A MW-class mercury target of the spallation target generates much larger amounts of radiactive nuclides than existing spallation enutron sources. To estimate the maximum level of public exposure under the guillotine break of mercury pipelines that is one of the major accidents of the target system, the hazard analyses were carried out by using a transportation model which considers heat transmission of mercury decay heat, diffusion of evaporated radioactive nuclides, etc. IN the analyses, mercury, iodine, bromine and noble gas were selected as the effective source term because of their high vapor pressures and activation levels. From the preliminary analytical results obtained under the conservative conditions of 2 m/s of the air velocity around the mercury leakage area, the maximum level of the public exposure was approximately 5.8 X 10~(-3) mSv. This level is negligible in comparison with the 1mSv one-year natural radiation exposure.
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机译：剥落靶的MW级汞靶所产生的放射性核素比现有的剥落质子源大得多。为了评估汞管道在断头台断裂下的最大公众暴露水平，这是目标系统的主要事故之一，使用运输模型进行了危害分析，该模型考虑了汞衰变热的热传递，蒸发的扩散在分析中，由于汞，碘，溴和稀有气体的蒸气压高且活化水平高，因此被选为有效的源术语。根据在汞泄漏区域周围空气流速为2 m / s的保守条件下获得的初步分析结果，公众暴露的最大水平约为5.8 X 10〜（-3）mSv。与一年1mSv的自然辐射暴露相比，该水平可以忽略不计。
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