A Day in Fukushima - Gamma Spectroscopy
Posted: 01 Dec 2019, 08:38
Hello there,
And so it’s time for the Fukushima Post.
On Saturday November 9 I left from Tokyo at 8:00 AM heading north. I entered the Fukushima prefecture about two and a half hours later and around 11:00 AM I arrived at Namie Town.
Before getting into details here’s an overview:
In little more than 7 hours spent in the area of the prefecture, close to Fukushima Daiichi (meaning number 1) nuclear power plant (from now on F1NPP), at Namie Town, Futaba Town, Tomioka Town, getting within 2 km from the F1NPP and staying inside the No-Go Zone as much as I could, my dosimeter recorded an accumulated dose of 1.60 µSv, corresponding to an average doserate of 0.22 µSv/h which is less than what you get walking the streets of Rome city centre.
I didn’t adjust the dosimeter to Japanese time, so the time you read in the graphs and in the GPS map is central Europe time, you need to add 8 hours to have the local Japanese time.
This is the graph of the average doserate in every hour of my stay. As you can see the highest average over an hour is just above 0.50 µSv/h, while the peak dose was 4.66 µSv/h measured (only for a few seconds) at the closest approach to F1NPP.
The dosimeter recorded the average dose every minute and collected a data point in the GPS map every 30 seconds (well, when the GPS signal was on, which sometimes wasn’t the case while I was inside the car).
This is the overall map showing most of my itinerary.
And this is the detail of the closest approach to the F1NPP. As you can see the hot spot was pretty short lived. As mentioned before the accumulated dose was 1.60 µSv.
This is me back in Tokyo that same night, the total accumulated dose of the day (journey from and to Tokyo included) was 1.88 µSv. Ok, let’s go back to the beginning.
Namie Town was one of the places most affected by the release of radioactive material from the accident following the earthquake and tsunami of March 11, 2011.
The city was evacuated the very next day and remained part of the evacuation zone until spring 2017 when residents were finally allowed to return.
Many buildings were too damaged because of the earthquake and were demolished, other will be soon (you can tell them by a small red sticker on the window). 20,000 people used to live there, only about 5% returned, both because fear of radiation and the fact that when you've spent years settling somewhere else you are not necessarily ready to go through that again.
There are rays of hope here and there. Works are in progress to resume the train line to the south, a new cafè just opened, and recently the dentist is back in town. But the situation isn’t pretty. Farmers are trying hard to get back to normality, I visited a number of shops selling local products (they don’t miss a chance to underline they are local), but in the rest of Japan people tend not to want to eat food coming from Fukushima, albeit there’s no real risk, the food is independently checked by local communities (people generally don’t trust the government here) and the limit of 100 Bq/kg of Cesium is far more severe than what is in place both in Europe and the US. So the food is perfectly safe, but most people won’t eat it just because of the stigma coming from the name “Fukushima”.
Fear and misconceptions made far more victims than radiation around here.
Going around, both on foot and in the car, the doserate is extremely low, never exceeding 0.15 µSv/h. So basically there was no point recording a spectrum in the town, too little counts, it would have taken a long time to accumulate enough data.
I wasn’t driving the car myself, because, well, it was a lot easier to hire a driver and so I could take care of my measurements even when in the car. I was also accompanied by a lady from Fukushima City who acted as a guide and translator with the local people. I was struck by the lack of people walking in the streets, but later on we bumped into a little festival which was taking place in the town to entertain the people who returned. This apparently happens every second Saturday of the month. Looking at them from a distance the remaining buildings seemed in good conditions, but a closer inspection revealed a clear state of disrepair. This above is the local school. The shoes you see were left there by the kids running away from the earthquake in the early afternoon on March 11, 2011. Since the city was evacuated the very next day nobody ever came back to take them, so they’re still where they were left back then.
I recorded the first spectrum while walking on a country road just outside the town. Nothing major, but for the first time doserate exceeded 0.70 µSv/h.
You can see black plastic bags in the area were the spectrum was taken. They are full of weakly contaminated soil, you see hundreds of them around there, but actually it was not them giving me the higher than average read, since getting closer to them the figure didn’t increase at all. The relatively hot spot was pretty circumscribed, just walking a meter or two the doserate decreased by more than a half. So, here’s the first spectrum, recorded over a 700 seconds time. Unsurprisingly Cs137 and Cs134 peaks are clearly visible. This is the end of part 1. Part 2 will be posted shortly.
