Current Status and Future Plan of

HTGR Development

Japan Atomic Energy Agency

Training Course on

High Temperature Gas-cooled Reactor Technology

October 19-23, Serpong, Indonesia

p.2

Recent Topics in Japan (1/2)

Following VIPs visited the HTTR.

The Former Minister of the MEXT, Hakubun Shimomura, on July 4, 2014.

The Parliamentary Vice-Minister of the MEXT, Tsutomu Tomioka, on August 6, 2014.

The Former Minister Environment, Nobuteru Ishihara and five members of the House of Representatives, Takeshi Noda et.al., on April 7, 2014.

They are all supportive of deployment and development of HTGR.

Technical development of HTGR is stated in the following policies.

“Strategic Energy Plan” approved by the Cabinet on April 11, 2014.

“Basic Policies for the Economic and Fiscal Management and Reform 2014” and “Japan revitalization strategy, revised 2014” approved by the Cabinet on June 24, 2014.

“Strategic Roadmap of Hydrogen and Fuel Cells” issued by the committee in the METI on June 23, 2014.

HTGR development supporting group consisting of more than 40 LDP members was made on July 19, 2014. The second meeting was held on March 10, 2015, and the following resolution was adopted.

Early restart of HTTR and reinforcement of HTGR related research Reinforcement of system discussing basic policy for commercialization of HTGR Reinforcement of international collaboration and human education

p.3

Recent Topics in Japan (2/2)

Nuclear science committee (NSC) of MEXT set up a task force on May 23, 2014, to evaluate the status of research and development of HTGR technology and nuclear heat utilization technology such as hydrogen production and power generation.

Task force issued an interim report and reported it to the NSC on October 1, 2014.

Items of research and development for the next 10 years are selected.

HTTR-GT/H2 test

HTTR safety test

Advanced fuel development

Gas-turbine component development

IS process hydrogen production development

Establishment of safety standards and design guideline

Industrial-academic-government forum for HTGR in Japan has been established.

A board member in industry participate in this forum.

Preparatory meeting was held on February 26, 2015, to discuss the vision of future commercial HTGR.

The first meeting was held on April 28, 2015.

The second meeting was held on September 29, 2015.

HTTR Project History

Reactor physics

Very High Temperature Reactor Critical Assembly (VHTRC)

Thermo-hydraulics Start Construction

Work

Installation of

Reactor Pressure

Vessel

Conceptual design

System integrity design

Basic design

Detail design

Application and

permission of construction

Construct ion

F i rs t cr i t i ca l i t y

Reactor thermal power（30MW）

Reactor outlet coolant

temperature 850℃

Reactor outlet coolant

temperature 950℃

850℃/30 days operation

950℃/50 days operation

Safety demonstration test

1973

1969 ～

1980

1974

～

1984

1981 ～

1985 ～

1988

1989

1990

1991 ～

1997

1998

2001

2002

2004

2007

2010

Research development and design

～

Construction of Reactor

Establishment of fundamental technology

Start of loss of forced

cooling test

Research and development

Fuel / material

In-pile Gas Loop(OGL-1)

Outside and inside of the HTTR

HTTR is the first HTGR in Japan. Reactor thermal power : 30MW Reactor inlet/outlet coolant temperature:

395/850,950C Primary coolant pressure: 4MPa Reactor core height/diameter: 2.9m/2.3m Average power density: 2.5W/cc Uranium enrichment: 3~10%(average6%)

H T T R

Long term high temperature operation

Construction

2013 New regulation standard issued

Confirmation of conformity of

the standard toward restart

p.4

Achievement in Fuel Technology Development

Fuel Technology

Establishment of commercial scale fuel manufacturing technology

(Collaborative work with NFI)

• Vibration dropping and gel-precipitation technologies which enable kernel fabrication with excellent sphericity and high density

• Continuous coating technology and compact formation technology which can minimize the failure in fabrication process

Evaluation of fuel performance

• FP containment performance is validated with irradiation test and OGL-1 loop test simulating HTTR environment.

• Failure mechanism of CFP is clarified by obtaining physical properties by post irradiation examination.

Demonstration of fuel performance by HTTR operation

• Demonstrate the superior fuel performance in continuous high temperature operation in HTTR

Vibrational dropping and gel-precipitation technology

Fuel irradiation data was obtained in OGL-1 loop installed in JMTR

p.5

Fuel compact

Fra

ctio

na

l re

lease

of

fissio

n g

as (

88K

r)

Operation date in 2010

10-9

10-8

10-7

10-6

10-5

10-4

(U.S.A.) Fort St. Vrain

(Germany) AVR

Continuous high temperature operation

Operational limit of the HTTR : 1×10-4

Task force of HTGR R&D, The strategy for future HTGR technology development, App. 1-2.

