Home

Kr85

Krypton-85 (Kr-85) is a radioactive isotope of the noble gas krypton, with a mass number of 85. It decays by beta minus emission to rubidium-85 and has a half-life of about 10.8 years. Because many krypton isotopes are inert gases, Kr-85 shares krypton’s chemical properties, remaining largely unreactive in the environment. Some decays from Kr-85 can be accompanied by gamma radiation from the daughter nucleus.

Kr-85 is not produced naturally in significant amounts but is generated in nuclear fission of uranium and

In radiotracer applications, Kr-85 is valued for its inert gaseous form, which allows it to mix with

Safety and regulation reflect its radiological nature. Kr-85 is a beta emitter; external exposure is low due

plutonium
and
during
the
reprocessing
of
spent
nuclear
fuel.
As
a
product
of
human
nuclear
activity,
it
is
released
in
small
quantities
to
the
atmosphere
from
nuclear
fuel
cycle
facilities,
and
it
becomes
part
of
the
global
radiological
background
of
krypton
in
the
air.
Its
long
half-life
makes
Kr-85
detectable
for
many
years
after
release,
enabling
its
use
as
a
tracer
in
environmental
studies.
air
or
dissolved
gases
in
water
without
reacting
chemically.
It
is
used
in
hydrology
and
groundwater
studies
to
date
young
groundwater
and
to
trace
gas
movement
and
mixing
processes.
The
ability
to
measure
Kr-85
activity
in
samples
collected
from
wells
or
air
samples
makes
it
a
useful
tool
for
understanding
groundwater
ages
on
timescales
of
decades.
to
beta
particles’
limited
penetration,
but
inhalation
or
ingestion
of
Kr-85
in
enclosed
environments
presents
radiological
risk.
Handling,
storage,
and
use
are
subject
to
nuclear
safety
and
environmental
regulations.