基于RASCAL软件的核电厂事故后放射性核素不同释放途径对公众剂量的影响

摘要

Objective To identify the effects of different release paths on public dose in the aftermath of a NPP accident.Methods RASCAL4.3 software was used to simulate the source terms of PWR NPPs and the characteristics of dose distribution in different release path scenarios of long term station blackout (LTSBO) accident.Results It had been shown that radioactivity was the highest in Scenario 2,which was the release path for releases of radionuclides into the environment due to steam generator tube rupture.Radioactivity was the lowest in Scenario 1,which was the release path for radionuclides to be released into the environment in the case of containment leakage or failure.TEDE dose was mainly distributed in the region within 40 km of the release point in different scearios.TEDE dose in the most sectors within 80 km was low than 10 mSv in Scenario 1,which was the release path via containment in containment leakage or failure and in Scenario 3,which was the release path by containment bypass.It was greater than 50 mSv in Scenario 2,which was the release path due to steam generator tube rupture.Conclusions For the environmental impact assessment,it should be paid more attention to the fact that the public health impact imposed by radionuclide release into the environment via the release path due to steam generator tube rupture in the aftermath of LTSBO accident at a NPP.%目的 探讨核电厂事故后放射性核素不同释放途径对公众照射剂量的影响.方法 利用核事故后果评价软件(RASCAL 4.3)对长期全厂断电(LTSBO)事故下压水堆核电厂不同释放途径情景下放射性核素所致公众照射剂量分布特征进行模拟计算.结果 通过蒸汽发生器传热管破裂释放途径进入到环境中的放射性核素活度最高,安全壳泄漏或失效时通过安全壳释放途径进入到环境中的放射性核素活度最低.不同释放情景下总有效剂量当量(TEDE)剂量主要分布在距释放点40 km区域内,当安全壳泄漏或失效时通过安全壳释放和通过旁路安全壳释放情景下80 km范围内大部分扇区TEDE剂量＜10 mSv,通过蒸汽发生器传热管破裂释放情景下80 km范围内大部分扇区TEDE剂量＞50 mSv.结论 在核电厂环境影响分析时应重点关注LTSBO事故时通过蒸汽发生器传热管破裂释放途径对公众健康造成的放射性影响.