Independent Report Concludes Radiation Risk at Motegi “Negligible”

July 25, 2011


As we reported back on July 20, nearly all of the MotoGP riders have indicated they intend to boycott the Motegi GP round scheduled for October 2 due to a concern about radiation resulting from the Fukushima nuclear disaster.  Below is a brief statement from the FIM regarding an independent assessment of the radiation risk associated with attendance by teams and personnel at this year’s Motegi round of the grand prix series. Following that is the “conclusion” section of the preliminary report, followed by a link to the entire preliminary report in English.

The FIM and Dorna Sports SL recently commissioned an independent report by a recognised body to investigate the current situation in Japan, in advance of the Grand Prix of Japan at Motegi which is scheduled to take place on 2 October.

This study is intended to complement the information already available from various Governments and the World Health Organisation, which addresses the general situation in Japan following the earthquake and subsequent tsunami that occurred in March. This independent investigation reports specifically on the situation in Motegi and its environs, making it much more relevant to MotoGP participants.

The official detailed report will be delivered later this week, but a preliminary report has already been made available – with an original version in Italian and an English translation provided by the Championship organisers.

ARPA, the agency commissioned for this report, has measured levels of radiation from all sources including the air, environment and food. The final conclusion is that “based on the estimate dose it can be said with no doubt that the radiation risk during the race event is negligible”.

Based on this information the FIM and Dorna Sports will announce later this week that, subject to there being no further serious incidents, the Grand Prix of Japan will take place on October 2 as planned.

Here is the conclusion reached by the independent assessment of the radiation risk (at least, in the preliminary report):


The measures analysis shows the presence of radioactivity contamination due to the Fukushima accident in the Motegi Twin Ring track areas, as it was expected.

The on-field-spectrometry analysis on soils shows in fact the presence of the Cs134 radionuclide released during the accident: air gamma intensity is higher than what it was in areas close to Motegi before the accident (acording to data coming from the Mobilityland Corp. Twinring Motegi technical staff).

Based on the measures taken it is possible to estimate the individual absorbed dose during the race event, in the assumption that the event duration will be one week and the ambient situation will stay the same until the race date.

The estimate is based on the measures for the ambient and inhalation gamma dose, while calculations have been made for the ingestion dose, considering the average Italian diet and food/beverages delivered in the TRM (rice, for instance, is still 2010 production and some foods like bread, pasta, oil, cheeses and some fruit are imported) and safely considering the minimum measurable concentrations of Cs134 e Cs137 as positive values.

Based on the experimental data the average air gamma dose (0.144μSv/h) resulting from the sum of the Cesium fallen on the ground after the Fukushima accident plus the natural radioactivity of the Motegi area, the gamma radiation dose estimate for one week, not considering any shield factor, can be 24μSv, and this figure can be considered normal. It is worth to remind here that the levels are in line with ambient values measure in other towns (e.g. Piacenza =0.0090μSv/h, Roma = 0.330μSv/h, Madrid = 0.190μSv/h).

The inhalation estimate dose for one week is less than one tenth of μSv, safely considering the maximum Cesium level (Cs134 e Cs137) as measured just once in the paddock area (Cs134 and Cs137 concentrations respectively 80 and 160mBq/m3).

The ingestion estimate dose for one week is less than some μSv, calculated as above said.

Table 5 summarizes our estimates.

Table 5 – Dose estimate for adult people in one week



< 0.1µSv


< 5µSv


about 24µSv


< 30µSv

The above mentioned weekly dose is in line with the average world natural sources dose of about 46μSv, obtained by the yearly average dose of 2.4mSv (Unscear 2000).

Based on the estimate dose it can be said by no doubt that the radiation risk during the race event is negligible.

Written in Motegi on July 22nd, 2011.

The entire text of the report can be found here.

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