Sometimes it seems like the only thing that prevents everything from going straight to hell is Bill Moyers. He's so damn sane and decent, it's almost spooky.

If Americans live with the tantalizing fear that Mike Wallace may unexpectedly pop up to catch them at some criminal wrongdoing, they also live with the dread that Bill Moyers may suddenly materialize to find them committing what they know to be a moral or ethical offense. The angels may weep; Moyers inquires.

In the first edition of "Our Times With Bill Moyers," the CBS News summer series premiering Sunday night at 8:30 on Channel 9 (immediately following the new half-hour version of "On the Road With Charles Kuralt"), Moyers hovers about the control room at Los Alamos National Laboratory during the testing of an explosive detonating device. Not The Bomb--just the fireworks it takes to set The Bomb off.

And everybody working on the project looks kind of nervous and ashamed, or as if they are trying to suppress looks of being nervous and ashamed, because however they may profess the legitimacy and virtue of their effort, Bill Moyers is there like a stalking conscience, not telling them that what they do is wrong, only asking them if it is. Of course it's wrong--but it's necessary. We know that, they know that, even Bill Moyers knows that. But somebody has to ask.

"Our Times With Bill Moyers" arrives at an odd moment for CBS News. Not only does the most respected of American broadcast journalism organizations find itself battling off lawsuits left and right (mostly right) these days, but now come reports that CBS News has been slapped with crippling new budget constraints by the management of CBS Inc., largely because the network sales department made a conjectural foul-up last year that resulted in a profit shortfall.

CBS is no longer officially run by a broadcaster, retired chairman and founder William S. Paley. It is now run by a businessman, former Pillsbury pooh-bah Thomas Wyman.

Because of the budget constraints, CBS News coverage of the pope's visit to Poland was severely limited (CBS was the only network not to broadcast the pope's arrival on Polish soil live), and there is now speculation that CBS News coverage of the 1984 election year may also be endangered. Is it paranoid, or overly cynical, to imagine that here in ReagAmerica, Moyers and Rather and Kuralt and Cronkite and Sawyer and Sauter and all the other imposing talent at CBS News could march angrily into Wyman's lair and summarily be told, "Sorry, no dice"? Perhaps it's time to take down the Edward R. Murrow plaques that decorate the CBS offices. Priorities, like so much else in the modern world, appear to have gone haywire.

The Moyers program promises to be, from its first two editions (the second, a look at the American way of divorce, airs in what will be the program's regular time slot, Tuesday at 8:30 p.m.), a splendidly industrious effort, serious-minded as all get out yet encouragingly unpretentious. On program one, Moyers visits Los Alamos for the 40th anniversary of the atomic bomb, the device that ended World War II and began a new era of definitive uncertainty for the human race. The big questions hang in the air; Moyers has the wisdom to ask them softly.

Dr. Isadore Rabi, one of the nuclear physicists who constructed the bomb used on Nagasaki, looks at Los Alamos and says he is sorry that it still exists. He calls it "an abomination." But a film clip shows a re-enactment, by Dr. Robert Oppenheimer and others, of the first test detonation, and a fellow scientist in the film clip says to Oppenheimer, "It's going to work all right, Robert, and I'm sure we'll never be sorry for it."

He couldn't have been more wrong in Oppenheimer's case. The Moyers program serves as a thoughtful, troubling footnote to one of the best documentaries ever made for television, Jon Else's award-winner "The Day After Trinity," shown by PBS in 1981 and repeated recently on the USA Cable Network.

In Los Alamos, Moyers finds high school students talking, even joking, about being near Ground Zero; a small conclave of rather furtive nuclear freeze advocates who nevertheless work on weaponry at the site; and an associate Episcopal pastor who is also an expert on detonators and is employed in that capacity at the plant. He tells Moyers, "My hands are clean." Paul White, a theoretical physicist, suggests it is more moral, or less immoral, to work on the construction of a nuclear device than to contribute to the manufacture of a handgun.

Elena Mannes produced the half hour; the executive producer and director is Andrew Lack. Moyers is not only the correspondent and auteur, but the guiding light. As always, his work is solid, provocative and, for other journalists, somewhat daunting; he is able to grab onto those great big and potentially ponderous "issues" and make them manageably immediate, if never simplistic. If we could impose a ban on journalists who join political administrations and then try to retrieve their credentials as journalists later, we would, it is true, mercifully rid ourselves of such public nuisances as Hodding Carter and Patrick Buchanan. But then we'd also lose Bill Moyers. It wouldn't be worth it.

One might reasonably wonder, however, in light of the budget horror stories coming out of New York, whether CBS is really behind this latest Moyers endeavor, or if the network has merely tossed Moyers a toy with which to keep him harmlessly busy during summer months, when prime-time ratings aren't very important anyway. It is a mundane question, but one appropriate to "Our Times."