The International Forum on theDecommissioning of the Fukushima Daiichi NPS
Aug. 29th, 2022

JAEA's Efforts on
Radioactive Waste/Fuel Debris Analysis

Shin-ichi Koyama
Japan Atomic Energy Agency
Collaborative Laboratories for Advanced Decommissioning Science（JAEA/CLADS）

This slide includes results obtained under research program by Agency for Natural Resources and Energy, Ministry of
Economy, Trade and Industry (METI) of Japan.

1

Contents

I.

JAEA's Mission for Radioactive Waste/Fuel Debris Analysis

II. Analysis of radioactive waste
III. Analysis of fuel debris
IV. Technical issues and perspectives
V. Conclusions

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I. JAEA's mission for radioactive waste/fuel debris analysis
JAEA is a member of a mountaineering expedition aiming for unclimbed peaks.
The best route has not been found yet, and JAEA will tackle together with ourknowledge and experience.

JAEA takes on the role of Sherpa as an expert by research and practice related to analysis.
JAEA will support the decommissioning work of TEPCO HD through knowledge andtechnology that can be used for safety and risk assessment.
JAEA’s contributions
・Analysis technology, research and development, expert.
・Experience and achievements in analyzing radioactive waste, irradiated fuel, and TMI-2 debris
・Results of 1F sample analysis (waste, sediment, etc.)
・Design, construction and operation of the Okuma Analysis and Research Center3

I. JAEA’s hot laboratories and human resource development
・As a human resource development base, training of young engineers and training and training of
external engineers are being carried out. Established a collaborative laboratory with
universities, implemented a cross-appointment system, and provided training for students

Lab.-1
Radioactive Material Analysis
放射性物質分析・研究施設
andResearch Facility

Fukushima

For fuel debris
analysisLab.-2Administrative
Bldg.

For radioactive
waste analysisx
Nuclear Science Research Institute (NSRI)

Lab. No.4

RFEF

Nuclear Fuel Cycle Engineering Laboratory (NCL)

Ibaraki
x

Pu-1
EDF

x

Oarai Research and Development Institute (ORDI)

Google mapより

FMF

AGF

The Laboratory-1 for the radioactive material analysis and research facility has been completed,and the Laboratory-2 is under construction.

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I. Radioactive material analysis and research facility•

Under construction of Radioactive Material Analysis and Research Facility tounderstand the properties of radioactive waste and fuel debris on the adjacent to 1F。

•

Radioactive materials with surface dose rate up to 1 Sv/h such as rubble, incinerated
ash, and secondary waste from water treatment will be analyzed. And also ALPStreated water will be analyzed by JAEA as third-party.

•

High-level radioactive materials such as fuel debris will be analyzed.

Laboratory-1

Laboratory-2

Administrative
Building

Radioactive Material Analysis and Research Facility① Administrative building【 Operation started in March 2018 】

N② Laboratory-1※【2022/6/24 Completion.
Scheduled to start analysis in 2022 】

注)赤破線内側は東電敷地※
黄色塗部分が分析・研究施設 ③ Laboratory-2 【Licensing /preparation for construction】※ TEPCO applied for an implementation plan as part of the specified nuclear facility and supervised security. JAEA is in charge ofdesign, construction and operation (analytical practice and facility operation).

5II. Analysis of radioactive waste Information and analysis required
Items for analysis andrisk assessment

Confinement, stability,
environmental effectDose, criticality,、臨界、火災爆発
fire/explosion

Generation

First
classification

Temporarystorage

Dose, stability

Volume reduction,
stabilization
Secondclassification

StorageThirdclassification

Conditioning

Disposal

Example on P.7, 8

Needs for analysis
Characterizing for storage
・Surface dose rate
・Fissile material
・Water, radioactivity content

Feedback forearly establishingmanagement
technologies

Characterization for processing(stabilization)

Characterization for processing(conditioning)→ Dependent on waste and processing
Example: ALPS slurry・ Particle size distribution: for filtering・ Viscosity: for drying
・ Radioactivity concentration: fordevice design
・ Chemical composition→ Dependent on waste and processing

Characterization for decomposition
・ Environmental chemical

Characterization for disposal (including
conditioning)・ Material
・ Amount
・ Radioactivity concentration
・ Environmental chemical affecting
radioactivity behavior

Data, result of evaluation✓ Currently, radioactivity concentration is analyzed for first through third classification.
✓ Waste of Fukushima Daiichi features...
• Difficult to predict radioactivity
composition including DTMs
• Enormous amount• High dose rate•••

Inventory estimation method
Analysis planning method
Analysis method for DTMs

Example on P. 9

Feedbackfrom data
Example on P. 10

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II. Analysis of radioactive waste

