PASADENA, (AP) -- NBC Entertainment President Jeff Zucker was prepared for tough questions from TV critics who have bashed his summer reality shows as tacky or worse: He wore a flak jacket adorned with the network's peacock logo.

The joke aside, Zucker and fellow executive Scott Sassa were serious in defending "Fear Factor," "Spy TV" and "Weakest Link" during an appearance Thursday before the Television Critics Association.

"I don't buy that we're known as the network of sleazy summer programming," Zucker said.

"We're proud these are compelling shows and people are responding to them," Sassa said.

Zucker noted that NBC "has kept the lights on this summer," attracting viewers to broadcast television with fresh reality programming while competitors have seen their ratings slump with series reruns. (CBS' foray into summer reality, "Big Brother 2," has drawn comparatively mediocre ratings.)

Displaying the motto "The Quality Shows on NBC," the executives conceded that the network's reality shows are not in the league of its Emmy-winning "The West Wing."

A broadcaster has an obligation to offer diverse programming for diverse tastes, Zucker said.

Shows like "Fear Factor," which subjects contestants to such tests as being placed in a pit with hundreds of rats, have proven appealing to viewers under 35, he noted.

Critics, who have called the shows mean-spirited and degrading, may be out of touch with such viewers, Zucker suggested. He also said the shows tend to attract the same kind of upscale, affluent audiences drawn to NBC's pre-eminent series.

NBC leads the other broadcast networks in the Emmy nominations announced last week, Sassa noted.

Additional episodes of "Fear Factor" and "Spy TV" have been ordered but have not been scheduled, the executives said, and "Weakest Link" will continue to be seen in prime time this fall.

Zucker contended a network couldn't afford to put on a schedule dominated by costly series, saying escalating star salaries and the failure of series to do well in reruns are a major issue facing networks.

In other announcements, the NBC executives said the network planned no changes in the fall lineup of programs it announced earlier this year. There would be some cast additions and changes, among them:

-- Robert Urich will join chef Emeril Lagasse's sitcom, "Emeril," which has been getting a negative early buzz and is being revamped.

-- Oded Fehr of the "Mummy" movies will join "UC: Undercover" as a series regular, while Ving Rhames ("Mission: Impossible") will appear in three episodes.

NBC also said that "Saturday Night Live" producer Lorne Michaels will develop a daytime talk show for the network.