The odd part about Oren Peli's success is that with each new film, the "Paranormal Activity" creator said he's actually feels less pressure to deliver. That's a pretty amazing sense of calm to have given the filmmaker's budgets have grown astronomically since the first "Paranormal" film in 2007.

You have to remember, the blockbuster horror thriller only took a reported $15,000 to make , yet raked in more than $193 million in ticket sales worldwide.

"The most pressure I felt was for the first 'Paranormal Activity,' because when it was released, whether it was going to be a hit or not, I knew it was going to be a life-altering event for me," Peli told me in a recent interview. "Since the film has opened so many doors for me, I actually feel like I don't have anything to prove anymore and instead just enjoying the opportunities that I have. Now it's about finding projects that I'm going to be fascinated about and enjoy making them."

But make no mistake about it. Just because Peli feels less pressure, it doesn't mean he's going to put less thought into the creative process. The less he worries, in fact, the more creative energy he generates: a valuable personality trait that powers his new horror thriller "Chernobyl Diaries," opening in theaters nationwide on Friday.

Written and produced by Peli and directed by Bradley Parker, "Chernobyl Diaries" follows six extreme tourists who hire a guide to help them explore the abandoned Ukrainian city of Pripyat -- a place left vacant by the Chernobyl nuclear disaster 25 years earlier. But when the group becomes trapped in the city and night falls upon them, they discover they may not be alone.

The film, of course, is grounded in historical events. In 1986, Chernobyl Nuclear Power Plant reactor No. 4 exploded, and as a result of the catastrophe, radioactive contamination greater than the amount of 400 atomic bombs was released into the atmosphere.

Peli told me he was shocked that no films have really addressed the Chernobyl disaster.

"When I started looking into the whole Chernobyl thing, I was surprised to find that have been no movies made about it," Peli said. "There have been video games made about Chernobyl and Pripyat. I thought it was a very sad, fascinating and eerie location, so it made perfect sense to me to be a very scary setting for a horror movie."

Peli explained that his idea for the "Chernobyl Diaries" came about by pure happenstance, when he stumbled on the Internet video footage and photos taken by extreme tourists in Pripyat. Little did Peli know, Pripyat, a city of 50,000 people next to Chernobyl nuclear plant, was evacuated literally overnight.

"I knew about Chernobyl but not about the abandoned city next to it," Peli said. "When you think about it, it makes sense that there would be a town next to it where the workers of Chernobyl were housed. I didn't know it existed and I didn't know you could visit it with the right tour guide under the right circumstances."

Also grounded in truth, Peli said, is that people really do visit Chernobyl as extreme tourists -- also known as shock tourists -- a twisted fact that stirred his curiosity.

"The fact that it's become somewhat of a tourist attraction is very mind-blowing to me," Peli said. "So I started thinking, 'If I were traveling through Europe and I was in the neighborhood, would I be tempted to visit?' And then I wondered, 'What kind of things could go wrong there?'"

While "Chernobyl Diaries" was filmed in Eastern Europe in Belgrade, Serbia and outside of Budapest, Hungary, Peli said he initially explored the idea of shooting the film in the real Pripyat.

"At the very early stages of the film, when I started looking into locations, I wanted to visit there and we were actually thinking about shooting part of the movie there. We just thought it would make a lot of sense," Peli recalled. "But what forever reason the Ukrainian government shut down tourism throughout most of 2011, so were unable to do it."

Peli said any reason to increase the push to film there fell by the wayside after he and his fellow filmmakers met with their nuclear scientist adviser about the potential dangers.

"He said, 'If you went there, you could hold up a Geiger counter and it'll show that the radiation was safe,'" Peli recalled. "But then he said, 'If you were going to walk around there and kick the wrong pile of dust, it may be hiding radiation. If you breathe in one of those radiation dust particles and it lodges in your lungs, that's no good.'"

Anybody who knows Peli's work (he produced the smash hits "Insidious" and two "Paranormal Activity" sequels) knows that the Israeli-born filmmaker doesn't exactly prescribe to the slash, gash and gore school of horror movie thought.

That's not to say he doesn't enjoy those sorts of films; instead, he just that he likes to focus on what scares him most: suspense brought on by the fear of the unknown.

"A particular monster or something like that doesn't frighten me as much as being confronted by something and not knowing what it is," Peli said. "It could be an invisible demon or a ghost -- you don't know what it is or what it wants from you."

As to his fears and how it relates to 'Chernobyl Diaries,' Peli said the tension in the atmosphere is amped up by the loss of control.

"You're helpless, you're in a foreign land and in an abandoned town, and on top of all the problems you'd have normally in an abandoned ghost town, you have radiation," Peli observed. "Plus, it's the middle of the night, you're hearing some sort of human or inhuman entity screaming, and it makes you wonder, 'What the hell is it? Is it something good or something bad? How I defend myself against it?' It's scary not having control of the situation."