Carbon steel, homogeneous reactor

Nuclear accidents. Nuclear accidents are likely to be rare in homogeneous reactors because of the large negative temperature coefficient (0.1 to 0.2% AA/°C) [30]. As an example, the worst accident considered in the HRE-2 [31] was one in which all the uranium suddenly collects in the reactor core and results in a reactivity increase of 2.5% Ak/sec. For this rate, starting at a power of only 0.4 watt, the maximum pressure in the pressure vessel would be approximately 3900 11), and the pressure stress in the carbon steel shell would be less than 30,000 psi. 

The general conclusion reached was that aqueous homogeneous reactors are potentially very low-cost plutonium producers however, considerable development work remains before large-scale reactors can be constructed. The major problem is due to the corrosiveness of the relatively concentrated uranyl sulfate solutions used in such reactors, which requires that all the equipment in contact with high-temperature fuel be made of titanium, or carbon-steel lined, or clad with titanium. The development of suitably strong titanium alloys, bonding methods, or satisfactory steel-titanium joints has not yet proceeded sufficiently to consider the construction of full-scale plutonium producers. Alternate approaches, such as the addition of Li2S04 to reduce the corrosiveness of stainless steel by the fuel solution (see Chap. 5), show promise but also require further development. 

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