Nuclear Damage Compensation and Decommissioning Facilitation Corporation

August 29, 2022
The 6th International Forum on Fukushima Daiichi Decommissioning (DAY 2)
Iwaki City Art and Culture Exchange Center "Alios”

Analytical Competence and University
Initiatives in Japan
Japan Nuclear Damage Liability andDecommissioning Corporation

Kazuo Minato

無断複製・転載禁止 原子力損害賠償・廃炉等支援機構©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

Lecture Contents

1◼ Characteristics of samples and objectives of the analysis➢➢➢

What is the sample to be analyzed?
What is the purpose of the analysis?
What is needed for the analysis?

◼ Existing analytical facilities, methods, and personnel◼ Issues related to analysis for 1F decommissioning◼ Measures to resolve the issues◼ New university initiatives◼ SummaryAll rights reserved. Japan Nuclear Damage Liability and Decommissioning Corporation©Nuclear Damage Compensation and Decommissioning Facilitation Corporation

What is the sample to be analyzed?

2◼ Debris, accident-derived waste
➢
➢
➢
➢
➢

The first core meltdown accident at a BWR in the world
No records of many plant parameters due to loss of power at the accident
Unclear operational status of the safety equipment
Injection of seawater to bring the accident under control
Many uncertainties regarding the state inside the reactors, the state of thedebris, fission products release paths, etc.
-

What you don't see in normal decommissioning
Unconfirmed properties
Many with high doses
A wide variety of subject
Difficult-to-measure nuclides
High timeliness to be required
Huge number of samples
Limited sample volume

Pebble-like deposits at the bottom of
the pedestal of Unit 2 of 1F(Courtesy of TEPCO)
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What is the purpose of the analysis?

3◼ Quick identification of basic properties➢

Nuclide inventory, chemical composition, chemical form, density, etc.

◼ The results of the analysis areimportant basic information
and applied in several areas➢

Decommissioning work-➢

Retrieval method
Storage management
Processing and disposal

Clarification of accident causes-

Understanding of phenomena
Improvement of nuclear safety◼ The analytical results are oneof the important criteria for
decisions for reducing therange of uncertainty in order tofacilitate 1F decommissioning

Incorporation of analyses and investigation results,
and their relationships (Technical Strategic Plan 2021)

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What is needed for the analysis?

4◼ Facilities➢

Facilities and equipment capable of handling debris
and accident-derived waste◼ Methods➢➢

Analytical methods, techniques, and equipment
applicable to debris and accident-derived waste
New analytical methods, technologies, andequipment required for debris and accidentderived waste◼ Personnel➢➢➢

Analytical technicians
Analytical specialists who evaluate and interpretthe results of the analysis
Analytical engineers who develop new methods,
techniques, and equipment(Courtesy of JAEA)
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Existing analytical facilities, methods, and personnel (1/7) 5◼ Do we have facilities, methods, and personnel for the analysis?
➢

Handling of debris and accident-derived waste-

The same manner as irradiated fuels and materials/radioactive wastes isrequired➢

Radiation controlled area (nuclear fuel handling, radioisotope handling)
Hot cell, glove box, hood

Existing irradiated fuels and materials examination facilities/radioactive
waste handling facilities, analytical methods, and personnel are available-

Nuclear Science Research Institute, Japan Atomic Energy Agency(JAEA-NSRI)
Oarai Research and Development Institute, Japan Atomic Energy Agency(JAEA-ORDI)
Nuclear Fuel Cycle Engineering Laboratories, Japan Atomic Energy Agency,(JAEA-NCL)
Nippon Nuclear Fuel Development Co., Ltd. (NFD)
MHI Nuclear Development Corporation (NDC)(University facilities and equipment)◼ Conducted analysis of 1F samples immediately after the accident
using these facilities, methods, and personnel
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Existing analytical facilities, methods, and personnel (2/7) 6◼ JAEA-NSRI➢

Analysis of the debris of TMI-2 (Three Mile Island Unit 2) in the US-

Part of the OECD/NEA international joint research
About 60 pieces of debris were shipped to Japan in 1991
Results contribute to clarification of accident progression, etc.

