KIWI was a series of nuclear reactors, designed and built in the late 1950s and 1960s as part of the Rover program, to develop the basic technology of nuclear thermal rockets (see nuclear propulsion). The KIWI-A series of tests developed the technologies of instrumentation and control, fuel element design and fabrication, and structural design. The KIWI-B series was designed to increase power 10-fold while maintaining the same size. It faced a problem first encountered with KIWI-A: internal vibrations caused by dynamic flow instability fractured portions of the fuel elements. This problem was finally overcome in KIWI-B4. The KIWI-TNT was a test reactor for the effects of sudden explosion and excursion. Other reactors developed during the Rover program were Phoebus, Pewee-1, and Nuclear Furnace 1.

 

KIWI series summary
project	date	max. power (MWt)	burn time (sec)
KIWI-A	Jul 1, 1959	70	300
KIWI-A'	Jul 8, 1960	88	307
KIWI-A3	Oct 19, 1960	112.5	259
KIWI-B1A	Dec 7, 1961	225	36
KIWI-B1B	Sep 1, 1962	880	several
KIWI-B4A	Nov 30, 1962	450	several
KIWI-B4D	May 13, 1964	990	40
KIWI-B4E	Aug 28, 1964	937	480
	Sep 10, 1964	882	150
KIWI-TNT	Jan 12, 1965	n/a	n/a

 

KIWI-B4E performance parameters
reactor power (MWt)	937
flow rate (kg/s)	31.8
fuel exit temp (K)	2330
chamber temp (K)	1980
chamber pressure (MPa)	3.49
core inlet temp (K)	104
core inlet pressure (MPa)	4.02
reflector inlet temp (K)	72
reflector inlet pressure (MPa)	4.32
periphery & structural flow (kg/s)	2.0