Graphite material IG-110

Achievement in Material Technology Development

p.6

Core graphite

structure

Development of a nuclear grade graphite (IG-110) which has superior mechanical strength and high irradiation resistance (Collaborative work with Toyo Tanso)

• Developed a graphite whose tensile strength is two times larger than conventional graphite by using isostatic pressure method.

• A structural design standard for graphite component was established based on the obtained material data considering irradiation effect.

High temperature heat resistant material Hastelloy XR

Currently, Hastelloy XR is the only material which can be used in highest temperature condition of 950oC as structural material in nuclear facility. The material is used for HTTR IHX.

IHX

Cross sectional view after corrosion test (1000℃ 10000hr)

Hastelloy X Hastelloy XR

Internal corrosion

Development of Hastelloy XR suitable to HTGR helium environment (Collaborative work with Mitsubishi Material Co.)

• Prevent corrosion due to impurity in helium environment by optimizing content of Mn、Si、Al、Ti、Co based on Hastelloy X.

• Improve creep resistance by optimizing B content..

Task force of HTGR R&D, The strategy for future HTGR technology development, App. 1-2.

Achievement in Core Physics Method Development

p.7 Task force of HTGR R&D, The strategy for future HTGR technology development, App. 1-2.

VHTRC outline Criticality experimental facility constructed to obtain HTGR

nuclear characteristic.

The calculation results of the following parameters with nuclear design code develoed are compared with experimental data obtained in VHTRC

a. Effective multiplier, b. CR reactivity worth

c. BP reactivity, d. Power distribution,

e. Temperature coefficient

Item Error considered in HTTR design

Accuracy of nuclear

design code

Effective multiplier Within 1 % Within 0.9 %

CR reactivity worth Within 10 % 7 %

BP reactivity Within 10 % 5 %

Power distribution Within 4 % 3 %

Temperature coefficient Within 10 % 1 %

Accuracy of nuclear design code used in the HTTR design

An example of the comparison between experiment and calculation (Temperature coefficient)

Difference between experiment and calculation results are within 3%. Hence, the accuracy of nuclear design is below the error assumed in the HTTR design.

First criticality in 1985. Operated until 1999. Dismantled in 2000.

Reflector Reflector

Core Core

The comparative results demonstrated that nuclear design code has sufficient accuracy for the HTTR design

N. Fujimoto, NED 233, 155-162 (2004).

Achievement in Thermal Fluids Method Development

p.8 Task force of HTGR R&D, The strategy for future HTGR technology development, App. 1-2.

Core：Fuel Stack Test Section (T1) ・Demonstrate manufacturing and assembling capability

of fuel element, and structural integrity ・Investigation of thermal fluid characteristics ・Investigation of the effect of core bypass flow on core

temperature distribution

Core bottom structure: In-core structure Test Section (T2) ・Demonstrate manufacturing and assembling capability of

graphite and metal component and structural integrity

・Investigate leakage flow between permanent blocks ・Investigate mixing characteristics in core bottom structure ・Insulation performance validation for carbon block

High temperature piping ・Demonstration of manufacturing capability and structural integrity ・Insulation performance validation

Helium circulator ・Validation of design performance ・Accumulation of operating experience

HENDEL: Helium Engineering Demonstration Loop Helium gas loop which can demonstrate the performance of major components under the same

condition of the HTTR

Purification system ・Validation of design performance ・Accumulation of operating experience

T1 test section Helium cooler

Heater

Permanent reflector

Core restraint High temperature

plenum block

HENDEL overview

Core support structure

Helium cooler ・Validation of design performance ・Accumulation of operating experience

Achievement in HTTR Operation

p.9

Core Physics

The adequacy of evaluation method for excess reactivity

was confirmed with the CR position date

⇒ Improvement in core performance can be expected

IHX

Impurity control

Established impurity control technology for reactor coolant

⇒ Enables design lives longer for core internal structures and high temperature components

Parameter Deviation

Nuclear power ±0.4％

Coolant temp. 3oC

Coolant flow ±0.5％

Plant control

Deviations of process values in primary system is small and controlled with design targets

⇒ Demonstrate long term stable operation capability

The heat generated in reactor was successfully delivered to secondary system though IHX

