COLUMBIA - S.C. Gov. Jim Hodges on Friday ordered state troopers to prepare to block shipments of weapons-grade plutonium from entering the state.

But if a standoff between Hodges and the U.S. Department of Energy is going to happen, it has been delayed a week.

The shipments originally were scheduled to begin as early as today. But a day after the Energy Department got the go-ahead from a U.S. District Court to begin moving the plutonium to South Carolina, the agency said it won't be geared up to send any plutonium until next Saturday.

Hodges on Friday issued an executive order that all shipments of plutonium be blocked from entering the state and said the Energy Department's delay did not change his plans.

"The plutonium still presents a threat to our state, and my executive order stands," he said.

Energy Department spokesman Joe Davis said the department still intends to ship plutonium to the Savannah River Site near Aiken, 160 miles southwest of Charlotte. And it will ask the Justice Department for legal help in response to Hodges' blockade.

"The court's decision allows DOE to move forward with plutonium shipments to South Carolina from Rocky Flats, Colo., and the department intends to proceed with those shipments," Davis said in a statement.

As a part of a nuclear disarmament agreement with Russia, the Energy Department plans to transform the plutonium into mixed-oxide, or MOX, fuel to be used in Duke Power's Charlotte-area nuclear reactors.

The governor is afraid the federal government will not build the MOX facility and instead store plutonium in South Carolina indefinitely. He has said he wants a court-enforceable agreement that the plutonium will be removed.

Hodges sued in May, asking for a judge to halt the shipments while the department finished environmental studies he said were not done.

But U.S. District Judge Cameron Currie ruled Thursday that Hodges was wrong and that a delay would interfere with the federal government's plans to shut down the Rocky Flats site. Hodges sent his appeal via overnight delivery to the 4th U.S. Circuit Court of Appeals in Richmond, Va., Thursday night. A date for the appeal had not been set as of Friday evening.

Hodges held a news conference Friday afternoon to announce his executive order. Hodges said the shipments pose an immediate hazard to the people of South Carolina and that gives him the authority to declare an emergency. He said he would continue his blockade until a court orders him not to.

"I know the folks in Washington will not like this action," he said. "But until ordered otherwise, I will continue to exercise every lawful power that I possess to keep plutonium from coming to our state and threatening our citizens' safety."

Davis of the Energy Department said Hodges legally can't prevent the department from shipping plutonium to the state. He said Currie made that clear in her Thursday ruling.

"We are extremely disappointed the governor has chosen to totally disregard the court's admonition," Davis said.

University of South Carolina law professor Eldon Wedlock said the Energy Department is probably right.

"(Hodges) is just trying to get press over the fact and trying to impress people with the gravity of the situation," Wedlock said.

The plutonium will be shipped in heavily armored tractor-trailers, escorted by a convoy of armed guards and tracked by satellite. Shipping routes and schedules won't be revealed to state and local authorities.

Edwin Lyman, a physicist who heads the anti-proliferation Nuclear Control Institute, said the plutonium oxides to be shipped from Rocky Flats could be the makings of a radioactivity-spreading dirty bomb or, in trained hands, a nuclear explosive.

Hodges raised this concern in his news conference. The government announced Monday it had arrested a man suspected of being involved in a terrorist plot to build such a dirty bomb. The man, Jose Padilla, also known as Abdullah al Muhajir, is being housed in a military jail in Charleston, 130 miles from SRS.

Said Lyman: "The whole thing's silly, given that the MOX facility won't be built and ready to accept waste for another four years. There's absolutely no reason to go ahead with these shipments when we're in a heightened state of alert."

According to a federal study of surplus plutonium, a severe accident involving one of the trucks would pose more risk to the public from the collision itself than from its cargo. No fatalities are likely, the study said.

The trucks themselves are so heavily armored they've been dubbed "rolling bank vaults," said Jim Hardeman, manager of environmental radiation for the Georgia Department of Natural Resources.

Hardeman said the chances of an accident or terrorist attack that releases radiation from the shipment as remote. But unlike shipments of highly radioactive used nuclear fuel, state authorities will get no heads-up when plutonium is headed their way.

Despite that and the Energy Department's announcement that shipments wouldn't begin for a week, S.C. Highway Patrol and transport police began carrying out the order to block shipments Friday afternoon. State Public Safety Director Boykin Rose said state police are deployed.

In April, Hodges supervised a drill in which troopers practiced stopping a truck. Friday, he said he had no option but to block the shipments.

"Once plutonium arrives, it will never leave," he said. "They want South Carolina to quietly become the nation's dumping ground. Any accident would potentially cause great damage to our state and to the people in the surrounding area."