The perils of speculation

The chairman of the Nuclear Regulatory Commission was invited to the White House briefing today to assure Americans that they had nothing to fear from the nuclear radiation coming out of Japan's damaged reactors and that the nuclear reactors in the United States were safe. When he was finished taking questions there was very little reassurance on either front.

When the White House press corps sought more specific and detailed information about both fallout and nuclear plant safety, the chairman, Gregory Jaczko, would not offer any. Instead he said he wouldn't want to speculate about either one. The irony is that dodging these questions as he did left the impression that his assertion of nothing to fear was nothing more the speculation. (watch his answers above)

He was asked directly if nuclear power plants in the United States were built to withstand a quake of the magnitude suffered by Japan. Jaczko said only, that "we have a strong safety program in place to deal with seismic events," and then veered off point to say that we would continue to support Japan's efforts to secure their plants to gather information on the event, "But I don't want to speculate too much about what exactly were the relevant factors in, in Japan at this point."

So, is this a yes or a no?

He was asked whether his assertion that no harmful radiation would reach the United States or its territories even in a worst case scenario - a full meltdown of one of the Japanese reactors. Jaczko answered that by saying, "I don't want to speculate on various scenarios, but based on the design and the distances involved, it is very unlikely there would be any harmful impacts."

Again, is this a yes or a no?

Chip Reid: U.S. nuclear agency chief leaves reporters with more questions than answers

Jaczko (at left) says he has no "detailed information" about the core in the reactor itself - he doesn't even specify which of the damaged reactors he is referring to. If this is the case, then how can he predict a low likelihood or probability of harmful radiation reaching the United States?

Asked if a similar set of circumstances could lead to a nuclear emergency like the one Japan is experiencing now, Jaczko says the United States has a "very strong program in place, a very strong safety program in place."

The problem with this answer is that the Japanese believed the sea walls they built and the Fukushima plants would keep tsunami waters out of the reactor - and their belief was misplaced. Now their plants are flooded with tsunami water and they have no reliable way to keep the reactors cool.

There are times in Washington when it is sometimes better not to take questions if all you have are one line answers. This appears to be a classic case where no briefing would have been better. Jaczko had only one line answers to questions that demanded more detailed answers. In the end, it all sounded like speculation; informed speculation maybe, but speculation nonetheless.

And late this afternoon someone in the White House press office figured this out and sent out the following statement: "Based on the type of reactor and nature of the events, NRC expert analysts see NO scenarios in which harmful levels of radiation would reach Hawaii, Alaska, the U.S. Territories or the West Coast of the United States."

Special report: Disaster in Japan
Nuclear meltdowns explained
Meltdown risk rising at Japanese nuclear plant

Video Below: How close is Japan to a nuclear meltdown?

Ward Sloane a CBS News Senior Producer based in Washington.