The international technology company SCHOTT recently participated in a Nuclear Safety Symposium hosted by the Chinese Nuclear Energy Association (CNEA). With this event, the CNEA successfully offered a valuable platform for 200 experts from Chinese, American, French, German and Korean design institutes, utility corporations, nuclear plants and technology companies to exchange ideas. The summit focused on the question of how the safety levels of nuclear power plants can be significantly improved. There was a wide consensus among the nuclear community that this can only be achieved by designing reactor containment structures and using component technologies that can reliably fulfill the higher safety specifications defined for Severe Accidents (SA).
SCHOTT's electronic penetration assembly for nuclear power plants Eternaloc™: EPAs are the vital conduit for the pass-through of power, control and instrumentation cables from the external environment into the heart of the power plant. Photos/graphics: SC
SA, which can result from flooding or station black-outs, can lead to high pressures and high temperatures. These scenarios create very complex requirements for the designs, parts and components of nuclear power plants, especially for the reactor containment building -- the heart of the nuclear power plant -- and provisions for its security concepts. This is the core element needed to maintain control during and after SA conditions.
“In order for the containment structure to fulfill its purpose in the future, it is mandatory that there is a consistent application of safety margins and higher specifications for all parts and components of the containment," said Dr. Oliver Fritz, member of the IEC (International Electrotechnical Commission) and Head of Technology, Nuclear Safety Division at SCHOTT. "The nuclear community worldwide is currently defining sufficient safety margins and adapting the specifications for improved safety in nuclear power. This can only prove to be successful if international standards such as those issued by the Institute of Elecrical and Electronics Engineers (IEEE), IEC, and others are also increased.”
SCHOTT has supplied its glass-to-metal sealed electrical penetration assemblies (EPAs) to more than 50 nuclear power plants worldwide.
EPAs are important safety equipment at nuclear power plants and an integral part of the containment integrity. SCHOTT’s EPAs, which carry the new brand name Eternaloc™, are all uniquely and exclusively based on the unparalleled robustness of the company’s glass-to-metal seal technology, which provides considerable advantages over organic epoxy seals.
SCHOTT recently designed a new generation EPA for the Swedish nuclear power plant, Forsmark 3, which is undergoing renewed investment to improve its safety and reliability. It can withstand the latest SA requirements defined by the operator -- the EPAs are required to withstand submerged conditions under 13 meters of water for at least 30 days, pressures of up to 8.3 bar, and temperatures up to 185 degrees Celsius. In addition, the EPAs must withstand a radiological exposure of 1.7 MGy at a dose rate of 2,360 Gy/h. The use of inorganic sealing material such as SCHOTT glass for the pressure boundary of the EPA minimizes the effect of high radiological exposures and maintains the containment integrity beyond SA.
SCHOTT has also developed EPAs that fulfill the demanding design specifications of Small Modular Reactors. These EPAs can even be used directly in reactor vessels since they can withstand high temperatures of 320 degrees Celsius and the pressures of 160 bar and beyond.
Background information on EPAs
Electrical penetration assemblies are the vital conduits for power, control, and instrumentation circuits in nuclear power plant reactor pressure vessels. Their performance is critical to running core functions within the reactor, and their seals must be strong enough to maintain the pressure boundary integrity of the containment vessel in all accident conditions.
SCHOTT’s Eternaloc™ EPAs are designed with superior and safer glass-to-metal seal technology. They provide considerable safety advantages over organic seals, which might break down under extreme temperatures and pressures, such as experienced at the Fukushima Daiichi nuclear power plant disaster. In contrast, inorganic, non-aging glass seals with significant heat- and radiation-resistant properties ensure the integrity of electrical penetration seals and containment vessels.
SCHOTT Eternaloc™ glass-to-metal sealed electrical penetrations are already protecting nuclear reactors worldwide and are qualified for 60 years of use. At SCHOTT’s own request, its EPA underwent stringent testing at Wyle Laboratories in Huntsville, Ala. in 2012. The SCHOTT EPA successfully passed an extensive qualification test program per IEEE standards 317 and 344, including full survivability in conditions analogous to an earthquake reaching a magnitude of 12 on the Richter scale.
Eternaloc™ is a trademark of SCHOTT AG.
SCHOTT (schott.com) is an international technology group with more than 125 years of experience in the areas of specialty glass and materials and advanced technologies. SCHOTT ranks number one in the world with many of its products. Its core markets are the household appliance, pharmaceuticals, electronics, optics, transportation, and architecture industries. The company is strongly committed to contributing to its customers’ success and making SCHOTT an important part of people’s lives with high-quality products and intelligent solutions. SCHOTT is committed to managing its business in a sustainable manner and supporting its employees, society, and the environment. The SCHOTT Group maintains close proximity to its customers with manufacturing and sales units in all major markets. Its workforce of around 16,000 employees generated worldwide sales of $2.6 billion (approximately 2.0 billion euros) for the 2011/2012 fiscal year.
Mike Lizun - Gregory FCA on behalf of SCHOTT
P: 610-642-1435 - E: mike[.]gregoryfca.com.