福島第一核電廠除役建議書 by 綠色和平東亞分部 Greenpeace East Asia

《福島第一核電廠除役建議書》中文摘要前奇異能源核能顧問佐藤暁 2021. 3

簡介福島第一核電廠事故十週年的今天，核能設施完成除役的時程，與 2011 年首次宣布的時程無異──30 至 40 年間除役。唯全球 189 座停止運轉的核電站中，只有 20 座完成除役，其中更只有 10 座可以開放民眾參觀，可見除役的困難。過去十年來，福島第一核電廠除役工作也確實達成幾個重要指標。然而，日本經濟研究中心預計福島的除役作業將耗費 3,300~7,600 億美元，而且根據本報告的分析，東京電力（TEPCO）及「核損害賠償、廢爐支援機構」（NDF）等日本政府機關當前的計畫，無法順利在 30 至 40 年間除役。因此，本報告建議必須廢止 2011 年的除役計劃。本報告涵蓋的議題如下：

廢燃料棒的移除廢燃料棒貯存池的危害，大多仍未解決。福島第一核電廠四號機廢燃料貯存池中， 1,533 個燃料束的移除作業，於 2013 年 11 月啟動、2014 年 12 月完成。鑒於工程與技術上的挑戰，一號機和二號機貯存池的廢燃料棒移除作業，目前排定的時程各為會計年度 2024~2026 年及 2027~2028 年。然而，2019 年 4 月啟動的三號機相關作業現已中止，直至 2020 年 12 月 29 日為止，566 個燃料束中仍有 112 個留在用後燃料棒貯存池。從廢燃料棒貯存池轉移至共用貯存池的燃料束，最終將會裝進乾式儲存槽。如同所有核輻射污染材料、核廢料一般，廢燃料棒在日本無處可去，將無限期地於現地留存。

輻射地下水減量十年後福島第一核電廠最明顯的地貌變化，就是矗立超過 1,000 個大型儲存槽。這是為了冷卻燃料殘骸，而持續不斷地注水，加上 30 公尺深的凍土牆仍無法隔離地下水，使得受核輻射汙染水量仍以每日超過 100 噸的速度不斷增加。雖有

日本當局提出每日水量減少目標，然而目前針對本問題，卻無有效的解決辦法。儲存糟內的輻射廢水，經過濾後只有約 27%達至可排放的標準。

延後燃料殘骸取出作業 50~100 年目前福島第一核電廠處於除役第二階段的起點，正準備取出燃料殘骸。燃料殘骸來自 2011 年 3 月爐心熔毀時，蓄積在反應爐槽座內的約 609~1141 噸高放射性燃料棒。NDF 以 40 年內除役為目標，先後提出兩套計劃：A 計畫是利用「反應爐上方灌水法」（Flooded Top Access），即從反應爐上方進入，藉由灌水至圍阻體，在水下移除碎片；該計畫最後在 2018 年放棄，改採 B 計畫，即「反應爐旁側乾式法」（Dry Lateral Access）。福島第一核電廠中受損程度較低的二號機組，目前選為 B 計畫先導計畫的實驗對象，小規模演練移除燃料殘骸樣本。原先預計在會計年度 2019 年下半年啟動 B 計畫，卻推遲至會計年度 2021 年。然而在 2020 年 12 月，又將 B 計劃推遲至會計年度 2022 年。當前的 B 計畫或可移除小型燃料殘骸樣本，但難以如預期地有效、大量取出殘留在反應爐內部及底下的燃料碎片，可能限縮其他能完整取出燃料殘骸的方案。完全取出殘骸將遙不可及，甚至連如何從受損程度更嚴重的一號機組和三號機組取出小型樣本，都摸不著頭緒，反應爐內的輻射量對作業人員依然過高。首要的第一步，便是檢討當前的燃料殘骸取出計畫。同時，延後相關作業，以減少對作業人員的輻射危害，並開發先進機器人科技，在未來 50 至 100 年間或所需的時程內，以機器人進行取出作業。

