The two identical gray concrete domes sit side by side on the shores of Lake Anna 80 miles southwest of Washington. They are the containment structures of two massive nuclear reactors owned by they Virginia Electric and Power Co.

One reactor, in operation a little more than a year, produces enough electricty to light homes in an area the size of Washington and most of Northern Virginia combined.

The other plant, the image of its sister, has been ready to go since June, but becaue of a federal moratorium has produced no power and will ultimately cost Virginia consumers at least $56 million in extra expenses.

What sense does a government policy make that lets one reactor operate at the North Anna plant and keeps an identical reactor sitting idle a few hundred feet away?

None at all, says Vepco, whose officials contend the situation is another example of misguided and poorly conceived federal regulations of the nuclear industry.

"It's a rather tragic situation and one that we just can't understand," says S. C. Brown, Vepco's constuction chief. "That reactor is as good if not better than any plant they've got running today, so why not let us run it?"

And while the Nuclear Regulatory Commission says publicly that its moratorium on licensing new power plants in "prudent," officials concede privately the action is more geared to placating Congress and public opinion following the nuclear accident at Three-Mile Island.

One high-ranking NRC official, asked to explain why the policy made sense technically, said "it has moved out of the technical arena and into the symbolic arean."

Another explanation is offered by Rep. Morris K. Udall (D-Ariz.), a leading critic of the NRC and the nuclear industry, who suggests the agency has become virtually paralyzed by criticism in recent months.

"They [the NRS] have been kicked around in all directions and the lowest common denominator is to sit around and do nothing," says Udall.

North Anna is not the only plant in the nation to suffer while the policymakers and the lawmakers rethink the nuclear option. Three other plants -- including one in New Jersey that is identical to an already operating plant -- have been ready to operate for several months and three more are expected to be ready early next year. All are considerably newer and presumably safer than many older reactors that are allowed to stay in service.

But it is at North Anna that the nuclear age has ground to its most visible halt.

Reactor One, which began producing electricity in 1978, has been out of operation since Sept. 25 when faulty equipment triggered a small release of radioactive gas. That problem has been corrected and the reactor will reopen when refueling is completed sometime next month.

Reactor Two is the one blocked by the NRC.

It originally was scheduled to open in 1975, but regulatory delays, construction snafus and reduced electric consumption pushed Reactor Two's completion date back four years.

The reactor was finally completed in June in the midst of the NRC's moratorium on new operating licenses fo r plants. NRC officials strongly hinted they would begin considering licenses again in August. But when members of the Presidenths Commission on Three-Mile Island -- the Kemeny Commission -- found out, they called NRC staffers on the carpet.

The result was that the NRC agreed to issue no new licenses until the commission's report was finished and its recommendations submitted to President Carter.

"We were keying very strongly for the latter part of August," says North Anna station manager William R. Cartwright. "Since then, we've just been kind of treading water."

Cartwritght says he would need about three months to load the reactor's 157 fuel rod assemblies, start it up and bring it to full throttle.

Until that time, all North Anna Two generatores is debt. Vepco calculates it spends at least$11 million each month for coal and oil it would not have to buy if the reactor were on line. And it pays out nearly $3 million in monthly interest on the money it borrowed to build the reactor.

Empty chairs in front of the control room panel, maintenance workers scurrying inside a containment dome that would be sealed off and empty if the reactor were in operation, a silent turbine -- those are the signs that Reactor Two is shut off.

"It's a little eerie to be in there and not hear that hum," says Vepco's Brown.

Just south of North Anna Two are 50-foot-high rusting steel shells designed to hold concrete for two more reactors that Vepco originally planned to build here.

During nuclear power's glory days in the early 1970s, Vepco planned to have all four reactors on line by 1978. In recent years, it has pushed back the dates of Three and Four to 1986 and 1987, respectively.

Last month, the company announced it was studying the idea of scrapping the two reactors altogether and replaceing them with coal-fired plants on the same site.

The company originally projected it could build all four reactors for about $1 billion. But it has spent nearly that much for the first two plants and has already invested $485 million in Three and Four, each of which is roughly 10 percent complete.

Most of the money was spent five or more years ago to purchase construction equipment and materials and the nuclear components for both plants. The materials are still at the site, piled outside or shelved in dozens of warehouses scattered on more than 1,000 acres of Vepco property.

In a series of large, corrugated steel garages lie the internal organs of two reactors including two 350-ton containment vessels in which the nuclear reaction takes place. Each vessel lies on its side on wooden beams. The warehouse walls are lined with insulation and temperatues are kept above 60 degrees.

The vessel covers are stored in separate warehouses, wrapped in plastic coccoons to discourage moisture and corrosion.

Vepco also keeps nearly 200 vehicles -- trucks, cranes, air compressors, even a diesel locomotive -- on the site. There are 20 acres of reels holding an estimated seven million feet of wire cable used to anchor pipes and other equipment.

The warehouse and storage areas appeared as deserted as a graveyard last week. The company has a corps of 15 quality-assurance inspectors who monitor stored items full time. Otherwise, few workers venture through the area these days.

"I haven't been through here in a long time," said Cartwright as he escorted visitors through the site last week.

Whether the equipment ever gets used to depends on decisions that will be made not at Vepco headquarters in Richmond but in Washington.

Harold Denton, director of the NRC's nuclear reactor regulation, said he expects it will be as least spring before the current "pause" -- the NRC does not like the word "moratorium" -- runs its course. Denton said the agency is waiting to evaluate recommendations from the White House, which has received the Kemeny report, and from its own Three-Mile Island study group.

Vepco's Brown says he would like to start operating North Anna Two and shut it down for modifications when the NRC decides what has to be done. And Rep. Udall agress that some quick resolution is needed for situations such as North Anna.

"You can't carry this on forever," says Udall. "We owe the country some decisions."