A succession for Vietnam. Le Duan seen to be settling outstanding foreign policy issues and quickening economic change to prepare for succession

Vietnamese leader Le Duan appears to be quietly preparing his political succession. If Mr. Duan's health holds, the succession process will probably be an undramatic affair spread over several years. But a rapid series of policy moves in the last six months indicate that the pace of change is quickening. They include:

Public recognition this year that Duan, whose official title is Communist Party general secretary, is the paramount Vietnamese leader.

The acceleration of the pace of economic changes, supported by Duan, but until recently hotly contested by some other leaders.

The recall to the Politburo of one of Duan's closest associates.

The declaration by Hanoi of a 1987 deadline for two key problems -- Kampuchea and United States servicemen missing in action (MIAs) in Vietnam.

The impression left by this flurry of changes is that Duan wants to clear up outstanding foreign policy problems -- Kampuchea and US nonrecognition of Hanoi -- and is trying to use his prestige to make sure the new economic policies are firmly underway before he steps down.

Until earlier this year, Le Duan was largely viewed as just the senior member of a collegial leadership. Others, such as head of state Truong Chinh, had prestige and influence at times rivaling Duan's.

But that situation seemed to change during the commemoration of the 10th anniversary of the capture of Saigon (now Ho Chi Minh City). Duan, not the group, was portrayed as the main architect of victory in the war against the US. A long series in the party newspaper Nhan Dan described his activities during the war, and a thick volume of his letters and directives to southern revolutionaries shed light on the background of a man who, up to then, had been a shadowy figure even to his own people.

The victory celebrations were followed by a sharp increase in the tempo of economic change. The policies introduced had mostly been under discussion, and had been facing tough opposition, since 1979.

The policies are essentially aimed at dismantling the massive and incompetent central bureaucracy and giving greater initiative to local administrators and planners and greater incentives to workers. Proponents of the policies view them as the only way to revive Vietnam's paralyzed economy and improve what is still one of the lowest standards of living in the world.

But the policies have been bitterly opposed by senior party leaders, who view them as a deviation from the path of socialist construction. Opposition has always been vented behind closed doors, but one of the main opponents to economic change is believed to be Truong Chinh.

The tempo of economic change began to pick up immediately after last May's victory anniversary. The most radical development came late last month when the government announced the end of the old ``egalitarian'' wage system and the introduction of a new system based on the principal of ``pay according to work.'' Sharp salary differentials -- based on such factors as the difficulty of work or amount of skill or training needed -- were announced.

The changes seem to be the work of a small group. Several key members are former underground organizers in the south, who only came into the central government after 1975. They appear to be impatient with the central bureaucracy and more open to grass-roots feeling. The best known member of this group is a deputy premier and Politburo member, Vo Van Kiet, a southerner who worked closely with Duan in the 1950s. This group seems to have made common cause with some of the more iconoclastic northern offici als such as another deputy premier, Tran Phuong, a Chinese-trained economist.

But the reformers could not have moved without Duan's support. Starting last year Duan, who is probably temperamentally similar to the maverick southern organizers, threw his weight openly behind the change-oriented policies. Le Duc Tho -- another top leader who is best remembered in the West as Henry Kissinger's negotiating counterpart in the Paris peace talks -- also appears to be backing the policies.

Another factor which is probably helping the reforms is Soviet leader Mikhail Gorbachev's ascent to power. The economic policies Mr. Gorbachev is promotingare strikingly similar to the Vietnamese changes. Up to now the clearest parallel to the new Vietnamese policies was a rather embarrassing one -- Deng Xiaoping's China.

The policies received more support at the top earlier this year when another old associate of Le Duan, Nguyen Van Linh, was unexpectedly reappointed to the Politburo. Mr. Linh, who has worked closely with Vo Van Kiet both during the war and since, had been dropped from the Politburo in 1982 and seemed destined for obscurity. Rumors circulating among officials in Hanoi now depict him as a possible successor to Le Duan.

The next Communist Party Congress is due early in 1986. There is a possibility that Duan would step down from his party general secretary post by then -- perhaps to become party chairman, a role which lapsed with the death of Ho Chi Minh in 1969 -- but the fact that a 1987 deadline has been set for solutions to the Kampuchea and MIA questions suggests that Duan wants to stay around beyond the '86 congress.

When Duan does step down, either Le Duc Tho or Nguyen Van Linh would seem the most likely -- and for Duan the most desirable -- successors.