Nuclear Power Recovery
Flow measurements are crucial to ensure a power plant is operating at maximum efficiency. Conventional flow measurement methods degrade over time becoming more susceptible to drift. Fouling of the venturi or nozzle can cause erroneous flow measurement readings, indicating a false flow increase. When a false flow increase remains undetected, the plant is forced to reduce its power causing unnecessary production losses.
With AMAG’s CROSSFLOW™ Clamp-on Ultrasonic Flow Meter’s proprietary signal processing and algorithms, the flow can be accurately measured to within 0.3%, providing confidence to increase production to previous levels, or potentially higher than previously achieved, leading to recovered power and increased revenue.
Measurement Uncertainty Recapture Power Uprate
Reactor power is determined based on the feedwater flow into the boilers, and since the feedwater flow measurement uncertainty accounts for as much as 90% of the total reactor power uncertainty, it determines how far below the license limit reactor is allowed to operate.
By installing AMAG’s CROSSFLOW™ Clamp-on Ultrasonic Flow Meter on feedwater pipes, the feedwater flow uncertainty can be reduced to within 0.3%, leading to an improved reactor power uncertainty, potentially allowing reactor power to be raised closer to the license limit, leading to power increase, and increased revenue.
CANDU Reactor Safety channel flow measurements
CANDU reactor orifice plate flow meters can suffer from edge degradation over time, resulting in erroneous flow readings. The safety margin, which is the difference between the measured channel flow and the specified low flow limit, is reduced due to increased boiling when a channel is refueled. Therefore, when the channel flow indication decreases due to orifice edge degradation, reactor power may need to be reduced to prevent possible activation of the safety system.
When AMAG’s CROSSFLOW™ Clamp-on Ultrasonic Flow meter is installed alongside the orifice plate on the feeders of safety shutdown flow channels, the erroneous flow readings can be corrected.
With these corrected, safety system activation can be avoided, which ensures production and revenue loss is prevented. For a typical plant, reduction in reactor power by 1% results in a loss of production of approximately $100,000/week.
Reactor Coolant Flow Measurement
Understanding the true total coolant flow and coolant flow distribution through the reactor are of key importance in nuclear plants. Accurate knowledge of the coolant flow is required to verify the safety analysis results. Reactor coolant flow is very difficult to measure.
With the installation of CROSSFLOW™ Clamp-on Ultrasonic Flow Meters, the coolant flow can be measured through individual channels in a CANDU reactor. Additional CROSSFLOW™ Clamp-on Ultrasonic Flow Meters can be installed at other locations in the reactor heat transport system, such as the coolant pump discharge to measure the total coolant flow.
Low Power Neutron Flux and Safety System Rundown Measurement
After a reactor is initially started or restarted after refurbishment it is important to measure the low power neutron flux and the effectiveness of the safety shutdown systems.
AMAG’s Flux Scanning System measures neutron flux decay when shutdown systems are activated. Then the actual neutron flux shape is compared to the prediction of the computer code. The results indicate if the safety system is performing within the specified required time.
The Flux Scanning System for measuring neutron flux at low power has been used during commissioning of CANDU plants and has identified deviations from optimal fuel loading. Correction of deviations from optimal fuel loading, before reactor power increase, has saved several days in commissioning schedules, provided cost avoidance of approximately $1M/day.
Emergency Core Cooling Test
The Emergency Cooling Injection System is designed to inject cold water into the reactor in case of accident. During the test, and when the system is activated, minimum flow must be met at all times. To ensure that the minimum flow requirement is satisfied the system must be tested regularly.
With AMAG’s CROSSFLOW™ Clamp-on Ultrasonic Flow Meter the flow can be continuously and accurately measured to within 0.3% during this test. This confirmed that the minimum flow requirement is satisfied to allow for the emergency cooling injection system to run in case of an emergency.
Thermal Performance Improvement
Blowdown Flow / Reactor Waste Clean Up
Blowdown or water clean-up flow is required to maintain boiler chemistry within specifications and is usually less than 1% of the total feedwater flow. Low velocity and possible presence of steam, makes accurate measurements of blowdown flow very difficult, and could easily result in a 50% or higher error with conventional flow measurement instruments.
Installation of AMAG’s CROSSFLOW™ Clamp-on Ultrasonic Flow meter reduces this measurement error, leading to reduction in the costs associated with the error. In a typical 1000 MWe plant an error of 50% could result in production losses of over $3M/year.
Thermal Performance Evaluation
The first step in thermal performance evaluation is to ensure you have accurate flow measurements. Station instruments like orifices and venturis are heavily relied upon, unfortunately these devices degrade over time and become inaccurate.
With the use of CROSSFLOW™ Clamp-on Ultrasonic Flow Meters the plant instrumentation can be calibrated to ensure proper accuracy. Often this calibration can be a less costly method of addressing nozzle fouling, which leads to a loss of MWe. If further thermal performance evaluation is needed, the highly accurate flow measurement provided by CROSSFLOW™ will be your first line of defense in the full evaluation process.
AMAG’s CROSSFLOW™ Clamp-on Ultrasonic Flow Meters and CORRTEMP™ Clamp-on Ultrasonic Temperature Meters can be installed to conduct a variety of measurements that contribute to Thermal Performance Evaluation, including measurement of feedwater, condensate, heater and re-heater drains, moisture separator drains, condenser cooling water and more.
Condenser Cooling Water Flow
Accurate knowledge of the Condenser Cooling Water (CCW) Flow is essential to evaluate the condenser performance, which is a crucial component of optimizing the plant’s efficiency. With AMAG’s CROSSFLOW™ Clamp-on Ultrasonic Flow Meter the CCW Flow can be accurately determined, which is then used as an input for the overall evaluation of the condenser’s performance.
The knowledge of the CCW Flow allows for accurate determination of reactor thermal power and identifies how effective the plant’s equipment is running to the manufacturer’s standards, ensuring the plant is producing optimally, to avoid unnecessary losses.