Results of analysis

Since JFY2011, radioactive waste and contaminated materials have been
analyzed, the number samples reached to 500.
Rubble is one of major waste due to its large volume. Secondary waste fromwater decontamination including sludge/slurry, adsorbent and concentrateshould be reduced its risk. These are the preferential targets of analysis.
Data obtained is utilized to discuss correlation of activity concentration (1),classification of waste according to nuclide composition (2).
Data is collected in a database “FRAnDLi” to open to public for use (3).
✓ https://frandli-db.jaea.go.jp/FRAnDLi/index.php?country=e

•

•

•

•

1号機
1号機
2号機
2号機

90Srの放射能濃度(Bq/g)

1000
103

3号機
3号機

10
101

-1
10
0.1

10-2

10-4

（白抜きは検出下限値）

0.001
10-3
100
1

102

100

104
10000

106
1000000

137Csの放射能濃度(Bq/g)(1) Correlation between
137Cs and 90Sr for rubble
collected inside reactor
buildings.*1(2) Transport ratio of nuclides tostuck of 1/2 units, SGTS piping,drain water.

(3) Database “FRAnDLi”.

*1：https://www.meti.go.jp/earthquake/nuclear/decommissioning/committee/osensuitaisakuteam/2017/05/3-04-03.pdf

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II. Analysis of radioactive waste•

Feedback to Fukushima Daiichi

TEPCO utilizes analysis data including physical and chemical properties to reduce risk for
waste storage by waste treatment as shown in report to government.
Sludge in contaminated water

東京電力ホールディングス株式会社, “α核種除去に向けた検討状況について,”
廃炉・汚染水対策チーム会合／事務局会議（第86回）, 2021年1月28日.

Slurry form ALPS

東京電力ホールディングス株式会社, “スラリー安定化処理に向けた設計について,”
特定原子力施設監視・評価検討会（第88回）, 資料1-2-1, 2021年2月22日.

Sludge from decontamination device

東京電力ホールディングス株式会社, “除染装置スラッジ、ALPSスラリーの安定化処理にむけた検討状況,” 特定原子力施設放射性廃棄物規制検討会 (第7回), 資料2,
2018年7月23日.

Zeolite contained in sandbag

東京電力ホールディングス株式会社, “プロセス主建屋における地下階環境調査の結果について,” 廃炉・汚染水・処理水対策チーム会合／事務局会
議（第93回）, 2021年8月26日.

8II. Analysis of radioactive waste Methods of inventory estimation and planning••To estimate inventory of various waste, estimation model is being developed.
Model includes parameters of transport of radioactive nuclides, which is derived
from analysis data. Analytical concentration is normalized with fuel compositionand statistically treated to obtain normal distribution parameters, and uncertainty
is evaluated with help of Bayesian approach. (1)。
To make efficient analysis plan for waste of uncertain, DQO process is combinedwith Bayesian statistics to set number of samples for classifying various waste,
which should be conformed to future conditioning/disposal (2).

Calculation model*1

Parameter*2(1) Calculation model for estimation of various
waste, which contaminated via waster and air.
*1：https://irid.or.jp/wp-content/uploads/2021/12/2020010kotaihaikibuturev2.pdf*2：https://irid.or.jp/wp-content/uploads/2021/01/2019011kotaihaikibutsu_02.pdf(2) DQO process applied for
waste management
9II. Analysis of radioactive waste Analysis methods for DTM nuclides••

Various radioactive nuclides including ”Difficult-To-Measure” nuclides, which areimportant for disposal safety are analyzed. Even gamma emitters, they need chemical
separation before gamma spectra determination; revealing most radionuclides are
regarded as DTM nuclides.
To aim analysis method of efficient, less time and effort, R&D has been conducted;
ICP-MS/MS application, automated chemical separation, sample distribution,
standardization (1).

(1) Consolidated analysis method for waste sample and further improvement*1*1：https://irid.or.jp/wp-content/uploads/2021/12/2020010kotaihaikibuturev2.pdf

10II. Analysis of radioactive waste Aiming at disposal classification•••

Objective of analysis is moved according to stepwise transition of waste
management; improving inventory estimation, classification of waste, establishingwaste confirmation method and operation of waste confirmation. (1)For these years, inventory estimation was major target along with analysis forestablishing safe storage .
Later, target will move to waste classification which considers future conditioning anddisposal. Progress will be changed for waste due to difficulty of sampling and statusof generation.
Now(1) 廃炉工程の進展に伴う分析目的の推移

11III. Fuel debris analysis - Required information and analysis technology Information and analysis items necessary for safety and risk assessment
A

Safety / risk assessment through fuel debris removal to storage / management＜Retrieval, storage＞
Radiation exposure,scattering (α dust, FP,gas generation),
criticality, heatgeneration

