Decree-Radiation Hazard
Prevention Law-

Radiation Hazard Prevention Law（１）Regulation by law
Radiation, radioisotopes, dose limits（２）Place safety management (facility standard)
Radiation facilities, structures, controlled areas, signs（３）Human safety management
Education training, health examination,
exposure measurement（ ４ ） Handling safety management (standard of
conduct)
Use, storage, disposal, transportation

Act on Preventionof Radiation
Hazards due toRadioisotopes,
etc.
MedicalAtomic Energy Basic Act
・Research, development andutilization of nuclear
energy is limited to the
purpose of peace
・Prevent radiation damage
・Ensure public safety

Radiation
regulation law

AtomicEnergyBasic Act

Nuclearpower
plant
regulations

Care Act

Radiation
放射線障hazard害
control
予防規定
regulations

Industrial
Safetyand Health Act

Pharmaceut
ical
Affairs Law

Enforcement
Regulations
for Road
Vehicles Act

Prevent radiation hazards and ensure public safety by
regulating the use of radiation, radioisotopes (RI) andradiation generators, and the disposal of materials
contaminated by RI based on the Atomic Energy Basic
Law.

The purpose of Act on Prevention ofRadiation Hazards due to Radioisotopes, etc.
•Ensuring worker safety（１） Radiation limit in the work room（２） Limit of concentration in air（３） Contamination measurement（４） Worker's dose limit

Control radiation
and radioactive
materials in theworkplace•Ensuring public safety（１） Dose limit at the boundary of controlled areas and theboundary of business establishments Control leaks of radiation（２） Exhaust and wastewater concentration
limitsmaterials
and radioactive（３） Contamination inspection room from radiation facilities
Established the above dose limit and concentration limit
values based on the recommendations of the ICRP
(International Commission on Radiological Protection)

The subject of Act on Prevention ofRadiation Hazards due to Radioisotopes, etc.
•Radiation– Alpha rays, proton beams, other heavily charged particles and beta
rays
– Neutron rays
– γ-rays and characteristic X-rays (only characteristic X-rays generated by orbital
electron capture)– Electron beam and X-ray with energy of 1 MeV or more

•Radioisotope– Those that emit radiation and exceed the specified quantity andconcentration– Excludes nuclear fuel materials, nuclear source materials, andradiopharmaceuticals•Radiation generator– Linear accelerator, cyclotron, etc.
– Not applicable to X-ray generators with less than 1 MeV

Radioisotope
Nuclide name

Ｈｰ３
Ｓｰ３５
Ｐｰ３２
Ｎｉｰ６３
Ｉｰ１２５
Ｃｏｰ６０
Ｃｓｰ１３７
Ｓｒｰ９０

Lower limit
Lower limit quantity
concentration （Ｂｑ/ｇ）
（ＭＢｑ）

１,０００
１００
０.１
１００
１
０.１
０.０１
０.０１

１×１０６
１×１０５
１,０００
１×１０５
１,０００
１０
１０
１００

※It is stipulated in the "International Basic Safety Standards(BSS)" commonly formulated by international organizations
such as the International Atomic Energy Agency (IAEA).
※ It assumes a certain exposure scenario and is calculated
for each nuclide based on scientific evidence after setting theexposure dose standard (effective dose) to 10 μSv per year
in normal times and 1 mSv per year in the event of an
accident.

Sealed Radioisotope•The isotopes that emit radiation contained in one
radiation source (one set or one set for one set or oneset) are subject to regulation when the minimum
quantity is exceeded.
For example ...
In the case of Co-60 with a minimum
quantity of 100 kBq
Even if there are 10 Co-60 sources with 50kBq perunit, it is not subject to regulation.
50kBq
50kBq

50kBq

50kBq

50kBq

50kBq

50kBq

50kBq

50kBq

50kBq

Unsealed Radioisotope•Only one type of unsealed radioisotope: If the total
amount possessed by one business establishment exceeds
the lower limit, it is subject to regulation.

•Two or more unsealed radioisotopes: If the sum of theratio of quantity by nuclide to notification quantity
exceeds 1, it is subject to regulation.
For example, in the case of H-3 with a minimum quantity of
1000MBq and S-35 with a minimum quantity of 100MBq ...
Even if each nuclide does not exceed the lower limit
quantity, if the sum of the ratios exceeds 1, it is subject toregulation.
300MBq

1000MBq
H-3

＋
S-35

80MBq

100MBq＜１
The sum of theratios is importantRadiation generator•Cyclotron•Synchrotron•Synchrocyclotron•linear accelerator•Betatron•Van de Graaff accelerator•Cockcroft–Walton accelerator
An X-ray generator of less than 1 MeV
is not a radiation generator under Act
on Prevention of Radiation Hazards due
to Radioisotopes.