建造具輻射圍阻的乾島本報告結論是，經由徹底反思，福島第一核電廠是有個合適的方案。否決掉 B 計畫後，C 計畫就此誕生，其中提出「乾島」（dry island）概念，以挖掘護城河的概念，在福島核電場建立 7 公里長的護城河，降低地下水的水位，遏止廠區地下水滲入。而既有的反應爐建物，將需要新圍阻體等多重安全建築結構，以阻擋輻射外洩。

福島第一核電廠做為儲存核廢料設施之長期管理

即使成功完全除役福島第一核電廠，推算也會產生 150~200 萬噸，可能被輻射污染的建築廢料，應被視為核廢料處理。然而，這已超過日本現在核廢料儲存設施的容量，因此，福島第一核電廠即便成功取出燃料殘骸，也只會於現地留存，而福島第一核電廠其實早已成為長期核廢料貯存場。免責聲明本報告作環保公益和資訊分享目的使用，不作為公眾及任何協力廠商的投資和決策參考，綠色和平亦不承擔因此引發的相關責任。本報告為綠色和平於研究期間內基於各種公開訊息獨立調查研究產出的成果，綠色和平不對報告中所涉及資訊的即時性、準確性和完整性擔保。詳細著作權及其他聲明以英文報告為主。

Fukushima Daiichi Decommissioning Time for a new long term strategic plan Greenpeace Briefing Shaun Burnie Greenpeace East Asia

March 2021

Briefing on “Decommissioning of the Fukushima Daiichi Nuclear Power Station - From Plan-A to Plan-B; Now, from Plan-B to Plan-C” by Satoshi Sato Written by: Shaun Burnie (sburnie@greenpeace.org), Senior Nuclear Specialist, Greenpeace East Asia Publish date: March 2021 Publisher: Greenpeace Japan and Greenpeace East Asia Seoul office Japan contact: kouhou@greenpeace.org South Korea contact: press.kr@greenpeace.org

Fukushima Daiichi plant, we were looking for an expert opinion on some of the main issues. GE was the main contractor and designer of the Fukushima Daiichi reactors, in partnership with Hitachi and Toshiba. Sato’s analysis, released by Greenpeace on 4th March 2021, points to the many problems with the current plans of TEPCO and the Japanese government. In fact, he concludes that the Strategic Plan of the Mid-Long Term Roadmap is unachievable in the timeframe proposed. Sato further concludes that an alternative path is desperately needed - a new approach that acknowledges the scale of the disaster and the amount of nuclear contaminated material and land. Sato gives the opinion that returning the site to greenfield is unattainable and that instead it is acknowledged what in reality it already is – a nuclear waste storage site. Rather than desperately trying to keep to an unrealistic and unattainable timetable, the report calls for a long term strategic approach. Beyond the decommissioning Plan A (abandoned by TEPCO in 2018), and the current unworkable Plan B, Satoshi Sato proposes a new Plan C.

Nine months after the triple reactor meltdown at the Fukushima Daiichi nuclear plant in March 2011, Tokyo Electric Power Company (TEPCO) announced that decommissioning of the site will be completed within 30-40 years. Practically, the people of Japan were told that some time between 2041 and 2051, the site would be returned to ‘greenfield.’ In the past decade, the complexity and scale of the challenge at the Fukushima Daiichi site has become slowly clearer. The decommissioning task at the Fukushima Daiichi site is unique in its challenge to society and technology. But still, the official time frame for TEPCO’s Road Map for decommissioning remains that set in 2011.

What is the reality of current official plans, and are there alternatives? To try and understand better the progress of TEPCO and possible alternatives, we commissioned consulting engineer Satoshi Sato.1 Having worked for General Electric (GE) for 18 years until the year 2002, including at the

1. Satoshi Sato is a consulting engineer, formerly a manager of technology and field engineering with General Electric (GE) Nuclear Division. For eighteen years (until 2002) he conducted over 100 inspections and assessments at Boiling Water Reactors throughout Japan. He was a GE site representative at the Fukushima Daiichi plant. His work included flaw evaluation, repair and inspection.

