A method for calculating the maximum possible future typhoon for the JAPCO site

Abstract

The present invention relates to a method for calculating the maximum possible future typhoon for a TEPCO site, and includes the steps of analyzing historical typhoons and selecting the largest typhoon in history as a reference typhoon, and reinforcing the reference typhoon using a coupled ocean-atmosphere model to calculate the maximum possible future typhoon.

Description

[Technical field]

[0001] The present invention relates to a method for calculating the maximum possible future typhoon for a nuclear power plant site. [Background technology]

[0002] Natural disaster countermeasure technologies for existing nuclear power plant sites include assessment of flood impacts (sea level) from blast and tsunami caused by typhoons as external hazards.

[0003] The design standard sea level assessment for the TEPCO site must take into account the end of the nuclear power plant's design life and strengthen the historical (standard) typhoon to a future typhoon, reflecting the rise in sea water temperature due to future climate change.

[0004] Until now, the methods used were to 1) increase the maximum wind speed of a reference typhoon to that of a super typhoon, or 2) increase it by applying an empirical equation for Atlantic typhoon intensity (sea surface temperature vs. maximum wind speed) and an atmospheric model. Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, an object of the present invention is to provide a method for calculating the maximum possible future typhoon for the site of a J-POWER plant using an updated regional climate model. [Means for solving the problem]

[0006] The above-mentioned object of the present invention is achieved by a method for calculating the maximum possible future typhoon for a TEPCO site, which includes a step of analyzing historical typhoons and selecting the largest typhoon in history as a reference typhoon, and a step of enhancing the reference typhoon using a coupled ocean-atmosphere model to calculate the maximum possible future typhoon.

[0007] Strengthening the reference typhoon may include using a future sea surface temperature rise value in a site area as an ocean-atmosphere boundary value of the ocean-atmosphere joint model, and taking into account a future sea surface temperature profile by water depth.

[0008] The ocean-atmosphere coupled model can predict the sea surface cooling effect due to the interaction between typhoons and the ocean using the future sea surface temperature rise value and the future sea surface temperature profile by depth.

[0009] The site area includes the TEPCO site and the surrounding sea area of ​​the TEPCO site, and the future sea surface temperature rise value can be obtained based on the sea surface temperature in the site area at the time of the reference typhoon and a scenario-based sea surface temperature rise value.

[0010] The future seawater temperature profile by water depth can be obtained by combining the water temperature distribution in the site area during the time of the reference typhoon and the rate of change by water depth predicted by a climate model. Effect of the Invention

[0011] According to the present invention, a method for calculating the maximum possible future typhoon for a nuclear power plant site is provided. [Brief description of the drawings]

[0012] [Figure 1] 1 shows an overview of a coupled ocean-atmosphere model according to one embodiment of the present invention. [Diagram 2] FIG. 1 is a diagram illustrating the sea surface cooling effect according to an embodiment of the present invention. [Diagram 3] 1 illustrates an example of a climate model-based future water temperature profile in one embodiment of the present invention. [Figure 4] 1 illustrates an example of a HYCOM-based future water temperature profile in accordance with one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The present invention considers the future sea surface temperature rise value as a forcing force for the sea surface boundary value of the ocean-atmosphere joint model, and calculates the sea surface cooling effect due to typhoon-ocean interaction using a future sea surface temperature profile by water depth. Through this, it is possible to prevent overestimation in strong wind areas when only using the Atlantic typhoon intensity empirical formula and atmospheric model, reduce the amount of sea level rise, and minimize the flooding of the nuclear power plant site due to wave overtopping and the impact of wave pressure on safety structures.

[0014] The present invention will now be described in detail with reference to the drawings.

[0015] The present invention described below can be carried out via a computer and communication means (intranet, internet, etc.).

[0016] In the present invention, first, historical typhoons are analyzed and the largest typhoon in history is selected as a reference typhoon.

[0017] After that, the design life of each nuclear power plant is conservatively taken into account in accordance with the nuclear power plant design standards (U.S. NRC), and the reference typhoon is strengthened using a state-of-the-art regional climate model, a coupled ocean-atmosphere model, in order to calculate the maximum possible typhoon in the future, when the life of the plant will expire.

[0018] The numerical model is called the Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) model system, which consists of the Regional Ocean Modeling System (ROMS) ocean model, the Weather Research Forecasting (WRF) atmospheric model, the Simulating Waves Nearshore (SWAN) wave model, and the Community Sediment Transport Modeling System (SCTMS) sediment model. The ocean model (ROMS) is coupled to the atmospheric model (WRF), so it is also called the coupled ocean-atmosphere model. The coupled ocean-atmosphere model exchanges variables (sea surface temperature, wind speed, atmospheric pressure, and atmospheric temperature) every 10 minutes via the Model Coupling Toolkit (MCT) coupler, as shown in Figure 1.

[0019] In strengthening the reference typhoon, the future sea surface temperature rise value in the site area is used as the ocean-atmosphere boundary value of the coupled ocean-atmosphere model, and the future sea water temperature profile by water depth is taken into account.

[0020] The reference typhoon and the probable maximum future typhoon can include wind speed and pressure, which can then be used as input data in the numerical analysis step to calculate the probable maximum sea level.