⇒ High temperature heat can be steadily transported to heat application system

High Temperature Component

HTGR R&D Items

p.10

HTGR technology Heat Application Technology

Commercial HTGR design

GTHTR300

Commercial HTGR design

Clean Burn HTGR for surplus plutonium burning

Establishment of safety standards and

international standardization

HTTR

Advanced Fuel Development

HTTR Safety Demonstration Test

He compressor

H2 facility

Basic technology development for H2 production and GT power generation are completed

Continuous H2 production test

Turbine blade alloy development

HTTR-GT/H2 test

Complete the system technology for construction of commercial lead plant

30 MWt and 950oC prismatic core

advanced test reactor (Operation start in 1998)

Advanced Fuel Development (1/2)

p.11

• R&D on Security-Enhanced Safety Fuel for Clean Burn HTGR

• Objectives

– Establish Pu-burn fuel technologies

• R&D items on fuel fabrication technologies

– (PuO2-surrogated) CeO2-YSZ kernel by sol-gel method

– ZrC coating on YSZ kernel by bromide process

– Continuous TRISO coating based on HTTR fuel technologies

• Schedule (started in Oct. 2014)

– 4 year project from 2014 to 2017

– YSZ fabrication and ZrC coating in 2015 and 2016

– TRISO coating on ZrC-coated YSZ in 2016 and 2017

PuO2-YSZ ZrC/SiC-TRISO

Kernel : UO2 PuO2-YSZ

ZrC coating on PuO2-YSZ kernel as free O2 getter to

reduce 50% (max. in target) of internal gas pressure

Buffer layer ： Low dense PyC

High dense PyC layer

SiC layer Conventional UO2 SiC-TRISO

• Current status

– Apparatuses for YSZ fabrication at NFI and ZrC coating with dummy YSZ particle at JAEA were maintained.

– YSZ fabrication and ZrC coating are in the progress.

YSZ fabrication apparatus ZrC coating apparatus

Ce-YSZ particle fabricated at NFI

ZrC on Ce-YSZ particle coated at JAEA

Buffer / IPyC / SiC / OPyC coated at NFI

Advanced Fuel Development (2/2)

p.12

• R&D on Sleeveless Oxidation-Resistant Fuel • Objectives

– Develop the advanced HTGR fuel performing higher heat removal than that of the HTTR to decrease the maximum fuel temperature during the normal operation

• R&D items – Fabrication technologies by hot press with Si & C

powders

– New inspection methods based on HTTR fuel technologies

• Schedule( started in Sep. 2014) – 3 year project from 2014 to 2016

– Start fabrication of SiC-matrix dummy compact in 2015

– Optimize fabrication and inspection conditions in 2016

・・・・・

Higher heat removal Graphite sleeve → Sleeveless

Upgrading oxidation resistance

Graphite matrix → SiC

Sleeveless oxidation-resistant fuel element

Conventional HTTR fuel rod

Center rod

SiC-matrix fuel compact

• Current status

– Overcoating device was prepared.

– Fabrication conditions for SiC-matrix dummy compact (pressure, temperature, time, …) were analyzed by design of experiments, etc.

– Oxidation testing furnace (~ 1,600C in O2 atmosphere) was constructed.

– Fabrication and oxidation tests for SiC-matrix dummy compact is in the progress.

Oxidation testing furnace Overcoating device

Establishment of Safety Standards

p.13

Safe

ty s

tan

dar

ds

for

com

me

rcia

l HTG

Rs

HTTR safety test HTTR-GT/H2 test

Safe

ty r

evie

w b

y N

RA

Drafting safety requirements Requirements for commercial HTGRs Requirements for coupling H2 facility to HTGR

Tie up with IAEA CRP on Modular HTGR safety design

The research committee on “Safety requirements for HTGR design” under Atomic Energy Society of Japan (FY13-14)

Drafting guideline for safety evaluation New research committee is planned (FY15-16)

HTTR H2 facility

Helium gas Turbine system

Design guidelines for fuel and structural materials

Advanced fuel development for commercial HTGRs

Data acquisition on inherent safety features of HTGR Data acquisition for analytical tools to evaluate safety of HTGR-H2. Data acquisition on integrity of fuel and structural materials

H2 Production Technology Development Strategy

p.14

2000

Lab-scale test

HTTR-GT/H2 test

Commercial use

Bench-scale test

Production of HI and H2SO4

H2SO4 decomp.

HI decomp.