Cross-sections
Uranium and zirconium oxides(ceramics) is the main component

Mixture of zircaloy and inconel (light brown)
UO2 (green)

debrisMixture of zircaloy andstainless steel (white)

Ag-In-Cd control
material (dark brown)
10 mm

Analysis of the debris of TMI-2 at JAEA-NSRI(Courtesy of JAEA)

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Existing analytical facilities, methods, and personnel (3/7) 7◼ JAEA-NSRI
Analysis of rubble, contaminatedwater, etc. of 1F➢ Analysis of simulated debris➢

Sampling of rubble

Glove boxes

Hot cells

Sampling of felled trees

Pretreatment of sample Analysis using solid-phaseextractants◆ Cooperation with TEPCO
on radioactivity analysis◆ Technical guidance to
TEPCO Power Technology

Debris Dissolution Tests in Hot Cells

Analysis of rubble(Courtesy of JAEA)

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Existing analytical facilities, methods, and personnel (4/7) 8◼ JAEA-ORDI➢➢➢

Analysis of rubble, contaminated water, etc. of 1F
Analysis of deposits, smear samples inside the PCV, etc.
Analysis of simulated debris

TEM (Transmission Electron Microscope)
Hot cells (Steel cells)

FIB(Sample thinning for TEM observation)u

STEM-EDS
Element Mapping

100nm
O

Cr

Fe

Analysis of deposits inside the PCV

Hot cells (Concrete cells)
FE-SEM(Field Emission Scanning Electron Microscope)(Courtesy of JAEA)

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Existing analytical facilities, methods, and personnel (5/7) 9◼ JAEA-NCL➢

Analysis of rubble, contaminated water, etc. of 1F

Hot cells

Appearance

Observation in a hot cell

Development of analytical method of the sludge

Analysis of secondary waste from water treatment(Sludge accumulated in decontamination equipment)

10μm

Optical microscopy

SEM-EDX analysis(Courtesy of JAEA)
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Existing analytical facilities, methods, and personnel (6/7) 10
◼ NFD
➢
➢
➢

FeCr2O4

Analysis of rubble, contaminated water, etc. of 1F
Analysis of deposits, smear samples inside the PCV
Analysis of simulated debris

Cubic(U,Zr,Fe,Cr)O2
Cubic(U,Zr,Fe,Cr)O2+FeCr2O4

Detailed structure of U-bearing particle
observed on the deposits from Unit 2(STEM-HAADF image)

Hot cells

SEI

20 µm

U

20 µm

Fe

20 µm

Zr

20 µm

TEM
(Transmission electron microscope)

U-bearing particles observed on thesmear sample from Unit 3 (SEM-EDS)
Sample preparation for SEM (Scanning electron microscope)(Courtesy of NFD)

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Existing analytical facilities, methods, and personnel (7/7) 11
◼ NDC
➢
➢

Analysis of rubble, contaminated water, etc. of 1F
Analysis of simulated debris

Hot cells

Beforedissolution

Addition of
nitric acid

Nitric acid dissolution ofsimulated debris in a hot cell

After solid-liquid
Afterseparation
dissolution

Nitric acid dissolution of simulated debris in a hot cell

Equipment of pretreatment
for radionuclide analysis

Chemical Analysis instruments(Left: ICP-MS; Right: ICP-AES)(Courtesy of NDC)

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Issues related to analysis for 1F decommissioning (1/3)

12◼ Are the existing facilities for analysis sufficient for 1F decommissioning?
➢➢➢

Other tasks, not able to concentrate on analysis for 1F decommissioning
Located in Ibaraki area away from 1F, poor timeliness
Insufficient capacity for analysis required for 1F decommissioning◼ New facilities are under construction and planned
adjacent to the 1F site and on the 1F site
Analysis and Research of Radioactive Materials
Laboratory-1 (completed, preparing to set up a controlled area)➢ Analysis and Research of Radioactive Materials
Laboratory-2 (under construction)➢ TEPCO Comprehensive Analysis Facility (under planning)➢

Image of facilities for Analysis and Research of radioactive materials(Courtesy of JAEA)
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Issues related to analysis for 1F decommissioning (2/3)

13◼ Are the existing methods of analysis sufficient for 1F decommissioning?
➢

What is required for 1F decommissioning-

To accommodate a huge number of samples
Efficient analysis for the decommissioning process
Field-oriented analysis for the decommissioning process
Analysis that leads to the determination of the cause of the accident
Effective use of limited analytical human resources
Reducion of the burden on analytical work

◼ New analytical methods, techniques, and equipment need to be
developed.
➢
➢
➢
➢
➢

Accelerated and automated analysis
Simplified and efficient analysis
Increased accuracy and sophistication of analysis
Specialized analysis for the decommissioning process
A statistical approach to estimating the whole from a small number ofsamples

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Issues related to analysis for 1F decommissioning (3/3)

14◼ Is the existing personnel for analysis sufficient for 1F decommissioning?
➢➢

Existing facilities require existing personnel for analysis
New facilities require new analytical personnel◼ Need to develop, secure, and retain new personnel for analysis➢

Need personnel with a wide range of knowledge and skills-

General chemical and instrumental analysis
Properties of various types of radiation and measurement methods
Physical, chemical, and biological properties of radioisotopes
Radiation protection, laws and regulations related to nuclear power and radiation
Chemical reactivity of fuels and materials, etc.

