decommissioning of nuclear power plantyankee rowe nuclear power plant before after decommissioning...

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The Electrochemistry Lab, Department of Engineering and System ScienceNational Tsing-Hua University

GROUP A

Decommissioning of Nuclear Power Plant

Auguest 2nd, 20191

2019 Maintenance Science

Summer School

presenter:土屋克嘉 Katsuyoshi Tsuchiya張孫易 Sun-Yi,CHANG蔡謹年 Ching-Nien,TSAI鄭雅云 Ya-Yun,CHENG施湘鈴 Hsiang-Ling,SHIH小松啓祐 Keisuke Komatsu小嶋拓実 Takumi Ojima

中野雅紀 Masanori Nakano


Outline

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Summer School

IntroductionDecommissioning of nuclear power plantThree decommissioning strategiesAnalyzing Pros and ConsFlow chart of decommission

Waste Management in Japan Current situation in Japan Waste Management in Taiwan Current situation in Taiwan Conclusions

プレゼンター

プレゼンテーションのノート

This our outline. Finally we will have some conclusions about this presentation.


Decommissioning of nuclear power plant

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What is “ decommissioning” ?Decommissioning is the process by which nuclear power plants are retired from service. Decommissioning is the final stage in the life of nuclear power plants.

Why do the nuclear power plants need to be decommissioned ?1) no economic benefits2) end of life3) outdated technology4) Termination of operational tasks5) changes in government policies 6) serious accident

The most important purpose of decommissioning is to remove the regulatory controls from facility, and then we can start reusing the site.


Summer School

プレゼンター


First, We want to explain what decommissioning is, in general way. Second, there are several reason for the decommissioning. Like, no economic benefits. ~~~~ And end of NPP life, outdated technology. Because some of NPP have operated for several years, they would terminated the operation license. Even the change in government policies will be one of reason. Like Taiwan. The final reason is for special situation, like FUKUSHIMA We think the most important reason of decommisioning is no economic benefits. And the most important purpose is to remove the ~~~~


Three decommissioning strategies

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Immediate dismantling Commence shortly after the nuclear power plant stop operating.Ex. France, Japan (JPDR)

Deferred dismantlingDismantling may be deferred for a period of up to several decades.Ex. England

Entombment The remaining radioactive material is permanently encapsulated on site.Ex. Russia (Chernobyl Nuclear Power Plant)


Summer School

プレゼンター


There are three strategies of decommisioning.


Analyzing Pros and Cons

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Summer School

Immediate dismantling Deferred dismantling

Duration Longer Shorter

Waste management [ton] More fewer

Cost More expensive cheaper

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Summer SchoolFlow chart of decommission

Cost Estimation

Risk Analysis

Project Scheduling Dismantling Waste Management

Decontamination

Site Remediation& Reuse

Start of decommissioning CompletionTime line


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Yankee Rowe Nuclear Power Plant

afterbefore

プレゼンター


Decommissioning is a large and wide issue. It consists of several technology. And we think these technology will influence each other, they are not independent. For example, which kind of dismantlement will directly influence on the cost. From other research, the result showed that it will cost the least money in 60 years of delayed dismantling. And we think the waste management is the essential part of decommissioning. As the professor mentioned in the lecture. So we will show about the difference of waste management between Japan and Taiwan.


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Summer SchoolWaste Management in Japan

: generated from decommissioning activities

Radioactive waste

High level waste(HLW) Low level waste(LLW)

L1 waste L2 waste L3 waste

Radioactive levelHigh Low

Amount generated ManyFew

・Spent fuel (Used radioactive materials)

・Materials contaminated by radioactive materials.

・Tools used for dismantling.

What’s radioactive waste ?


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Summer SchoolWaste Management in Japan

HLW is generated as below

Nuclear power plant

Spent fuel

Reprocess

UraniumPlutonium

About 95%

About 5% HLW

solidified glass body

Reuse for fuel


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Summer SchoolCurrent situation in Japan

HLWIn Japan, we partition spent fuel into uranium and plutonium and HLW.

LLWIn Japan, we divide LLW into 3 types L1, L2 and L3 depending on its value of radioactivity.