Safety / risk
assessment items

Radiation exposure, scattering(α dust, FP, gas generation),
criticality, heat generation＜ Transfer, storage ＞＜ Temporary storage ＞
Criticality, heat
Analytical facility
generation,(Okuma,debris amount
Ibaraki area)

Laboratory-2

Analytical needs

Outside (on-site)

R/B

・ Appearance and weight・ Surface dose rate

Feedback

Temporary storage equipment

・ Appearance and weight・ Surface dose rate
・ Non-destructive analysis of nuclear
fuel materials, etc.(Sorting withradioactive waste) *・ Surface dose rate, dimensions (particlesize), density, hardness・ Nuclide
inventory, composition・ Chemical form,
surface condition・ Moisture content,
organic matter content, hydrogen・ FP
emission behavior, thermal characteristics*) has not been established
Example on P.17

Feedback

Example on P.15,16

Analysis /evaluation results

12III. Fuel debris analysis - Required information and analysis technology Information and analysis items necessary for safety and risk assessment
B Safety / risk assessment in fuel debris processing
・In addition to the items applicable to temporary storage, the same analysis items as
radioactive waste are applied. (Inventory evaluation: 38 Nuclide analysis, etc. ）C

Safety / risk assessment of fuel debris remaining in the container
Safety / risk
assessment items

Current status
Fig. Core status(Estimated debris distribution)
Upper structural
material
Shroudpart

RPV Lower headpart

Heat generation, criticality,
scattering of fine particles,leakage of radioactive
substances,(hydrogen generation)

Analytical needs

Control rod partCore residue
Pedestal part

Control rod,
Guide tube partDry well floor
Part・ Surface dose rate, dimensions(particle size), density, hardness
・ Nuclide inventory, composition
・ Chemical form, surface condition
・ Moisture content, organic matter
content, hydrogen
・ FP emission behavior, thermal
characteristics

Estimation
・ Plant information
・ Internal investigation results(Dosimetry, analysis of sediments, etc.)
・ Analysis by calculation codesuch as thermal behavior
・ Analysis of retrieved fuel debris
Analytical facility (Okuma, Ibaraki area)

Analysis /evaluation results

Feedback
Example on P.14

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III. Fuel debris analysis - Construction of a system to integrate data and information 【Decommissioning research database（debrisWiki）】【JAEA Report】
This report summarizes the knowledge andexperience of technology development
implemented by JAEA, and systematicallysummarizes needs, issues, and analysis methods.

A hub of information required by users
Provide users with up-to-date, technicallyreviewed, and correct information.
◼ Compilation of knowledge created by experts ineach field.
◼ Used as a work tool for field workers.
Core status map (Example of Unit 2)◼
◼

Same structure as
the widely known
Wikipedia

A table of contents covering everythingfrom removal to disposal and accidents

Core status - Estimated information on the distribution of debris
throughout the reactor
On-site information - centralized search for 1F information
Accident progression - Based on the latest knowledge
Analysis data - Raw data, comprehensive interpretation of results
Past knowledge - Past SA accidents and 1F decommissioning

14III. Fuel debris analysis - 1F samples analysis (approach for samples of unknown composition) Analysis technology and characterization (samples obtained from 1F internal investigation)
1/2u-SGTS plumbing smear (2020) [1]

Weight(ng)Fe areaanalysis

Zn areaanalysis

Cs areaanalysis

Fe areaanalysis

U areaanalysis

U isotopic ratio

3cm

Outer
appearance

Std. radiation
source（～48kBq）

Si areaanalysis

3cm

IP（10min.)◆ Outer appearance and IP• Describe detailed information.
• Identify high-dose sites, collectsamples.

◆ Dissolution／γ-ray／ICP-MS• Dissolution by 8N HNO3 + HF, γray of the residue, confirmed low
137Cs (less than 1/100)• Quantitative analysis and isotope
ratio evaluation (ICP-MS)• Uncertainty evaluation◆ SEM/WDX• Qualitative analysis, characteristic X-ray peakidentification, characteristic X-ray image◆ TEM• Base of identification and the range of quantitative analysis.
• Increase the accuracy of oxygen analysis by ultra-thin film
processing and zeta factor method.
Elemental map of U
(Including influence of Ag signal)◆ SEM/EDX••

Describe the basis for identification and overlap
Describe the grounds for selecting the target
area for TEM analysis

Composition of main elements (at%)

