A moderately strong earthquake has rattled the Tokyo region, but there are no immediate reports of damage or injuries.
The Japan Meteorological Agency (JMA) says the quake hit at midday on Sunday with a magnitude of 5.
Its epicentre was 40km underground in Ibaraki prefecture, northwest of Tokyo.
[…]
Japan’s nuclear regulator says a nuclear power plant in the area suspended operations while it checked for any problems.
[…]
The “difficult-to-return zones,” which cover a total of 337 square kilometers, are areas where the radiation level exceeded 50 millisieverts per year after the accident at the Fukushima No. 1 nuclear plant. Those areas are off-limits, in principle.
In some of the areas, however, radioactive contaminants have been washed away by rain or blown away by wind. Radiation from those substances has also dissipated naturally.
In front of the Environmental Radioactivity Monitoring Center of Fukushima in the central district of Okuma town, the radiation level is now about 9 millisieverts per year, about one-fifth the level of five years ago.
According to the policies of the government and the ruling parties, if radiation levels are reduced to 20 millisieverts or lower in some areas due to decontamination work, people are allowed to live there.
Of the areas, those where residents or workers for decommissioning of crippled nuclear reactors are expected to live will be subject to intensive decontamination work along with areas on both sides of main roads.
[…]
According to the annual survey conducted by the Reconstruction Agency on evacuees, only about 10 percent of households evacuating from four municipalities around the nuclear plant are hoping to return home.
Read more at Some restricted zones to be lifted near Fukushima nuclear plant
このまま原子力推進に突き進んでいって、本当に大丈夫なのだろうか。
原子力発電所などの安全性を評価する新規制基準が設けられてから今月で３年が過ぎたが、発足当初に比べ原子力規制委員会の後退姿勢が目立ってきた。
原発再稼働を推し進めようとする電力各社などに厳しい姿勢で臨むことが求められたはずなのに、毅然（きぜん）とした対応に乏しい。
複数の原子炉が一気に炉心溶融（メルトダウン）に見舞われた福島第１原発事故の教訓が、はるかかなたにかすんでいるようにも思える。
不信感を抱かれかねない一例になったのが、原発の運転延長問題。規制委は先月初めて、運転開始から４０年が経過していた関西電力・高浜１、２号機（福井県）の延長を認めた。期間は「最長２０年」なので、結局は６０年もの長々期運転が可能になる。
原発の運転期間は福島第１原発事故の後、原子炉等規制法によって「原則４０年」と決められた。事故でウラン燃料が溶融した１～３号機は運転開始から３５～４０年の老朽原発だったことから、法律に「寿命」が盛り込まれたという経緯がある。
原発の耐用年数がおよそ３０～４０年だろうということは、事故のずっと以前から指摘されていた。たとえ重大な不具合が見つからなくとも、廃炉の時期を決めておくのは合理的な事故予防策のはずだ。
原子炉等規制法では確かに最長２０年の延長も認めているが、規制委が発足した２０１２年９月に田中俊一委員長は「４０年を超える原発は厳しくチェックし、運転させない姿勢で臨むべきだ」とまで話していた。
ところが、今年になって田中委員長は「お金をかければいくらでも（延長のための）技術的な点は克服できる」と発言しているのだから、理解に苦しむ。
[…]
もっと読む。
大飯原発･基準地震動の過小評価は深刻
関西電力・大飯原子力発電所の耐震安全性をめぐる問題で、2014年9月まで原子力規制委員会でナンバー2(委員長代理）を務めていた島崎邦彦・東京大学名誉教授(地震学）が、「原発が大地震に見舞われた場合の実際の揺れは現在の基準地震動(想定される最大の揺れ)を上回る可能性が高い」との見解を7月15日の記者会見で明らかにした。規制委は6月、島崎氏から大飯原発の耐震設計の基礎となる基準地震動算定で関電の計算に過小評価の疑いがあると指摘されたことを受けて、現在の計算方法を手直ししたうえで新たに検証計算を実施。その結果を踏まえて「耐震安全性には問題がない」との結論を7月13日付けで出したばかりだった。ところがその2日後、地震学の専門家である島崎氏から「基準地震動の過小評価は明らかだ」と、まったく逆の意見を突き付けられた。
規制委は7月19日に急遽、島崎氏を招いて意見交換の場を持つことになったが、規制委の耐震審査のやり方そのものが信頼性を問われる形になっている。
基準地震動の計算は再びやり直し？
7月13日の規制委会合で田中俊一委員長は、「島崎さんには原子力規制庁の事務方から試算結果を説明し、ご納得のうえで安心したとおっしゃっていただいた」と説明した。だが、15日の記者会見で島崎氏は納得どころか規制庁による試算方法のおかしさを指摘。「今回の規制委の議論および結論には納得できません」と記した田中委員長宛ての書簡の写しを配布した。「この問題の議論は打ち切り」(7月13日の規制委会合での田中委員長の発言）になるはずだったところが、規制委は基準地震動を再々計算しなければならない状況に追い込まれている。島崎氏が大飯原発の基準地震動評価について問題提起した経緯は、6月20日の記事「元原子力規制委員が大飯原発の危険性を警告」で詳しく述べている。その要点をかいつまんで説明すると、関電が大飯原発の基準地震動を計算するうえで採用した「入倉・三宅式」と呼ばれる活断層評価のモデル式を用いて地震モーメント(地震の震源の大きさ）を試算した場合、実際よりも過小評価となる可能性が高いというものだ。その結果として、基準地震動の過小評価にもつながり、ひいては原発の耐震安全性に懸念が持たれることになった。
