High Safety Standards Required for Power Plant Operation

The nuclear power plant prioritizes safety as the utmost consideration, particularly when it comes to the selection of pump seals. During the initial construction phase of THIRD NUCLEAR POWER STATION TAIWAN POWER COMPANY, the condensate system's feedwater pump utilized a gland packing seal. However, since its commissioning, this sealing method proved ineffective in containing the high-pressure and high-flow condensate water, leading to an annual leakage of up to 40,000 tons. Recognizing the critical importance of safety, the nuclear power plant urgently demanded a new sealing solution that guarantees 100% reliability. This means the seal must not fail during operation, avoiding the need for shutdowns due to seal malfunctions, and replacements should only occur during annual maintenance.

Introduction of Custom Dual Mechanical Seals

Amidst stringent operating conditions and elevated safety requirements, finding a suitable solution became increasingly challenging. Eventually, the nuclear power plant turned to Scenic. After in-depth consultations, they decided to adopt the dual cartridge mechanical shaft seal from Scenic. The patented self-aligning structure of Scenic seal proved capable of withstanding the vibrational pressures associated with large rotating equipment. Additionally, the use of wear-resistant silicon carbide as the sealing surface material addressed both environmental concerns and efficiency requirements.

Following its implementation, the cartridge-type dual mechanical shaft seal seamlessly met all the specified criteria. To date, it has been operating steadily for over 20 years, showcasing outstanding sealing performance and marking a significant milestone in Taiwan's nuclear energy sector.

WORKING CONDITION

• Industry: Nuclear Power Plant 
• Equipment: Vertical Water Feeding Pumps for Condenser 
• Temperature: 95°C 
• Feedwater Flow: 1357.6 m³/hr 
• Pressure: 43 kg/cm² Shaft Diameter: 5.5 in 
• Rotating Speed: 1200 RPM

BEFORE: Stuffing Box / Gland Packing

The original seal of the high-pressure, high-flow, and large-diameter feedwater pump was gland packing made of asbestos. The packing wrapped around the pump shaft to prevent leakage. Due to intense vibrations during operation, securing the packing tightly around the shaft was essential to prevent leaks. However, this led to friction, causing damage to the pump shaft and a decline in sealing efficiency over time.

Declining in Sealing Efficiency

• Asbestos packing poses environmental hazards.
• The pump shaft experiences wear and tear from the packing, reducing its lifespan. Wear and tear on the packing seal leads to inadequate sealing.
• Extensive leakage of condensate water causes corrosion of the pump body.

Unsafe Working Environment

• The worksite is flooded with leaking water, creating a worrisome work environment.
• Workers frequently need to approach the active feedwater pump to adjust the packing.

AFTER: Customized Cartridge Double Seal

Introducing Scenic dual cartridge mechanical seals, effectively addressing issues such as pump shaft wear, condensate water leakage, energy inefficiency, and workplace safety concerns in one comprehensive solution. The system has been operating reliably for over 20 years.

Enhanced Equipment Reliability

• Using eco-friendly, wear-resistant materials for improved environmental protection and sealing performance.
• The patented cartridge seal, with self-alignment, compensates for shaft run-out, balanced structure, and self-cooling. This prevents wear on the feedwater pump's shaft, extending its service life and saving energy.
• The mechanical seal provides consistently stable sealing, saving 40,000 tons of condensed water annually.

Improved Working Safety

• The work site is kept dry and slip-free for a safer environment.
• No need to adjust leaking packing, reducing the risk of personnel injuries.