Development of a Secondary SCRAM System for Fast Reactors and ADS Systems

Table 1

Impact on normal operation and SCRAM worth for different neutron absorbing materials in per cent mille (pcm). For all materials except lithium, which is a liquid at the working temperatures, 61% of the theoretical density was used. Uncertainty on these values is about 150 pcm.

Absorber mat.	Density (kg/m^3)	Normal (pcm)	SCRAM (pcm)
Natural B4C	1540	−789	−1178
90% B^10 B4C	1540	−1368	−4565
Natural Li	530	−847	−18
90% Li^6	530	−931	−1869
Europium	3198	−840	−1132
Tantalum	10130	−876	−600