[…]
もっと読む。
[…]
The LNT model has been repeatedly endorsed by scientific bodies like the National Academy of Sciences, the National Council on Radiation Protection and Measurements , and the International Commission on Radiological Protection.
I recently took part in a readers’ forum of Physics Today, a monthly magazine published by the American Institute of Physics. I was responding to an article written by Jeffrey Siegel, Charles Pennington, and Bill Sacks. Their article questioned the validity of the LNT model and supported a threshold model based on fruit-fly data collected 70 years ago. These authors have neglected the studies that showed the validity of the LNT model.
The diagram below shows the difference between the LNT model and an alternative threshold model. The threshold model suggests that below certain exposure levels, there is no observable risk of cancer from radiation. Adoption of the threshold model has an implication of relaxing the current radiation protection standards.
I responded to correct the inaccuracy by quoting the 2006 reportHealth Risks from Exposure to Low Levels of Ionizing Radiation: BEIR VII Phase 2, a 20-year study that followed 110,645 Chernobyl cleanup workers, and a cohort study of 308,297 workers in the nuclear industry which all showed a simple proportionate relationship between radiation dose and cancer risk.
Recently a petition was made to the Nuclear Regulatory Commission (NRC) to amend its “Standards for Protection Against Radiation.” Petitioners requested the NRC to remove LNT from the agency’s regulatory framework. NRDC submitted a comment opposing the petition. Not only NRDC, but even the Environmental Protection Agency itself, commenting on the petition , said: “[o]ver the last half century, numerous authoritative national and international bodies have convened committees of experts to examine the issue of LNT as a tool for radiation regulation and risk assessment … Again and again, these bodies have endorsed LNT as a reasonable approach to regulating exposures to low dose radiation.”
Read more at Hold Fast to Linear No-Threshold for Radiation Protection
文部科学省が、高速増殖炉もんじゅ（福井県敦賀市）の新たな運営主体に関する原子力規制委員会への回答を８月以降とする方向で調整していることが １６日、分かった。現運営主体の日本原子力研究開発機構から関係部門を切り離し、新法人を設置する方向。核廃棄物の有害度を減らすための実験なども事業目 標に盛り込む方針だ。
文科省は、国の核燃料サイクルの一翼を担う新法人を完全民営化するのはなじまないとして、国の権限が強く及ぶ特殊会社や認可法人などの形態を軸に検討している。
More than one million packages of radioactive nuclear material are transported within Canada every year, from spent nuclear fuel to nuclear gauges for breweries. Now the government is gearing up to make sure that they’re safe and sound, although it won’t be seeking to update outdated and potentially inadequate safety regulations.
Both the Canadian Nuclear Safety Commission (CNSC) and Transport Canada have regulations in place for the transport of radioactive material, but the CNSC, which is responsible for ensuring Canada’s handling of nuclear material is up to international standards, is soliciting input for a planned Transport Risk Assessment that it hopes will “provide confirmation” that the risks “are low and the safety of packages is high.”
These risks might include vehicle collisions and the risk of releasing radioactive material in the event of a fire or a package being dropped, according to Edwin Lyman, senior global security scientist with the Union of Concerned Scientists.
