Quantification of long-term fate and health-risk of remobilized radiocesium through porous and fractured aquifers below a dam

Jaehyun Lee; Weon Shik Han; Peter K. Kang; Seonkyoo Yoon; Sungwook Choung; Jeonghwan Hwang; Jehyun Shin

doi:10.1016/j.jhydrol.2022.128513

Quantification of long-term fate and health-risk of remobilized radiocesium through porous and fractured aquifers below a dam

Jaehyun Lee, Weon Shik Han, Peter K. Kang, Seonkyoo Yoon, Sungwook Choung, Jeonghwan Hwang, Jehyun Shin

Earth and Environmental Sciences-Twin Cities

Research output: Contribution to journal › Article › peer-review

2 Scopus citations

Abstract

Understanding the long-term fate and transport of radiocesium (¹³⁷Cs) through porous and fractured aquifers is critical for the risk assessment of nuclear accidents. In particular, characterizing ¹³⁷Cs transport below a dam storing potable water is critical for assessing the risk of ¹³⁷Cs migration. In this study, a 2D cross-sectional aquifer model was developed based on Paldang Reservoir in South Korea, and transport of desorbed ¹³⁷Cs beneath a dam was investigated systematically. Various scenarios investigated ¹³⁷Cs transport within the reported ranges of distribution coefficient (K_d) and local temperature conditions (basal heat flow and reservoir-bottom temperature) affecting the ¹³⁷Cs desorption rate and hydrogeologic heterogeneity (hydraulic conductivity and fracture networks). The characteristics of the ¹³⁷Cs plume represented by the average plume concentration and the migration rate of the mass center were assessed, and the health risk of chronic exposure for humans was predicted. In base-case (K=8.64×10⁻² m/day and K_d=10 mL/g), approximately 0.06 % of initially released ¹³⁷Cs was transported downstream over 300 years; the maximum migration rate was 5.1×10⁻⁴ m/day, and a maximum annual radioactive dose was 4.5 mSv/y after 230 years. The notable effect of K_d on the migration rate (5.1×10⁻⁵ ∼ 9.9×10⁻⁴ m/day) and annual dose (9.1×10⁻¹¹ ∼ 130 mSv/y) indicates that the K_d is a critical parameter that controls the transport of ¹³⁷Cs in the subsurface aquifer. The effect of temperature on ¹³⁷Cs transport was relatively insignificant, but it still had a noticeable effect, especially on the desorption rate. In addition, 50 realizations of heterogeneous K and K_d were generated to evaluate the influence of physical and chemical heterogeneity on ¹³⁷Cs transport. The migration rate and annual dose of ¹³⁷Cs plume showed large variability when K and K_d were correlated. Finally, ¹³⁷Cs transport was evaluated in fractured aquifers and assessed the importance of fracture orientation and connectivity.

Original language	English (US)
Article number	128513
Journal	Journal of Hydrology
Volume	614
DOIs	https://doi.org/10.1016/j.jhydrol.2022.128513
State	Published - Nov 2022

Bibliographical note

Funding Information:
This research was supported by the Subsurface Environmental Management (SEM) project through the Korea Environmental Industry and Technology Institute (KEITI) funded by the Ministry of Environment (Grant Number: 2018002440003), the Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education [Grant Number 2021M2E1A1085187], and the Korea Basic Science Institute funding (C230120, C280100).

Publisher Copyright:
© 2022 Elsevier B.V.

Keywords

Cs
Dam
Fractured aquifer
Heterogeneity
Radiocesium
Transport

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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title = "Quantification of long-term fate and health-risk of remobilized radiocesium through porous and fractured aquifers below a dam",

abstract = "Understanding the long-term fate and transport of radiocesium (137Cs) through porous and fractured aquifers is critical for the risk assessment of nuclear accidents. In particular, characterizing 137Cs transport below a dam storing potable water is critical for assessing the risk of 137Cs migration. In this study, a 2D cross-sectional aquifer model was developed based on Paldang Reservoir in South Korea, and transport of desorbed 137Cs beneath a dam was investigated systematically. Various scenarios investigated 137Cs transport within the reported ranges of distribution coefficient (Kd) and local temperature conditions (basal heat flow and reservoir-bottom temperature) affecting the 137Cs desorption rate and hydrogeologic heterogeneity (hydraulic conductivity and fracture networks). The characteristics of the 137Cs plume represented by the average plume concentration and the migration rate of the mass center were assessed, and the health risk of chronic exposure for humans was predicted. In base-case (K=8.64×10−2 m/day and Kd=10 mL/g), approximately 0.06 % of initially released 137Cs was transported downstream over 300 years; the maximum migration rate was 5.1×10−4 m/day, and a maximum annual radioactive dose was 4.5 mSv/y after 230 years. The notable effect of Kd on the migration rate (5.1×10−5 ∼ 9.9×10−4 m/day) and annual dose (9.1×10−11 ∼ 130 mSv/y) indicates that the Kd is a critical parameter that controls the transport of 137Cs in the subsurface aquifer. The effect of temperature on 137Cs transport was relatively insignificant, but it still had a noticeable effect, especially on the desorption rate. In addition, 50 realizations of heterogeneous K and Kd were generated to evaluate the influence of physical and chemical heterogeneity on 137Cs transport. The migration rate and annual dose of 137Cs plume showed large variability when K and Kd were correlated. Finally, 137Cs transport was evaluated in fractured aquifers and assessed the importance of fracture orientation and connectivity.",

keywords = "Cs, Dam, Fractured aquifer, Heterogeneity, Radiocesium, Transport",

author = "Jaehyun Lee and Han, {Weon Shik} and Kang, {Peter K.} and Seonkyoo Yoon and Sungwook Choung and Jeonghwan Hwang and Jehyun Shin",

note = "Funding Information: This research was supported by the Subsurface Environmental Management (SEM) project through the Korea Environmental Industry and Technology Institute (KEITI) funded by the Ministry of Environment (Grant Number: 2018002440003), the Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education [Grant Number 2021M2E1A1085187], and the Korea Basic Science Institute funding (C230120, C280100). Publisher Copyright: {\textcopyright} 2022 Elsevier B.V.",

