15.61. Reactor behavior, as inferred from EBR-II tests and extensive analyses, indicates an ability to safety accommodate a wide variety of accident scenarios. However, traditional sodium-cooled reactor concerns regarding the positive sodium void reactivity effect and the possibility of fuel failure propagation in the event of fuel assembly blockage may have

/ Gas Expansion Module 3 Ш Shield 48

Reflector 42

Radial Blanket 33

(3 Driver Fuel 42

Internal Blanket 24

ф Control 6

^>3 Ultimate Shutdown 1

Total: 199

Fig. 15.6. ALMR reference metal core (General Electric Co.).

to be addressed. Also, an additional containment structure enclosing the primary system may be required.

15.62. The advantages of modular design yield cost estimates that are competitive with those for other advanced reactors and fossil-fueled sys­tems after about four full-size power stations are built and operated. Since the need to produce fissile material by breeding appears to be at least several decades away, there is time for a prototype plant test program to test further passive safety features and refine the system design. This could be done by first building a single module or as an alternative, a single commercial power block, if necessary funds are made available.