Based on Geant4 modeling, we simulated the underwater Čerenkov light field in open seawater and coastal seawater, which was excited by different kinds of γ-rays. The γ-rays were originally released by fission products and activation products in the reactor coolant. The physical characteristics of the underwater Čerenkov light field were mathematically analyzed, including the spatial distribution principle, the correlation between the energy density and elevation angle, the energy density functions of Čerenkov photons, and the Čerenkov photon spectrum. Compared with other published research results, it was proved that the Čerenkov photons are in the range of 200–810 nm in both seawater types, but the peak wavelength in these seawater types is 420 nm (open seawater) and 570 nm (coastal seawater), and the strong absorption and scattering of suspended particles caused large attenuation in the ultraviolet range and infrared range. Čerenkov photons were symmetrically distributed along the emitting direction of γ-rays, and the maximum energy density of Čerenkov photons appeared at the center of the emission direction of γ-rays. The Čerenkov halo might only be observed in clear open seawater. The research results also show us that in the following field experiment, to collect the Čerenkov photons in water, deploying underwater photo-electric detection devices outside the reactor compartment of the floating nuclear power plants would be an effective way to locate the suspected coolant leakage position and leakage rate.

中文翻译：

---

基于Geant4建模的两种海况下浮式电站反应堆舱壳外水下Čerenkov光场空间分布原理研究

基于Geant4建模，我们模拟了开阔海水和沿海海水中被不同类型γ射线激发的水下Čerenkov光场。γ 射线最初是由反应堆冷却剂中的裂变产物和活化产物释放的。对水下Čerenkov光场的物理特性进行了数学分析，包括空间分布原理、能量密度与仰角的相关性、Čerenkov光子的能量密度函数和Čerenkov光子光谱。与其他已发表的研究结果相比，证明 Čerenkov 光子在两种海水类型中都在 200-810 nm 范围内，但在这些海水类型中的峰值波长分别为 420 nm（开阔海水）和 570 nm（沿海海水） , 悬浮颗粒的强烈吸收和散射在紫外区和红外区引起较大衰减。Čerenkov光子沿γ射线发射方向对称分布，Čerenkov光子的最大能量密度出现在γ射线发射方向的中心。Čerenkov 晕可能只能在清澈的开放海水中观察到。研究结果还表明，在接下来的野外实验中，为了收集水中的切伦科夫光子，在浮式核电站反应堆舱外部署水下光电探测装置将是定位可疑冷却剂泄漏位置的有效方法。和泄漏率。Čerenkov光子沿γ射线发射方向对称分布，Čerenkov光子的最大能量密度出现在γ射线发射方向的中心。Čerenkov 晕可能只能在清澈的开放海水中观察到。研究结果还表明，在接下来的野外实验中，为了收集水中的切伦科夫光子，在浮动核电站反应堆舱外部署水下光电探测装置将是定位可疑冷却剂泄漏位置的有效方法。和泄漏率。Čerenkov光子沿γ射线发射方向对称分布，Čerenkov光子的最大能量密度出现在γ射线发射方向的中心。Čerenkov 晕可能只能在清澈的开放海水中观察到。研究结果还表明，在接下来的野外实验中，为了收集水中的切伦科夫光子，在浮式核电站反应堆舱外部署水下光电探测装置将是定位可疑冷却剂泄漏位置的有效方法。和泄漏率。