Research of Thermal Hydraulic Conditions Effect on PWR CIPS Risk

Shuqi Meng,Tianming Ruan,Yousen Hu,Yisong Hu,Yalun Yan

doi:10.3389/fenrg.2022.823872

Shuqi Meng, Tianming Ruan + Show 3 more

Open Access

https://doi.org/10.3389/fenrg.2022.823872

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Abstract

In order to reveal the effect of thermal hydraulic conditions on the PWR CIPS risk, the evaluation of a PWR CIPS risk in the first cycle under different core flow rates, average primary temperatures, power levels, and primary pressures was conducted by combining thermal hydraulic codes LINDEN and CRUD (Chalk River unidentified deposit) analysis software CAMPSIS. The research result illustrating the essential effect of thermal hydraulic conditions on CIPS is changing the SNB (subcooled nucleate boiling) level of the fuel assembly’s surface; thus, boron precipitation and local power distribution will be affected. Theoretical evidence and statistical support of the effect of thermal hydraulic conditions on the PWR CIPS risk could be obtained via this research.

Highlights

During power operation, the corrosion products in the primary circuit of the PWR will deposit on the fuel surface and form a CRUD (Yoo et al, 2020) (Chalk River unidentified deposit)
Jiao et al (2021) developed a deposition model which could calculate the axial CRUD thickness and solid phase distribution of fuel; Li and Lyu developed an analysis code for calculating the CRUD deposition and radioactivity level in the PWR primary loop based on the concentration difference driving principle (Li, 2017; Li et al, 2018; Lyu et al, 2020); Zou et al (2013) developed a thermal-physical-chemical coupling CIPS analysis model; Yang and other researchers used American commercial software to evaluate CIPS risks of AP1000 and CAP1400 units during power operation (Yang and Tang, 2012; Yang et al, 2020)
Thermal hydraulic conditions are developing in the direction of intensifying SNB, and the risk of the CIPS is increasing, which is consistent with the international PWR operation experience (Sabol et al, 1997; Deshon, 2004; Lange, 2017), further proving the importance of SNB’s influence on the CIPS

Summary

INTRODUCTION

The corrosion products in the primary circuit of the PWR (pressurized water reactor) will deposit on the fuel surface and form a CRUD (Yoo et al, 2020) (Chalk River unidentified deposit). With the decrease of 3°C reference temperature, the maximum boron precipitation decreases from 96 to 68 g, and the maximum SNB rate and total mass evaporation rate decrease by 9.27 and 23.24%, respectively; 3) By increasing the reference power (Deshon, 2004) (3411 MW) by 2%, the maximum boron precipitation increases from 96 to 145 g, and the CIPS risk level elevates from a low risk to medium risk. With the decrease of 2% reference power, the maximum boron precipitation decreases from 96 to 68 g, and the maximum SNB rate and total mass evaporation rate decrease by 3.32 and 33.39%, respectively; 4) By reducing the reference pressure (Deshon, 2004) (15.50 MPa) by 0.5 MPa, the maximum boron precipitation increases from 96 to 122 g, and the CIPS risk level elevates from a low risk to medium risk. Thermal hydraulic conditions are developing in the direction of intensifying SNB, and the risk of the CIPS is increasing, which is consistent with the international PWR operation experience (Sabol et al, 1997; Deshon, 2004; Lange, 2017), further proving the importance of SNB’s influence on the CIPS

CONCLUSION

Findings

DATA AVAILABILITY STATEMENT