A Day in Fukushima - Gamma Spectroscopy

[Go-Figure]

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.

01- Average Dosesrate Graph.png (30.44 KiB) Viewed 4602 times

02 - Peak Dosesrate Graph.png (23.76 KiB) Viewed 4602 times

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.

[Go-Figure]

Part 2

Next stop was Ukedo. There was a small town here with about 2000 people living in it. Looking at it from the newly built seawall it’s actually hard to believe it, the tsunami washed it all away, killing hundreds.

The only building still standing is the elementary school, which was left as a memorial, the kids who were here the day of the tsunami were all saved by the fact they and their teachers decided to go to the nearby hills after the tsunami warning was issued.
The school clock is still stuck at the time the tsunami hit the coast.

From the seawall Fukushima Daiichi Nuclear Power Plant (from now on F1NPP) is clearly visible, it’s just 6 km away.

With the F1NPP visible in the background the doserate is the lowest so far, barely reaching 0.05 µSv/h, which was good news, but no way to collect a spectrum here.

Next stop wasn’t supposed to be a stop because it was National Route 6 going south through the No-Go Zone towards Futaba Town and Tomioka Town, having the closest approach to F1NPP in the process.
In the No-Go Zone you can’t stop the car, let alone step down of it. You cannot even open the window of the car, but the doserate, albeit higher than in the places I visited before, isn’t worrying at all, mostly in the region of 0.30 µSv/h.
There’s a gas station along the road. Here you can stop and step down to service the car.
Again, the doserate wasn’t high, but I wanted to take at least one spectrum inside the “zone” so I took advantage of the situation by stepping out for nearly 20 minutes to record another spectrum.

A few km down the road we reached our closest approach to F1NPP, just a couple of km away. We stopped the car for maybe a minute or two before a local policeman told us (kindly but firmly) to move away.

Doserate was still pretty low.

Then suddenly the read jumped to 4 µSv/h, this is were I recorded the peak rate. A couple of minutes later was already reduced by a factor 4.
I immediately started to record another spectrum, while at the same time using the occasion to compare the doserate from the dosimeter with that from the Geiger counter. In this environment, where most radioactivity comes from Cs137, the two readings was much closer than they use to be elsewhere. So Basically, here even just a Geiger counter can be used as a doserate meter with a smaller than usual margin of error.

Doserate was going down quickly as we moved south, and I wanted to get to at least a million counts for this spectrum, so I asked the driver to turn back toward the hotter area.
You can’t stop in the No-Go Zone, but nothing prevents you from going back and forth…and so we did for nearly 20 minutes, the time required to record the last spectrum of the day. Same peaks, but a bit smoother than the previous ones. Average doserate 1.29 µSv/h.

Next was Tomioka Town, some 10 km south of the F1NPP.
The place is pretty surreal, a road going through the town acts as border between the area where people can live and the No-Go Zone where nobody is supposed to set foot.

The road is showed above. The No-Go Zone is on the right side. The dose inside the zone is displayed at several spots. As you can see it's not high at all.

Right at the limit of the fence we are in the region of 0.35 µSv/h and elsewhere in town is much lower than that.

Likely it won’t be too long before the ban is lifted in the part of the town which is still not accessible, but for now this is the scenario on the other side of the guardrail. It remains to be seen how many people will actually come back.

We then had a very good sushi in a local supermarket which just opened, before heading to the newly rebuilt rail station.

No need to comment on the next one.

Last stop was the coast again, just to see a glimpse of the other nuclear power plant in the area, Fukushima Daini (Number 2), just a little more than a km away from where we were standing.

And then it was time to head back to Tokyo, which is 3 hours drive from Tomioka.

Reconstruction, both material and human, is a difficult process in this area. As far as I could see people who came back are determined to rebuild their communities. The biggest hurdle, besides the obvious ones for a region devastated by a 9.0 magnitude earthquake and a monster tsunami, is not radioactivity, which is generally low, but fear, misconceptions and lack of information.

Five days later I took a plane to get back to Europe and my dosimeter recorded an accumulated dose of 44 µSv (and this is likely an underestimation, as I explained here viewtopic.php?f=5&t=688).
I wonder how many of the people who shared that flight with me would have been too scared of radiation to follow me for a day in Fukushima where they would have been exposed to a dose nearly 30 times lower.

Massimo

[Conor Whyte]

Great post! I have visited Fukushima many times in the 1990's and again in March of 2000. Fukushima is still a beautiful area. It was so sad to see the devastation from the earthquake. I also lost friends in that quake and tsunami, many of whom lived in Sendai city and Miyagi-pref.
I had just returned to Canada after moving back temporarily from Seoul and then suddenly this tragic event occured. My sister-in-law was studying in Tokyo when the Mt 9.1 quake struck. ---many hours on the phone to the Red-cross.

This event hit me like a tonne of bricks.

[Go-Figure]

I can barely imagine what it was like to have friends and relatives in the area at the time of the earthquake and tsunami.
I've read and studied a lot about Fukushima over the years so I had been thinking for a long time that it'd be interesting to see with my own eyes and measure with my own instruments.
When I told people like friends and family about this idea the reaction was always the same "are you crazy? that's bloody dangerous!". Problem was I knew it wasn't dangerous at all, and I also knew that sort of misconception is precisely what is harming the recovery in the area, inflicting even more pain to the people already hit by such a catastrophe.
So in the end collecting data that would help me to challenge those misconceptions became one of the main reasons which, almost a year ago, convinced me to go.
Actually I didn't have any instrument back then, it all started because of that.

Massimo

[pilgrim]

Great post Massimo, very interesting, excellent work!

[Svilen]

Very nice reports Massimo, both of them! Thanks for taking the time to share this experience and the pictures too.
"Fear and misconceptions made far more victims than radiation around here" - this is a really important point and I also hope, that publications like this one, counter fight the radioactivity-related stigma stemming from misinformation and incompetence.

[gwgw]

A really interesting read!

[Sesselmann]

Massimo,

Thanks for sharing your adventure, great report, enjoyed reading it.

Steven

[Peter-1]

hello,
a very interesting report. Thank you for showing us the photos as well.

greetings
Peter

[luuk]

Hi Massimo,
Thanks for the nice report about your Fukushima trip, interesting reading material.
Luuk