Effective dose limit (general public)•Public

１ｍSv/year（Excluding exposure to naturalradiation and medical care ）Important
People cannot measure the dose
It is necessary for the radiation handler to control
and measure the radiation and make sure that it
does not exceed it.

Reference（World average）
Natural radiation 2.4ｍSv/ｙｒ
Medical exposure 0.6ｍSv/ｙｒ（Japan average）
1.5ｍSv/ｙｒ
2.3ｍSv/ｙｒ

Effective dose limit (radiation workers)
Important
Other than thefollowing

Effect Women
ive Women during
Dose limit

pregnancy

Lens of the eye

100mSv / 5 years
50mSv / yr
5mSv / 3 months

Internal exposure 1mSv
from pregnancy tochildbirth
150mSv / yr

500mSv / yr
Equiv Skin
Abdominal surface 2mSv from pregnancy toalent of women during childbirth

Dose limit pregnancy

Placesafetymanagement
各種線量限度・濃度限度

Places where there is little riskof landslides and inundation

OfficeRadiation
facility

Main structural parts are
made of fireproof structure
or non-combustible material

各種線量限度・濃度限度

Office boundary

OfficeRadiation
facility

Effective
dose

２５０μSv/
３ months

Set up the shield wall

Public limit

Adjust usage

１ｍSv/yr

Office boundary

各種線量限度・濃度限度
Effective dose

Office

１mSv/week ５０mSv/yr
Radiation
facilityWorkspacehoodOffice boundary

各種線量限度・濃度限度
Outer walls, fences, etc.

OfficeControl area

Radiation
facility
Effective dose：１．３mSv/３months
１/１０ of Air concentration limit
１/１０ of surface concentration limit

Office boundary

各種線量限度・濃度限度
OfficeRadiation
facility
Lower than exhaustControlarea
exhaustconcentration limit
Lower than draining draining
concentration limit

Office boundary

各種線量限度・濃度限度
OfficeItems to take out

Control area

Radiation
facility

exhaust

１/10 of surface
concentration limit
α rayβray, γ ray

draining

４ Bq/ｃｍ２
４０ Bq/ｃｍ２

各種線量限度・濃度限度
OfficeControl area

Radiation
facilityWorkspaceexhaustdraining

Automatic display device•Doors that people normally enter and exit
must be equipped with a device that
automatically displays the presence orabsence of use.
(In the case of a room
where one or a set
uses a sealed
radioisotope orradiation generator of
400 GBq or more.)

In useInterlock•Doors that people normally enter and exit will
be equipped with interlocks to prevent people
from entering unnecessarily.
(In the case of a room where one or a set uses a
sealed radioisotope or radiation generator of
100 TBq or more.)•However, this is notnecessary if a wall isinstalled in the roomso that the dose isbelow the dose limit.

Moo
rage

Lead glass

Door

Automatic
dispray

Control panel

If the doorway is open, theradiation source is not come out.

Radiation facility inspection•Before using：Get a facility inspection
Cannot be used unless passed•After starting use：
get regular inspections and confirmations•When changing the permission contents:：
Need new permission

Radiation facilities are required toalways comply with legal standards

The quantity that can be used is determined for eachnuclide, period, purpose, and location.
(For radiation generators, energy, time, direction, etc.)

Permits vary depending on the radiation facility.
Confirm the permission contents of the facility to
be used in advance.

Radiation handlers•A person who enters a controlled area byengaging in the handling and management ofradioactive isotopes or radiation generators.

•Radiation handlers need to be educated training,
have a medical examination, and have exposure
measurements.

•(Persons engaged in handling)
It is a sealed radioisotope, and the device is wellshielded, and the device surface may be a controlled
area. In that case, he is not a radiation worker
because he does not enter the controlled area. No
health check and exposure measurements are
required.

Education training（１）Before entering the controlled area
for the first time
（New education）（ ２ ） After entering the controlled area,
every period not exceeding one year
（re-education）•The number of hours for each item is set.
•If you have sufficient knowledge and skills,
you can omit some of them.

