This evening I found the cause for the raw fuel smell I had every time I filled the gas tank up. The tank would be moist with fuel by the filler pipe.
In my case the problem was with the fuel pump plastic cover. On the fuel pump cover you have the fuel supply and return lines, plus the pump motor connection and one more boss that according to the Volvo manual, is used for the heater connection.
That boss has a section that ends in a sharp corner, where the plastic cover stress cracked. This is a design flaw and I am sure my car is not the only one with this problem.
Using a Dremel with a very small burr, and sand paper, I roughed the cracked plastic, both on the inside and outside, and used Cargo's "QuikSteel Plastic Tank Repair Kit" putty that "is impervious to gasoline...." to seal the crack.
The putty kit was around $9 at Autozone.
The V70 has easy access to the top of the fuel pump thus no need to drop the fuel tank.
Of course, if working on the fuel pump, do it when the tank is almost empty, remember to remove the fuel pump fuse with the engine running as to drop the pressure on the supply line, clean around the pump insert before removing the pump and keep paper towels or rags handy to collect any fuel spilled and eliminate any possible ignition sources.
The fuel pump wires on top of the pump cover, were encapsulated with something that fell apart due to the repeated flooding with fuel. I encapsulated them with candle wax to prevent water and dirt from accumulating by the wires. Candle wax can also be used to temporarily seal a leaky fuel tank.
I hope this information helps.
AS