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.