CNN又在危言聳聽，真的是自毀信譽。
About CNN's "news" - US assessing reported leak at Chinese nuclear power facility ..
https://twitter.com/pretentiouswhat/status/1404330429214203906
(1)
Taishan is a Chinese plant built with French technology with a large French equity stake and Framatome is a French MNC offering technical services everywhere around the world (including the USA).
(2)
Taishan is owned by CGN, which is on the US Entity List. Thus it would normally be forbidden to transfer US-derived technical information or data to CGN. A waiver may be obtained, however, for reasons of "operational safety", which is what Framatome is applying for.
(3)
They're likely applying because either A. the information they are preparing to transfer originated in the US, or B. they don't want to impact their business in the US by doing work with CGN without full transparency. Probably both actually.
(4)
So doesn't sound like Framatome reached out for help per se. Rather, they reached out for approval to conduct work to fix/mitigate the problem.
If there's no safety threat, as this paragraph starts, then the rest is just silly, superfluous, and alarmist :
(5)
IMO, the technocratically-inclined nuclear specialists in the US DOE and NRC are way unlikely to take concern troll political cheap shots (unlike, e.g. the State Dept).
If they say that it's not an issue, then CNN et al. are left scrambling for innuendo to gin up concern...
(6)
As for why ambient dose around the plant is exceeding the approved levels, that could be due to any number of things. One or several cracked fuel rods in the core might do it. Cracked fuel rods are pretty common, usually due to manufacturing defects.
(7)
You wouldn't normally shut down a reactor and refuel for cracked fuel rods though. You keep operating, and do a bunch of physics calculations to restribute power in the core, and also redo environmental dose calculations. This work is possibly what Framatome is applying for. 😎
The article doesn't cite any figures for the original allowable dose level or the doubled dose level. So it's pretty hard to tell if its anything to be concerned about. These allowable limits are usually set super low by several orders of magnitude, though.
(8)
To illustrate that point: Compare normal plant worker dose per annum versus the dose level likely to cause an increase in cancer risk:
Update: AFP has a quote from EDF (the 30% owner of the plant) saying there is an issue with noble gas buildup, which supports the theory of failed (cracked) fuel rods IMO.
Detection of radiation from Xe-133 or Xe-135 is one of the main methods for detecting this.
it's a undesirable but fairly common phenomenon. It's also called "fuel failure".
Here's an older, but very authoritative summary if you're feeling nerdy:
https://www-pub.iaea.org/MTCD/Publications/PDF/te_1345_web/t1345_part1.pdf
這邊有中文的詳細說明:
整个事件过程中，机组状态稳定，无其他异常。根据《国际核与辐射事件分级手册》，该运行事件被界定为0级事件。
核子小孩：本文是事件曝光五天的一些新資料、核工專家說法整理及部分個人分析。要留意的是：
1. 現時並沒有任何機構或研究組織測到異常輻射；
2. 絕大部分專家都指向是少量燃料棒有破損，有輻射墮性氣體進入一循環管道，甚至未滲入圍阻體，也沒有進入自然環境；
3. 氙135等含輻射惰性氣體積聚在壓水堆，是會減慢核反應，降低功率，而不是讓其爆炸；且其可經一循環的過濾系統處理；
4. 法方主要是因為中廣核已被列入美方限制清單，才要向美方申請豁免，以利用已有技術穩定墮性氣體的濃度；
5. 台山EPR反應堆的核燃料都是法國原廠組裝封箱送過來，他們也負責未來8年零備件維修服務，中國暫還未購買EPR任何產品的授權生產權(即還未有權生產任何相關產品)。
照部分核工專家所云，較傾向是一個反應堆(尤其是早期反應堆)常遇到的問題：燃料粒或燃料棒封裝外殼裂開。基本上封裝可以只容許中子穿過並進行受控的裂變反應，而絕大部分裂變殘留物都會留在封裝內。不過一個反應堆隨時有五萬支以上燃料棒及數十萬(甚至百萬)顆鈾鋯合金燃料粒，有少量出現瑕疵的機會並非不常見，再加上製造、運輸或安裝時出現小問題，也容易令燃料封裝破裂，破裂後就會滲出一些帶放射性的惰性氣體如氙135或氪同位素，大都是半衰期10日內的物質，之後大都會變成可固化的中低輻射度廢物。
根據Katie Mummah所言，美國過去面對燃料棒破損的經驗，大約是小規模的繼續運行，然後讓第一迴路的水流經過濾系統濾出並存放到封罐內，再等十多日衰變到較低輻射能量的物質，能固化的就固化成中 / 低度核廢料處理，無法固化的就稀釋排走，直到下一次大修時才取出損壞的燃料棒 / 粒處理掉；若是較大規模的話，因為氙135是中子毒葯，大量積聚會吸收過多慢中子，大幅減低反應堆功率甚至停止運作，就要停機並取出燃料棒，並進行清洗工作了；台灣方面也有核工程師(張文杰先生，現任中山科學研究院工程師)在自己的面書專頁指出台灣處理三間核電廠的手法，其實沒什麼分別。再講，IAEA 2003年其實已編輯了一套300多頁用於當年一個技術會議的論文「學報」，當中已提到不少燃料封裝破裂處理的流程。總之這種問題無論嚴重與否，一早就有既定流程可處理。
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