Nuclear Penetration Assemblies

Since 1965, Teledyne has designed and manufactured Electric Penetration Assemblies (EPAs) for the Commercial Nuclear, Navy, and Defense markets. Our success stems from our ability to offer custom-engineered products that meet all performance and reliability requirements of the nuclear industry.  We have hundreds of EPAs in over a dozen nuclear electric generating stations across the United States.

Hermetic, fused-glass seals are one reason for the high performance of Teledyne’s EPAs.  These seals possess great mechanical strength and rigidity, and they show superior resistance to temperature cycling. The inherent insulation properties of glass are ideal for nuclear applications, since glass is a radiation-tolerant, stable, inorganic material.

Teledyne’s EPAs reduce installation costs by eliminating time-consuming pigtail splicing in terminal boxes or wire trays.  All field connections can be accomplished in a simple, straightforward fashion.  The result is a faster, neater installation with fewer wiring errors and significantly reduced labor costs.

Teledyne has complete capabilities for designing, manufacturing, testing, and documenting EPAs in accordance with IEEE Standard 317 and has both N and NPT ASME certifications.  We are dedicated to research and development as the industry and its needs change. This allows us to offer custom-engineered products that meet a wide variety of specialized nuclear applications.

Teledyne’s penetrators have been in place in power plants and submarine applications maintenance free for over 45 years. Teledyne is upgrading its designs to meet current specifications and the 60-year life requirement.

Specifications and Details

• 11.75 bar versus 2 bar
• LOCA pressure profile
• 60-year life versus 40-year life
• Gamma radiation:  5 M
• 2-hour fire barrier
• Temperature shock:  -40 to 400°F/-40 to 204°C
• Synergistic HPHT exposures
• Mechanical shock
• Hermeticity:  He leak rate <1x10-8 cm3/sec
• Penetrator features
• Analyzed for ASME code compliance

The following include SSE and OBE seismic loads coupled with LOCA environments:

• Glass-to-metal conductor seals
  • Dual redundant seals on each conductor
  • Designed for LOCA environments
  • High-temperature fusing process >1,800°F
  • Furnace PLC controlled
  • Extremely stable final properties

• Conductors from #16 AWG to 1,000 MCM, coax, triax

• Containment terminations, inside and out, designed per customer request
  

  • Terminal block(s)
  • Pigtails with connector(s)
  • Lugs
  • Kitted junction box enclosures
  • Modular approach

• Redundant metal flange seals
  

  • Long life under radiation environment
  • Inert gas charged between seals with monitoring
  • Increased metal seal load included in ASME code analysis

• Class 300 flange and above

• Nozzle wire tray details
  

  • Tray is supported independently through the nozzle for seismic event with negligible load on flange plate
  • Wire tray with wire bundles installed is linked to the flange plate for installation as a unit, i.e., no on-site buildup
  • Dovetail wedge design for positive lateral capture of wire tray to interior of nozzle
  • Aluminum wire tray for lightweight installation handling; tray is outside containment, but stainless steel or other materials are available, as required by the customer
  • Independent isolation of wire bundle for magnetic loads