Radiological Protection of People and the Environment in the Event of a Large Nuclear Accident


Draft document: Radiological Protection of People and the Environment in the Event of a Large Nuclear Accident
Submitted by Shinpei Tanno (Sugar Nat), HIT (Hotspot Investigators for Truth)
Commenting as an individual

First of all, about the new publication, it says that in emergency exposure situation responders and even residents are able to be exposed to radiation under 100mSv or 100mSv/year. ICRP Publication 103 or 111 are totally different from the new publication. From the viewpoint of selecting from the standard of 20mSv-100mSv compared to the previous publication103 and 111, it is clear that the inhabitants are exposed to more radiation.It is considered that the concept based on ALARA's principle is to allow residents to evacuate or move as long as over 1mSv or 1mSv/year of exposure to radiation. At the very least, the standards for publication103 should not be changed.

Then, in publication 111, the standard under the existing exposure situation is to select 1-20 mSv / year from below, but in the new publication, it is 10 mSv / year or less. Although it is gradually lowered, this suggests only an option to be dealt with by decontamination or weathering during that time and does not allow evacuation or migration from places with exposure doses of 1 mSv/year. Under the existing exposure situation, the standard should be 1 mSv or less, which should be the minimum standard in accordance with ALARA principles. At least publication103 and 111 standards should not be changed.

The value of the radiation control area level was found even in the area of ​​Mizumoto Park, Tokyo, in an area below 1 mSv/year. 4 out of 15 locations exceeding 40,000 Bq / u were found. Enter the detailed data for that one location.

Mizumoto Park C Block 

The date of making the sample: 

2019/2/24 16:25〜17:07

 

GPS: 35.783493,139.886998

Scintillation Counter Hotspot Finder(30sec average value)

5cm  from the ground 0.114μSv/h

1m   from the ground 0.115μSv/h

Measurement Data from Fukushima Preservative Service Association of Health 

Germanium Semi-Conductor (SEG-EMS)

Measurement Date:2019/5/21

Measurement Time: 3600sec Sample Weights 78.9

Container: U8(100ml)

 

Cs134  144Bq/Kg±6.58Bq/Kg

Cs137 1,810Bq/Kg±23.1Bq/Kg

All Cs  1,954Bq/Kg

 

77,085Bq/u



The maximum reading’s hotspot in the park is also listed. In addition, since this hot spot was the responsibility of Katsushika City, Katsushika City measured and decontaminated. Katsushika City measured September 27, 2019. The value of 1cm on the ground surface is 2.9μSv / h. The value of ground surface 1m was 0.49μSv / h. In addition, it is the place where decontamination was performed on October 1 and 2, 2019.

Mizumoto Park A block ”Kawasemi no Sato” (gutter's mud) (East Tokyo)

2019/03/02/ 13:43ー15:11

GPS 35.794338,139.861267

Weather: Sunny day  The day before making the sample: Rainy day

Sample: (wet)(gutter's mud)

Scintillation Counter Hotspot Finder(30sec average value)

 

Major Factor of the hotspot 

 Administrators in this facility called Kawasemi no Sato took gutter's mud and under a downspout mud.They threw it away in the bush along with the building. Even though the Ministry of the Environment acknowledges that gutter's mud is highly contaminated. Because of the vast amount of the mud, it makes ambient radiation readings 3 meters away from the center of the hotspot quite high.

 

The range of the hotspot: 220cm x 550cm

Sampling range of the hotspot: 12.5cm x 10cm

Depth of the hotspot: more than 5cm

Sampling Depth: 2cm

 

Measurement Data from Fukushima Preservative Service Association of Health

 

Measurement Data

Measurement Date: 2019/05/21

Cs134   2,536Bq/Kg  ±32.5Bq/Kg

Cs137 33,033Bq/Kg  ±116Bq/Kg

All Cs    35,569Bq/Kg 

Sample Weights 119.9g

Measurement Time: 1800sec

 

Readings above the hotspot 

1m 0.573μSv/h、50p 1.130μSv/h、5p 2.881μSv/h

 

Readings 3 meters away from the center of the hotspot

1ⅿ 0.162μSv/h、50cm 0.156μSv/h、5cm 0.116μSv/h

Even below the air dose value of 0.23 μSv / h, which is the national index value of 1mSv/year, there are scattered hotspots that exceed the Shiteihaikibutsu(Shiteihaikibutsu is the specified waste exceeding over 8,000Bq/Kg) level.This hot spot was the highest in Mizumoto Park, but 13 out of 34 samples exceeded 8000 Bq / Kg.Shiteihaikibutsu is safely disposed of with incineration ash generated at the drainage facility or incineration facility after the nuclear accident or incineration sludge exceeding 8,000 Bq / Kg with the worker protected with a mask or tiebeck(protective clothing). It is a standard that can be done. This safety is a question, but in the first place, there are situations where there are things that must be protected by bringing a mask or tiebeck to the living space.The fact that the risk surveys, hot spot hazards, and even decontamination responses are not written cannot be overstated.This is the situation even on land below 0.23μSv / h.