Main issues in Sato’s report

• Construction of steel structure containment over the main reactor buildings to prevent weathering and contamination of the wider environment • Delay nuclear fuel debris removal for 50-100 years or longer, reducing worker exposure and potential radiation contamination off site • Long term management of the Fukushima Daiichi site as a nuclear waste storage facility

• Spent fuel removal • Move to air cooling of reactor core fuel debris and consequent reduction in accumulation of contaminated water • Creation of a ‘dry island’ around the entire nuclear plant site through the construction of a 7km long deep moat – one aim being to stop groundwater contamination

The above diagrams show the 7km moat concept built around the Fukushima Daiichi site.

Comparison of Decommissioning Options Option

TEPCO - Plan A

Sato - Fukushima Closure Plan

Plan B

Plan C

Status

Aborted by 2018

Disqualified by IRID in 2014

On-going plan developed by NDF

New Proposal

End State

Green Field

“Dry Island” isolated by moat as final disposal site

Green Field (?)

“Dry Island” isolated by moat as final disposal site

Target Schedule

40 Years

Indefinite

Method to Isolate Groundwater Flow

Frozen Wall + Pump

Moat

Frozen Wall + Pump

Moat + Enhanced Air / Water tightness

Method to Cool Fuel Debris

Water-Cooled

Air-Cooled

Dicision Suspended

Air-Cooled

Underground Hot Cell Extendable Mast

Dry Lateral Access Multi-Axis Arm Robot

Humanoid Robot Human Body Motion

Not Discussed

Leave As-is after Decontamination

Method of Fuel Debris Retrieval Method to Dismantle RPV

Flooded Top Access Extendable Mast

(Partially Dismantled)

Leave As-is after Decontamination

Dismantling PCV, Rx. Bldg.

Not Discussed

Achievability

Extremely Difficult Uachievable

Difficult Achievable

Extremely Difficult (Unknown)

Presumably Easy

Safety / Exposure

Unacceptably Dangerous

Less Exposure

More Exposure

Minimum Exposure

(Partially Dismantled)

The above table shows the options for each of the main challenges at the Fukushima Daiichi site.

Global Decommissioning and Molten Fuel Debris

remain relatively few examples of successful completed decommissioning. As of mid-2020, 189 commercial nuclear reactors have been permanently shut down, of which 169 are awaiting or are in various stages of decommissioning.2 Only 20 units have been technically fully decommissioned - 14 in the U.S., five in Germany, and one in Japan. Of these, only 10 have been returned to greenfield sites.

Decommissioning of nuclear facilities - the dismantlement of reactor buildings and removal and storage of all contaminated materials, including high level waste spent fuel, is a complex and dangerous undertaking anywhere in the world. After nearly 70 years of the commercial nuclear industry, there

2. WNISR 2020, “Decommissioning Status Report – Soaring Costs”, in World Nuclear Status Report 2020, September 2020, See https://www.worldnuclearreport.org/The-World-Nuclear-Industry-Status-Report-2020-HTML.html#_idTextAnchor341

2030 – which would require approximately 30 reactors to operate. The prospects for attaining that goal are small. Greenpeace estimates in 2014 indicated an 8% share as more likely, with an upper range of 12-14%. One of multiple obstacles to restart reactors remains public opinion. Consistent polling shows the majority of the Japanese public oppose restarting nuclear reactors.

None of the decommissioning projects, completed or otherwise, include a nuclear power plant site with six boiling water reactors, three of which have suffered meltdown of their reactor cores. The most complex challenge at the site is the presence of an estimated 609-1141 tons of nuclear fuel debris, often referred to as corium. This material is estimated to lie at the bottom and under the Reactor Pressure Vessels of Fukushima Daiichi Units 1, 2 and 3.3 The plans to remove even sample amounts of this material from reactor Unit 2 are now not planned until 2022. The report to Greenpeace by engineer Sato makes clear that there are no plans on how to proceed beyond this stage and that the current approach through the side of the Reactor Pressure Vessel is not credible.

The Fukushima Daiichi disaster shattered what remained of the safety myth of nuclear power in Japan. By setting a timetable of only 30-40 years to successfully decommission the plant, not only the removal of all nuclear wastes and contaminated material from the site but from Fukushima prefecture, the government and nuclear industry are trying to assuage a critical public. ‘Even with a triple reactor meltdown we can solve the problem and return the site to what it was before’ appears to be the simplistic thinking on display. By these means, the hope is that public opinion will shift towards supporting nuclear power. However, like the timeframe set in their decommissioning Road Map – the prospects for success with this approach are close to zero.

