# Inventory and accuracy of U.S. nuclear weapons in 1990.

Came across a superb resource during my research on nuclear armaments: Physics and Nuclear Arms Today (Readings from Physics Today)

(Update 4/2/20: Title of post revised.)

The book has articles from the early 1980s through 1991. Lots of good stuff.  I bought the book especially for one article from 1983 dealing with US and Soviet nuclear forces. The gold mine in that article was a detailed inventory of strategic weaponry as of 1990. It gives a detailed listing of U.S. and Soviet land, submarine, and air based strategic weapons, including count, yield, equivalent megaton, and circular error probable (CEP). Lots of info I’ve been looking for a long time.

Information in that table is credited to The Military Balance 1989-90. At a price of over \$200 for the paperback, don’t think I’ll be buying my own copy.

This post will give info on US weapons. Next post will describe the Soviet inventory. Third post will make some comparisons.  Width limits on web pages mean there will be multiple tables.

A few notes on the columns. Yields are listed in megatons. CEP is circular error probable, or the average accuracy of a weapon.  CEP is the distance at which 50% of the weapons would hit closer and 50% would hit further away.

A one megaton weapon is not ten times more powerful than a 100 kiloton weapon. To compare the destructive power a factor called equivalent megaton is used. The article and table explained this, which is brand new information to me.  The equivalent megaton (EMT) is calculated using a formula:  yield in megatons raised to the two-thirds power, or y^(2/3).

For example, a 200 kt ACLM has .34 EMT.  A 335 kt Minuteman III  has .48 EMT. The MMIII has rated power 67% higher but is actually only 41% more powerful.

This is the inventory by system and power of different US weapons. The number of launchers is listed along with yield and equivalent megaton.  One launcher is an ICBM silo, SLBM tube, or bomber. The total MT and EMT is then calculated.

UPDATE 4/2/20: I realized last night there was a major error in the following table. I added the weapon yield and the number of warheads instead of multiplying them. Table has been corrected. Instead of the preferred method of striking out the error and italicizing the correction, I replaced the table.

 launcher yield equiv mt total mt total Equiv mt Minuteman II 450 1.200 1.13 540 508 Minuteman III Mk12 200 0.170 0.31 102 184 Minuteman III Mk12A 300 0.335 0.48 302 434 Peacekeeper 50 0.350 0.50 175 248 —- —- —- total land based 1,000 1,119 1,375 x Poseidon C-3 224 0.040 0.12 90 262 Trident D-4 384 0.100 0.22 307 662 SLCM 300 0.200 0.34 60 103 —- —- —- total sea based 908 457 1,026 x B52G int. bomb or SRAM 69 1.000 1.00 828 828 B52G int. bomb or SRAM 98 1.000 1.00 1,176 1,176 external ALCM above 0.200 0.34 235 402 B-52H int. bomb or SRAM 99 1.000 1.00 1,188 1,188 external ALCM above 0.200 0.34 238 406 B-1B int.& ext. all SRAM 97 1.000 1.00 3,686 3,686 or int. & ext. all ALCM alternate 0.200 0.34 737 1,261 reverse above options (97) (1.20) (1.3) (4,423) (4,947) B1-B, assume 1/2 load SRAM 97 1.000 1.00 1,843 1,843 assume 1/2 load of ALCN above 0.200 0.34 369 630 —- —- —- total bomber based 363 5,876 6,474 —- —- —- total of above 2,271 7,452 8,875

UPDATE 4/1/20: I just realized there is a major error in the above table; please disregard. Update 4/2/20: Error has been corrected.

For those weapon systems, here is the number of launchers, warheads per launcher, and total warheads for the weapon class. The CEP in meters is listed. Then the probability of destroying a missile silo hardened to 2,000 pounds per square inch. The options there are no, yes, 4 m (site would not only be destroyed but also under at least 4 meters of dirt), and range (PSI would be high enough but range wouldn’t allow reaching into the missile fields).

 launcher warhead total warhead CEP (m) 2000 psi Minuteman II 450 1 450 370 4 m Minuteman III Mk12 200 3 600 220 4 m Minuteman III Mk12A 300 3 900 220 4 m Peacekeeper 50 10 500 100 4 m —- —- total land based 1,000 2,450 . Poseidon C-3 224 10 2,240 450 no Trident D-4 384 8 3,072 450 no SLCM 300 1 300 75 range —- —- total sea based 908 5,612 . B52G int. bomb or SRAM 69 12 828 B52G int. bomb or SRAM 98 12 1,176 external ALCM above 12 1,176 B-52H int. bomb or SRAM 99 12 1,188 external ALCM above 12 1,188 B-1B int.& ext. all SRAM 97 38 3,686 or int. & ext. all ALCM alternate 38 3,686 reverse above options (97) (76) (7,372) B1-B, assume 1/2 load SRAM 97 19 1,843 assume 1/2 load of ALCN above 19 1,843 —- —- total bomber based 363 9,242 —- —- total of above 2,271 17,304

I made a long list of assumptions to derive the above tables.