Overview of the geological disposal project ofhigh-level radioactive waste in Japanin Japanca. 8 mm

ca. 4.2 m

ca.10 mm

Spent Fuel
Example of Pellet(PWR case)ca. 5％
Glass rawmaterials

ca. 95％Cooled for 30-50 years at temporary storage
facilities in Rokkasho Village, Aomori, etc.

Radioactive waste liquid
Diameter ca. 40 cm

Exhaust

Moltenglass

Electrodeca. 500 kg

Canister

Molten glass(Stainless steel)Solidiﬁed glass

Specialized Transport
VesselNuclear Power
Plant

Reprocessing

Reprocessing
Plant

High-level radioactive waste(Photo Courtesy of JNFL)

Temporary storage

Vitriﬁed wasted

Storage pool for Spent Fuel

Spent Fuel

Height ca. 130 cm

Reprocessing of Spent Fuel

Nuclear power plants

Uranium, plutonium, etc. (reused)

TemporaryStorage Facility(Rokkasho Village)

Cooling air outlet
Cooling airinlet
Storage tube lidConcrete(Thk ca.2 m)

to cooling air outlet

Low pressure

Vitriﬁed wasted
9 stucked
Storagetube
Ventilation
tube
Cooling air

vitriﬁed wasted

Storage pit

Edited from "Graphical Flip-chart of Nuclear & Energy Related Topics" Japan Atomic Energy Relations Organization (JAERO)

Specialized Transport
VehicleSpecialized Transport
Vessel(Rokkasho Village)

Area : 1-2 km2of vitriﬁed waste

Interim storage:

Equivalent to2,530c.a. 27,000(As of April 2024)(As of April 2024)

Increase
depending on
operation ofNuclear PowerPlants

If over 19,000 tons of spent fuel is reprocessed,
the amount of vitriﬁed waste, including that
already reprocessed is equivalent toc.a. 27,000 vitriﬁed waste canisters.
NUMO is planning a disposal facility with thecapacity to be able to dispose of more than
40,000 vitriﬁed waste canisters.

Geologicaldisposal= 100 Vitriﬁed Waste Canisters

over time (more than 99.9% decay in 1,000 years.)of Vitriﬁed waste
Total amount of radioactivity
per vitriﬁed waste canister（GBq）
10 7

Surface dose

After 1,000 years

1m
distance dose

Surface dose(mSv/hr)(mSv/hr)

110,000

1,500,000(mSv/hr)

1m
distance dose

1.4

19Large pore spaces,
faster ground water ﬂow

Vitriﬁed waste is disposed ofin a stable deep underground,isolated from human life
environment and radionuclides
are contained.

The radioactivity of vitriﬁed waste decreases rapidly

Immediately after productionof vitriﬁed waste

Near the ground surface

More than 300 mRadioactivitydecay(mSv/hr)

10 6
10 51m1m

10 4
10 3※Sv (sievert): Unit for expressing the effect of radiation on human

10 3

Disposal
Site

Ports neardisposal site

Surface Facility

Amount

10 2Plug

10 4

10 5

10 6Round trip between
Tokyo and New York
Referenceby airplane

Time after 50 years of interim storage (years)※Bq (becquerel) is a unit for radioactivity (G: Giga, one billion Bq)※The above ﬁgure is shown on a logarithmic scale.

CT scan (1 time)

2.4 - 12.9 mSv

0.08 - 0.11 mSv
Edited from " Graphical Flip-chart of Nuclear & Energy Related Topics" Japan Atomic Energy Relations Organization (JAERO)

Method of Geological Disposal
The multiple barriers are constructed in deep underground

Multiple barrier system

Engineered Barrier
Systemrock mass (Natural Barriers), which has an isolation andcontainment function, with Engineered Barrier Systems(EBS) applied to increase safety.

Deep underground＋- Isolated from biosphereIsolation

Natural Barrier(Rock mass)- Dense rock mass and slow groundwater ﬂow- Slow degradation due to low oxygen
content

Containment

H LW

Height: ca.130 cm
Diameter: ca. 40 cm
Weight: ca. 500 kg

Height ca. 310 cm
Diameter ca. 220 cm
Thickness ca. 70 cm
Weight ca. 17.5 tons

Height: ca.170 cm
Diameter: ca. 80 cm
Thickness: ca. 20 cm
Weight: ca. 6 tons

EBS No.1

EBS No.2

EBS No.3(bentonite)(metal container)

Sorting

HullEndpiece

Area : 6 -10 ㎢

Buffer

Overpack

Vitriﬁed Waste

Underground Facility

Barrier No.1

Compression

Barrier No.2

Filler(Cement/Mortar)

Barrier No.3

Buffer material(Clay)
Backﬁllmaterial

Host rock

TRU
Canister
WasterpackageFuelassembly

Structuralframe

Buffermaterial

Waste
package Disposal tunnel

Engineered barriers

Natural barriers

Options for disposal
H12V method
Operational period

Horizontal PEM concept
HLW inOperational period
fabrication
canister Bentonite buffer

Post closure period
Bentonitebuffer
Backﬁll

Disposal tunnel

HLW infabrication
canisterTunnelsupport
Deposition holePEM
handling
Overpackshell

Overpack

Geological disposal will be implemented based on the Final Disposal Act, and a disposal

Implementation
processsite will be selected after a step-wise investigations processes. The site investigationand selection will take about 20 years, and more than 100 years is required if the construction, operation, and closure of the repository are also included. It is the responsibility of the current generation to proceed geological disposal so as not to postpone
the burden to future generations. In July 2017, “Scientiﬁc Characteristics Map” waspublished by the Agency for Natural Resources (ANRE) of Energy Ministry of Economy,
Trade and Industry (METI).

Revised April 2024

Legal process for selection of repository site(Underground facility)

Selection ofpotential
repository site

(Borehole etc.)
Avoid obviously
unsuitable sites

Check suitability(e.g. boreholes)

Selectionofp o t e n t i a l

New process added toinitiate literature survey

Ensure the site
is suitable andsafe

ClosureDetailed
Investigation

Operation

Preliminary
Investigation(PI)

Construction- Application by municipalities- Proposal by government

Intensive Dialogue activities(public meeting etc.)

Government publishes
Scientiﬁc Characteristics Map

Literature
Survey (LS)Will not proceed to the next phase if governor or mayor opposes

Examples of unsuitable sites

When selecting a disposal site, volcanoes, active
faults, and areas with large uplift/subsidence will beavoided. In addition, sites with valuable mineral
resources will also be avoided.

Valuable naturalresource

volcanoactive fault

原子力発電環境整備機構
Nuclear Waste Management Organization of Japan

Mita NN Building 2F, 4-1-23 Shiba, Minato-ku, Tokyo 108-0014, Japan
TEL：03-6371-4003 (Public Relations Department Representative)

NUMO Web Page

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

Dwq kmmineral resources

Project overview and technologicaldevelopment related to geological disposal, etc.
are introduced. You can also view the latest
information on events and other activities.
Revised April 2024