Thank you sir,
I found it.
To extract the numeric value of the SSB you need to:
reg_aov <- aov(scores~groups,data)
summary_aov <- summary(reg_aov)
summary_aova[1]][1,2]
Which stands for:
[[1]] The first (and only) object in the object of type list contains the summary call.
[1,2] The first row and the second column (which is where the numeric value is stored).