Education training items and hours（１）Effect of radiation on the human bodyover ３０minutes（２）Safe handling of radioisotopes orradiation generators
over ４hours（３）Decree on prevention of radiation damage
caused by radioisotopes and radiation
generators
over １hours（４）On-campus rules
over３０minutes

Health checkup（ １ ） Before entering the controlled area for
the first time（２）After entering the controlled area, every
period not exceeding one year （Actually every
period that does not exceed 6 months）（ ３ ） If any of the following applies, without
delay
イ Inhalation or oral intake by mistake
ロ Skin is contaminated beyond the surface
density limit
ハ The wound surface of the skin is contaminated
ニ Exposure to radiation exceeding the effective
dose limit or equivalent dose limit

Hearth check（１）Interview
イ Presence or absence of radiation exposure
history Includes electron and X-rays withenergies less than 1 MeV
ロ About those who have a history of exposure
Work location, content, duration, dose, presenceor absence of radiation damage, and other conditionsof radiation exposure（２）Examination or examination
イ Blood pigment amount or hematocrit value in peripheral
blood, red blood cell count, white blood cell count andwhite blood cell percentage
ロ Skinハ Eye
ニ Other parts or items specified by the Minister of
Education, Culture, Sports, Science and Technology

Measurement of
personal exposure dose
The measurement results of personal
exposure dose are permanently stored.
（１）Measurement of external exposure
Man (chest) Woman (belly)：
Continuous measurement while entering
the controlled area
※If you do not have a radiation measuring
instrument, you will be prohibited from entering
the controlled area.

（２）Measurement of internal exposure
Whole body counter, calculation

Measures for those who have or may
have suffered radiation damage（１）Radiation handlers•Reduced access time to controlled areas•No entry into the controlled area
•Relocation to work with less risk of
exposure•Provide necessary health guidance（２）Persons other than radiation workers•Take appropriate measures such as diagnosis
by a doctor and necessary health guidance
without delay.

To prevent radiation damage

Supervise

Follow the
instructions of theradiation protection
supervisor

Handling standards（１） Criteria for use（２） Criteria for refilling（３） Storage standards（４） Standards for transportation（５） Criteria for disposal（６） Criteria for disposal outside
the officeCriteria for use（１）Use of radioisotopes or radiation
generators shall be carried out in thedesignated facilities.
（２）Effectively utilize the three elements oftime, distance, and shielding to control the
exposure dose.
Proportional to timeInversely proportional to the squareof the distance
Beta rays are acrylic plates
Gamma rays are shielded by lead

Criteria for use（３）Keep the concentration in the air in the workroom and the surface density of objects thatpeople touch below the limit.
（４）Wear work clothes and protective equipment in
the work room. When leaving, inspect forcontamination.
（ ５ ） Prohibit eating, drinking and smoking in thework room.

Criteria for use（６）Do not unnecessarily remove radioactive
isotopes from the work room or controlledarea.
（ ７ ） When a person other than a radiation
handlers enters, follow the instructions of
the radiation handlers.

Criteria for use（８) When the sealed radioisotope is moved andused, immediately after use, check for any
abnormalities such as loss or leakage with aradiation measuring instrument. If any
abnormality is found, take necessary measures
to prevent radiation damage.
Monitoring of work environment

Storage standards（１）Store in storage room or storage box（２） Do not exceed the storage capacity（３）Place in a storage container and use asaucer / absorbent so that the surface
density limit is not exceeded.
（４）Take measures to prevent people fromentering unnecessarily (key / fingerprint
verification, etc.)

Conditions of transfer
Approval of the supervisor
is required for transfer
A office
Permitted
quantity

3H :

10MBq

Permitted
quantity※storage capacity

3H : 20MBq

3H : 10MBq

14C : 10MBq

B office

14C :

10MBq

14C : 5MBq

Standards for transportation
Ａ ． Transportation within the office(inside the facility)(１) Enclose in a container and transport(２) 10 cm or more on each side, no cracks
or damage
Since there( ３ ) Surface
2mSv are/ h detailed
or less, regulations
surfacedensity
1/10
or lessforeach,follow the instructions of

the Radiation protection supervisor
Ｂ ． Transportation outside the office
whenactually transporting.
(between
offices)(１) L-type, A-type, B-type shipments(２) Container test (watering / dropping /penetration / compression)

exhaust port

Criteria for
disposal（Gas）
Confirm that theconcentration of（１）Gaseous radioisotope
radioisotopeisMonitorbelowinthethe
limit exhaust
Purify or exhaustequipment.

Charcoal filter※ When exhausting, check that it is
HEPA
below
the filter
limit
Radiation
Pre filter
facilityDisposal
criteria(liquid)

Drain(２）Liquid radioisotope Confirm that theconcentrationofイ Purify
or drain in the drainage facility.
Monitorradioisotope is

ロ Enclose in a containerbelow
andthestore
limit in astorage /disposal facility.
ハ Incinerate
in an incinerator.
Dilution tank
ニ Solidify in the solidification processing
Radiationequipment.
Water tank
※ When draining, check that facility
it is below
the limit

Disposal criteria (solid)（３）Solid radioisotope
イ Incinerate in an incinerator.
ロ Enclose in a container and store in a storage/disposal facility.

