September 2014 - Design /production: FFI
FFI FACTS
www.ffi.no
Effects of
Nuclear Weapons
Norwegian Defence Research Establishment
(FFI) has conducted research on the impact of
nuclear weapons since its foundation in 1946.
Today, the fear of nuclear proliferation, including nuclear terrorism, remains high.
What is a nuclear weapon?
Nuclear weapons get their explosive yield when energy is released
from processes in a very large number of atomic nuclei. There are
two different processes:
 Nuclear fission (a chain reaction of splitting uranium or
plutonium nuclei)
 Nuclear fusion (fusing of hydrogen isotopes)
The yield of a fission weapon is limited to a few hundred kilotons
(that is, limited to a yield similar to that of a few hundred thousand
tons of conventional explosives), while fusion weapons may have
an almost unlimited yield. More advanced nuclear technology is
needed to design a fusion weapon.
Hydrogen bomb. Fireball resulting from the test detonation of a hydrogen bomb at Bikini Atoll on May 21, 1956. Photo: Scanpix
An operational nuclear weapon must have a means of delivery such
as a missile or an airplane. Today, most nuclear weapons are strategic weapons, designed to be delivered over large distances, but
weapons designed for tactical use on the battlefield also exist.
Note that a nuclear weapon is very different from a so-called
“dirty bomb” which consists of conventional explosives contaminated with radioactive materials.
Effects of nuclear weapons
Because the yield of a nuclear weapon is so large, it can be detonated in the air high above the target and cause enormous damage on
the ground. For air and surface detonations, the explosive energy is
released into the atmosphere. Typically, about 85 % of the energy
is released as pressure and heat, while about 15 % is released as
ionising radiation. In general, there will also be a powerful electromagnetic pulse associated with the detonation. Depending on the
details of the detonation, this pulse may destroy or disable electric
and electronic equipment over a large area. Nuclear fallout is radioactive particles from the bomb itself and from the ground that may
be carried far from the detonation site and contaminate large areas.
 Idealised nuclear fission chain reaction splitting uranium or plutonium nuclei.
The small, red particles are neutrons.
If a nuclear detonation took place in Oslo
FFI has modelled the effects nuclear weapons with different yields
would cause if they were detonated downtown Oslo. The coloured
circles represent the areas affected by the various nuclear weapons effects if a bomb of a given size was detonated. The black circle
represents the area damaged by the immediate radiation, the red
line represents the outer line of damage from the thermal effects
(burns and fires), and the blue circle represents the area damaged
by the pressure wave. The data is generated using HPAC, a package
of software modules and legacy codes distributed and developed by
the U.S. Defense Threat Reduction Agency.
World nuclear forces as of January 2012
Country
Deployed Othertotal
warheadswarheadsInventory
USA
2 150
5 850
~8 000
Russia
1 800
8 200
10 000
UK
160
65
225
France
290
10
~300
200
~240
India
80–100
80–100
Pakistan
90–110
90–110
~80
~80
China
Israel
North Korea
Total
20 kt surface burst
Prompt radiation radius: Thermal radius: Blast radius: 1.7 km
2.3 km
4.2 km
?
~4 400
~14 600
~19 000
 Source: SIPRI Yearbook 2012 from the Stockholm International Peace Research
Institute.
Today, the Treaty on the Non-Proliferation of Nuclear Weapons
(NPT) remains the most significant international agreement in the
field of disarmament and non-proliferation. The signing of the New
START Treaty in April 2010, which calls for a new reduction in strategic nuclear weapons, represents an important step forward and
enhances the prospects of further global nuclear arms control.
20 kt air burst 600 m above ground
Prompt radiation radius: 1.6 km
Thermal radius: 4.5 km
Blast radius: 5.6 km
Contacts:
Elin Enger
Steinar Høibråten
Monica Endregard
[email protected] [email protected]@ffi.no
This fact sheet was prepared with the financial support of
1 Mt air burst 2000 m above ground
Prompt radiation radius: 2.4 km
Blast radius: 20 km
Thermal radius: 24 km
Norwegian Defence Research Establishment , P.O. Box 25, N-2027 Kjeller, Tel: +47 63 80 70 00
Office address: Instituttveien 20, N-2007 Kjeller