①

③

②

U particle

④

O

Mg

Al

Si

Cr

Fe

Ni

Zn

Zr

Ag

U

①

～70

0.2

0.3

0.2

0.1

3.0

0.0

0.3

0.1

0.7

24.7

②

～70

0.1

0.3

0.2

0.2

8.5

0.0

0.3

0.1

0.7

21.1

③

～70

0.0

0.4

0.0

0.1

3.0

0.0

0.2

0.1

0.7

23.1

④

～70

0.1

0.3

0.0

0.2

12.1

0.0

0.2

0.0

0.5

14.7

It is possible to estimate knowledge on the chemical properties of fuel debris and to estimate and evaluate accident
scenarios, and provides basic knowledge for estimating the situation inside the reactor based on analysis.
https://irid.or.jp/wp-content/uploads/2021/09/2020004seijyouhaaku.pdf

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III. Fuel debris analysis - Analysis system and improving the quality of analysis data Technology and system for evaluating the characteristics of fuel debris will be established as an approach forsamples with unknown composition.
The simulated fuel debris prepared by an independent organization will be supplied to the hot laboratories in Japan.
The elemental composition will be analyzed using the own technology possessed by each laboratories.
Hotlaboratories
Simulated fuel debris(uniform composition)
・Including U
・1F composition

NDC

JAEA Oarai
TohokuUniversity
NFD

JAEA NSRI

Dissolution
methodDissolution
rate

HNO3

～60%

HNO3
+ HF

～90%

Aqua regia
+HF

98%

Alkalifusion100%

Remarks
・Simple method
・Dissolves U and B compounds
・Complement the overall elemental
composition by analyzing residue
・Improved dissolution rateby adding a small amount of HF

Conducted by remotecontrol within the cell・Almost complete dissolution
・High accuracy
・Possibility of fluoride precipitation

・Complete dissolution
・High accuracy
・Contamination of alkaline reagent
Verification of accuracy andand crucible components
error for each analysis target
element and operation

Analysis techniques for 4 basic evaluation items (morphology of analysis samples, nuclide/element
content, phase state/distribution, density, etc.), which are important for fuel debris analysis
items, are defined and shared among the parties concerned.
https://dccc-program.jp/files/202108jaea.pdf

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III. Fuel debris analysis - Non-destructive assay technology for sorting of fuel debris andradioactive wastes -・Destructive analysis of recovered PCV materials up to the order of kilograms stored is difficult.
・In order to reflect the sorting of fuel debris and radioactive waste in the future, non-destructive
assay technology will be developed to sort them according to the amount of nuclear fuel material.
Candidate methods currently under consideration in the IRID project:(Participating organizations in the project: MHI, Toshiba ESS, Hitachi GE, JAEA collaboration)(1) Active neutron method, (2) Passive neutron method, (3) Muon scattering method,(4) X-ray CT method, (5) Passive gamma ray method
A cooperative system consisting of 3 centers and 4 divisions has been established in JAEA, andpreparations for testing (examination of test methods, production of simulated models, changes inauthorization, etc.) are underway. Elemental technology verification tests for (1), (2), and (5) will
mainly start in 2023.

Small
pulsedneutrongenerator

ChamberCd

He-3proportional counter
polyethylene

Active neutron method (JAWAS-T)
NSRI/NUCEF/BECKY

Passive neutron method (PSMC)
NCL/Pu-center

Considered for use in passive gamma-ray
measurement, etc.
NSRI/RFEF

Overview of basic test equipment for non-destructive assay measurement methods(JAEA facilities and equipment scheduled to be implemented from 2023)

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IV. Technical issues and future perspective
Continuing analysis and preparing for next step
→ Analysis will conducted at existing laboratories in Ibaraki-area. Newly built Laboratory1 at Fukushima Daiichi will start operation near future.
→ Object should be determined for each waste. Obtained data will be utilized forestablishing inventory estimation and be constituent knowledge base, which isessential to disposal safety.

Analysis method development→ R&Ds for improvement and DTM nuclides and sentencing waste and fuel debris will be
conducted.
Human resource development and international cooperation→ Continuous human resource development is carried out through guidance by nuclear
fuel and radiation experts and practical experience at facilities.
Develop JAEA staff and external human resources (joint research, MEXT projects, etc.)→ Collaboration with overseas related organizations will be promoted through OECD/NEA
projects and joint research.

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V. Conclusions
・JAEA will continue to support the analysis and sampling work at the 1F decommissioning inorder to build knowledge and technology that can conduct safety and risk assessment as an
all-Japan effort with NDF and TEPCO.

・Analysis of radioactive waste will soon begin at the Laboratory-1 of Okuma Analysis andResearch Center. Efforts will be made to reduce risks in waste management and develop
waste classifications for waste disposal. Analysis of the existing facilities will also continue
to contribute to the steady progress of 1F decommissioning.

・ Preparation for fuel debris analysis and development of a decommissioning researchfundamental database that can be used by workers and users are in progress.

・ We will utilize the current research and development for human resource development
toward the construction and operation of the Okuma Analysis and Research Center and the
TEPCO HD Comprehensive Analysis Facility.

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