But international standards for these kinds of tests were developed decades ago, Lyman said, and don’t take into account collisions on high-speed roadways. According to a CNSC spokesperson, the risk assessment is meant to “refine current techniques” and will not “identify ‘unsafe practices or inadequate regulations’.”
[…]
Another kind of transport risk—missing nuclear material—won’t be addressed by the CNSC’s planned risk assessment, a spokesperson for the regulator confirmed. CNSC report released last year revealed that in 2014-2015, 14 packages of radioactive material simply went missing. Of those, six were recovered. In 2012-2013, 16 packages of radioactive material went missing, and only five were recovered.
Read more at Canada’s Nuclear Material Risk Assessment Won’t Look Into Unsafe Practices
鹿児島県知事選で当選した三反園訓（みたぞのさとし）氏が公約通り、九州電力に川内原発（同県薩摩川内市）の一時停止や再点検を申し入れた場合の対応について、九電の山元春義取締役（原子力担当）は「長期間、安全第一で運転してきた。（申し入れがあれば）丁寧にきっちり発電所の状況を説明させていただきたい」と述べ、運転継続に理解を求める考えを示した。１５日、同原発を視察した県議会総務委員会の委員の質問に答えた。
山元取締役は「国の規制基準をクリアし、安全をしっかり守っている。まずはしっかり安全運転を続ける」と継続運転を強調した。
定期検査でいったん停止させた原発を再び稼働させる際、法的には県知事や地元の薩摩川内市長の同意は必要はない。
ただ、三反園氏は「脱原発」を公約に掲げており、今後、地元の理解をどうやって得るかを問われた山元取締役は「現段階では定期検査の計画については変更ない。手順通りに地元に報告しながら進めていく」と説明。熊本地震を受けた施設の点検については「揺れはあまりなかったが、地震計など機器を入念に確認していく」と安全確保に取り組む考えを示した。
[…]
もっと読む。
China aims to launch a series of offshore nuclear power platforms to promote development in the South China Sea, state media said again on Friday, days after an international court ruled Beijing had no historic claims to most of the waters.
Sovereignty over the South China Sea is contested by China, the Philippines, Vietnam, Malaysia, Brunei and Taiwan, and any move to build nuclear reactors is bound to stoke further tension in the region.
The China Securities Journal said 20 offshore nuclear platforms could eventually be built in the region as the country seeks to “speed up the commercial development” of the South China Sea.
“China’s first floating nuclear reactor will be assembled by the China Shipbuilding Industry Corporation’s (CSIC) subsidiary, Bohai Heavy Industry, and the company will build 20 such reactors in the future,” the newspaper said.
“The marine nuclear power platform will provide energy and freshwater to the Nansha Islands,” it said, referring to the disputed Spratly Islands.
[…]
Read more.
Nuclear power means nuclear waste and the Czech Republic, like many other European countries, is faced with the headache of where to store the waste long term. A shortlist of seven locations for geological tests for suitable deep storage resulted in howls of protest from most of the citizens and mayors living near the sites. And that has forced a rethink from the ministry and state body piloting the selection process.The Czech Republic has been producing nuclear power for just over 30 years now with the two plants at Dukovany and Temelín responsible for producing around a third of the country’s electricity. And there are plans to boost that proportion with more plants in the future.
But the high level nuclear waste produced from the process is still being stocked on site at the plants with plans for a deep storage site hitting furious opposition from most of the seven preliminary sites earmarked for geological tests. Five of those sites have launched or allied themselves to legal proceedings aimed at stopping the surveys and sent back millions of crowns in payments aimed at compensating locals for the inconvenience.
Now the Ministry of Industry and Trade says it will bow to the opposition and seek to push ahead with surveys at one locality near Třebíč in Vysočina and another straddling Vysočina and South Moravia.
Minister Jan Mládek said the decision was not a defeat for the ministry:
“I would put it completely differently. We are in the search for consensus because we do not believe that we can build a permanent storage facility for used nuclear fuel in the localities where the municipalities are hostile to this idea. So we are trying to reach a consensus. At the same time, we need the places which are geologically stable, which are good for possible building of permanent storage for nuclear fuel. And we hope in this way we will reach a consensus in a quicker way.”
And do you think there is a real chance that the remaining two localities will accept the idea?
“Yes, because they were the localities that did not start court action against the state.
[…]
Read more.
A nuclear power plant in Byron, Illinois. Taken by photographer Joseph Pobereskin (http://pobereskin.com).