Demonstration of one-week continuous

hydrogen production by glass apparatus

(0.03 m3/h-H2)

Elemental technologies

H2 production test facility

Integrity of key components in the IS

process environment (corrosion resistance , heat resistance)

Industrial material component test

HTTR

Helium gas turbine

H2 facility

Verification of integrity of total components and stability of hydrogen production

Development of strength evaluation methodology for ceramic components

Bunsen reactor

H2SO4 reactor

HI reactor Uncovering an closed-

cycle continuous

operation condition

(0.001 m3/h-H2)

Present

Technology transfer to private company

Continuous H2 Production Test

p.15

2013 FY2014 FY2015〜

Process ・H2 production: 100 L/h scale

・Electric heating

Component materials

Liquid phase

• Fluoroplastic lining

• Glass lining

• Silicon carbide (SiC)

ceramic

• Graphite (impervious)

Gaseous phase

•Hastelloy C-276

•JIS SUS316

Decomposer

Decom-

poser

Distillation

column

Reactor

Separator

EED

Bunsen reaction section

H2SO4 decomposition section

Hydrogen iodine (HI) Decomposition section

S (sulfur) I (iodine)

H2O H2 O2

H2 Production Test Facility

Continuous hydrogen production test -Verification of integrity of total components and stability of hydrogen production

Test schedule

Construction

Preparation for operation

Integrated operation

Operation for each section

• Confirmation check of components and devices • Pump flowrate calibration •Airtightness test • Flow tests of gas and water •Heating and cooling test

Status Confirmation of basic function

GT Technology Development Strategy

p.16

GTHTR300 basic design and component development

(2001- ) Collaborative work with MHI

World’s first successful operation of axial He compressor, He compressor design method validated

Full-size turbine hot-function test

850oC

Plant uprate

Present

Conceptual design for GTHTR300 power generation system

(1998-2001)

Technology transfer to private company

HTTR-GT/H2 construction

and operation (2015-2024)

GTHTR300 Commercial lead plant

(2025)

•850oC reactor outlet •Full size reactor build to allow uprate to 300 MWe without design modification

•Turbine disc/casing clearance confirmation

Single turbine disc

•Basic design, safety design, and cost estimation •Developed high-efficiency He compressor, compact heat exchanger, etc. •Turbine blade alloy development

Plan

• Diffusion experiment using stable

isotope

• Demonstration of FP plate-out

reduction under reactor simulated

condition

Key Technology Elements

• Optimization of crystalline microstructure for

heat-resistant Ni-base alloy

• Optimization of chemical element for heat-

resistant Ni-base alloy

Expected reduction of FP plate-out

FP

FP plate-out

Base material

Turbine blade

Depth from surface (μm) 100

1015

1014

Standard Optimization of crystalline

microstructure

Optimization of crystalline

microstructure

& chemical composition

Gas turbine Reactor

FP

co

nta

ined

am

ou

nt

(ato

m/m

2)

Turbine Blade Alloy Development

p.17

p.18

HTTR-GT/H2 Test Project

Project goal

1. Licensing

License acquisition of world’s

first nuclear GT/H2 cogeneration

plant

2. Operability

Confirm safe & reliable operation

3. Complete system technology

HTTR demonstration test system layout

Reactor

IHX

Helium

gas turbine H2 plant

HTTR Heat utilization system

HTTR demonstration test system configuration

Project plan

• Design, construction & operation for HTTR-

GT/H2 plant

• Establish new licensing framework for coupling

GT/chemical plant to nuclear reactor

• Demonstration of key technology (e.g. shaft

seal) reliability in system performance

IHX

Gas turbine

Recuperator Precooler

Reactor

H2 plant

Cooler

Isolation

valve

2nd IHX

-0.1

0

0.1

0.2

0

20

40

60

80

100

120

0 5

p.19

Safe & Reliable GT Operation

HTGR-GT system LWR-ST system*

Reactor

Turbine

0 5

1

0

0

0.2 Δ

M

C

P

R ΔMCPR

0

20

40

60

80

100

120

0 5 10 15Elapsed time (s) 0 15

Reactor

pressure

1

0

Peak fuel temp.