◼ JAEA and others have accumulated sufficient knowledge and experiencein the handling of alpha nuclides and fuel analysis techniques➢➢

Personnel exchange between TEPCO and JAEA is important
Analytical specialists who evaluate and interpret the results of the analysis
are rare, and it is important to work on increasing this number

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Measures to resolve the issues

15◼ Government Assistance➢

Project of decommissioning, contaminated water and treated water management-➢

Targeting applied research, practical application research, and on-site
demonstration of high difficulty

Nuclear energy science & technology and human resource development project-

Targeting domestic and foreign universities and research institutions that promote
fundamental and basic research and human resource development initiatives◼ Initiatives by various industrialacademic-governmental institutions➢➢

Fundamental, basic and applied researchby domestic and foreign universities,
JAEA, and other research institutions
Practical application research, and on-site
demonstration by IRID, manufacturers
including overseas companies, TEPCO, etc.

Scope of R&D for decommissioning and implementation entities(Technical Strategic Plan 2021)
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New university initiatives (1/4)

16◼ Elucidation of basic property of radioactive microparticles(Results of a group led by Professor Igarashi of Kyoto University (then Ibaraki University))➢

Insoluble radioactive microparticles released into the environment were
found and a foresighted study was initiated-➢Discovery of induced fluorescence-➢

Elucidation of basic properties by various analytical methods
Detectability of Cs-containing glassy materials by fluorescenceContribution to risk reduction in decommissioning workand deepening of accident progression scenarios

UV light
excitation

Particle a few µm in diameterwith high Cs concentration(Type A; derived from Unit 2)

蛍光強度(相対値)

5000
4000

T-12粒子
正味UV蛍光スペクトル（背景光除去)3000
2000

Particle tens to hundreds ofµm in diameter with

1000
0
420 440 460 480 500 520 540 560 580 600 620

波長 (nm)Fluorescence emitted from Type B particle irradiated with UV light

low Cs concentration(Type B; derived from Unit 1)(Courtesy of Prof. Igarashi, Kyoto University)

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New university initiatives (2/4)

17◼ Development of a rapid analytical method for strontium-90(Results of a group led by Professor Takagai of Fukushima University)➢

Analytical method based on inductively coupled plasma-mass spectrometry(ICP-MS)-➢

Complex analytical work and skilled techniques⇒ Automatic pretreatment, automatic control and measurement systems
Long time (2 weeks to 1 month)⇒ Measurement time: 23 minutes, detection limit: 0.3 Bq/L

Practical use at the 1F site from December 1, 2014

The first practical use
technology applied to
1F site developed byuniversity

Overview of Rapid Analytical Methods for 90Sr (Courtesy of Professor Takagai, Fukushima University)
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New university initiatives (3/4)

18◼ Technological development of micro-domain quantitative imaging of solid
samples(Results of a group led by Professor Takagai of Fukushima University)➢

Laser Ablation - Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS)-

Development of a simultaneous determination method for stable and radioactive
isotopes without the use of solid reference materials, and its application to mapping(Courtesy of Professor Takagai, Fukushima University)
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New university initiatives (4/4)

19◼ Tie-up type human resource development(Efforts by a group led by Professor Takagai of Fukushima University)➢

Tie-up between Fukushima University and JAEA researchers-

Graduate students, postdocs, and cross-appointment members staying at JAEA (Miharu) to
conduct research
Course credit for lectures and practical training by JAEA researchers at Miharu
Lectures for students in collaboration with TEPCO for both research promotion and education
Volunteer education in cooperation with private companies, government agencies, and TEPCO＝Talents to soar
(Ability to develop)

Collaborative
Laboratory
•
•
•
•

JAEA
TEPCO
Research institutes
Private companies

Analytical engineers who can analyze both chemical and physical analysis
Simulator with a background in physics and chemistry
Analytical engineers who handle big data
Physical and chemical engineers capable of handling AI

Image of human resources to be
developed through this project(Courtesy of Professor Takagai, Fukushima University)

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Summary

20◼ The analytical results are one of the important criteria for decisions for
reducing the range of uncertainty in order to facilitate decommissioningof the 1F➢

Debris and accident-derived waste are not found in normal decommissioning➢

Quick identification of basic properties that is useful for decommissioning work andclarification of accident causes◼ Existing analytical facilities, methods, and human resources are notsufficient for 1F decommissioning in a timely manner➢

Need new analytical facilities for 1F decommissioning➢

Need to establish an analysis system with shared roles, taking advantage of thecharacteristics of the existing and new facilities➢

Need simplified, efficient, accurate, sophisticated analytical methods to meet the
purpose of analysis➢

Need to develop, secure, and retain new human resources for analysis◼ Young people are eagerly awaited to participate in the decades-longdecommissioning of the 1F reactors➢

Need to support activities at universities that can be a source of human resources
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All rights reserved. Japan Nuclear Damage Liability and Decommissioning Corporation©Nuclear Damage Compensation and Decommissioning Facilitation Corporation