Some say the workers battling the crisis at the Fukushima Dai-ichi nuclear plant on the northeast coast of Japan are on a suicide mission.

Messages from the workers inside the plant to their loved ones offers chilling insight into what's going through their minds.

The 180 workers are being rotated in and out of the danger zone, then sleeping and eating in a small decontaminated area. They know the world is depending on them to avert catastrophe. They're also aware that it may cost them their lives. Their families know it too.

"My husband is working, knowing he could be radiated" one woman said.

In an e-mail he told her, "Please continue to live well. I can not be home for a while."

Another e-mail from one of the family members, which was made public on national television, read, "My father is still working at the plant. They are running out of food. We think conditions are really tough. He says he's accepted his fate, much like a death sentence."

The families have also shared heartbreaking messages on Twitter.

"My dad went to the nuclear plant. I never heard my mother cry so hard. People are struggling, sacrificing themselves to protect you. Please dad, come back alive."

Michael Friedlander, a former U.S. nuclear official, worked in crisis management at similar American nuclear plants and says the workers are prepared to die.

"I can tell you with 100 percent certainty they are absolutely committed to doing whatever is humanly necessary to make these plants in safe condition," he explained.

It's not the first time workers were in this situation. In 1961, eight men who were part of the crew of the first Soviet nuclear submarine sacrificed themselves to save a failing reactor onboard the sub during its maiden voyage, inspiring the major motion picture, "K-19: The Widowmaker," which starred Harrison Ford as the captain of the vessel.

Currently, the Japanese nuclear workers are undertaking the feed and bleed mission, where they feed the reactor seawater to bleed the heat away from it through steam.

"They're probably drinking cold water and eating military style packages. It's cold. It's dark, and you're doing that while trying to make sure you're not contaminating yourself while you're eating," Friedlander said.