Furthermore, although samples were taken in the Karino area of ​​Namie-machi in Fukushima, a residential restricted area where surface decontamination was performed, there were many places where contamination remained dark even after decontamination was completed. As of February 26, 2017, the air dose to the school route around Karino Elementary School was the lowest value at 1m from the ground was about 0.6 μSv / h, and the highest value at 1m from the ground was about 1.7 μSv / h. The air dose in the forest in front of Karino elementary school was an average of 2 to 3 μSv / h. The highest value was 3.8 μSv / h. The measuring instrument was Hotspot Finder. Is this safe? Even if only the air dose is seen, it is the value of the radiation control area. There is also a sample from the Karino area. This is also described.

Karino in Namie-machi in Fukushima prefecture

2017/02/26 10:24−11:57

 

37.37.507075,141.951347

 

The day made a sample was Sunny day

Soil condition: slightly dry

Instruments Hotspot Finder、TERRA-P MKS05

 

The major factor of the hotspot

There is a dent in between roadway and sidewalk. Environmentally enriched by rainwater.

The sample is consists of soil, moss, and sand.

width15cm,length 27cm

 

Measurement result

Cs134   43,027Bq/Kg  ±4,303Bq

Cs137  268,993Bq/Kg  ±26,900Bq

All Cs  312,020Bq/Kg ±27,242Bq

 

Readings above the hotspot

1m 3.32μSv/h、50p 5.83μSv/h、5p 20.4μSv/h

(only 5cm on the hotspot was measured by TERRA-P MKS05. other readings are Hotspot finder.)

 

Readings 2m away from the hotspot

1ⅿ 1.23μSv/h、50cm 0.93μSv/h、5cm 0.57μSv/h

 

 

hotspot area 

width 32cm、length 15cm

 

 

This value is the value of Shiteihaikibutsu level. However, Shiteihaikibutsu exceeding 100,000 Bq / Kg is a value that must be strictly managed in the concrete structure. In such a situation, Some parts of Namie such as Karino is no longer restricted areas while such a level of contamination remained in the living space.The Karino area is a formerly restricted area at the end of March 2017. The standard for the restricted area’s cancellation is too high. The concept is that the air dose should be 3.8 μSv / h or less in terms of air dose. Forest areas are not covered by the indicators. As a result of the management using only μSv / h, it is a fact that the country did not investigate such hot spots and could not even grasp the situation even after the surface decontamination. The new publication does not include such a risk management concept.

Then, in the residents' living space such as the area of ​​40,000 Bq / m2 or more per square meter be considered for surface decontamination. It is clear that it is not excessive to manage risk at a minimum. 

There is an example in which soil exceeding 100 Bq / Kg in the recycling standard established by the IAEA is detected even in places below 1mSv/year. There is no mention in the new ICRP publication on this. ICRP needs to answer this.

The statements in the new publication are often deviating from the ICRP ALARA principle. There is no threshold of radiation levels for the effect of health risk. This is the principle of ICRP thought.

Thinking about protective measures from a social, psychological, and economic point of view seems unlikely that the Scientific Committee carries out the logic of science. This is also considered to deviate from the ALARA principle. At least, it should be the same as the Chernobyl Law, and as with the Chernobyl Law, the response at Becquerel should be determined based on the actual measured value of soil contamination using soil contamination. Specifically, 185,000 Bq / u plus 1 mSv / year (Conservatively, the additional exposure is a 24-hour calculation of 0.114 μSv / h) should be written in the new publication as an area where immigration rights occur. Over 37,000 Bq / m2 should be described as a zone that is recognized as a radioactively contaminated area.

The radioactive contamination in eastern Japan as of 2010 was 72 Bq / Kg in Nagano Prefecture. If the soil density is 1.3、it is only 4,680 Bq / u. The median is 4.2 Bq / Kg. If the soil density is 1.3, it is 273 Bq / u. It is true that this was the value in Kankyohoushasen Database(the environmental radiation database supervised by the NRA.)It is clear that there is an obvious increase in dose values ​​from soil contamination after the Fukushima nuclear accident.

Although it is a district that exceeds 1mSv/year, it is not Fukushima Prefecture, the Ministry of the Environment found out in 2011 a Becquerel survey of the hot spot in Nedo in Kashiwa City in Chiba prefecture. Rather than 8000 Bq / Kg, it is a fact that a value exceeding 100,000 Bq / Kg was found in the living space. It is a fact that the enhancement of decontamination measures to make these hot spots at least ZERO must be included in the publication. The Ministry of the Environment's decontamination guidelines version 2 does not clearly state that hot spots will be dealt with actively.

That is why Japan seems to say that residents should coexist with hot spots that are scattered in a situation where no protective measures are taken. There must be no such thing. Therefore, it should be stated that it is necessary to make ZERO hot spots exceeding 8000 Bq / Kg at a minimum. This is even though far from the ALARA principle.

From these viewpoints, based on the ALARA principle, we would like to ask for a rewrite of the measures with at least the same contents as the Chernobyl Law.

I think that thinking about science from a social, psychological, and economic perspective is abandoning science.

We demand that the new publication requires a form that shows the idea of ​​the precautionary principle based on the ALARA principle from the scientific point of view.


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