And so it’s time for the Fukushima Post.
On Saturday November 9 I left from Tokyo at 8:00 AM heading north. I entered the Fukushima prefecture about two and a half hours later and around 11:00 AM I arrived at Namie Town.
Before getting into details here’s an overview:
In little more than 7 hours spent in the area of the prefecture, close to Fukushima Daiichi (meaning number 1) nuclear power plant (from now on F1NPP), at Namie Town, Futaba Town, Tomioka Town, getting within 2 km from the F1NPP and staying inside the No-Go Zone as much as I could, my dosimeter recorded an accumulated dose of 1.60 µSv, corresponding to an average doserate of 0.22 µSv/h which is less than what you get walking the streets of Rome city centre.
I didn’t adjust the dosimeter to Japanese time, so the time you read in the graphs and in the GPS map is central Europe time, you need to add 8 hours to have the local Japanese time.
This is the graph of the average doserate in every hour of my stay. As you can see the highest average over an hour is just above 0.50 µSv/h, while the peak dose was 4.66 µSv/h measured (only for a few seconds) at the closest approach to F1NPP.
The dosimeter recorded the average dose every minute and collected a data point in the GPS map every 30 seconds (well, when the GPS signal was on, which sometimes wasn’t the case while I was inside the car).
This is the overall map showing most of my itinerary.
And this is the detail of the closest approach to the F1NPP. As you can see the hot spot was pretty short lived. As mentioned before the accumulated dose was 1.60 µSv.
This is me back in Tokyo that same night, the total accumulated dose of the day (journey from and to Tokyo included) was 1.88 µSv. Ok, let’s go back to the beginning.
Namie Town was one of the places most affected by the release of radioactive material from the accident following the earthquake and tsunami of March 11, 2011.
The city was evacuated the very next day and remained part of the evacuation zone until spring 2017 when residents were finally allowed to return.
Many buildings were too damaged because of the earthquake and were demolished, other will be soon (you can tell them by a small red sticker on the window). 20,000 people used to live there, only about 5% returned, both because fear of radiation and the fact that when you've spent years settling somewhere else you are not necessarily ready to go through that again.
There are rays of hope here and there. Works are in progress to resume the train line to the south, a new cafè just opened, and recently the dentist is back in town. But the situation isn’t pretty. Farmers are trying hard to get back to normality, I visited a number of shops selling local products (they don’t miss a chance to underline they are local), but in the rest of Japan people tend not to want to eat food coming from Fukushima, albeit there’s no real risk, the food is independently checked by local communities (people generally don’t trust the government here) and the limit of 100 Bq/kg of Cesium is far more severe than what is in place both in Europe and the US. So the food is perfectly safe, but most people won’t eat it just because of the stigma coming from the name “Fukushima”.
Fear and misconceptions made far more victims than radiation around here.
Going around, both on foot and in the car, the doserate is extremely low, never exceeding 0.15 µSv/h. So basically there was no point recording a spectrum in the town, too little counts, it would have taken a long time to accumulate enough data.
I wasn’t driving the car myself, because, well, it was a lot easier to hire a driver and so I could take care of my measurements even when in the car. I was also accompanied by a lady from Fukushima City who acted as a guide and translator with the local people. I was struck by the lack of people walking in the streets, but later on we bumped into a little festival which was taking place in the town to entertain the people who returned. This apparently happens every second Saturday of the month. Looking at them from a distance the remaining buildings seemed in good conditions, but a closer inspection revealed a clear state of disrepair. This above is the local school. The shoes you see were left there by the kids running away from the earthquake in the early afternoon on March 11, 2011. Since the city was evacuated the very next day nobody ever came back to take them, so they’re still where they were left back then.
I recorded the first spectrum while walking on a country road just outside the town. Nothing major, but for the first time doserate exceeded 0.70 µSv/h.
You can see black plastic bags in the area were the spectrum was taken. They are full of weakly contaminated soil, you see hundreds of them around there, but actually it was not them giving me the higher than average read, since getting closer to them the figure didn’t increase at all. The relatively hot spot was pretty circumscribed, just walking a meter or two the doserate decreased by more than a half. So, here’s the first spectrum, recorded over a 700 seconds time. Unsurprisingly Cs137 and Cs134 peaks are clearly visible. This is the end of part 1. Part 2 will be posted shortly.