"Right now iodine-131 levels in spinach and milk have gone over the standard limits, but it’s safe to eat it once or twice. The other thing is iodine-131 has a half-life of eight days so its effects will wear off quickly.

"Being exposed to 100mSv of radiation at once could raise the chances of getting cancer, but if the levels can be kept below 50mSv it should be alright. Radiation exposures considered safe for the nuclear power plant workers has been set to a total of 50mSv per year, and this is secure.

"People seem to be worried that radiation exposure will lead to cancer later on in life. But if we exposed 100 people to a 100mSv dose of radiation, only one or two people would have a chance of getting cancer (one in three Japanese people die from cancer). Thus, it’s unlikely more people will get cancer as a result of these events."

No need to worry about radiation exposure for general public

"In the area between 10 – 20km from the nuclear plant, those who have already been evacuated might have been exposed to about 1mSv of radiation. However, there is no difference between several micro-SV and 100mSV in terms of their effect in causing cancer.

"It should also be noted that the effect of radiation of exposure, 100 times of 1mSv and 100mSv at a time, is very different. The people we should be worrying about in regards to radiation exposure are those working at the site of Fukushima Daiichi nuclear power plant. We need to think about how to secure their health. Otherwise people do not need to worry about radiation exposure.

"It is argued that the effect of low-level radiation exposure on health conditions cannot be demonstrated. However, 'no evidence of no effect', does not necessarily mean we should worry about the effect. It is understandable that people fear the radiation exposure because it is invisible, but radiation can be measured in scientific ways. That is, we have a means to prevent harm from radiation. We should not panic. I would ask you to behave in a rational manner as a member of the society."

What’s next

"Radiation has spread across a wide area so it would be a problem if food is contaminated through the food chain and then sold at markets. We need to collect data about what areas have been contaminated in what ways, and be open with sharing this data. Using this information will help us to calculate radiation levels absorbed into our body within a year, and if the total annual intake is anywhere between a few tens of mSv to 100mSv, then regulations need to be put in place. I do think this will toughen Japan’s already strict food safety standards, but we need to pay particular attention to prevent negative rumours from spreading.

"Given the scale of the impact of this earthquake and its consequent tragedies, I argue that people in this nation should be prepared to help relieve the burden the people of Fukushima now face. It is now that we need to follow the example of the Japanese way and carry on in a harmonious and calm way as our ancestors have through history."

【Notes】

・ The Science Media Centre of Japan (SMCJ) is an independent, non-profit group for the news media, giving journalists access to evidence-based science and expertise.

・ Regardless of the medium, we welcome our material to be used by journalists who want to make scientific views heard in society.

・ The views expressed in this post are those of the individuals and organisations indicated and do not reflect the views of the SMC or its employees.

・ The SMCJ sends such information to those registered on our mailing list. To sign up, please click on the link below.

（Please be warned that registration involves giving us some information about yourself. Those who we think are not real journalists may be denied access to our mailing list. This is to prevent our information from being abused, and we ask for your understanding. However, considering the emergency we are in now, we have decided to put up all of our information publicly on this website)

　　【Journalist Registration】Please contact us from HERE

【About this article】

○ Feel free to use these quotes in your stories.

○ In terms of crediting the SMCJ (optional), we would ask you to name is as one of the following:

  -Science Media Centre of Japan

  -Science Media Centre of Japan (Corp)

  -SMCJ

  -SMC-Japan.org

○ When sharing links, we ask that you please use: http://www.smc-japan.org

【Contact us】

○ Please contact the SMCJ with your comments on our service at:

   Science Media Centre of Japan (Corp)

　　Tel/Fax: 03-3202-2514

　　E-mail: inquiry[at]smc-japan.org

Expert response to radiation exposure

kakubayashi — Sun, 20 Mar 2011 12:41:58 +0000

Ver.1.1 (Updated: 110320-22:20)

Feel free to use these quotes in your stories, but please read our notes at the bottom in regards to the information here.

If you have any questions, please don't hesitate to contact us.

* Please be aware that the comments below are in response to the information that was available at the time they were given.

According to information as of March 18 14:42 JST.

Dr Makoto Kondo

Lecturer, Department of Radiology, Keio University School of Medicine.