A Road Map for restarting nuclear power not decommissioning The Fukushima Daiichi accident has been catastrophic for the prospects of nuclear power in Japan. Whereas 54 commercial nuclear reactors were available and operating in Japan in 2011, all were shutdown by 2013, and only nine have been restarted. Four are currently operating as of 1st March 2021. One direct link between the decommissioning of Fukushima Daiichi and nuclear energy are the efforts by TEPCO to restart its Kashiwazaki Kariwa reactors in Niigata prefecture. Despite being located in a high seismic zone and opposed by the majority of the public in Niigata, TEPCO are desperate to restart unit 6&7 reactors as a way of generating revenue in part to cover their annual decommissioning costs.4

The threats and challenges of Fukushima Daiichi are not going to be solved in the short term, not in decades and perhaps not within the next 100 years. Through that time, they will be a constant reminder to the people of Japan and beyond that the risks, consequences and legacy of nuclear power are long lasting.

The Basic Energy Plans of the Abe and now Suga Governments have set a target of 20-22% electricity to be generated by nuclear power by

3. The IRID estimated Unit 1 - between 232 and 357 tonnes, with a nominal value of 279 tonnes; Unit 2 - between 189 and 390 tonnes, with a nominal value of 237 tonnes; Unit 3 between 188 and 394 tonnes, with a nominal value of 364 tonnes.IRID, “Estimation of fuel debris distribution by the analysis and evaluation,” Japan Atomic Energy Society Fuel Debris Research Committee, 4 October 2016, http://irid.or.jp/wp-content/uploads/2016/10/20161004.pdf (in Japanese) 4. Greenpeace Japan, “TEPCO’S Atomic Delusion”, Shaun Burnie, 25 June 2018, See https://www.greenpeace.org/ static/planet4-japan-stateless/2019/08/3d2e8976-atomic_delusion.pdf

Conclusion

For the past decade, Greenpeace, along with others, have had severe doubts about the prospects for decommissioning. The analysis of Satoshi Sato helps us to understand why it’s justified to have these doubts. While it has been a long decade since the start of the Fukushima Daiichi nuclear disaster, there is no end date for when its legacy of contamination will be over.

During the past decade, the official narrative of 30-40 years to decommission Fukushima Daiichi has become almost like a mantra. But it is meaningless – delusional. What is reality, is that the cost estimates for the disaster only increase. In 2019, the respected Japan Center for Economic Research projected that the total costs for managing the Fukushima nuclear site and off-site, could range from 35-81 trillion yen, or US$330-760 billion.5 Ultimately, and almost certainly, the bulk of these costs will be covered by Japanese taxpayers and ratepayers. How such vast sums of money are to be spent and whether it has any prospect of being effective is a vitally important matter of public policy and accountability.

The Fukushima Daiichi disaster has impacted many tens of thousands of lives, the people of Fukushima prefecture most especially and not least the nuclear workers who have toiled in terrible conditions at the site and in the wider decontamination program over the past decade. The Japanese government and TEPCO owe it to these workers, and the many thousands to come in the future, as well as the citizens of Fukushima prefecture and broader Japanese society, to start an honest discussion of the prospects at Fukushima Daiichi. Not another year should pass without a new credible plan for Fukushima Daiichi and one that ends all talk of 30-40 year decommissioning.

The TEPCO officials and politicians today who maintain the pretense of a several decades to manage the decommissioning of the second largest commercial nuclear disaster in history will be gone by the middle of the century. Satoshi Sato in his analysis warns that by the 2040’s we will still only be in the early stages of dealing with this disaster.

5. JCER, “Accident Cleanup Costs Rising to 35-80 Trillion Yen in 40 Years”, March 2019, See https://www.jcer.or.jp/ jcer_download_log.php?f=eyJwb3N0X2lkIjo0OTY2MSwiZmlsZV9wb3N0X2lkIjo0OTY2Mn0=&post_id=49661&file_post_ id=49662