Reduce Heat Exchanger Maintenance Costs through Online Monitoring - MTA-MA-008

Administrative Items
Date	12/15/2020
Functional Area Where Benefits Will Be Realized	Maintenance Engineering
Reference Implementation Guidance	Continuous On-Line Monitoring (COLM): Heat Exchanger, General Tube Type (EPRI 3002012774) EPRI Preventive Maintenance Basis Database (PMBD) (EPRI 3002005428)
Industry SME	EPRI – Kurt Crytzer EPRI – Tim Eckert EPRI – Richard Pepin Contact: NuclearPlantMod@epri.com
Previous Implementation	Please contact EPRI for implementation examples and contacts.
Implementation Enablers	MTA-MA-003 – Implement a Wireless Network Infrastructure Using a Distributed Antenna System (DAS) MTA-MA-004 – Implement a Wireless Network Infrastructure Using WiFi
SWEEP Score	Cost – Level 3 – Implementation costs should be less than $1 million. Savings – Level 1 – Savings are less than $1 million per year. Payback – Level 1 – Payback period varies based on extended inspection and maintenance intervals, and pre-COLM plant practices, but annualized benefits are expected to be low relative to the cost of implementation. Thus, payback period may be greater than five years. Licensing Readiness – Level 3 – Elements of this approach have already been implemented at nuclear power plants. Technology readiness – Level 3 – The technology is ready for wide operational deployment. Advanced OLM has already been implemented at fossil facilities and piloted at nuclear facilities. Implementation proficiency – Level 2 – Implementation proficiency is dependent on site-specific experience related to wireless data infrastructure, wireless data transmission for maintenance and monitoring, cyber-security protocols, etc.
Applicability	All reactor types All geographic regions
Keywords	On-line monitoring; heat exchanger; equipment reliability; condition-based maintenance; quick guides
Business Case Analysis Cross-Reference	Plant Modernization Business Case: Monitoring and Diagnostic Program Development (EPRI 3002018424).

Description

Data acquisition and processing tools have reached the point where Continuous Online Monitoring (COLM) of equipment is possible and cost‑effective. COLM can be used to transition from time‑based to condition‑based maintenance, which reduces maintenance costs by eliminating or reducing premature maintenance activities. COLM also provides valuable insights into equipment health that may help to detect incipient failures before major equipment damage. This MTA specifically applies to the monitoring of heat exchanger components.

A heat exchanger transfers heat between fluids. To function properly and to ensure efficient heat transfer, heat exchanger components require routine inspection and maintenance (e.g., removing fouling and deposits). Properly implementing heat exchanger COLM could allow for the extension of existing maintenance intervals. Multiple sensors and wireless gauge readers can be used to support heat exchanger COLM, including temperature, pressure, flow, and level sensors that may already be monitored by a site. Plants can also consider implementing vibration sensors to detect failure mechanisms, although experience has shown that these sensors are less useful for pinpointing the root cause. Additionally, humidity sensors can be used on air‑water heat exchangers. In addition to these sensors, water pH, turbidity, total suspended solids, oxidation‑reduction potential, radiation, acoustic and chloride monitors can be used for monitoring the heat exchanger water loop.

For the purpose of this MTA, the boundary of a heat exchanger is defined as follows, consistent with the EPRI Preventative Maintenance Basis Database (PMBD):

Includes:

• Heat exchanger nozzle to nozzle
• Shell
• Supports
• Tubes

Excludes:

• Control systems and devices (e.g., temperature and pressure control valves, safety relief valves, external vents and drains, insulation)

Consistent with the EPRI COLM guideline for tube‑type heat exchangers, Main Steam Reheaters (MSRs) and Feedwater heaters are also not within the scope of this MQG.

Benefits

Benefits Estimate

Level 1 – Savings for one unit implementing heat exchanger COLM are expected to be less than $1 million per year from extending maintenance intervals.

Benefits Description

• Potential labor savings for extending PM task intervals by transitioning to condition‑based maintenance; for example, manual reading of gauges by operators could be replaced by wireless gauge readers.
• Improved visibility to heat exchanger condition through more frequent data collection and real‑time monitoring, allowing earlier detection of adverse conditions and reducing equipment forced outages and corrective maintenance (CM) costs.
• Reduction in maintenance‑induced failures due to less frequent maintenance.

Costs and Schedule

Cost

Level 3 – Implementation costs associated with sensors should be less than $1 million (up to 23 sensors per heat exchanger). These costs include the sensors, installation, and software and can be shared site‑ or fleet‑wide if other components implement OLM.

Schedule

Six months to two years, which includes planning and implementing new sensors.

Scope Context

Per unit, with multiple heat exchangers per unit. A unit is expected to have at least five heat exchangers that are suitable for COLM.

Risks

IT risks associated with integrating with existing plant network, data storage, and analysis software. Addressing IT concerns at the requirements phase of the project (e.g., how the sensor data will be gathered and used) will mitigate this risk.

Sensors can vary in implementation difficulty and costs.