[0021] The topographical data used in the atmospheric model (WRF) can be USGS 30-second high-resolution topographical data, and the horizontal resolution of the model can be configured at 5km. The domains of the atmospheric model (WRF) and the ocean model (ROMS) are the same, and are set so that the typhoon can fully develop before approaching and making landfall on the Korean Peninsula.

[0022] The coupled ocean-atmosphere model will use future sea surface temperature rise values ​​and future sea surface temperature profiles by depth to calculate the sea surface cooling effect due to the interaction between typhoons and the ocean.

[0023] The sea surface cooling effect conspiracy refers to the cooling phenomenon that occurs during typhoon formation due to vertical mixing of the upper ocean and upwelling, as shown in Figure 2. Vertical mixing is the process in which strong winds at the ocean surface create warm currents in the upper ocean, causing the cold ocean water at the bottom to mix with the warm ocean water at the top. In addition, upwelling is the process in which the ocean water at the top disperses due to the rotating characteristics of a typhoon, causing the lower ocean water to upwell in the center. Therefore, the lower sea surface temperature plays a role in reducing the energy supplied to the typhoon.

[0024] The ocean model (ROMS), which is one of the components of the ocean-atmosphere coupled model, uses the current (HYCOM_CTRL) and future (HYCOM_10, HYCOM_40) ocean temperature profiles by depth. The ocean model also uses various other variables (salinity, ocean currents, sea level, etc.), but the present invention is characterized by the use of the current and future sea surface temperatures (SST) and the profiles by depth.

[0025] The future sea surface temperature rise value can be obtained based on the sea surface temperature in the site area during the reference typhoon and the scenario-based sea surface temperature rise value.

[0026] The scenario may use, for example, the scenario-based sea surface temperature rise values ​​from the IPCC Sixth Climate Change Report.

[0027] The future seawater temperature profile by depth can be obtained by combining the water temperature distribution in the site area during the reference typhoon period and the rate of change by depth predicted by a climate model.

[0028] In the numerical analysis of the ocean-atmosphere joint model, 3D seawater temperature profile data is required at each ocean grid point, and HYCOM (hybrid coordinate ocean model) data as shown in Figure 4 can be used. 3D ocean water temperature data for 10 and 40 years into the future can reflect the trend of change in the seawater temperature profile for the next 70 years in the Northwest Pacific Ocean (Figure 3) as predicted by the CMIP6 CMCC-ESM2 climate model. In other words, the future seawater temperature change rate by water depth can be applied to the current HYCOM 3D profile.

[0029] In Figure 3, WNP (2015-2024) shows the average water temperature file for the Northwest Pacific Ocean (WNP, green box) region in the current (2015-2024) climate, while WNP (2085-2094) shows the average value in the future (2085-2094) climate. From these results, it can be seen that future water temperature changes will be greatest in the surface layer, tending to decrease as the water depth increases, and that there will be almost no change in water temperature below a depth of 500m.

[0030] In this way, in the present invention, in the input data for the ocean-atmosphere coupled model that can calculate the effect of cooling the sea surface, 1) future sea surface temperature rise values ​​are taken into consideration as forcing forces at the TEPCO site and in the sea areas around the Korean Peninsula, and 2) an analytical technique is used to calculate the maximum possible future typhoon at the TEPCO site using a future sea surface temperature profile by water depth.

[0031] By applying the methodology of the present invention, it is possible to reduce the amount of sea level rise by utilizing the cooling effect of the sea surface caused by typhoon-ocean interaction in the sea areas around the JAPCO site and the Korean Peninsula, rather than in the Atlantic Ocean environment.

[0032] According to the present invention as described above, it is possible to reduce the maximum possible sea level rise from a blast tsunami caused by the largest possible typhoon compared to the site height of a nuclear power plant (approximately 10 m).

[0033] In addition, the impact of flooding on nuclear power plant sites and safety structures due to the reduction in the maximum possible sea level rise can be minimized.

[0034] The above-mentioned embodiments are merely examples for explaining the present invention, and the present invention is not limited thereto. A person having ordinary skill in the art to which the present invention pertains would be able to implement the present invention by modifying it in various ways, and therefore the technical scope of the present invention should be determined by the appended claims.

Claims

1. In the method of calculating the maximum possible future typhoon for the JAPCO site, A step of analyzing historical typhoons and selecting the largest typhoon in history as a reference typhoon; a step of enhancing the reference typhoon using a coupled ocean-atmosphere model to calculate a future maximum possible typhoon; The method includes:

2. The strengthening of the standard typhoon is as follows: using the future sea surface temperature rise value for the site region as an ocean-atmosphere boundary value of the coupled ocean-atmosphere model; considering a depth-specific future ocean temperature profile; 2. The method of claim 1, comprising:

3. The method according to claim 2, wherein the ocean-atmosphere coupled model calculates the sea surface cooling effect due to the interaction between a typhoon and the ocean using the future sea surface temperature rise value and the future sea surface temperature profile by depth.

4. The site area is: The said site of the nuclear power plant and the surrounding sea area of ​​the said site are included, The future sea surface temperature rise value is The sea surface temperature in the site area during the reference typhoon; 2. The method of claim 1, wherein the scenario-based sea surface temperature rise values ​​are derived based on the sea surface temperature rise values.

5. The future seawater temperature profile by water depth is A water temperature distribution in the site area during the reference typhoon period; The method according to claim 4, wherein the rate of change by depth predicted by a climate model is used in combination.

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