Couple of quick thoughts for you:

1) Not sure a radar plot is possible in SSRS -- (Don't see it as an option in SSRS 2005, at the very least)

2) If you're plotting individual risk scores, a scatter plot would be sufficient I would imagine.

3) Radar graphs are usually a poor method for visualizing data -- see the links below for various explanations:

http://www.perceptualedge.com/articles/dmreview/radar_graphs.pdf

http://www.scottlogic.com/blog/2011/09/23/a-critique-of-radar-charts.html

http://dataintuition.blogspot.com/2011/12/taking-radar-chart-off-map.html?m=1