用語
せ/D
線量拘束値
dose constraint
最適化ツール
防護の最適化を達成するためのツール
どのような線量か？
予測的で着目する線源に関連した個人に対する線量（リスク拘束値として用いる場合もある（潜在被ばくに対して））
線量限度との関係
管理下にある線源全てからの曝露が線量限度を超えないようにすることを意図している。
適用状況
計画被ばく状況に適用
職業被ばく
事業者により策定され用いられる。
For occupational exposure, the dose constraint isa tool to be established and used in the optimization of protection and safety by the person or organization responsible for a facility or an activity.
IAEA GSR part3
公衆被ばく
規制当局により策定される。
医療被ばく
carers and comfortersや生物医学研究の被験者を対象とする。
導入提案例
放射線審議会（第98回）
資料第98‐5号： 獣医療法施行規則及び関連告示に係る放射線障害の防止に関する技術的基準の改正等について
参考資料等
IAEA
IRRS
Optimization
（略）
"With regard a proposal to introduce the ICRP/IAEA concept of dose constraints into the legislation to serve as an optimization tool, the Radiation Council reports its view that the dose constraints are not necessary since the introduction of specific dose constraints for occupational exposure may hinder the flexible and optimized management of licensees’ radiation protection measures. The previously mentioned Article 3.2 of the Ordinance on Prevention of Ionizing Radiation Hazards also precludes optimization. There are no regulatory mechanisms that allow the NRA to evaluate the effectiveness of optimization actions such as access to a national dose database or occupational radiation protection benchmarking between similar nuclear power plants. There are no guidelines for the Licensees to follow as to how to implement optimization and how to evaluate optimization initiatives (see Recommendation R3)."
IRRSフォローアップミッション報告書
IRRSフォローアップミッション報告書の公開
RF5
Recommendation: The NRA should strengthen its approach to optimization, including the use of dose (or risk) constraints as appropriate, and promote consistent application of the optimization principle across all facilities and activities.
IAEA Comprehensive Report on the Safety Review of the ALPS Treated Water at TEPCO’s Fukushima Daiichi Nuclear Power Station (FDNPS)
The relevant international safety standards require the establishment of dose constraints as part of the process for optimization of protection for any planned exposure situation. For the discharge of the ALPS treated water, the establishment of a prospective and discharge-related restriction on the individual dose attributable to the discharge, provides a basic level of protection for the most highly exposed individuals due to the discharge, and serves as an upper bound on the dose in the optimization of protection for the discharge.
The IAEA notes that dose constraints are not dose limits (see fundamental safety principle 6: limitation of risk to individuals) in the international safety standards: exceeding a dose constraint does not represent non-compliance with regulatory requirements, but it could result in follow-up actions.
TEPCO carried out a radiological environmental impact assessment (REIA) to estimate the dose to the representative person resulting from the discharges of ALPS treated water and to evaluate the compliance with the dose constraint of 0.05 mSv in a year. The process carried out by TEPCO for the elaboration of the REIA is consistent with relevant international safety standards. Further detailed information regarding the REIA can be found in Part 3 (Section 3.4).
After discussions between the Task Force and METI/TEPCO during the first mission, the Task Force noted that the concept of a dose constraint does not exist in Japanese law. Following discussions with the Task Force, NRA confirmed that the criterion of 0.05 mSv per year established by NRA for the discharge of ALPS treated water – which is the operational target for nuclear power stations in Japan – could be interpreted as a dose constraint. Paragraph 5.16 of GSG-9 [9] states that “in practical terms, dose constraints should be selected within the range of 0.1 to less than 1 mSv in a year”. With this in mind, the Task Force noted that the selected dose constraint of 0.05 mSv per year is below this range and is therefore conservative.
The Task Force understands why these two criteria are used by NRA and noted that the use of the two dose criteria is not an issue of consistency with the international safety standards. However, the Task Force believes that having two dose criteria, apparently both relating to the discharge of ALPS treated water but calculated in very different ways, could be a source of confusion for interested parties. Therefore, the Task Force viewed it as important for NRA to devote effort towards explaining this difference to the public to avoid unnecessary confusion.
The NRA explained that optimization of the radiation protection of workers at FDNPS is conducted using dose limits and concentration limits for radioactive materials in the air inhaled. Some Task Force members highlighted that there is no single way to implement optimization of occupational exposure and added that the approach followed by the NRA is well documented.
TEPCO benefits from the implementation of optimization of protection and the use of dose constraints for the radiation protection of workers in addition to their own long-term operational experience. TEPCO effectively utilizes safety measures such as target values, daily dose follow-ups, and work permits related to workplace characteristics (including ALPS treated water discharge facility).
Report
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おすすめ
キーワードの例
新着情報
・決定しきい値（決定限界）
・不確実性のロンダリング装置（としての統計学？）
・ALPS treated water
・シングル・ボイス
・電子スピン共鳴法を用いた線量推計
・非医療目的での放射線を利用した人体のイメージング
最終更新記事
・国際原子力機関の総会での意思決定
・肥料や堆肥に含まれる放射性物質
・放射性セシウムのCodexの基準と日本の食品の基準
・青森県の野生キノコ
・プール解析 pool analysis
・管理区域 controlled area
・原子力発電所事故後の体表面スクリーニング
・トリチウムの化学形別の線量換算係数
・半減期 half life
・WHOと米国の水道水中の放射性物質の基準の違い
記事一覧
・学習問題（分野別）
・用語（五十音順）
アクセス数トップ10
・ホット・パーティクル hot particle
・原子力発電所事故後の体表面スクリーニング
・子孫核種 progeny nuclide
・余命損失 Loss of life expectancy
・県民健康調査 Fukushima Health Survey
・安定ヨウ素剤 stable iodine tablets
・サブマージョン submersion
・放射線リスクコミュニケーション 相談員支援センター Support center for social workers engaged in recovery from the nuclear disaster
・薪ストーブをめぐる近隣トラブル
・不当表示 misleading representation
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