Q: Are the effects of radiation exposure on an adult different from a child?

　“There is a large difference in radiation effects on adults compared to children. Even in the case of radiation exposure from CT (X-ray computed tomography) scans, the chances of a child developing cancer is so many times higher than adults. Children’s bodies are underdeveloped and easily affected by radiation, which could cause cancer or slow body development. It can also affect their brain development. A developing brain is delicate. Although this is still under debate, there have been reports of children who had their heads exposed to radiation in an effort to remove angiomas (benign tumours) but later on developed intellectual disabilities in their teens.

"Unborn babies are also undergoing fast developments, so are equally vulnerable to radiation.”

Q: What are the effects on reproductive organs?

“Along with lymphocytes, the reproductive organs are sensitive to radiation. A man’s reproductive organs can be affected by a 1Sv dose of radiation. While depending on the age, ovaries are more tolerant to radiation than testes, and it takes a total of about 15Sv of radiation to stop the ovaries from functioning. But again, this depends on the age and a 6Sv dose may be enough to impair ovary function in women around 40 years old."

Q: Do we need to worry about internal radiation right now?

“As long as a significant amount of radioactive material is not being released into the environment, there is nothing to worry about. The amounts of radiation being recorded in areas further than 30km from the nuclear plant, such as Tokyo, Chiba and Kanagawa prefectures, are such that there is no need to worry about internal radiation damage.

Q: If there are no immediate health effects, what about the possible long-term effects?

“'No immediate effects' means there is no show of immediate symptoms caused by radiation exposure. The more radiation a person is exposed to, the bigger the chances it will cause cancer in the long run.

“There is an internationally-recognized prediction chart (published by the International Commission on Radiological Protection in 2007) that outlines the likelihood of getting cancer in comparison to the amount of radiation. According to this, it predicts that if one million people were exposed to a 10mSv dose of radiation, 500 people would die from cancer.

“At the moment, not a lot of people are being exposed to radiation so there are no long term effects to worry about. If the current radiation levels can be kept, I think we can return to a normal life soon.”

Q: What conditions would cause immediate health effects?

“Even if a nuclear power plant worker were exposed to their annual 50mSv limit at once, they will make a recovery as long as they keep away from any more radiation. At the moment there are a few regions that are getting high radiation recordings, but the half-life of the radioactive materials in the air right now are short so the amount of radiation in the air will quickly deplete once the amount being released at the plant goes down.

"But there have been studies that have analysed the data of 400,000 or so nuclear power plant workers in the world, and they have suggested that even radiation exposures to amounts less than 10mSv have led to cancer developments.

“I am not sure whether or not, or how much, the local residents around the power plant are being exposed to radiation, but if it is a similar amount to that of the workers at the power plant, there may be a possibility their health condition has been affected by the exposure.

“In the future, if there is a chance radioactive material is released into the environment, its affects will depend on what type it is. Gamma ray radiation would be dangerous, but so far there have been no reports that this is being released. (I am not a nuclear physicist, but I have heard it is very unlikely that) if the reactor went critical and sent cesium and iodine out into the air, absorbing these materials would be extremely dangerous.

“But, no matter what happens, I think I will stay here (at the Keio University Hospital in central Tokyo).”

【Notes】

・ The Science Media Centre of Japan (SMCJ) is an independent, non-profit group for the news media, giving journalists access to evidence-based science and expertise.

・ Regardless of the medium, we welcome our material to be used by journalists who want to make scientific views heard in society.

・ The views expressed in this post are those of the individuals and organisations indicated and do not reflect the views of the SMC or its employees.

・ The SMCJ sends such information to those registered on our mailing list. To sign up, please click on the link below.

（Please be warned that registration involves giving us some information about yourself. Those who we think are not real journalists may be denied access to our mailing list. This is to prevent our information from being abused, and we ask for your understanding. However, considering the emergency we are in now, we have decided to put up all of our information publicly on this website)

　　【Journalist Registration】Please contact us from HERE

【About this article】

○ Feel free to use these quotes in your stories.

