Testing of an accident consequence assessment model using field data

野外実測データを用いた事故影響評価モデルの検証

本間 俊充; 松原 武史; 富田 賢一*

Homma, Toshimitsu; Matsubara, Takeshi; Tomita, Kenichi*

環境影響評価に用いられる計算モデルの性能検証には、モデル予測結果と実測データの比較が最適である。確率論的事故影響評価コードOSCAARの陸域生態圏移行モデルは、IAEA等の国際協力計画におけるチェルノブイリデータを用いたシナリオによって妥当性検証がなされてきた。本研究では、原子炉事故で重要なI-131の甲状腺への取り込みとCs-137の長期被ばくモデルの検証計算について報告する。

This paper presents the results obtained from the application of OSCAAR to the Iput dose reconstruction scenario of BIOMASS and also to the Chernobyl I fallout scenario of EMRAS, both organized by International Atomic Energy Agency. The Iput Scenario deals with Cs contamination of the catchment basin and agricultural area in the Bryansk Region of Russia, which was heavily contaminated after the Chernobyl accident. This exercise was used to test the chronic exposure pathway models in OSCAAR with actual measurements and to identify the most important sources of uncertainty with respect to each part of the assessment. The OSCAAR chronic exposure pathway models almost successfully reconstructed the whole 10-year time course of Cs activity concentrations in most requested types of agricultural products and natural foodstuffs. The Plavsk scenario provides an good opportunity to test not only the food chain transfer model of I but also the method of assessing I thyroid burden. OSCAAR showed in general good capabilities for assessing the important I exposure pathways, but also limitations using constant isotopic ratio I /Cs provided by the scenario to estimate I deposition for whole Plavsk district.