Treatment ProblemHLW Be disposed of There are no final repositoriesUranium and plutonium Be reused as fuel Reprocessing plant stops operation now

Disposal way Main player Radioactivity criteria[1],[2] (examples)L1 Subsurface disposal Japan Nuclear Fuel

Limited(JNFL)α nuclide ≤ 100 GBq/ton

L2 Pit disposal JNFL α nuclide ≤ 10 GBq/tonCo-60 ≤ 1 PBq/ton

L3 Trench disposal Electric power plant Co-60 ≤ 10 GBq/ton

[1]原子炉等規制法施工令,[2]第二種廃棄物埋設事業規則


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Summer SchoolWaste Management in Taiwan

HLW

ILW

LLW

VLLW

EW

VSLW

ILW

Class-A

LLW

Greater than Class-C

Class-B & Class-C

HLW

EW

Activ

ity

Half-life

IAEA TAIWAN

プレゼンター


In Taiwan, the waste of decommissioning can be divided into two types, high level waste and low level waste. High level waste includes spent fuel and the radioactive waste of nuclear reprocessing. Low level waste refers to radioactive wastes and used radioactive sources produced from medical, agricultural, industrial, education and research organizations, including the wastes which are contaminated. Low level waste can be divided into four levels by activity. From the lowest level to the highest level are class-A, class-B, class-C and Greater than class-C (GTCC) respectively. The classification standard in Taiwan is the same as standard in the U.S, but different from IAEA.


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Summer SchoolWaste Management in Taiwan

プレゼンター


After being replaced with fresh fuel, the radiation and temperature of spent fuel are quite high. Therefore, the spent fuel has to be stored in spent fuel pool at nuclear power plant for about 10 years. This way is called wet storage. During the wet storage, temperature and radiation of the spent fuel decrease. The spent fuel can be stored in dry storage cask and cooled by air. Finally, when the final deep geological disposal facility is established, the waste will be stored at the site for the long term. Low-level waste is divided into two categories: wet waste and dry waste. Low-level wastes have to be solidified, segmented and burned to reduce their volume and package into cask. After those steps, low-level waste will be sent to the low-level waste plants in nuclear power plants. Finally, when the low-level radioactive waste disposal facility is established, the wastes will be stored at the site.


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Summer SchoolCurrent situation in Taiwan

Immediate dismantlementTime limit of decommissioning : 25 yrs ( Dec,2018 – Dec,2033 )

Jinshan Nuclear Power Plant

Capacity of spent fuel

pool (assemblies)

Unit 1 3074 / 3083

Unit 2 3076 / 3083

Spent fuel pool is full.Dry storage system can not be operated. Environment issues

Final disposal site has not been determined yet.

the fuel can not be removed from the core.

Jinshan

プレゼンター


In Taiwan, There is one nuclear power plant, Jinshan power plant need to be decommissioned, because of the politic issue about “no-nuclear power in 2025” The actual reason is that the termination of operation license. In taiwan, we choose the immediate dismantlement. And the time limitation is 25 years. The time limitation is determined by the articles about the nuclear power plant facility. This nuclear power plant stopped operating in last year. And the following is the situation now. The spent fuel pool is already full. We can see the table. There is no space to store more spent fuel. dry storage system has finished the construction, it cannot be operated. Because the license have been passed. It is relative to the environment issue. The local government asked TAIpower company to determined the final diposal site, and then the dry storage system can start operation. Therefore, now in Jinshan nuclear power plant, the fuel is still inside the reactor, it cannot be removed.


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Summer SchoolCurrent situation in Taiwan

In Taiwan, some of low-level radioactive waste is temporarily stored in the Lanyu temporary storage site. The other is stored in the low-level waste storage plant in each nuclear

power plant.

The permanent storage site was undecided because the local government refused to cooperate with the referendum of low-level waste final disposal site selection.

プレゼンター



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Summer SchoolConclusions

The most important purpose of decommission is to remove the regulatory controls from facility, and then we can start reusing the site.

The options of waste management will significantly influence on the following project of decommission.

In Japan, deffered dismantlement has been adopted for NPPs which are under decommissioning.

In Taiwan, deffered dismantlement is a more suitable solution than immediate dismantlement.


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Summer SchoolReferences

[1] https://www.nei.org, Nuclear Energy Institute[2] https://www.taipower.com.tw/tc/index.aspx, Taiwan Power Company[3] https://www.aec.gov.tw, Atomic Energy Council[4] Selection of decommissioning strategies: Issues and factors, IAEA[5] https://www.iner.gov.tw, Institute of Nuclear Energy Research [6] https://www.numo.or.jp, NUMO VISION

https://www.nei.org/

https://www.taipower.com.tw/tc/index.aspx

https://www.aec.gov.tw/

https://www.iner.gov.tw/

https://www.numo.or.jp/

Thanks for your attention!

Q&A


Summer School

decommissioning of nuclear power plantyankee rowe nuclear power plant before after decommissioning...

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