○ In terms of crediting the SMCJ (optional), we would ask you to name is as one of the following:

  -Science Media Centre of Japan

  -Science Media Centre of Japan (Corp)

  -SMCJ

  -SMC-Japan.org

○ When sharing links, we ask that you please use: http://www.smc-japan.org

【Contact us】

○ Please contact the SMCJ with your comments on our service at:

   Science Media Centre of Japan (Corp)

　　Tel/Fax: 03-3202-2514

　　E-mail: inquiry[at]smc-japan.org

Reactors at Fukushima will not reach recriticality

kakubayashi — Sun, 20 Mar 2011 12:18:04 +0000

Ver.1.0 (Updated: 110320-20:42)

Feel free to use these quotes in your stories, but please read our notes at the bottom in regards to the information here.

If you have any questions, please don't hesitate to contact us.

* Please be aware that the comments below are in response to the information that was available at the time they were given.

Information as of March 20 01:14 JST.

Ritsuo Yoshioka

Mr Yoshioka is the President and CEO of the Japan Functional Safety Laboratory. He is currently involved in training and educating about functional safety standards in Japan.

Why the situation will not reach recriticality at Fukushima Daiichi

　“Let me talk about a recriticality (when nuclear fission reactions keep occurring like when the power plant is operating) in terms of the nuclear reactor and the spent fuel pool.

"For a light-water nuclear reactor to achieve criticality, three things need to happen:

1. The 1cm diameter fuel rods need to be lined up with about 1.5cm of space in between them.

2. All the fuel needs to be immersed in water.

3. The control rods need to be removed.

Unless all these conditions are met, criticality would not be achieved.

"Therefore, the following is true:

As long as the control rods are suppressing the fuel rods, a critical situation will not occur
Spent nuclear fuel cannot reach criticality without water.

"In regards to the spent fuel in the pool, the pool in Unit 4 is empty so criticality will not occur. It was reported that someone had seen water inside the pool, but Tokyo Electric Power later clarified that it was the other pool that did not have any fuel in it.

The pool in Unit 3 does have water (the steam coming out is from the water) but it will not go critical, because the fuel batches are not aligned in a way to reach criticality.

It is because of these reasons that I believe a recriticality accident at Fukushima Daiichi nuclear power plant will not happen."

About the spread of radioactive material

“As long as the containment vessels in Unit 1, 2, and 3 have not been damaged, radioactive material will not be released outside. “Spent fuel has been exposed to air and has been releasing small amounts of radioactive material. The lighter radioactive material has already been released in the form of a hydrogen gas explosion and has already spread out. As long as there are no more explosions, it is unlikely that any more will be released. I don’t think radiation levels will go much higher than what they are now.

“Heavier radioactive material (such as uranium, plutonium, or cobalt, which have significant effects of humans) has been released in minute amounts, but they are so heavy that they are building up at the bottom of the pool. As long as the situation does not reach recriticality, they will not spread out in large amounts.

“A recriticality accident is unthinkable, and there is no need to worry about more radioactive material spreading than it is right now.”

【Notes】

・ The Science Media Centre of Japan (SMCJ) is an independent, non-profit group for the news media, giving journalists access to evidence-based science and expertise.

・ Regardless of the medium, we welcome our material to be used by journalists who want to make scientific views heard in society.

・ The views expressed in this post are those of the individuals and organisations indicated and do not reflect the views of the SMC or its employees.

・ The SMCJ sends such information to those registered on our mailing list. To sign up, please click on the link below.

（Please be warned that registration involves giving us some information about yourself. Those who we think are not real journalists may be denied access to our mailing list. This is to prevent our information from being abused, and we ask for your understanding. However, considering the emergency we are in now, we have decided to put up all of our information publicly on this website)

　　【Journalist Registration】Please contact us from HERE

【About this article】

○ Feel free to use these quotes in your stories.

○ In terms of crediting the SMCJ (optional), we would ask you to name is as one of the following:

  -Science Media Centre of Japan

  -Science Media Centre of Japan (Corp)

  -SMCJ

  -SMC-Japan.org

○ When sharing links, we ask that you please use: http://www.smc-japan.org

【Contact us】

○ Please contact the SMCJ with your comments on our service at:

   Science Media Centre of Japan (Corp)

　　Tel/Fax: 03-3202-2514

　　E-mail: inquiry[at]smc-japan.org