Low-Yield Earth-Penetrating Nuclear Weapons

[Clara T]

Low-Yield Earth-Penetrating Nuclear Weapons
By Robert W. Nelson


Fig. 1 Diagrams like this one give the false impression that a low-yield earth penetrating nuclear weapon would "limit collateral damage" and therefore be relatively safe to use. In fact, because of the large amount of radioactive dirt thrown out in the explosion, the hypothetical 5-kiloton weapon discussed in the accompanying article would produce a large area of lethal fallout. (Philadelphia Inquirer/ Cynthia Greer, 16 October 2000.)

Despite the global sense of relief and hope that the nuclear arms race ended with the Cold War, an increasingly vocal group of politicians, military officials and leaders of America's nuclear weapon laboratories are urging the US to develop a new generation of precision low-yield nuclear weapons. Rather than deterring warfare with another nuclear power, however, they suggest these weapons could be used in conventional conflicts with third-world nations.

Critics argue that adding low-yield warheads to the world's nuclear inventory simply makes their eventual use more likely. In fact, a 1994 law currently prohibits the nuclear laboratories from undertaking research and development that could lead to a precision nuclear weapon of less than 5 kilotons (KT), because "low-yield nuclear weapons blur the distinction between nuclear and conventional war."

Last year, Senate Republicans John Warner (R-VA) and Wayne Allard (R-CO) buried a small provision in the 2001 Defense Authorization Bill that would have overturned these earlier restrictions. Although the language in the final Act was watered down, the Energy and Defense Departments are still required to undertake a study of low-yield nuclear weapons that could penetrate deep into the earth before detonating so as to "threaten hard and deeply buried targets." Legislation for long-term research and actual development of low-yield nuclear weapons will almost certainly be proposed again in the current session of Congress.

<snip>

"What's needed now is something that can threaten a bunker tunneled under 300 meters of granite without killing the surrounding civilian population." Statements like these promote the illusion that nuclear weapons could be used in ways which minimize their "collateral damage," making them acceptable tools to be used like conventional weapons.


Fig. 4 The 100 KT Sedan nuclear explosion, one of the Plowshares excavation tests, was buried at a depth of 635 feet. The main cloud and base surge are typical of shallow-buried nuclear explosions. The cloud is highly contaminated with radioactive dust particles and produces an intense local fallout.

http://fas.org/faspir/2001/v54n1/weapons.htm

[oneighty]

1. There have been nukes

with yields less than 5kt for years.

Nothing new there.

180

[Clara T]

3. History of the B61

Although an August 1995 authorization date is given for the development of the B61-11, the project appears to trace back to the W-61 EPW (earth penetrating warhead) project begun in 1989. The EPW was also a derivative of the B61-7, packaged in a high-strength steel case, and had gotten as far as production engineering in 1991.

The B61-11 has a reported capability to destroy targets at depths of several hundred feet at its highest yield setting.

Efforts are currently underway at Sandia to develop a new weapon using the B61 warhead package. This is the BIOS (Bomb Impact Optimization System), a guided glide bomb that would permit release of nuclear weapons at a greater range from the target, and by using the GPS satellite system would permit delivery with 1 meter accuracy. B61 Development Schedule
4 August 1960
Sandia and LASL authorized to study light weight FUFO bomb
16 October 1961
Program to develop light weight FUFO bomb initiated
18 January 1963
FUFO bomb designated TX-61
20 August 1963
Free fall ballistic tests begun on bomb
May 1965
Production engineering of B61-0 begun
October 1966
First war reserve quality B61-0 built
21 December 1966
First war reserve quality B61-0 accepted into inventory
January 1967
Quantity production of B61-0 begins
January 1969
Quantity production of B61-0 ends
February 1969
Quantity production of B61-1 begins (later modified to Mod 7, still in stockpile)
April 1971
Quantity production of B61-1 ends
April 1972
Development engineering of B61-3 and B61-4 begins
May 1979
Development engineering of B61-7 (conversion of B61-1 begins)
August 1979
Quantity production of B61-4 begins
October 1979
Quantity production of B61-3 begins
May 1983
Quantity production of W-85 begins (later converted to B61-10)
September 1985
Quantity production of B61-7 begins
April 1989
Production engineering of B61-10 begins (conversion of W-85)
June 1990
Quantity production of B61-10 begins
August 1995
B61-11 development authorized
February 1996
Drop test of B61-11 conducted in Alaska
January 1997
B61-11 enters service, quantity production of conversion kits begins

Deployment

Initial manufacture October 1966
Quantity manufacture begins January 1967
Initial deployment 1967
Approximately 3150 B61 bombs of all mods have been manufactured.
Currently in service: 600 tactical bombs (mods 3, 4 and 10) and 750 strategic bombs (mod-7). Mod-7s are currently being converted to Mod-11, which can be used in either a tactical or strategic role.
Of the 12 mods manufactured, 5 remain in service. The oldest bombs are arguably B61-7 bombs (converted B61-1 bombs), manufactured in their original model starting in 2/69, but since rebuilt (starting in 9/85). The oldest mod currently in service is the B61-4 first manufactured in 8/79. The "newest" bombs are the Mod-11, but these are just Mod-7 warheads repackaged in a new body.

http://nuclearweaponarchive.org/Usa/Weapons/B61.html

[bananas]

4. How deep would a 5kt have to bury itself?

It would have to go pretty deep, maybe they could use precision guidance to send it down an oil well.


Fig. 5 Underground nuclear tests must be buried at large depths and carefully sealed in order to fully contain the explosion. Shallower bursts produce large craters and intense local fallout. The situation shown here is for an explosion with a 1 KT yield and the depths shown are in feet. Even a 0.1 KT burst must be buried at a depth of approximately 230 feet to be fully contained. (Adapted from Terry Wallace, with permission.)

...

For typical values for steel and concrete, we expect an upper bound to the penetration depth to be roughly 10 times the missile length, or about 100 feet for a 10 foot missile. In actual practice the impact velocity and penetration depth must be well below this to ensure the missile and its contents are not severely damaged.

Given these constraints, it is simply not possible for a kinetic energy weapon to penetrate deeply enough into the earth to contain a nuclear explosion.

[MnFats]

2. actually the mini technology has gotten 'better'

bunker-busting qualities, concentrated destruction over a smaller area....

of course Bush is pursuing refinements of these nukes.

if he gets them, wanna bet he'll use them?

i want big odds if you take that bet...