IN a move to offset a drop in oil shipments from the Soviet Union, Cuba is pushing forward with an ambitious nuclear power program aimed at making the Caribbean island energy self-sufficient. Cuba's four-reactor complex is being built in the town of Juragu'a, in its Cienfuegos region, about 250 miles due south of Miami on the island's southern coast. Construction began in 1983. Some 10,000 Cubans are currently working under supervision of 450 Soviet advisers and nuclear scientists, Cuban officials say.
The imperative of declining oil supplies has pushed the project faster of late. Cuban President Fidel Castro said in a July speech that Soviet oil shipments have fallen below the agreed upon 13.3 million tons annually.
``Fidel Castro is bent on making Cuba the first Caribbean country to operate a nuclear power plant,'' said Alfredo Miguel Oquendo, a Cuban nuclear physicist who defected to Spain Aug. 3. Reached by telephone in Madrid hours after his defection, Mr. Oquendo, spent the last year working at the Juragu'a site. Safety questioned
Several nuclear energy experts and specialists in Cuban affairs, however, express reservations about potential risks posed by the Cuban nuclear project.
Oquendo corroborates some of these, saying: ``Our technology and personnel at this point are lacking in expertise.''
Despite world concern about the risks of Soviet-administered nuclear projects, Cuban officials in Washington point out that the Juragu'a plant in Cienfuegos will use Soviet-designed VVER-440 model pressurized-water reactors, entirely different from the graphite-core type involved in the 1986 Chernobyl accident.
Cuba plans to build a total of eight reactors, with two more nuclear plants by the year 2000. One is to be in eastern Holguin province, the other in the island's western portion, according to the Cuban Nuclear Energy Committee.
The plant at Juragu'a, which will have four Soviet-designed pressurized-water reactors, and is Cuba's biggest development project, costing more than $2.5 billion and financed under Cuban-Soviet cooperation accords.
Cuban officials insist disruptions in economic links with Eastern Europe and the Soviet Union resulting from sweeping political and economic reforms will not affect Cuba's program.
But Oquendo noted that a treaty signed with Czechoslovakia in the early '80s to supply hardware for the plant has already been scuttled. ``Due to the changing political landscape in the socialist world, the plant, which was scheduled to go into operation this year, will probably be delayed two years,'' Oquendo said. ``But construction will go on,'' he added. ``Castro will go on no matter what happens.'' Energy independence
Cuba has no coal reserves and lacks hydroelectric and solar energy facilities. The government depends on imports, mainly oil from the Soviet Union, for 70 percent of its energy. The completed plant's output of 1,600 megawatts would meet about 20 percent of Cuba's energy needs, saving about 2.4 million tons of domestic oil consumption.
``In the event of a blockade on Cuba, the completion of the Juragu'a plant would give Cuba autonomy in the energy front,'' says Marcelo Alonso, a Cuban-born physicist who monitors Cuba's program from Miami.
Anthony Owen, director of the Catawba nuclear plant in South Carolina, who visited the Juragu'a complex in October at the invitation of the Cuban government, says, ``The reactors are critical for Cuba's future. They represent economic independence.''
Communist Party Central Committee member Jorge Gomez Barata has said Castro's main worry is not a Soviet cutoff, but an inability by Moscow to fulfill pledges due to a declining Soviet economy. Delays in Soviet-financed fuel deliveries prompted Cuban officials to convene an emergency fuel economy and efficiency conference June 14.
To address international safety concerns, Cuba's chief nuclear technician Pedro Abigantus says each of the plant's reactors will be encased in its own five-feet-thick concrete and steel dome. Mr. Abigantus also recalls the October visit of William Lee, president of the World Association of Nuclear Operators and the Duke Power Company in North Carolina, who praised the Cuban nuclear program. ``We were very impressed,'' Mr. Lee said in remarks delivered in Cuba. Operating concerns
But Juan Rodriguez, a former Cuban intelligence officer who defected in Jan. 1987, disagrees. ``Cubans may be capable of assembling the plant, but operating it safely without Soviet help is a different matter,'' Mr. Rodriguez says. Though living in Washington, Rodriguez worked with Fidel Castro Diaz-Balart, the President's son, to set up the nuclear project in the early '80s. Mr. Diaz-Balart heads Cuba's nuclear energy program.
``The fact that the reactors are water-pressurized is only less of a sin,'' says Dr. Behram Kursunoglu, a physicist at the University of Miami's Center for Theoretical Studies. ``Depending on the atmospheric situation, a leak in the plant would create radioactive clouds affecting the South Florida coast.''
A 1989 Department of Energy team analysis of the Soviet designed VVER nuclear reactors describes them as ``quite susceptible to radiation induced embrittlement'' a condition that could lead to radiation leaks. DOE officials are also concerned about the absence in Soviet-designed reactors of safety features standard in the United States and Europe.
``The Soviet Union's rules, regulations, standards, procedures, infrastructure, economic structure and approaches used to design construct and operate nuclear facilities are considerably different from those used ... in the US,'' the DOE report said.
The State Department is working through the Vienna-based International Atomic Energy Agency, of which Cuba is a member, to guarantee that Cuba abides by international safeguards. A State Department official says the US will not stand in the way of the plant, but will monitor shipment of nuclear parts to Cuba.
Despite concerns over the safety of plant operation, the State Department official says the US is not worried about a Cuban nuclear weapons program evolving from the reactor program. This is because of the low grade of uranium used by the reactors.