Reactor

power

Reactor behavior of HTGR-GT system for loss of generator load event is different from

that of LWR-ST system

- Change system pressure instead of isolating turbine from reactor

- Pressure transient has no effect on core reactivity

Design consideration will be reviewed through licensing for coupling GT to the HTTR

Operating scheme will be validated in the HTTR-GT/H2 test

Rela

tive r

ati

o t

o r

ate

d v

alu

e

Loss of load event may be excluded from AOO in HTGR gas turbine system

Reactor

System pressure control

Turbine

Turbine isolation

Elapsed time (s)

Rela

tive r

ati

o t

o r

ate

d v

alu

e

Reactor

pressure

Reactor

power

*Tohoku Electric Power Co., Higashi-Dori NPP, Analysis for AOO (2008). MCPR: Smallest ratio of the predicted critical heat flux power

to the operating power

-0.2

p.20

Licensing for H2 Cogeneration

H2 plant Nuclear facility

Atmospheric chemical dispersion is already considered in current regulation

Assurance of reactor safety against postulated

event initiated in H2 plant

- Fundamental safety objective of nuclear facility

should not be altered Construction of H2 plant under non-nuclear

regulation

- Fundamental difference exists in safety philosophy

between nuclear facility and H2 plant

- Need to comply with a request from potential users

of nuclear heat from economical point of view

Safety Design Approach

Safety Events for Coupling H2 Plant

Chemical inflow

Temperature &

pressure transients

Draft Safety Requirements*

*Established by AESJ research committee on safety requirement for HTGR

Abnormal events in heat application plant shall be defined as external hazards and, it is required

to prevent harmful disturbances on reactor if they do occur.

If normal operation and abnormal events in heat application plant may affect the normal

operation of reactor system, the design for the heat application shall be such as to ensure that the

safety requirements of reactor system are all met.

Safety requirements and design considerations will be established through licensing review

for coupling H2 plant to the HTTR by Nuclear Regulatory Authority

GTHTR300 HTTR-GT/H2 plant

H2 plant

Cooling

tower 冷却器

10MW

850oC

950oC

395oC

950oC

594oC

Reactor 600MW

360oC

150oC

850oC 〜650oC

170MW 0.7MW 650oC

850oC

p.21

HTTR-GT/H2 System Outline

HTTR-GT/H2 is designed

to simulate commercial

GTHTR300 system design and

operation modes

H2 plant

Fo

r H

2 p

rod

uct

ion

2nd IHX

Gas turbine

Recuperator Precooler Recuperator Precooler

Gas turbine

Reactor

Cooling

tower

IHX IHX

Thermal power (IHX) 10 MWt

IHX heat supply temperature 900oC

GT inlet temperature 650oC

GT pressure ratio 1.3

Turbine flow rate 6-12 kg/s

H2 plant heat load 0.7MWt

To cooling tower

R&D

BUILDING

RB

CTB

SFSB

Exhaust

stack

MB0 50

scale (m)Nuclear facility

SFHB

H2 plant area

Trench

CTB: Cooling tower building

MB: Machinery building

RB: Reactor building

SFHB: Spent fuel handling building

SFSB: Spent fuel storage building

TB: Turbine building

N

TB

p.22

HTTR-GT/H2 Plant Layout

2nd IHX

Recuperator

Turbine

Compressor

Generator

Precooler

HTTR-GT/H2 plant layout

GT component layout

0

50

100

150

0 4 8 12p.23

HTTR-GT/H2 Planned Test Startup and shutdown operation

Load-following operation

Loss of load test

H2 plant upset simulating test

60

70

80

90

100

110

-2 0 2 4 6 8 10

Fuel temperature

Reactor pressure

Reactor power

Elapsed time [s]

No

rmalize

d v

alu

e [

%]

Elapsed time [h]

Po

wer-

to-H

2 r

ati

o [

%]

70

80

90

100

110

-50 0 50 100 150 200

Elapsed time [s]

Power generation rate

Fuel temperature

Reactor power N

orm

alize

d v

alu

e [

%] Power generation rate

H2 plant

heat supply

No

rmalize

d v

alu

e [

%]

100

0

Elapsed time 0

Turbine speed

Reactor power

Power

generation

rate

p.24

2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025

C&R

CONSTRUCTION

PLANT DESIGN

COMMISSIONING, OPERATION

LICENSING & REGULATORY

Conceptualdeign

Design

HTTR-GT

Site preparation

HTTR modification

Componentinstallation

Commissioning Operation

Commissioning Operation

Site preparation

Site construction

Pre-licensingdiscussion

Reactorinstallationlicensing

Licensing

Approval ofoperational safety program

Detailed deign

Componentfabrication

Pre-serviceinspection

Approval of construction plan

Component fabrication

HTTR-GT/H2

HTTR-GT/H2 Test Draft Schedule