Elastomer Technology

Shieldseal 664 - Radiation grade

A specially developed peroxide cured ethylene-propylene terpolymer that is a further development of Shieldseal 663. With a nominal 65 IRHD hardness this compound is suited to extrusion manufacturing, moulding and mould joining operations and use where a softer, more pliable compound is required.

Typical applications
Moulded or extruded seals and other components, where a long service life is needed and ionising radiation is present, this material is particularly suitable for products such as inflatable seals or door seals.

It is particularly suited to applications involving air, hot water and steam. This, together with its suitability for contact with a wide range of media including dilute acids and alkalis, ketones, lower alcohols, and silicone oils and greases, makes it suitable for use in processes associated with nuclear waste.

Specification testing
Evaluated for resistance to ionising radiation by monitoring changes in important physical properties over time while irradiated with gamma radiation.

The results of radiation/thermal testing, carried out in accordance with international standards, show that Shieldseal 664 has excellent long-term radiation resistance up to a dose of 1200kGray in radiation conditions that include elevated temperatures up to 70°C. Thermal pre-ageing of the samples did not significantly alter the end-of-life ageing characteristics.

Further information on these tests as carried out by an independent test house and James Walker Technology Centre can be supplied upon request.

Special features

  • Excellent long-term resistance to ionising radiation
  • Strong resistance to short-term high pressure and temperature spikes encountered in accidental conditions in nuclear power plants
  • Very low levels of ions such as Cl- and SO42- that can leach from materials to promote metalwork corrosion within a nuclear reactor

Operational properties of Shieldseal 664

  • Temperature capability: -40°C (at atmospheric pressure) to +125°C constant, or +150°C intermittent
  • Hardness (nominal): 65 IRHD
  • Tensile strength: 16MPa
  • Elongation at break: 380%
  • Water soluble sulphate content:<20ppm (well below levels required for PMUC approval)
  • Water soluble chloride content:<20ppm (well below levels required for PMUC approval)

(Typical values quoted: Please consult James Walker before using for specification purposes)

How supplied
Shieldseal 664 is available as precision moulded or extruded components. We are also willing to partner with equipment manufacturers and end-users to develop, prototype and evaluate materials or specific components for custom applications.

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