Radiation monitoring in Japan
Encyclopedia
Radiation levels in Japan are continuously monitored in a number of locations, and a large number stream their data to the internet. Some of these locations are mandated by law for nuclear power plants and other nuclear facilities. Some of them serve as part of a national monitoring network for use in a nuclear emergency. Others are independent monitoring stations maintained by individuals.

Interest in the levels of radiation all over the nation increased dramatically during the Fukushima I nuclear accidents. At that time, a number of people began streaming from monitoring stations, and some international organizations conducted special monitoring operations to asses the state of radiation levels near the power plant and throughout Japan.

Monitoring at Nuclear Power Plants

Regulations per the Japanese Nuclear Safety Commission
Japanese Nuclear Safety Commission
Japan's is a commission established within the Cabinet of Japan as an independent agency to play the main role in nuclear safety administration. Commissioners are appointed by the Prime Minister of Japan on Diet approval...

 prescribe some standards that a monitoring system at a power producing nuclear plant must adhere to. For the purposes of regulation, monitoring systems are divided into two categories.
  • Category 1: Design of the monitoring system has to fit S-class seismic criteria and have diversity and independence in the channels that constitute the system.
  • Category 2: These detectors are connected to the plant emergency power system.


Additionally, a condition for both categories is that it have the ability to monitor continuously and record its results.

During normal operation, plants have to monitor gas and liquid radioactive effluent releases. The only type that requires continuous monitoring is radioactive noble gasses, although some require monitoring only for every discharge. Other types of radiation must be monitored weekly or monthly according to the regulations.

Operating power plant sites stream readings from environmental radiation detectors located around or on periphery of the site, detectors measuring radiation levels leaving the plant stack (gaseous effluents), and detectors monitoring the radiation of the discharged waste heat water. Official monitoring websites of nuclear power plants in Japan are listed below.

Monitoring Organizations and Individuals

Radiation monitoring in Japan is preformed and publicly streamed by a number of organizations and individuals.

SPEEDI Network

The Nuclear Safety Division of the Ministry of Education, Culture, Sports, Science and Technology streams information from a national network of detectors, called the System for Prediction of Environment Emergency Dose Information (SPEEDI). It has been called a "computer-based decision support system" by researchers, and its function is for real-time dose assessment in radiological emergencies. In 1993 it had been developed for domestic local range accidents and was in the process to scale up to a national scale emergency response program linked to local governments. A worldwide version (WSPEEDI) was under development.

The government recommendation that people voluntarily evacuate from places in the 20-30 km range from the Fukushima Daiichi plant came after the Nuclear Safety Commission
Japanese Nuclear Safety Commission
Japan's is a commission established within the Cabinet of Japan as an independent agency to play the main role in nuclear safety administration. Commissioners are appointed by the Prime Minister of Japan on Diet approval...

 watchdog released forecasts based on SPEEDI measurements. It was found that radiation levels differed significantly based on geography and wind direction, and it was suggested that because of this, the way evacuation areas were being designated should be changed and become more detailed. The Yomiuri Shinbun calculated radiation doses based on data from the Fukushima prefectural government and found they corresponded with the forecasts.

On the evening of March 15, Mr. Kan called Mr. Soramoto, who used to design nuclear plants for Toshiba, to ask for his help in managing the escalating crisis. Mr. Soramoto formed an impromptu advisory group, which included his former professor at the University of Tokyo, Toshiso Kosako, a top Japanese expert on radiation measurement.
Mr. Kosako, who studied the Soviet response to the Chernobyl crisis, said he was stunned at how little the leaders in the prime minister’s office knew about the resources available to them. He quickly advised the chief cabinet secretary, Yukio Edano, to use Speedi, which used measurements of radioactive releases, as well as weather and topographical data, to predict where radioactive materials could travel after being released into the atmosphere.

Ishikawa Lab, Hino, Tokyo

A lab in Hino Tokyo received major attention after the accident. The researcher was streaming readings from a Geiger counter bought six years ago on his website.

Pachube
Pachube
Pachube is an on-line database service provider allowing developers to connect sensor data to the Web and to build their own applications on it....

The site Pachube allows users to stream various sensor data to the web in real time and was put to use for monitoring radiation by a large number of users after March 2011. There was only 1 location streaming into Pachube before the accident, but a large number have since started to stream to the site. The community has converged on a standard way to report the information in order to disseminate the large variety of sources, such as detector model.

The manager of developer relations at Pachube said that he foresaw a range of applications of the data, including cell phone applications. He also noted that the sensors will allow people to cross-check readings for accuracy and could inspire healthy skepticism. Pachube has hundreds of Geiger counters streaming, but there are still concerns that these may not be dense enough.

RDTN

The site RDTN.org is another crowd-sourcing initiative to gather and disseminate radiation data that was set up after the Sendai quake. RDTN launched a micropatronage campaign to raise $33,000 in order to buy 100 Geiger counters to jumpstart their network. Their goal is to assemble 600 Geiger counters to provide independent measurements of radiation. The intent is to provide additional context to the official word, not a replacement.

Monitoring by International Organizations in Japan

After the Fukushima disaster begun, some international organizations conducted operations in order to aid in emergency efforts.

Greenpeace

Greenpeace sent radiology experts to the villages of Iitate
Iitate, Fukushima
is a village located in Sōma District, Fukushima, Japan.As of 2003, the village has an estimated population of 6,858 and a density of 29.80 persons per km²...

and Tsushima in the Fukushima Prefecture. They found levels up to 100 mSv/h in the village of Iitate, and based on that, recommended that the government widen the 20 km no-go zone, which Iitate lies outside of, to at least 30 km. An official of the NSA said that high radioactivity levels detected by the NGO could not be considered reliable, although some members of Greenpeace stressed that their numbers corresponded in other areas. The New York Times called the reporting by Greenpeace (with a well-known anti-nuclear position) a "guarded endorsement to the radiation data published by the Japanese government", due to the general correspondence between the numbers. Members of Greenpeace stressed that there has been distrust of the official data, and that their contention was not the radiation levels, but the action that was taken.

United States Federal Agencies

Three days after the earthquake, the DOE, along with the NNSA sent 33 people and 8.6 tons of equipment to Japan, including consequence management response teams and a NNSA aerial system that took thousands of radiation readings over the next two weeks.

Monitoring in Other Nations

The South Korea Korea Atomic Energy Research Institute operates 59 radiation monitoring centers across the nation of South Korea. After the Fukushima disaster begun, radiation monitoring activities increased across the country but radiation levels remained normal.

External Links

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