Enhanced Performance Monitoring of the Steam Turbine Cycle at Ringhals Nuclear Power Plant

Abstract

Nuclear power plays a key role in the ongoing energy transition, where efficient performance monitoring is essential to ensure reliable power production. In this thesis, performance monitoring at the Ringhals nuclear power plant is evaluated with the aim of enhancing the understanding of the steam turbine cycle performance, particularly focusing on the condenser and steam turbine.

A comprehensive literature review was conducted, in which industry standards established by organizations such as the Electric Power Research Institute (EPRI) and World Association of Nuclear Operators (WANO) were examined and further compared with current performance monitoring
methodologies at Ringhals. The review indicated that while Ringhals generally operates in accordance with industry standards, some areas for improvement were identified, such as increased indirect performance monitoring and clearer definitions of responsibilities.

The study further includes the development of a Python-based on-line monitoring tool, enabling centralized, real-time and historical evaluation of key performance indicators. The tool integrates multiple key performance indicators into a unified monitoring platform by presenting them through
dashboards with associated warning limits, supporting the identification of performance deviations and fault diagnostics.

This thesis demonstrates that combining insights from industry standards, based on the results from the literature review, with the developed on-line monitoring tool can provide a deeper understanding of the steam cycle performance and improved performance monitoring practices, particularly with respect to the condenser and turbine.

Popular Abstract

Enhanced Performance Monitoring of the Steam Turbine Cycle at Ringhals Nuclear Power Plant

When deviations are detected too late, the consequences have often already oc-
curred. Making decisions based on historical data is like dressing according
to yesterday’s weather forecast. Real-time monitoring of the steam cycle per-
formance is therefore crucial for identifying changes as they occur and taking
appropriate action before they result in production losses or increased costs.

In Sweden, nuclear power plays a central role in electricity production. It is therefore important to ensure that plants operate under desired conditions, mak-
ing reliable and continuous monitoring essential. Even small changes in power plant performance can result in major consequences. Fouling, deposits or air
leaks may gradually reduce power production and lead to significant economic losses over time. To prevent this, plant performance is continuously monitored
using various measurements. However, the challenge is that these measurements rarely change one at a time. Instead, many signals vary simultaneously as operating conditions change, for example temperature or load. This makes it difficult to determine whether a deviation is part of normal day-to-day variation or an early sign of actual performance degradation within the steam turbine cycle.

The study consisted of a comprehensive literature review combined with the development of a Python-based monitoring tool. Two key components of the steam cycle, the condenser and steam turbine, were the primary focus of the
project. During the literature review, established industry standards were analyzed and used as a reference to assess whether the existing performance mon-
itoring practices at Ringhals were in accordance with recommended approaches.

A Python-based model was developed to provide a centralized view of the steam cycle performance. The tool collects data from multiple measuring sensors in the
power plant, performs calculations of some studied parameters and presents key performance indicators in a clear and accessible manner. This enables several
parameters and components of the steam cycle to be evaluated simultaneously. The integrated tool is useful for continuous monitoring and improves the ability
to identify changes in performance in the steam cycle.

The results showed that a deep evaluation of industry standards for steam cycle performance improves the understanding of both the importance of performance
monitoring and how it can be applied in practice. By comparing existing monitoring approaches with established industry standards, based on operational
experience from nuclear plants worldwide, gaps can be identified and targeted monitoring strategies can be integrated.

The study also demonstrated that tracking multiple performance parameters simultaneously, rather than relying on individual measurements, provides a clearer and more reliable picture of the plant’s actual condition. This makes it easier to identify patterns, deviations and potential causes of performance degradation in both the condenser and the turbine.

The results are valuable for decision-making, enabling earlier identification of performance deviations and reducing the risk of production losses. Both the
on-line monitoring tool and the results from the literature review contribute to an improved understanding of the steam cycle performance, which is of high
importance at a nuclear power plant.

• author: Ahlgren, Ellinor and Ahrberg, Josefin
• supervisor: Johan Revstedt
• organization: Department of Energy Sciences
• alternative title: Utveckling av ångturbincykelns prestandaövervakning på ringhals kärnkraftverk
• course: MVKM01 20261
• year: 2026
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Nuclear Power Steam Turbine Cycle Performance Monitoring
• report number: ISRN: LUTMDN/TMHP-26/5673-SE
• ISSN: 0282-1990
• language: English
• id: 9233106
• date added to LUP: 2026-06-12 11:14:52
• date last changed: 2026-06-12 11:14:52