Fukushima Daiichi: international response

Being a friendly nuclear neighbour

19 April 2012

During and after the Fukushima Daiichi incident technical support organizations played a key role in providing reliable information to governments, media and the public. But the events in Japan have highlighted areas for potential improvements, Caroline Peachey reports.

Technical support organizations in Europe operated or supported their national nuclear emergency centres by providing technical and radiological information on the Fukushima accident, and giving advice to national regulators and governments. The work carried out by TSOs included: preliminary safety assessments of the situation, evaluation of accident progression, radiological source term assessments, radiation dispersion calculations, and estimates of the environmental impact and radiological consequences of the accident.

On 7-8 November, the Eurosafe Forum met in Paris to hear papers presented by members of the European TSO Network (ETSON). The members of ETSON are Bel V (Belgium), GRS (Germany), IRSN (France), ÚJV (Czech Republic) and VTT (Finland). JNES (Japan) and SSTC (Ukraine) are associate members.

Access to information

Eurosafe presentations made by Frank-Peter Weiss (scientific-technical director, GRS) and Edouard Scott de Martinville (head of international relations department, IRSN) on behalf of ETSON both outlined lessons learned from operation of the technical emergency centres during the Fukushima accident. A number of areas for improvement were highlighted, in particular the potential for better international networking.

ETSON members experienced a trio of common difficulties, Weiss said, reporting the findings from a member workshop held in Cologne in July. First, it was difficult to obtain sufficient safety-relevant information about the Fukushima Daiichi reactors when the European emergency centres started operation. Information was initially available from reports to the Convention on Nuclear Safety (CNS), the IAEA Power Reactor Information System (PRIS), and from other open sources such as IAEA News and the INES website. However, this information was inadequate to fully understand the design basis of the plants, their general operating regime, and the pre-planned accident management measures. In particular, information was missing about plant layout including detail on the locations and elevations of the emergency diesel generators and batteries.

Second, it proved difficult to get reliable and consistent information on: the status of the reactors and the spent fuel pools, the damage that occurred in different units, the radiological situation, as well as the on-site accident management actions taken, and whether they were effective or not. There was a lot of information from the operator TEPCO, the regulator NISA and the public media. The problem was finding out what information was valid and topical. This was further impeded by the fact that the most reliable information was reported in Japanese. One TSO hired a Japanese native speaker to watch TV, giving them access to the latest information.

Finally, some of the TSOs did not have detailed expertise in boiling water reactors, which further complicated things for them.

There was also the issue of increased workload to deal with.

Bel V says that although it was not involved in communication with the public, it has a received a large amount of additional work related to the European stress tests, which has to be handled alongside normal inspections, periodic safety reviews and licensing work that cannot be halted.

Communication with the public

In addition to the technical issues, at least some of the TSOs initially underestimated the efforts required to interact with the public via the media. Many were not adequately prepared to deal with the influx of enquiries from the press and TV. There were not enough staff trained in communication and in some cases the infrastructure was not sufficient. Weiss explained that German TSO GRS had just one room in its emergency centre, so experts drafting situation reports had to jostle with TV camera crews conducting interviews. (Weiss said that GRS plans to improve the emergency centre and is trying to get funding from the Federal Environment Ministry (BMU)).

In the weeks following the Fukushima incident, GRS was confronted with around 700 media and individual requests for information, and carried out over 30 TV interviews. In response to the intensive need for information GRS launched a special Fukushima Information Portal (http://fukushima.grs.de), which received around 5 million page views by October 2011. ÚJV (Czech Republic) also shared most of its information on the web, receiving approximately 20 questions a day via a Fukushima portal over the first month. Weiss said that GRS decided to launch the dedicated Fukushima portal after it received a large number of hits to its website. He added that GRS had underestimated the effort required to constantly publish updated information on the Internet over such a long period of time.

In France, IRSN set up a dedicated ‘health unit’ to evaluate putative heath consequences for people exposed to radioactive releases in Japan and France. A core team of eight experts in communication, radiobiology, dose assessment and health risk assessment were supported by 16 staff from IRSN’s internal dosimetry, external dosimetry and radiobiology departments. The heath unit received around 1000 phone calls and 300 emails in the four weeks following the tsunami. Although six dedicated phone lines were set up for Fukushima inquiries (three for each France and Japan), only 30 phone calls were received from Japan. Jean-Rene Jourdain, Representative of the Directorate of Radiation Protection and Human Health at IRSN told participants that operating a toll-free number could have increased the number of calls from Japan. Jourdain noted that enquiries from France peaked in late March, when radiation could be detected over the country (Figure 1).

