January 30, 2012
Operators at Byron Generating Station declared an
Unusual Event at 10:18 a.m. CT, due to the loss of offsite
power and Unit 2 coming offline.
Byron Station Declares Unusual Event
Unit 2 automatically taken offline; diesel generators start
BYRON, Ill. (January 30, 2012) - Operators at Byron
Generating Station declared an Unusual Event at 10:18 a.m.
CT, due to the loss of offsite power and Unit 2 coming
The nuclear facility's diesel generators activated as
designed to provide power to the facility when there is a
loss of offsite power to the facility. The facility remains
in a safe condition. Station engineering experts are
looking into the cause of the loss of offsite power.
Byron Station is designed to depressurize to reduce steam
pressure as part of the many redundant safety systems built
into the facility. Steam from the unit is released through
safety relief valves that are specifically designed for
this purpose. The steam, which will evaporate quickly,
contained expected levels of tritium. Local residents may
see or hear the steam release in progress, which will
continue throughout the day until the unit cools down.
These types of station releases are regulated by the
Nuclear Regulatory Commission.
There is no health or safety impact to workers or to the
public from the release, and Exelon Nuclear has notified
all appropriate local, state and federal officials of the
An Unusual Event is the lowest of four emergency
classifications established by the U.S. Nuclear Regulatory
Tritium is an isotope of hydrogen with a weak level of
radioactivity. It is formed naturally in the upper
atmosphere, is a component of rain and is found in
virtually all of earth's surface water. Tritium is produced
in greater concentrations in commercial nuclear reactors
and is routinely discharged into the environment under
strict regulatory guidelines. Tritium eventually breaks
down into helium.
Byron's Unit 1 continues to supply clean electricity to
Byron Generating Station is in Ogle County, Ill., about 25
miles southwest of Rockford.
Exelon Corporation is one of the nation's largest
electric utilities with more than $18 billion in annual
revenues. The company has one of the industry's largest
portfolios of electricity generation capacity, with a
nationwide reach and strong positions in the Midwest and
Mid-Atlantic. Exelon distributes electricity to
approximately 5.4 million customers in northern Illinois
and southeastern Pennsylvania and natural gas to
approximately 490,000 customers in the Philadelphia area.
Exelon is headquartered in Chicago and trades on the NYSE
under the ticker EXC.
Paul DempseyExelon Nuclear