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doi = "10.1016/j.jhydrol.2022.128513",

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T1 - Quantification of long-term fate and health-risk of remobilized radiocesium through porous and fractured aquifers below a dam

AU - Lee, Jaehyun

AU - Han, Weon Shik

AU - Kang, Peter K.

AU - Yoon, Seonkyoo

AU - Choung, Sungwook

AU - Hwang, Jeonghwan

AU - Shin, Jehyun

N1 - Funding Information: This research was supported by the Subsurface Environmental Management (SEM) project through the Korea Environmental Industry and Technology Institute (KEITI) funded by the Ministry of Environment (Grant Number: 2018002440003), the Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education [Grant Number 2021M2E1A1085187], and the Korea Basic Science Institute funding (C230120, C280100). Publisher Copyright: © 2022 Elsevier B.V.

PY - 2022/11

Y1 - 2022/11

N2 - Understanding the long-term fate and transport of radiocesium (137Cs) through porous and fractured aquifers is critical for the risk assessment of nuclear accidents. In particular, characterizing 137Cs transport below a dam storing potable water is critical for assessing the risk of 137Cs migration. In this study, a 2D cross-sectional aquifer model was developed based on Paldang Reservoir in South Korea, and transport of desorbed 137Cs beneath a dam was investigated systematically. Various scenarios investigated 137Cs transport within the reported ranges of distribution coefficient (Kd) and local temperature conditions (basal heat flow and reservoir-bottom temperature) affecting the 137Cs desorption rate and hydrogeologic heterogeneity (hydraulic conductivity and fracture networks). The characteristics of the 137Cs plume represented by the average plume concentration and the migration rate of the mass center were assessed, and the health risk of chronic exposure for humans was predicted. In base-case (K=8.64×10−2 m/day and Kd=10 mL/g), approximately 0.06 % of initially released 137Cs was transported downstream over 300 years; the maximum migration rate was 5.1×10−4 m/day, and a maximum annual radioactive dose was 4.5 mSv/y after 230 years. The notable effect of Kd on the migration rate (5.1×10−5 ∼ 9.9×10−4 m/day) and annual dose (9.1×10−11 ∼ 130 mSv/y) indicates that the Kd is a critical parameter that controls the transport of 137Cs in the subsurface aquifer. The effect of temperature on 137Cs transport was relatively insignificant, but it still had a noticeable effect, especially on the desorption rate. In addition, 50 realizations of heterogeneous K and Kd were generated to evaluate the influence of physical and chemical heterogeneity on 137Cs transport. The migration rate and annual dose of 137Cs plume showed large variability when K and Kd were correlated. Finally, 137Cs transport was evaluated in fractured aquifers and assessed the importance of fracture orientation and connectivity.

AB - Understanding the long-term fate and transport of radiocesium (137Cs) through porous and fractured aquifers is critical for the risk assessment of nuclear accidents. In particular, characterizing 137Cs transport below a dam storing potable water is critical for assessing the risk of 137Cs migration. In this study, a 2D cross-sectional aquifer model was developed based on Paldang Reservoir in South Korea, and transport of desorbed 137Cs beneath a dam was investigated systematically. Various scenarios investigated 137Cs transport within the reported ranges of distribution coefficient (Kd) and local temperature conditions (basal heat flow and reservoir-bottom temperature) affecting the 137Cs desorption rate and hydrogeologic heterogeneity (hydraulic conductivity and fracture networks). The characteristics of the 137Cs plume represented by the average plume concentration and the migration rate of the mass center were assessed, and the health risk of chronic exposure for humans was predicted. In base-case (K=8.64×10−2 m/day and Kd=10 mL/g), approximately 0.06 % of initially released 137Cs was transported downstream over 300 years; the maximum migration rate was 5.1×10−4 m/day, and a maximum annual radioactive dose was 4.5 mSv/y after 230 years. The notable effect of Kd on the migration rate (5.1×10−5 ∼ 9.9×10−4 m/day) and annual dose (9.1×10−11 ∼ 130 mSv/y) indicates that the Kd is a critical parameter that controls the transport of 137Cs in the subsurface aquifer. The effect of temperature on 137Cs transport was relatively insignificant, but it still had a noticeable effect, especially on the desorption rate. In addition, 50 realizations of heterogeneous K and Kd were generated to evaluate the influence of physical and chemical heterogeneity on 137Cs transport. The migration rate and annual dose of 137Cs plume showed large variability when K and Kd were correlated. Finally, 137Cs transport was evaluated in fractured aquifers and assessed the importance of fracture orientation and connectivity.

KW - Cs

KW - Dam

KW - Fractured aquifer

KW - Heterogeneity

KW - Radiocesium

KW - Transport

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Quantification of long-term fate and health-risk of remobilized radiocesium through porous and fractured aquifers below a dam

Abstract

Bibliographical note

Keywords

UN SDGs

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