The 6th Fukushima Daiichi Decommissioning International Forum in 2022（2022/08/29）

Basics for Sampling andAnalysis at Nuclear Facilities
Akira Kirishima
Professor, Tohoku University

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CONTENTS• Analysis at Nuclear facilities• Classification and activity contents of radioactive waste• Characteristics of waste in Fukushima Daiichi NPP• General flow in waste analysis• Requirements for waste analysis• Finally

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ANALYSIS AT NUCLEAR FACILITIES
Analysis: the act of examining a substance, especially by separating it into its parts,
in order to discover what it is or contains (Cambridge dictionary)
Nuclear waste
generation

Action Planning Based on
the Analysis results••

Operation of
nuclear facilities

Analysis・Nuclides 90Sr, 241Am, etc.
・Activity (Bq)・Distribution(homo- or heterogeneous)・Chemistry (crystal structure,solubility, stability, etc.)!) If analysis data is insufficient, more conservative and overequipped storage and disposal facilities could be selected. A
lack of analysis data could result in larger waste volume.
Illustrations from Graphical Flip-chart of Nuclear & Energy Related Topics, © JAERO••

Selection of safer storagemethods
Waste processing andconditioning plan
Waste disposal plan
Waste management costestimation

Future Disposal3• A suitable disposal
method is selected
depending on the activity
contents and origin of
the waste.
• Treatment andconditioning will be
conducted for safe
disposal facility operation.
【Subject】
Where is the fueldebris placed on?
(to be analyzed)

For adequate
radioactive waste
management at
FDNPP, the “Analysis”
is critically important.
That should cover not
only activity contents,
but also hardness, heat,chemical feature, andetc.
4Decommissioningof normalreactors

An appropriate
waste classification
is demanded toperform this ideal
decommissioning.

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Cost estimation codes for the decommissioning of normal nuclear facilities areproposed. These methods allows easy estimation of decommissioning costs basedon the characteristics and similarities of facilities, dismantling methods,etc.
From JAEA R&D Review 2020-21

Required info.: The total floor area of the controlled area and the amount of
dismantled waste, classified by disposal type (e.g., radioactive or non-radioactive)
and by materials (e.g., concrete or metal), etc.

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WASTE IN FUKUSHIMA DAIICHI NPP……….

From TEPCO holdings inc.

From IRID Subsidy Project of Decommissioning and Contaminated Water Management in the FY2016 and FY2017 Supplementary Budgets, “R&D forTreatment and Disposal of Solid Radioactive Waste “, Accomplishment Report for FY2018, July 2019•••

Difficulty in estimating the amount of waste produced（Necessity of Analysis）.
The amount of waste will change depending on the way of decommissioning mission.
Limited analysis data points due to the limitation in the hard- and software.
Challenge: Development of the Analysis strategy covering both hardware and HR.

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General flow in waste analysis

1.Planning and sampling

Sampling at Fukushima Daiichi NPP
https://www.jaea.go.jp/04/ntokai/fukushima/fukushima_02.html• Set the target of the analysis. (What is the
purpose of this analysis?)• Make a suitable plan of the sampling. (samplenumbers and its amount)• Select sampling techniques. (remote or contactsampling)• Check the achievability of the plan in the point ofsite situation.
Sludge sampling at the turbine building
出典：JAEA-IRID

廃炉・汚染水対策チーム会合／事務局会議（第28回）, 平成28年3月31日

8General flow in waste analysis

2.Pretreatment

High dose

Low dose

Operability：Low

Concrete Cell withmanipulators

HighGlobe Box

Fume Hood (Draft chamber)• Conditioning and adjustment of the samples for the following analysis.
• Select suitable hardware depending on the dose level and feature of the sample.
• Generally, the operability of high shielding hardware is low. (trade-off relation)
Photos from JAEA web https://www.jaea.go.jp/04/ntokai/hot/hot_04.html and ATOMICA

9©Tohoku University, Kirishima lab.

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General flow in waste analysis 2.Pretreatment (in chemistry)
Dissolution byheated andconcentrated
nitric acidIon exchange toreduce salinity

dillution

Liquid samples containing particles

Liquid sample

Liquid phase

Radiation counting・γ-ray spectrometry
・α spectrometry

dillution
Filtration to separate particles
from liquid
Liquid sample

11General flow in waste analysis
Ge semiconductor detector（γ ray spectrometry）

3.Radiation counting (activity)
Si semiconductor detector（α spectrometry）

Example of α spectrum

Determine activity content(which nuclide?, how much?)

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General flow in waste analysis 4.Mass spectrometry(activity det.)
ICP-MS

Photo：High Resolution ICP-MS
system ” Thermo Fisher Scientific
ELEMENT 2” @IMRAM Tohoku Univ.

ionionIonize elements in the liquid sample by an
inductively coupled plasma. The atomized
elements are detected by a mass
spectrometer. Modern powerful tool forseveral radioactive nuclides.

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General flow in waste analysis
5. Instrumental analysis (characterization)
Scanning Electron Microscope(SEM)

Analyze fine structure

Powder X-ray diffract
meter (p-XRD)

Analyze crystal structure

Sample(simulated fuel debris)

Investigate the chemicaland physical features ofthe target.
A. Kirishima et al. / Journal of Nuclear Materials 527 (2019) 151795

14河北新報 朝刊3面
2022/06/20(c) KAHOKU SHIMPOPUBLISHING CO.

日刊工業新聞 21面
2022/06/22(c) NIKKAN KOGYOSHIMBUN,LTD

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General flow in waste analysis
6.Compilation and interpretation of analysis results• Evaluate and validate the data from eachanalysis step.
• Make a total interpretation of the analysis
with multidimensional view. Then compile
into a conclusive “fact of the sample”.

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Data from：【JAEA】令和2年度補助事業：燃料デブリの分析精度の向上及び熱挙動の推定のための技術開発の成果の概要 https://dccc-program.jp/3797

Requirements for waste analysis (in human resource aspect)【General analysis flow】

1. Planning and sampling
2. Radiation counting (activity)
3. Mass spec.(activity)

4. Instrumental analysis(characterization)
5. Compilation and interpretation【Personnel in analysis】• Well trained in the operationof the responsible analysis
procedure. Require abilities
to detect trouble at theoperation and to report itproperly.
（Skilled Technician)＊able to be educated in an
equipped training facility【Manager and Evaluator of the analysis】• A person who well understands the objective of the analysis and is able
to make a sampling plan.
• A person who is able to compile and validate variety of analysis data,then derives conclusion of the analysis project.
(Expert) How to educate? This education demands much time
17and cost. Need smart strategy!!

Finally【Analysis of the radioactive waste generated in the decommissioning operation】
Purpose：Prepare a waste catalog that is necessary for the waste management.
Features：Difficulty in estimating the amount and character of waste.
Issues：Limited analysis data due to the limitation in the hardware and personnel.
Education of analysis managers and evaluators.
【Analysis of fuel debris】

Purpose①（decommissioning）
Collecting fundamental information (activity component, heat release,hydrogen generation, chemistry, etc.) for designing the safe storage,
treatment process, and final disposal system of the debris.
Purpose②（Accident-progression analysis）
Acquiring information on what happened at the accident and how it
progressed, which contributes the cause investigation and enhancement of
the safety of nuclear facilities. More detailed information is demanded
than“Purpose ①”.
IssuesSame ones as above mentioned. Additionally, more detailed analysis isrequired depending on the theme. As a result, purpose ② consumes moretime and cost. Need smart arrangement between purpose ① and ②.

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