NRA presentation
C4 Occupational Radiation Protection
KONISHI Koji
Nuclear Regulation Authority JAPAN
2nd IAEA Regulatory Review Mission on ALPS Treated Water Handling
18 January 2023
* This presentation is modified not to include the IAEA’s
current perspectives as the IAEA’s review is still on-going.
1. Regulation
The NRA requires TEPCO to take measures for ORP such as area controlling, managing
and recording dose, etc.
• NRA Ordinance for Fukushima Daiichi NPS
– Article 9 Limit on Access to Controlled Area
– Article 10 Measures for Dose
• NRA Notification for Fukushima Daiichi NPS
– Article 5 Dose Limits for Radiation Workers
• Specific Regulatory Requirements(*)
– II.12. Management of workers’ exposure dose
According to Reactor Regulation Act, TEPCO establishes the "Implementation plan" (not
"Operational safety programme") for Fukushima Daiichi NPS to manage the installations
and operations of facilities integrally. The Chapter III of Implementation plan covers
operational safety measures including radiation protection.
Effective dose:
100 mSv per 5 years and 50 mSv per year
Lens of eye:
100 mSv per the 5 years and 50 mSv per year
Skin:
500 mSv per year
(*) Items required for Measures which should be taken at TEPCO’s Fukushima Daiichi NPS in line with the Designation as the Specified Nuclear Facility
★(Note) For specific descriptions of each article, please refer to the reference material list of relevant
laws and regulations which the NRA submitted to IAEA in Feb. 2022 for last mission.11. Regulation21
The NRA examines whether the regulatory requirements as shown on P.2 are satisfied, and
then approves the Implementation plan.
Also, the NRA checks whether TEPCO’s activities comply to the approved Implementation
plan by daily operational inspections.2Measures such as zoning of activity area or wearing radiation protection equipment are
established in the Implementation Plan.
Activities relevant to the discharge of ALPS treated water are conducted in Green-zone,
where the contamination level is the lowest. Therefore, a general dust musk is only needed
to be worn.3Reference: Zoning (Area control) in Fukushima Daiichi NPS
(source) TEPCO HP: https://www.tepco.co.jp/en/hd/decommission/progress/environment/index-e.html
as of May 20184Reference: Clothing in each zone
(source) TEPCO HP: https://www.tepco.co.jp/en/hd/decommission/progress/environment/index-e.html
General working wears and dust masks are used in most part of the site
(G zone: over 95%)
2. Monitoring Requirements52. a.
The NRA establishes Dose limits for radiation workers. (please refer to P.2)
Based on the approved Implementation Plan, TEPCO controls the dose of workers by
means of recording levels, reporting levels and investigation levels.
2. b.
The NRA requires TEPCO to record data such as ambient dose rate of controlled area,
dose of radiation workers (including lens of eye and skin), etc., and keep the data for
certain period depending on the sort of information.
• NRA Ordinance for Fukushima Daiichi NPS
– Article 3, Paragraph (1), (v) Radiation control record, (a)~(l)
Sort of data Storage period
ambient dose rates 10 years
dose for workers at least 5 years of until the worker quit
Example:
2. Monitoring Requirements62. c. 1
CHIYODA Technol Corporation, which provide IMS to TEPCO, is certified by "Japan
Accreditation Board" based on ISO/IEC 17025.
2. c. 2
Considering the suggestion of IRRS in 2016, the NRA revised the ordinance to ensure the
reliability of individual monitoring service.
Specifically, NRA Ordinance for quality control requires that monitoring equipment shall be
calibrated or verified by the method that can be traced to the standard of metrology.2.d.Ambient dose rate of workplace where workers enter for activity of ALPS treated water
discharge is around 1 μSv/h level* and α or β contamination is not a dominant factor of
exposure. Therefore, the situation does not require special management for the lens of
eyes, skin or extremities.
(*) Survey map of the overall site: https://www.tepco.co.jp/decommission/data/surveymap/pdf/2022/f1-sv2-20221223-j.pdf
3. Optimization7Based on the Regulatory Requirement*, the NRA examines the TEPCO’s Implementation
Plan whether they establishes target values or special arrangement for protection when the
activities at relatively high radiation place are planned.
In case of ALPS treated water discharge-related activities, the NRA confirmed that this kind
of high exposure is not assumed through the examination of the Implementation Plan.
Furthermore, the NRA continuously confirms by daily operational inspections that TEPCO
takes measures for optimization of occupational radiation protection based on the approved
Implementation Plan such as planning of daily work or decontamination of workplace.
(*) "considering workability of radiation workers under the current exposure condition, dose rate of the workers’ entry area
and exposure dose associated with their work shall be reduced as low as reasonably achievable, by taking necessary
radiation protection measures, such as providing shield, deployment of equipment, remote control, prevention of radioactive
material leaks, ventilation and decontamination, etc."
4. Contractors8"Radiation workers", which are subject to the regulation of radiation protection, are
defined that "operators of a nuclear reactor or workers for transportation, storage,
disposal, decontamination, etc., of nuclear fuel material or material contaminated
by nuclear fuel, who enter controlled area" and therefore contractors are included
in this definition.
The NRA receives reports from TEPCO about records of dose of Radiation
workers including contractors*. Also the NRA ensures by the daily operational
inspections that TEPCO conforms to the Radiation protection programme
established in the Implementation Plan including for contractors .
(*) Exposure level of radiation workers including contractors are also shown in TEPCO’s HP in each month.
https://www.tepco.co.jp/en/hd/decommission/progress/environment/index-e.html
5. National Dose Registry95. a.
"Radiation Effects Association (Registry Center)" is designated to be the registry
institution of dose records of radiation workers by METI Notification in 2009.
In case of radiation workers for Fukushima Daiichi NPS, the dose records are also
delivered to the Association as stipulated in the NRA Ordinance*.
(*) NRA Ordinance for Fukushima Daiichi NPS Article 3, Paragraph (4)
5. b.
Dose of radiation workers under normal situation and in case of emergency works
are required to be included.