#Radioactive Materials Leak at Japan Proton Accelerator Research Complex (J-PARC) in Ibaraki, Researchers Accidentally Inhaled Radioactive Gold

(UPDATE 2) For the latest, see my posts here and here.

(UPDATE) From Jiji Tsushin (5/25/2013):

施設内の放射線量が上がった際に担当者が換気扇を回し、外部に放射性物質を放出していたことが25日、分かった。許可を出した三浦太一・高エネ研教授は会見で、「通常運転時も半減期の短い放射性物質で線量が上がることがあり、すぐ減衰するとの認識だった。結果として浅はかだった」と謝罪した。

When the radiation level inside the facility rose, the person in charge turned on the ventilating fan and released radioactive materials outside the facility. Professor Taichi Miura at High Energy Accelerator Research Organization, who authorized the ventilation, apologized in the press conference, saying "Radiation level rises even in the normal operation because of radioactive materials with short half life, so we thought they would decay quickly. But it turned out to be imprudent."

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Japan Atomic Energy Agency (JAEA), who operates J-PARC, didn't bother to notify the Nuclear Regulatory Agency (secretariat of the Nuclear Regulatory Authority, mostly made of people from NISA) for 2 days, because they did not think there was any leak of radioactive materials.

According to Asahi, the researchers suffer internal radiation of exposure of 1.7 millisievert, and the contamination of the facility is 40 becquerels per square centimeter.

Apparently, the Ibaraki prefectural government was not too happy about the incident and the fact that JAEA didn't bother to notify the authority and the prefectural government, and held an angry press conference at 2AM on May 25.

The official story of the accident, from Asahi Shinbun (5/25/2013, 1:37AM):

原子力機構で放射性物質漏れ　研究者ら４人が内部被曝

Radioactive materials leak at JAEA facility, 4 researchers suffer internal radiation exposure

日本原子力研究開発機構は２５日、茨城県東海村のＪ―ＰＡＲＣの原子核素粒子実験施設で、放射性物質が施設の外に漏れたと明らかにした。中にいた研究者ら少なくとも４人が内部被曝（ひばく）した。漏洩（ろうえい）は止まっており、拡大の恐れはないという。被曝した４人のうち、最大の被曝量は１・７ミリシーベルトという。原子力機構は外部に漏洩した放射性物質の量を調べている。

Japan Atomic Energy Agency disclosed on May 25 that there was a leak of radioactive materials outside the nuclear and particle research facility at J-PARC in Tokai-mura in Ibaraki Prefecture. At least 4 researchers inside the facility suffered internal radiation exposure. The leak has stopped, and there is no danger of the leak spreading further. The maximum radiation exposure was 1.7 millisievert, according to JAEA. JAEA is currently investigating how much radioactive materials have leaked outside the facility.

原子力機構や原子力規制委員会によると、放射能漏れがあったのは２３日午前１１時５５分ごろ。陽子ビームを金にあて素粒子を発生させる実験をしていた。装置が誤作動を起こして陽子ビームは通常の４００倍の出力になり、金が蒸発。放射性物質が漏れて研究者が吸い込んだ。現場には当時、研究者ら約３０人がいたという。

According to JAEA and the Nuclear Regulatory Authority, the leak took place at 11:55AM on May 23. They were conducting an experiment of generating elementary particles by hitting gold with proton beam. The equipment malfunctioned, and the output of the proton beam increased to 400 times the normal strength, and gold was vaporized. Radioactive materials [radioactive gold vapor] leaked [from the equipment], and were inhaled by the researchers. There were about 30 researchers when the accident happened.

施設の汚染は最大で１平方センチあたり約４０ベクレル。現在、施設内を立ち入り禁止にしている。原子力機構は発生当時、外部への放射能漏れはないと考え、国に報告しなかった。Ｊ―ＰＡＲＣは大型の加速器を備えた素粒子などを調べる実験施設。

Contamination of the facility is about 40 becquerels per square centimeter maximum. Currently the facility is off-limit. At the time of the accident, JAEA didn't think there was a leak of radioactive materials, and did not report to the government. J-PARC is a facility to study elementary particles with large accelerators.

Equipment malfunctioned. That's the official story.

Let us now turn to "baseless rumors" among knowledgeable researchers (like this one, from Professor Hayano of Tokyo University) for what may really have happened. According to the unverified rumors, it was not the equipment that malfunctioned. Researchers made a mistake, and instead of hitting the target (gold) with low, continuous proton beam over a long period of time they accidentally hit it with high-intensity proton pulses.

According to NHK quoting the Ibaraki prefectural government, the monitoring post outside the facility showed a slight increase in radiation level between 3PM and 6PM on May 23. The radiation level is normally between 70 to 130 nanogray/hour, but it rose by 10 nanogray/hour on May 23.

Never trust the Japanese with a gigantic facility like a proton accelerator. Or a nuclear reactor. They are not only incapable of operating them properly, but when an accident happens they don't tell you.

(How do you get rid of radioactive gold in the body? Does anyone know?)

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