Experimental and numerical analysis on safety condenser performance based on P1 experiments at the PKL facility

IF 1.9 3区工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY

Nuclear Engineering and Design Pub Date : 2025-04-10 DOI:10.1016/j.nucengdes.2025.114016

I. Gómez-García-Toraño , S. Schollenberger , L. Dennhardt , A. Wielenberg , M. Vernassière , S. Buchholz , O.S. Al-Yahia , E. Garcia , M. Polidori , N. Sobecki , F. Lahovský , F. de-Bouet-du-Portal , G. Grippo , M. Montout

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Abstract

Passive systems are being considered for advanced reactor designs because of their enhanced reliability against an extended loss of offsite power. Particularly, the SAfety COndenser (SACO) stands out because of its capacity of passively removing core decay heat through the steam generators by condensing steam inside a immersed heat exchanger. This article presents recent experimental data and the associated numerical calculations on the vertical straight-tube SACO installed at the PKL facility. In particular, the SACO power removal capacity has been studied within the frame of test P1.1 consisting of steady state phases A, B, C and D with varying pool liquid levels and a Core Exit Temperature of 237 °C i.e. 20 K subcooling.

Experimental results show the SACO capability to transfer its nominal power of 450 kW despite the accumulation of nitrogen in the straight tubes. Improved venting procedures of phases A2 and C2 allowed a partial removal of nitrogen from the tubes and hence, an increase of the maximum core power to keep the CET constant in comparison to their counterpart phases A and C. The accumulation of nitrogen in the tubes leads to the formation of passive zones characterised by a degraded heat transfer towards the pool and significant cool-down of the liquid film.

An important numerical work has also been conducted using the CATHARE-3, ATHLET, TRACE, RELAP-5 system thermalhydraulic codes and

Neptune_cfd

, either in standalone mode or coupled with CATHARE-2. Several approaches have been adopted in order to model the primary system, SACO pool, straight tubes, boundary and initial conditions (e.g. nitrogen content, heat losses), auxiliary components (heaters, pump cooling), which add up to the physical models when analysing discrepancies with experimental results. Generally, codes are able to predict the phenomena happening in PKL, although further efforts should be invested in the use of 3D approaches to model the pool and the improvement of condensation modelling in vertical tubes for the SACO-operating region.

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基于PKL设施P1试验的安全凝汽器性能试验与数值分析

无源系统正被考虑用于先进的反应堆设计，因为它们具有更强的可靠性，可以抵御大面积的场外电力损失。特别是，安全冷凝器（SACO）脱颖而出，因为它能够通过浸入式热交换器内的蒸汽冷凝，被动地通过蒸汽发生器去除堆芯衰变热。本文介绍了安装在PKL设施的立式直管式中美合作所的最新实验数据和相关的数值计算。特别是，在测试P1.1的框架内，研究了SACO的功率去除能力，该测试由稳定相A， B， C和D组成，具有不同的池液位，堆芯出口温度为237°C，即20 K过冷。实验结果表明，尽管氮气在直管中积累，SACO仍能传输450kw的标称功率。改进的A2和C2阶段的排气程序允许从管中去除部分氮，因此，与对应的a和c阶段相比，增加了最大堆芯功率以保持CET恒定。氮在管中的积累导致被动区域的形成，其特征是向池传递的热量降低和液膜的显着冷却。此外，还使用CATHARE-3、ATHLET、TRACE、RELAP-5系统热工代码和neptune - cfd进行了重要的数值计算，可以单独使用，也可以与CATHARE-2结合使用。在分析与实验结果的差异时，采用了几种方法来模拟主系统、SACO池、直管、边界和初始条件（例如氮含量、热损失）、辅助组件（加热器、泵冷却），这些方法加起来构成了物理模型。一般来说，代码能够预测PKL中发生的现象，尽管应该进一步努力使用3D方法对池进行建模，并改进中美合作所操作区域垂直管中的冷凝建模。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Nuclear Engineering and Design 工程技术-核科学技术

CiteScore

3.40

自引率

11.80%

发文量

377

审稿时长

5 months

期刊介绍： Nuclear Engineering and Design covers the wide range of disciplines involved in the engineering, design, safety and construction of nuclear fission reactors. The Editors welcome papers both on applied and innovative aspects and developments in nuclear science and technology. Fundamentals of Reactor Design include: • Thermal-Hydraulics and Core Physics • Safety Analysis, Risk Assessment (PSA) • Structural and Mechanical Engineering • Materials Science • Fuel Behavior and Design • Structural Plant Design • Engineering of Reactor Components • Experiments Aspects beyond fundamentals of Reactor Design covered: • Accident Mitigation Measures • Reactor Control Systems • Licensing Issues • Safeguard Engineering • Economy of Plants • Reprocessing / Waste Disposal • Applications of Nuclear Energy • Maintenance • Decommissioning Papers on new reactor ideas and developments (Generation IV reactors) such as inherently safe modular HTRs, High Performance LWRs/HWRs and LMFBs/GFR will be considered; Actinide Burners, Accelerator Driven Systems, Energy Amplifiers and other special designs of power and research reactors and their applications are also encouraged.