The Frenchman suffered a spectacular exit in Sochi after spearing sideways into the wall at the high-speed Turn 3 on lap 11, having lost the rear of his Lotus while trying to follow McLaren's Jenson Button.
"It was my biggest impact for quite a while and when I knew I was going to hit the wall I took my hands off the wheel, closed my eyes and braced myself," Grosjean said.
"I'm feeling pretty good, especially considering the force of the impact; I broke my seat!
"It's a testament to all the safety inherent in the car and the other safety devices, so a little thank you to Bell, HANS, Enstone, the circuit, the FIA and the marshals and medical personnel. Also a big thank you to my crew who had to pick up the pieces and put the car back together."
Lotus technical director Nick Chester said preliminary investigations appeared to rule out any sort of failure as a cause of the accident.
"There is no indication in the data and in the parts that anything broke and subsequently caused the accident," he explained. "It isn't easy to draw conclusions in any accident investigation but it looks like Romain was maybe a little bit close to the McLaren and lost some downforce, running out of grip effectively.
"The car stood up well to the impact. The right hand side of the car suffered the damage - front and rear suspension right hand side, the nose, the rear wing, crash structure.
"We haven't seen anything however that should stop us getting the car back together [for the United States]."
Watch: Grosjean's high-speed crash in Sochi
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