A while back, ok a long time back, Wizards of the Coast published "The Primal Order" which intended to be a cap-stone book about religion and deities in role-playing games. I can't recall (and my version of TPO is currently packed away), but there may have been some information about deities growing a following. ((full disclosure -- I contributed to the book in the preparation of the conversion notes for RoleMaster and AD&D; however I have no monetary stake in Wizards of the Coast))

Having worked at a nuclear power plant, we used boric acid as a moderator for the fission process. I've never see it "violently fissions". See en.wikipedia.org/wiki/Control_rod and en.wikipedia.org/wiki/Neutron_moderator for more on the used of Boron in nuclear powerplants.

Given that force due to gravity on an object is $F = mg$ and it is also given by $F = GM_pm/r_p^2$. Combining these two, we find that $g=GM_p/r_p^2$. Given that you know the mass and radius of the planet, you can calculate $g$.

Given that the density of earth is $5.51 g/cm^3$, making your planet smaller than earth and small than earth means the density should be higher. Note, that you already have set the circumference by defining the radius ($C = 2r\pi$), at least at first pass

May want to look a Trevor Dupuy's book "Numbers, predictions and war" amazon.com/Numbers-prediction-war-history-evaluate/dp/…

@BillBlondeau, I've been toying with similar ideas (i.e. just doing reading a researching at this time), but I'd be interested to see what gaming tools that you've found (you can just provide the URL's). THanks.

You can also look at Hashima Island, as described here: en.wikipedia.org/wiki/Hashima_Island

@Liath - you are correct we should not assume a fantasy world. I just lifted the table from my notes as-is. Mea Culpa

@gilgamec for an earth-like world, probably very little at all. However for a fantasy world, you could integrate magical scales as well. Additionally, take a look at the Aria gaming system. They have a number of tables describing every thing from technology level to influence of humanities to magic use. Trejder might be able to find something of use there.

I had one, think I modified it from space master (or maybe The Primal Order). I'll see if I can find it or at least a reference when I get home.