In another seminar, Florence Sentuc from GRS explained another challenge experienced by the TSOs: communicating the radiological information to the public in a comprehensible yet professional way. This was achieved by many short articles and explanatory figures that were posted on the GRS website. Weiss said that in hindsight GRS would have paid more attention to its website and the use of social media (Facebook, Twitter) from the start of the crisis.

Jourdain noted that for IRSN the Fukushima crisis pointed out a degree of ignorance about radiation protection issues in French medical communities, especially with regard to stable iodine prophylaxis.


After a few days, ETSON members started to exchange information by making their situation reports mutually available in English. This made up for some of the problems with data acquisition.

The collaboration was impeded, however, as the networks had not been exercised before, the experts to be contacted were not identified, and there were language problems. Nevertheless, the experience of ENTSO members shows that there is room for more international collaboration and support in emergency situations.

Foreign TSOs could help with managing local response by contributing to the evaluation of the accident progression, assessment of the source term, and to prediction of the radiological consequences. Support is also possible by delivering radiation measurement equipment and radiological advice.

But at the conference it was recognized that the exchange of information with international partners is not the first priority for the country affected by the nuclear accident.

In the case of Fukushima Daiichi, Japan was supported by vendors (see also pp13-17, NEI June 2011), and (after a delay) by the US Department of Energy (DOE), which provided aerial measurement capabilities to map the activity deposited on the ground. IRSN also sent real time radiation measuring devices to its embassy in Tokyo and gave advice to French representatives and citizens in Japan.

During the short-term initial emergency-response phase, useful collaboration between TSOs is currently limited due to their obligation to serve their nation and its own emergency response system.

These issues could only be resolved by making the international collaboration of the technical crisis centres an official and integral part of their work, which would likely require state-level negotiations, and so are unlikely, conference speakers said.


During the July workshop ETSON members made a number of proposals aimed at improving future collaboration between TSOs. These include short, medium and long-term practical steps that need to be taken to create an international network of emergency centres, regardless of the international framework.

In the short term (2-5 years), TSOs should: nominate contact persons; establish lines of communication for data exchange by telephone, fax and internet; define the specification of safety-related plant data to be published on commonly-accessible data libraries; agree standards of data to be exchanged on plant status, the radiological and metrological situation, and the contents, language and formats of these reports.

Beyond these technical steps, most of the ETSON members have agreed to exchange the results from their post-Fukushima research and analysis activities within the next 2-5 years. These programmes typically involve an in-depth analysis of the event sequence at the different units of the Fukushima Daiichi NPS using best-estimate computation tools and integral codes.

In the medium term, possibly in the next 5-10 years, tools should be updated and harmonized. This will include the required input decks for the source-term assessment and the radiological consequence analysis. In addition, benchmarking of the assessment methods and simulation tools that are available to the partners should be performed. Finally, there was consensus among the workshop participants that common regular crisis centre exercises should be carried out to assure the proper functioning of the network in case of a real event.

In the longer run, 10 years and more, TSOs should strive for common use of safety assessment methods and analysis tools, including plant and radiological simulation tools.

Case study: Working with lack of data

Gunter Pretzsch explained how Germany's GRS estimated the radionuclide inventory at the reactor units and spent fuel pools of Fukushima NPP without any specific design data on the fuel used at the plant.
The calculation of the nuclide inventory was carried out with the computer code system KENOREST-2008, developed by GRS. This system comprises the three-dimensional Monte Carlo Code KENO-Va solving the Boltzmann transport equation and the one-dimensional burn-up code OREST, consisting of the spectrum code Hammer to calculate cross sections and the code ORIGEN to calculate the nuclide inventory for different decay times of radionuclides.
In a first step, benchmark calculations were carried out to evaluate the calculation code. For benchmarking, GRS used experimental data on the Fukushima Daiini NPP fuel from the NEA spent fuel isotopic composition database (SFCOMPO). The fuel element parameters of both reactor types are almost identical. The burn-up data were taken from the power history given in a Japanese technical paper and scaled with respect to the sample position. To verify the results, the calculated and experimental data were compared.
In a second step, the fuel rods in the UO2 and MOX fuel elements were characterized and burn-up and decay calculations were performed. The data available to calculate the inventory of MOX fuel elements were insufficient. Thus additional data available at GRS for a generic MOX fuel element were used with a conservative approach.
The third step considered the decay calculations of the real fuel elements contained in the spent fuel pools at the date of the accident.
Finally, a GRS selection process resulted in 25 nuclides out of the total nuclide inventory of 572 nuclides with essential contribution to the potential radiation exposure of the population.

Figure 1: IRSN's web traffic spiked when radiation could be detected over France Figure 1: IRSN's web traffic spiked when radiation could be detected over France
GRS Fukushima web page GRS Fukushima web page

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