•Handed over to Japan Radioisotope
Association
Follow the disposal classification(Combustibles, flame-retardant, non-combustibles,
animals, inorganic liquids, organic liquids)

Write up（１）Use(type, quantity, date of use, purpose, method,
location, name)（２）Storage(type, quantity, storage period, method,
location, name)（３）Transportation(transportation date, method,
name)（４）Disposal(type, quantity, disposal date, method,
location, name)（５）Inspection (date of implementation, item, name)（６）Education and training (date of implementation,
item, name)※ Closed every year, stored for 5 years after
closingMeasurement (handling place)
Ａ．Dosimetry of the place (stored for 5 years)
Confirm that it does not exceed 1mSv / week,
1.3mSv / 3months, 250μSv / 3months
Measuring method: Radiation measuring instrument
Measurement location(Radiation amount): Use / storage / disposal facility,
controlled area boundary, place of residence in businessestablishment, business boundary(RI contamination): Work room, disposal work room,
contamination inspection room

Measurement（handler）
Ｂ ． Measurement of(permanent storage)

individual

exposure

dose（１）Measurement of external exposure
Male (chest) Female (belly)：１ｃｍ、７０μｍdose equivalent
Radiation measuring instrument: glass badge, pocket
dosimeter, etc.

Continuous measurement during the controlledarea entry period（２）Measurement of internal exposure
When inhaled or orally ingested by mistake.
Places where ingestion may occur Once every 3monthsRadiation injury prevention regulations（１）Duties / organization（２）Maintenance, management and inspection ofradiation facilities
Details
will be etc.
（３）Use of radioactive isotopes andgenerators,
explained in the（４）Measurement / recording / preservationoflecture that follows.
radiation amount, etc.存（５）Education and training / health examination（６）Bookkeeping（７）Measures in case of danger
It must be prepared and notified to the NRA
before the start of use of radioisotopes.
Any changes must be notified to the NRA within
30 days from the date of the change.

Radiation injury prevention regulations•It must be prepared and notified to the NRA
before starting the use of radioisotopes.

•Any changes must be notified to the NRA
within 30 days from the date of the change.

•It must provide for duties and organizations
relating to persons engaged in the handlingof radioisotopes or radiation generators.

On-site inspection•On-site inspections are conducted by
the NRA to ensure that the Radiation
Hazard Prevention Law is complied withand that radiation control is being
carried out smoothly.

•You will be asked to improve theproblem.

Reports
The permit notification user must immediately report
the situation and response to the NRA within 10
days in the following cases.
１）When the radioisotope is stolen or the whereabouts
are unknown.
２）When the concentration limit or dose limit isexceeded when the radioactive isotope is purified byexhaust or drainage equipment and discarded.
３）When a radioisotope leaks out of the controlled area.
４）When a radiation worker is exposed to radiationthat may exceed the effective dose limit orequivalent dose limit

Accident•In the event of a radioisotope theft,
unknown location, or other accident,
the permit notification user must
notify the police officer or coast guard
officer without delay.

Corresponding at the time ofdanger
•If there is a risk of radiation damage due toan earthquake, fire or other disaster,
immediately notify the police officer or coast
guard officer.
•In the event of a danger, the user must
notify the NRA without delay of the date andtime, location, cause, situation of radiation
injury, and the content of first aid measures.
•The above situation and measures against it
must be reported to the NRA within 10 days.

（１）The used amount of radioactive
material exceeded the permitted amount.
（２）When I tried to dispose of theequipment, it was equipped withradioactive material.
（３）There is no record of handlingradioactive materials.
Stop all medical treatmentusing radiation

（１）The used amount of radioactive
material exceeded the permitted
amount.
The used amount of radioactive material
is licensed for each nuclide and period.
Do not use more than this quantity.
Check in advance whether the nuclide/ amount you want to use is within thepermitted range.

（２）When I tried to dispose of theequipment, it was equipped withradioactive material.
Do not carry equipment setted upradioactive materials without
permission.
Check in advance whether the nuclide/ amount you want to purchase iswithin the permitted range.

（３）There is no record of handlingradioactive materials.
A record must be recorded each time
radioactive material is used, stored or
disposed of it.
Record the date of use, storage, anddisposal, nuclide, quantity, name of thehandler, etc.

Use of radioactive materials

It can only be handled by licensed
radiation facilities.
Taking out radioactive materials

Only possible with the permission of the
Radiation protection supervisor.
（Destination is limited to radiation facilities）